[libcamera-devel,v2,2/2] libcamera: pipeline: ipa: raspberrypi: Use dma heap allocs for LS tables

8821 diff mbox series

Remove use of vcsm allocations and replace with dma heap allocations.
The pipeline handler now passes the fd of the allocation over to the IPA
instead of the raw pointer.

Also use libcamera::FileDescriptor for fd lifetime management.

This commit must be built alongside the accompanying BCM2835 ISP kernel
driver changes at https://github.com/raspberrypi/linux/pull/3715.
Otherwise a mismatch will cause undefined behavior.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
---
 include/linux/bcm2835-isp.h                   |   4 +-
 include/linux/vc_sm_cma_ioctl.h               | 135 ----------------
 src/ipa/raspberrypi/raspberrypi.cpp           |  29 +++-
 .../pipeline/raspberrypi/dma_heaps.cpp        |  77 +++++++++
 .../pipeline/raspberrypi/dma_heaps.h          |  43 +++++
 .../pipeline/raspberrypi/meson.build          |   1 +
 .../pipeline/raspberrypi/raspberrypi.cpp      |  46 ++----
 src/libcamera/pipeline/raspberrypi/vcsm.h     | 149 ------------------
 8 files changed, 160 insertions(+), 324 deletions(-)
 delete mode 100644 include/linux/vc_sm_cma_ioctl.h
 create mode 100644 src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
 create mode 100644 src/libcamera/pipeline/raspberrypi/dma_heaps.h
 delete mode 100644 src/libcamera/pipeline/raspberrypi/vcsm.h

Hi Naush,

Thank you for the patch.

On Wed, Jul 15, 2020 at 10:39:11AM +0100, Naushir Patuck wrote:
> Remove use of vcsm allocations and replace with dma heap allocations.
> The pipeline handler now passes the fd of the allocation over to the IPA
> instead of the raw pointer.
> 
> Also use libcamera::FileDescriptor for fd lifetime management.
> 
> This commit must be built alongside the accompanying BCM2835 ISP kernel
> driver changes at https://github.com/raspberrypi/linux/pull/3715.
> Otherwise a mismatch will cause undefined behavior.
> 
> Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> ---
>  include/linux/bcm2835-isp.h                   |   4 +-
>  include/linux/vc_sm_cma_ioctl.h               | 135 ----------------
>  src/ipa/raspberrypi/raspberrypi.cpp           |  29 +++-
>  .../pipeline/raspberrypi/dma_heaps.cpp        |  77 +++++++++
>  .../pipeline/raspberrypi/dma_heaps.h          |  43 +++++
>  .../pipeline/raspberrypi/meson.build          |   1 +
>  .../pipeline/raspberrypi/raspberrypi.cpp      |  46 ++----
>  src/libcamera/pipeline/raspberrypi/vcsm.h     | 149 ------------------
>  8 files changed, 160 insertions(+), 324 deletions(-)
>  delete mode 100644 include/linux/vc_sm_cma_ioctl.h
>  create mode 100644 src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
>  create mode 100644 src/libcamera/pipeline/raspberrypi/dma_heaps.h
>  delete mode 100644 src/libcamera/pipeline/raspberrypi/vcsm.h
> 
> diff --git a/include/linux/bcm2835-isp.h b/include/linux/bcm2835-isp.h
> index e7afc367..45abb681 100644
> --- a/include/linux/bcm2835-isp.h
> +++ b/include/linux/bcm2835-isp.h
> @@ -108,7 +108,7 @@ enum bcm2835_isp_gain_format {
>   * @grid_stride:	Row to row distance (in grid cells) between grid cells
>   *			in the same horizontal location.
>   * @grid_height:	Height of lens shading tables in grid cells.
> - * @mem_handle_table:	Memory handle to the tables.
> + * @dmabuf:		dmabuf file handle containing the table.
>   * @ref_transform:	Reference transform - unsupported, please pass zero.
>   * @corner_sampled:	Whether the gains are sampled at the corner points
>   *			of the grid cells or in the cell centres.
> @@ -120,7 +120,7 @@ struct bcm2835_isp_lens_shading {
>  	__u32 grid_width;
>  	__u32 grid_stride;
>  	__u32 grid_height;
> -	__u32 mem_handle_table;
> +	__s32 dmabuf;
>  	__u32 ref_transform;
>  	__u32 corner_sampled;
>  	__u32 gain_format;
> diff --git a/include/linux/vc_sm_cma_ioctl.h b/include/linux/vc_sm_cma_ioctl.h
> deleted file mode 100644
> index 21b8758e..00000000
> --- a/include/linux/vc_sm_cma_ioctl.h
> +++ /dev/null
> @@ -1,135 +0,0 @@
> -/*
> -Copyright (c) 2012, Broadcom Europe Ltd
> -All rights reserved.
> -
> -Redistribution and use in source and binary forms, with or without
> -modification, are permitted provided that the following conditions are met:
> -    * Redistributions of source code must retain the above copyright
> -      notice, this list of conditions and the following disclaimer.
> -    * Redistributions in binary form must reproduce the above copyright
> -      notice, this list of conditions and the following disclaimer in the
> -      documentation and/or other materials provided with the distribution.
> -    * Neither the name of the copyright holder nor the
> -      names of its contributors may be used to endorse or promote products
> -      derived from this software without specific prior written permission.
> -
> -THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
> -ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
> -WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
> -DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
> -DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
> -(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
> -LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
> -ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> -(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
> -SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> -*/
> -
> -/*
> - * Copyright 2019 Raspberry Pi (Trading) Ltd.  All rights reserved.
> - *
> - * Based on vmcs_sm_ioctl.h Copyright Broadcom Corporation.
> - */
> -
> -#ifndef __VC_SM_CMA_IOCTL_H
> -#define __VC_SM_CMA_IOCTL_H
> -
> -/* ---- Include Files ---------------------------------------------------- */
> -
> -#include <linux/types.h>	/* Needed for standard types */
> -
> -#include <linux/ioctl.h>
> -
> -/* ---- Constants and Types ---------------------------------------------- */
> -
> -#define VC_SM_CMA_RESOURCE_NAME               32
> -#define VC_SM_CMA_RESOURCE_NAME_DEFAULT       "sm-host-resource"
> -
> -/* Type define used to create unique IOCTL number */
> -#define VC_SM_CMA_MAGIC_TYPE                  'J'
> -
> -/* IOCTL commands on /dev/vc-sm-cma */
> -enum vc_sm_cma_cmd_e {
> -	VC_SM_CMA_CMD_ALLOC = 0x5A,	/* Start at 0x5A arbitrarily */
> -
> -	VC_SM_CMA_CMD_IMPORT_DMABUF,
> -
> -	VC_SM_CMA_CMD_CLEAN_INVALID2,
> -
> -	VC_SM_CMA_CMD_LAST	/* Do not delete */
> -};
> -
> -/* Cache type supported, conveniently matches the user space definition in
> - * user-vcsm.h.
> - */
> -enum vc_sm_cma_cache_e {
> -	VC_SM_CMA_CACHE_NONE,
> -	VC_SM_CMA_CACHE_HOST,
> -	VC_SM_CMA_CACHE_VC,
> -	VC_SM_CMA_CACHE_BOTH,
> -};
> -
> -/* IOCTL Data structures */
> -struct vc_sm_cma_ioctl_alloc {
> -	/* user -> kernel */
> -	__u32 size;
> -	__u32 num;
> -	__u32 cached;		/* enum vc_sm_cma_cache_e */
> -	__u32 pad;
> -	__u8 name[VC_SM_CMA_RESOURCE_NAME];
> -
> -	/* kernel -> user */
> -	__s32 handle;
> -	__u32 vc_handle;
> -	__u64 dma_addr;
> -};
> -
> -struct vc_sm_cma_ioctl_import_dmabuf {
> -	/* user -> kernel */
> -	__s32 dmabuf_fd;
> -	__u32 cached;		/* enum vc_sm_cma_cache_e */
> -	__u8 name[VC_SM_CMA_RESOURCE_NAME];
> -
> -	/* kernel -> user */
> -	__s32 handle;
> -	__u32 vc_handle;
> -	__u32 size;
> -	__u32 pad;
> -	__u64 dma_addr;
> -};
> -
> -/*
> - * Cache functions to be set to struct vc_sm_cma_ioctl_clean_invalid2
> - * invalidate_mode.
> - */
> -#define VC_SM_CACHE_OP_NOP       0x00
> -#define VC_SM_CACHE_OP_INV       0x01
> -#define VC_SM_CACHE_OP_CLEAN     0x02
> -#define VC_SM_CACHE_OP_FLUSH     0x03
> -
> -struct vc_sm_cma_ioctl_clean_invalid2 {
> -	__u32 op_count;
> -	__u32 pad;
> -	struct vc_sm_cma_ioctl_clean_invalid_block {
> -		__u32 invalidate_mode;
> -		__u32 block_count;
> -		void *  /*__user */start_address;
> -		__u32 block_size;
> -		__u32 inter_block_stride;
> -	} s[0];
> -};
> -
> -/* IOCTL numbers */
> -#define VC_SM_CMA_IOCTL_MEM_ALLOC\
> -	_IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_ALLOC,\
> -	 struct vc_sm_cma_ioctl_alloc)
> -
> -#define VC_SM_CMA_IOCTL_MEM_IMPORT_DMABUF\
> -	_IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_IMPORT_DMABUF,\
> -	 struct vc_sm_cma_ioctl_import_dmabuf)
> -
> -#define VC_SM_CMA_IOCTL_MEM_CLEAN_INVALID2\
> -	_IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_CLEAN_INVALID2,\
> -	 struct vc_sm_cma_ioctl_clean_invalid2)
> -
> -#endif /* __VC_SM_CMA_IOCTL_H */
> diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
> index b1f27861..8efc9aa5 100644
> --- a/src/ipa/raspberrypi/raspberrypi.cpp
> +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> @@ -15,6 +15,7 @@
>  #include <libcamera/buffer.h>
>  #include <libcamera/control_ids.h>
>  #include <libcamera/controls.h>
> +#include <libcamera/file_descriptor.h>
>  #include <libcamera/ipa/ipa_interface.h>
>  #include <libcamera/ipa/ipa_module_info.h>
>  #include <libcamera/ipa/raspberrypi.h>
> @@ -65,12 +66,14 @@ public:
>  	IPARPi()
>  		: lastMode_({}), controller_(), controllerInit_(false),
>  		  frame_count_(0), check_count_(0), hide_count_(0),
> -		  mistrust_count_(0), lsTableHandle_(0), lsTable_(nullptr)
> +		  mistrust_count_(0), lsTable_(nullptr)
>  	{
>  	}
>  
>  	~IPARPi()
>  	{
> +		if (lsTable_)
> +			munmap(lsTable_, MAX_LS_GRID_SIZE);
>  	}
>  
>  	int init(const IPASettings &settings) override;
> @@ -137,7 +140,7 @@ private:
>  	/* How many frames we should avoid running control algos on. */
>  	unsigned int mistrust_count_;
>  	/* LS table allocation passed in from the pipeline handler. */
> -	uint32_t lsTableHandle_;
> +	FileDescriptor lsTableHandle_;
>  	void *lsTable_;
>  };
>  
> @@ -357,8 +360,24 @@ void IPARPi::processEvent(const IPAOperationData &event)
>  	}
>  
>  	case RPI_IPA_EVENT_LS_TABLE_ALLOCATION: {
> -		lsTable_ = reinterpret_cast<void *>(event.data[0]);
> -		lsTableHandle_ = event.data[1];
> +		/* Remove any previous table, if there was one. */
> +		if (lsTable_)
> +			munmap(lsTable_, MAX_LS_GRID_SIZE);
> +
> +		lsTable_ = nullptr;

Not that it matters much, but I would have but the assignment inside the
if block, it seems logical to me to group it with munmap.

> +
> +		/* Map the LS table buffer into user space. */
> +		lsTableHandle_ = FileDescriptor(event.data[0]);
> +		if (lsTableHandle_.isValid()) {
> +			lsTable_ = mmap(nullptr, MAX_LS_GRID_SIZE, PROT_READ | PROT_WRITE,
> +					MAP_SHARED, lsTableHandle_.fd(), 0);
> +
> +			if (lsTable_ == MAP_FAILED) {
> +				LOG(IPARPI, Error) << "dmaHeap mmap failure for LS table.";
> +				lsTable_ = nullptr;
> +			}
> +		}
> +
>  		break;
>  	}
>  
> @@ -1026,7 +1045,7 @@ void IPARPi::applyLS(const struct AlscStatus *lsStatus, ControlList &ctrls)
>  		.grid_width = w,
>  		.grid_stride = w,
>  		.grid_height = h,
> -		.mem_handle_table = lsTableHandle_,
> +		.dmabuf = lsTableHandle_.fd(),
>  		.ref_transform = 0,
>  		.corner_sampled = 1,
>  		.gain_format = GAIN_FORMAT_U4P10
> diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> new file mode 100644
> index 00000000..c29a1a25
> --- /dev/null
> +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> @@ -0,0 +1,77 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2020, Raspberry Pi (Trading) Limited
> + *
> + * dma_heaps.h - Helper class for dma-heap allocations.
> + */
> +#include <fcntl.h>
> +#include <linux/dma-buf.h>
> +#include <linux/dma-heap.h>
> +#include <sys/ioctl.h>
> +#include <unistd.h>
> +
> +#include "libcamera/internal/log.h"
> +
> +#include "dma_heaps.h"

This should be the very first header to be included, to test that it can
be compiled self-contained. This helps avoiding future compilation
breakages when other headers are reworked.

> +
> +namespace libcamera {
> +
> +LOG_DECLARE_CATEGORY(RPI)
> +
> +namespace RPi {
> +
> +DmaHeap::DmaHeap()
> +{
> +	dmaHeapHandle_ = ::open(DMA_HEAP_CMA_NAME, O_RDWR, 0);
> +	if (dmaHeapHandle_ == -1) {
> +		dmaHeapHandle_ = ::open(DMA_HEAP_CMA_ALT_NAME, O_RDWR, 0);
> +		if (dmaHeapHandle_ == -1) {
> +			LOG(RPI, Error) << "Could not open dmaHeap device";
> +		}
> +	}
> +}
> +
> +DmaHeap::~DmaHeap()
> +{
> +	if (dmaHeapHandle_)
> +		::close(dmaHeapHandle_);
> +}
> +
> +FileDescriptor DmaHeap::alloc(const char *name, std::size_t size)
> +{
> +	unsigned int pageSize = getpagesize();

The getpagesize() man page states that "Portable applications should
employ sysconf(_SC_PAGESIZE) instead of getpagesize()". But do we need
this ? The dma-heap implementation rounds up the requested size to a
multiple of PAGE_SIZE internally. Of course none of the userspace API is
documented, so whether this is an implementation detail or an API
guarantee is not known :-@ How can we seriously merge an API these days
without documentation ?

> +	int ret;
> +
> +	if (!name)
> +		return FileDescriptor();
> +
> +	/* Ask for page aligned allocation. */
> +	size = (size + pageSize - 1) & ~(pageSize - 1);
> +
> +	struct dma_heap_allocation_data alloc = {};
> +
> +	alloc.len = size;
> +	alloc.fd_flags = O_CLOEXEC | O_RDWR;
> +
> +	ret = ::ioctl(dmaHeapHandle_, DMA_HEAP_IOCTL_ALLOC, &alloc);
> +
> +	if (ret < 0) {
> +		LOG(RPI, Error) << "dmaHeap allocation failure for "
> +				<< name;
> +		return FileDescriptor();
> +	}
> +
> +	ret = ::ioctl(alloc.fd, DMA_BUF_SET_NAME, name);
> +	if (ret < 0) {
> +		LOG(RPI, Error) << "dmaHeap naming failure for "
> +				<< name;
> +		::close(alloc.fd);
> +		return FileDescriptor();
> +	}
> +
> +	return FileDescriptor(std::move(alloc.fd));
> +}
> +
> +} /* namespace RPi */
> +
> +} /* namespace libcamera */
> diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.h b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> new file mode 100644
> index 00000000..80892fd4
> --- /dev/null
> +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> @@ -0,0 +1,43 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2020, Raspberry Pi (Trading) Limited
> + *
> + * dma_heaps.h - Helper class for dma-heap allocations.
> + */
> +#ifndef __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__
> +#define __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__
> +
> +#include <libcamera/file_descriptor.h>
> +
> +namespace libcamera {
> +
> +LOG_DECLARE_CATEGORY(RPI)
> +
> +namespace RPi {
> +
> +/*
> + * /dev/dma-heap/linux,cma is the dma-heap allocator, which allows dmaheap-cma to
> + * only have to worry about importing.
> + *
> + * Annoyingly, should the cma heap size be specified on the kernel command line
> + * instead of DT, the heap gets named "reserved" instead.
> + */
> +#define DMA_HEAP_CMA_NAME "/dev/dma_heap/linux,cma"
> +#define DMA_HEAP_CMA_ALT_NAME "/dev/dma_heap/reserved"

I would move this to the .cpp file.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Please let me know if you would like me to make those small
modifications when applying the series, or if you would like to send a
v3.

> +
> +class DmaHeap
> +{
> +public:
> +	DmaHeap();
> +	~DmaHeap();
> +	FileDescriptor alloc(const char *name, std::size_t size);
> +
> +private:
> +	int dmaHeapHandle_;
> +};
> +
> +} /* namespace RPi */
> +
> +} /* namespace libcamera */
> +
> +#endif /* __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__ */
> diff --git a/src/libcamera/pipeline/raspberrypi/meson.build b/src/libcamera/pipeline/raspberrypi/meson.build
> index dcfe07c5..ae0aed3b 100644
> --- a/src/libcamera/pipeline/raspberrypi/meson.build
> +++ b/src/libcamera/pipeline/raspberrypi/meson.build
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: CC0-1.0
>  
>  libcamera_sources += files([
> +    'dma_heaps.cpp',
>      'raspberrypi.cpp',
>      'staggered_ctrl.cpp',
>  ])
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index 7450062f..431de44d 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -13,6 +13,7 @@
>  
>  #include <libcamera/camera.h>
>  #include <libcamera/control_ids.h>
> +#include <libcamera/file_descriptor.h>
>  #include <libcamera/formats.h>
>  #include <libcamera/ipa/raspberrypi.h>
>  #include <libcamera/logging.h>
> @@ -30,8 +31,8 @@
>  #include "libcamera/internal/v4l2_controls.h"
>  #include "libcamera/internal/v4l2_videodevice.h"
>  
> +#include "dma_heaps.h"
>  #include "staggered_ctrl.h"
> -#include "vcsm.h"
>  
>  namespace libcamera {
>  
> @@ -285,23 +286,13 @@ class RPiCameraData : public CameraData
>  {
>  public:
>  	RPiCameraData(PipelineHandler *pipe)
> -		: CameraData(pipe), sensor_(nullptr), lsTable_(nullptr),
> -		  state_(State::Stopped), dropFrame_(false), ispOutputCount_(0)
> +		: CameraData(pipe), sensor_(nullptr), state_(State::Stopped),
> +		  dropFrame_(false), ispOutputCount_(0)
>  	{
>  	}
>  
>  	~RPiCameraData()
>  	{
> -		/*
> -		 * Free the LS table if we have allocated one. Another
> -		 * allocation will occur in applyLS() with the appropriate
> -		 * size.
> -		 */
> -		if (lsTable_) {
> -			vcsm_.free(lsTable_);
> -			lsTable_ = nullptr;
> -		}
> -
>  		/* Stop the IPA proxy thread. */
>  		if (ipa_)
>  			ipa_->stop();
> @@ -330,9 +321,9 @@ public:
>  	/* Buffers passed to the IPA. */
>  	std::vector<IPABuffer> ipaBuffers_;
>  
> -	/* VCSM allocation helper. */
> -	::RPi::Vcsm vcsm_;
> -	void *lsTable_;
> +	/* DMAHEAP allocation helper. */
> +	RPi::DmaHeap dmaHeap_;
> +	FileDescriptor lsTable_;
>  
>  	RPi::StaggeredCtrl staggeredCtrl_;
>  	uint32_t expectedSequence_;
> @@ -1006,27 +997,16 @@ int PipelineHandlerRPi::configureIPA(Camera *camera)
>  	entityControls.emplace(0, data->unicam_[Unicam::Image].dev()->controls());
>  	entityControls.emplace(1, data->isp_[Isp::Input].dev()->controls());
>  
> -	/* Allocate the lens shading table via vcsm and pass to the IPA. */
> -	if (!data->lsTable_) {
> -		data->lsTable_ = data->vcsm_.alloc("ls_grid", MAX_LS_GRID_SIZE);
> -		uintptr_t ptr = reinterpret_cast<uintptr_t>(data->lsTable_);
> -
> -		if (!data->lsTable_)
> +	/* Allocate the lens shading table via dmaHeap and pass to the IPA. */
> +	if (!data->lsTable_.isValid()) {
> +		data->lsTable_ = data->dmaHeap_.alloc("ls_grid", MAX_LS_GRID_SIZE);
> +		if (!data->lsTable_.isValid())
>  			return -ENOMEM;
>  
> -		/*
> -		 * The vcsm allocation will always be in the memory region
> -		 * < 32-bits to allow Videocore to access the memory.
> -		 *
> -		 * \todo Sending a pointer to the IPA is a workaround for
> -		 * vc_sm_cma not yet supporting dmabuf. This will not work with
> -		 * IPA module isolation and should be reworked when vc_sma_cma
> -		 * will permit.
> -		 */
> +		/* Allow the IPA to mmap the LS table via the file descriptor. */
>  		IPAOperationData op;
>  		op.operation = RPI_IPA_EVENT_LS_TABLE_ALLOCATION;
> -		op.data = { static_cast<uint32_t>(ptr & 0xffffffff),
> -			    data->vcsm_.getVCHandle(data->lsTable_) };
> +		op.data = { static_cast<unsigned int>(data->lsTable_.fd()) };
>  		data->ipa_->processEvent(op);
>  	}
>  
> diff --git a/src/libcamera/pipeline/raspberrypi/vcsm.h b/src/libcamera/pipeline/raspberrypi/vcsm.h
> deleted file mode 100644
> index bebe86a7..00000000
> --- a/src/libcamera/pipeline/raspberrypi/vcsm.h
> +++ /dev/null
> @@ -1,149 +0,0 @@
> -/* SPDX-License-Identifier: LGPL-2.1-or-later */
> -/*
> - * Copyright (C) 2019, Raspberry Pi (Trading) Limited
> - *
> - * vcsm.h - Helper class for vcsm allocations.
> - */
> -#ifndef __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__
> -#define __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__
> -
> -#include <iostream>
> -#include <mutex>
> -
> -#include <fcntl.h>
> -#include <linux/vc_sm_cma_ioctl.h>
> -#include <sys/ioctl.h>
> -#include <sys/mman.h>
> -#include <unistd.h>
> -
> -namespace RPi {
> -
> -#define VCSM_CMA_DEVICE_NAME "/dev/vcsm-cma"
> -
> -class Vcsm
> -{
> -public:
> -	Vcsm()
> -	{
> -		vcsmHandle_ = ::open(VCSM_CMA_DEVICE_NAME, O_RDWR, 0);
> -		if (vcsmHandle_ == -1) {
> -			std::cerr << "Could not open vcsm device: "
> -				  << VCSM_CMA_DEVICE_NAME;
> -		}
> -	}
> -
> -	~Vcsm()
> -	{
> -		/* Free all existing allocations. */
> -		auto it = allocMap_.begin();
> -		while (it != allocMap_.end())
> -			it = remove(it->first);
> -
> -		if (vcsmHandle_)
> -			::close(vcsmHandle_);
> -	}
> -
> -	void *alloc(const char *name, unsigned int size,
> -		    vc_sm_cma_cache_e cache = VC_SM_CMA_CACHE_NONE)
> -	{
> -		unsigned int pageSize = getpagesize();
> -		void *user_ptr;
> -		int ret;
> -
> -		if (!name)
> -			return nullptr;
> -
> -		/* Ask for page aligned allocation. */
> -		size = (size + pageSize - 1) & ~(pageSize - 1);
> -
> -		struct vc_sm_cma_ioctl_alloc alloc;
> -		memset(&alloc, 0, sizeof(alloc));
> -		alloc.size = size;
> -		alloc.num = 1;
> -		alloc.cached = cache;
> -		alloc.handle = 0;
> -		memcpy(alloc.name, name, 32);
> -
> -		ret = ::ioctl(vcsmHandle_, VC_SM_CMA_IOCTL_MEM_ALLOC, &alloc);
> -
> -		if (ret < 0 || alloc.handle < 0) {
> -			std::cerr << "vcsm allocation failure for "
> -				  << name << std::endl;
> -			return nullptr;
> -		}
> -
> -		/* Map the buffer into user space. */
> -		user_ptr = ::mmap(0, alloc.size, PROT_READ | PROT_WRITE,
> -				  MAP_SHARED, alloc.handle, 0);
> -
> -		if (user_ptr == MAP_FAILED) {
> -			std::cerr << "vcsm mmap failure for " << name << std::endl;
> -			::close(alloc.handle);
> -			return nullptr;
> -		}
> -
> -		std::lock_guard<std::mutex> lock(lock_);
> -		allocMap_.emplace(user_ptr, AllocInfo(alloc.handle,
> -						      alloc.size, alloc.vc_handle));
> -
> -		return user_ptr;
> -	}
> -
> -	void free(void *user_ptr)
> -	{
> -		std::lock_guard<std::mutex> lock(lock_);
> -		remove(user_ptr);
> -	}
> -
> -	unsigned int getVCHandle(void *user_ptr)
> -	{
> -		std::lock_guard<std::mutex> lock(lock_);
> -		auto it = allocMap_.find(user_ptr);
> -		if (it != allocMap_.end())
> -			return it->second.vcHandle;
> -
> -		return 0;
> -	}
> -
> -private:
> -	struct AllocInfo {
> -		AllocInfo(int handle_, int size_, int vcHandle_)
> -			: handle(handle_), size(size_), vcHandle(vcHandle_)
> -		{
> -		}
> -
> -		int handle;
> -		int size;
> -		uint32_t vcHandle;
> -	};
> -
> -	/* Map of all allocations that have been requested. */
> -	using AllocMap = std::map<void *, AllocInfo>;
> -
> -	AllocMap::iterator remove(void *user_ptr)
> -	{
> -		auto it = allocMap_.find(user_ptr);
> -		if (it != allocMap_.end()) {
> -			int handle = it->second.handle;
> -			int size = it->second.size;
> -			::munmap(user_ptr, size);
> -			::close(handle);
> -			/*
> -			 * Remove the allocation from the map. This returns
> -			 * an iterator to the next element.
> -			 */
> -			it = allocMap_.erase(it);
> -		}
> -
> -		/* Returns an iterator to the next element. */
> -		return it;
> -	}
> -
> -	AllocMap allocMap_;
> -	int vcsmHandle_;
> -	std::mutex lock_;
> -};
> -
> -} /* namespace RPi */
> -
> -#endif /* __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__ */

Hi Naush,

On Thu, Jul 16, 2020 at 02:20:15AM +0300, Laurent Pinchart wrote:
> Hi Naush,
> 
> Thank you for the patch.
> 
> On Wed, Jul 15, 2020 at 10:39:11AM +0100, Naushir Patuck wrote:
> > Remove use of vcsm allocations and replace with dma heap allocations.
> > The pipeline handler now passes the fd of the allocation over to the IPA
> > instead of the raw pointer.
> > 
> > Also use libcamera::FileDescriptor for fd lifetime management.
> > 
> > This commit must be built alongside the accompanying BCM2835 ISP kernel
> > driver changes at https://github.com/raspberrypi/linux/pull/3715.
> > Otherwise a mismatch will cause undefined behavior.
> > 
> > Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> > ---
> >  include/linux/bcm2835-isp.h                   |   4 +-
> >  include/linux/vc_sm_cma_ioctl.h               | 135 ----------------
> >  src/ipa/raspberrypi/raspberrypi.cpp           |  29 +++-
> >  .../pipeline/raspberrypi/dma_heaps.cpp        |  77 +++++++++
> >  .../pipeline/raspberrypi/dma_heaps.h          |  43 +++++
> >  .../pipeline/raspberrypi/meson.build          |   1 +
> >  .../pipeline/raspberrypi/raspberrypi.cpp      |  46 ++----
> >  src/libcamera/pipeline/raspberrypi/vcsm.h     | 149 ------------------
> >  8 files changed, 160 insertions(+), 324 deletions(-)
> >  delete mode 100644 include/linux/vc_sm_cma_ioctl.h
> >  create mode 100644 src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> >  create mode 100644 src/libcamera/pipeline/raspberrypi/dma_heaps.h
> >  delete mode 100644 src/libcamera/pipeline/raspberrypi/vcsm.h
> > 
> > diff --git a/include/linux/bcm2835-isp.h b/include/linux/bcm2835-isp.h
> > index e7afc367..45abb681 100644
> > --- a/include/linux/bcm2835-isp.h
> > +++ b/include/linux/bcm2835-isp.h
> > @@ -108,7 +108,7 @@ enum bcm2835_isp_gain_format {
> >   * @grid_stride:	Row to row distance (in grid cells) between grid cells
> >   *			in the same horizontal location.
> >   * @grid_height:	Height of lens shading tables in grid cells.
> > - * @mem_handle_table:	Memory handle to the tables.
> > + * @dmabuf:		dmabuf file handle containing the table.
> >   * @ref_transform:	Reference transform - unsupported, please pass zero.
> >   * @corner_sampled:	Whether the gains are sampled at the corner points
> >   *			of the grid cells or in the cell centres.
> > @@ -120,7 +120,7 @@ struct bcm2835_isp_lens_shading {
> >  	__u32 grid_width;
> >  	__u32 grid_stride;
> >  	__u32 grid_height;
> > -	__u32 mem_handle_table;
> > +	__s32 dmabuf;
> >  	__u32 ref_transform;
> >  	__u32 corner_sampled;
> >  	__u32 gain_format;
> > diff --git a/include/linux/vc_sm_cma_ioctl.h b/include/linux/vc_sm_cma_ioctl.h
> > deleted file mode 100644
> > index 21b8758e..00000000
> > --- a/include/linux/vc_sm_cma_ioctl.h
> > +++ /dev/null
> > @@ -1,135 +0,0 @@
> > -/*
> > -Copyright (c) 2012, Broadcom Europe Ltd
> > -All rights reserved.
> > -
> > -Redistribution and use in source and binary forms, with or without
> > -modification, are permitted provided that the following conditions are met:
> > -    * Redistributions of source code must retain the above copyright
> > -      notice, this list of conditions and the following disclaimer.
> > -    * Redistributions in binary form must reproduce the above copyright
> > -      notice, this list of conditions and the following disclaimer in the
> > -      documentation and/or other materials provided with the distribution.
> > -    * Neither the name of the copyright holder nor the
> > -      names of its contributors may be used to endorse or promote products
> > -      derived from this software without specific prior written permission.
> > -
> > -THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
> > -ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
> > -WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
> > -DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
> > -DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
> > -(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
> > -LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
> > -ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> > -(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
> > -SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> > -*/
> > -
> > -/*
> > - * Copyright 2019 Raspberry Pi (Trading) Ltd.  All rights reserved.
> > - *
> > - * Based on vmcs_sm_ioctl.h Copyright Broadcom Corporation.
> > - */
> > -
> > -#ifndef __VC_SM_CMA_IOCTL_H
> > -#define __VC_SM_CMA_IOCTL_H
> > -
> > -/* ---- Include Files ---------------------------------------------------- */
> > -
> > -#include <linux/types.h>	/* Needed for standard types */
> > -
> > -#include <linux/ioctl.h>
> > -
> > -/* ---- Constants and Types ---------------------------------------------- */
> > -
> > -#define VC_SM_CMA_RESOURCE_NAME               32
> > -#define VC_SM_CMA_RESOURCE_NAME_DEFAULT       "sm-host-resource"
> > -
> > -/* Type define used to create unique IOCTL number */
> > -#define VC_SM_CMA_MAGIC_TYPE                  'J'
> > -
> > -/* IOCTL commands on /dev/vc-sm-cma */
> > -enum vc_sm_cma_cmd_e {
> > -	VC_SM_CMA_CMD_ALLOC = 0x5A,	/* Start at 0x5A arbitrarily */
> > -
> > -	VC_SM_CMA_CMD_IMPORT_DMABUF,
> > -
> > -	VC_SM_CMA_CMD_CLEAN_INVALID2,
> > -
> > -	VC_SM_CMA_CMD_LAST	/* Do not delete */
> > -};
> > -
> > -/* Cache type supported, conveniently matches the user space definition in
> > - * user-vcsm.h.
> > - */
> > -enum vc_sm_cma_cache_e {
> > -	VC_SM_CMA_CACHE_NONE,
> > -	VC_SM_CMA_CACHE_HOST,
> > -	VC_SM_CMA_CACHE_VC,
> > -	VC_SM_CMA_CACHE_BOTH,
> > -};
> > -
> > -/* IOCTL Data structures */
> > -struct vc_sm_cma_ioctl_alloc {
> > -	/* user -> kernel */
> > -	__u32 size;
> > -	__u32 num;
> > -	__u32 cached;		/* enum vc_sm_cma_cache_e */
> > -	__u32 pad;
> > -	__u8 name[VC_SM_CMA_RESOURCE_NAME];
> > -
> > -	/* kernel -> user */
> > -	__s32 handle;
> > -	__u32 vc_handle;
> > -	__u64 dma_addr;
> > -};
> > -
> > -struct vc_sm_cma_ioctl_import_dmabuf {
> > -	/* user -> kernel */
> > -	__s32 dmabuf_fd;
> > -	__u32 cached;		/* enum vc_sm_cma_cache_e */
> > -	__u8 name[VC_SM_CMA_RESOURCE_NAME];
> > -
> > -	/* kernel -> user */
> > -	__s32 handle;
> > -	__u32 vc_handle;
> > -	__u32 size;
> > -	__u32 pad;
> > -	__u64 dma_addr;
> > -};
> > -
> > -/*
> > - * Cache functions to be set to struct vc_sm_cma_ioctl_clean_invalid2
> > - * invalidate_mode.
> > - */
> > -#define VC_SM_CACHE_OP_NOP       0x00
> > -#define VC_SM_CACHE_OP_INV       0x01
> > -#define VC_SM_CACHE_OP_CLEAN     0x02
> > -#define VC_SM_CACHE_OP_FLUSH     0x03
> > -
> > -struct vc_sm_cma_ioctl_clean_invalid2 {
> > -	__u32 op_count;
> > -	__u32 pad;
> > -	struct vc_sm_cma_ioctl_clean_invalid_block {
> > -		__u32 invalidate_mode;
> > -		__u32 block_count;
> > -		void *  /*__user */start_address;
> > -		__u32 block_size;
> > -		__u32 inter_block_stride;
> > -	} s[0];
> > -};
> > -
> > -/* IOCTL numbers */
> > -#define VC_SM_CMA_IOCTL_MEM_ALLOC\
> > -	_IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_ALLOC,\
> > -	 struct vc_sm_cma_ioctl_alloc)
> > -
> > -#define VC_SM_CMA_IOCTL_MEM_IMPORT_DMABUF\
> > -	_IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_IMPORT_DMABUF,\
> > -	 struct vc_sm_cma_ioctl_import_dmabuf)
> > -
> > -#define VC_SM_CMA_IOCTL_MEM_CLEAN_INVALID2\
> > -	_IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_CLEAN_INVALID2,\
> > -	 struct vc_sm_cma_ioctl_clean_invalid2)
> > -
> > -#endif /* __VC_SM_CMA_IOCTL_H */
> > diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
> > index b1f27861..8efc9aa5 100644
> > --- a/src/ipa/raspberrypi/raspberrypi.cpp
> > +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> > @@ -15,6 +15,7 @@
> >  #include <libcamera/buffer.h>
> >  #include <libcamera/control_ids.h>
> >  #include <libcamera/controls.h>
> > +#include <libcamera/file_descriptor.h>
> >  #include <libcamera/ipa/ipa_interface.h>
> >  #include <libcamera/ipa/ipa_module_info.h>
> >  #include <libcamera/ipa/raspberrypi.h>
> > @@ -65,12 +66,14 @@ public:
> >  	IPARPi()
> >  		: lastMode_({}), controller_(), controllerInit_(false),
> >  		  frame_count_(0), check_count_(0), hide_count_(0),
> > -		  mistrust_count_(0), lsTableHandle_(0), lsTable_(nullptr)
> > +		  mistrust_count_(0), lsTable_(nullptr)
> >  	{
> >  	}
> >  
> >  	~IPARPi()
> >  	{
> > +		if (lsTable_)
> > +			munmap(lsTable_, MAX_LS_GRID_SIZE);
> >  	}
> >  
> >  	int init(const IPASettings &settings) override;
> > @@ -137,7 +140,7 @@ private:
> >  	/* How many frames we should avoid running control algos on. */
> >  	unsigned int mistrust_count_;
> >  	/* LS table allocation passed in from the pipeline handler. */
> > -	uint32_t lsTableHandle_;
> > +	FileDescriptor lsTableHandle_;
> >  	void *lsTable_;
> >  };
> >  
> > @@ -357,8 +360,24 @@ void IPARPi::processEvent(const IPAOperationData &event)
> >  	}
> >  
> >  	case RPI_IPA_EVENT_LS_TABLE_ALLOCATION: {
> > -		lsTable_ = reinterpret_cast<void *>(event.data[0]);
> > -		lsTableHandle_ = event.data[1];
> > +		/* Remove any previous table, if there was one. */
> > +		if (lsTable_)
> > +			munmap(lsTable_, MAX_LS_GRID_SIZE);
> > +
> > +		lsTable_ = nullptr;
> 
> Not that it matters much, but I would have but the assignment inside the
> if block, it seems logical to me to group it with munmap.
> 
> > +
> > +		/* Map the LS table buffer into user space. */
> > +		lsTableHandle_ = FileDescriptor(event.data[0]);
> > +		if (lsTableHandle_.isValid()) {
> > +			lsTable_ = mmap(nullptr, MAX_LS_GRID_SIZE, PROT_READ | PROT_WRITE,
> > +					MAP_SHARED, lsTableHandle_.fd(), 0);
> > +
> > +			if (lsTable_ == MAP_FAILED) {
> > +				LOG(IPARPI, Error) << "dmaHeap mmap failure for LS table.";
> > +				lsTable_ = nullptr;
> > +			}
> > +		}
> > +
> >  		break;
> >  	}
> >  
> > @@ -1026,7 +1045,7 @@ void IPARPi::applyLS(const struct AlscStatus *lsStatus, ControlList &ctrls)
> >  		.grid_width = w,
> >  		.grid_stride = w,
> >  		.grid_height = h,
> > -		.mem_handle_table = lsTableHandle_,
> > +		.dmabuf = lsTableHandle_.fd(),
> >  		.ref_transform = 0,
> >  		.corner_sampled = 1,
> >  		.gain_format = GAIN_FORMAT_U4P10
> > diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> > new file mode 100644
> > index 00000000..c29a1a25
> > --- /dev/null
> > +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> > @@ -0,0 +1,77 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2020, Raspberry Pi (Trading) Limited
> > + *
> > + * dma_heaps.h - Helper class for dma-heap allocations.
> > + */
> > +#include <fcntl.h>
> > +#include <linux/dma-buf.h>
> > +#include <linux/dma-heap.h>
> > +#include <sys/ioctl.h>
> > +#include <unistd.h>
> > +
> > +#include "libcamera/internal/log.h"
> > +
> > +#include "dma_heaps.h"
> 
> This should be the very first header to be included, to test that it can
> be compiled self-contained. This helps avoiding future compilation
> breakages when other headers are reworked.

And that shows that the LOG_DECLARE_CATEGORY(RPI) statement in
dma_heaps.h is not needed :-)

> > +
> > +namespace libcamera {
> > +
> > +LOG_DECLARE_CATEGORY(RPI)
> > +
> > +namespace RPi {
> > +
> > +DmaHeap::DmaHeap()
> > +{
> > +	dmaHeapHandle_ = ::open(DMA_HEAP_CMA_NAME, O_RDWR, 0);
> > +	if (dmaHeapHandle_ == -1) {
> > +		dmaHeapHandle_ = ::open(DMA_HEAP_CMA_ALT_NAME, O_RDWR, 0);
> > +		if (dmaHeapHandle_ == -1) {
> > +			LOG(RPI, Error) << "Could not open dmaHeap device";
> > +		}
> > +	}
> > +}
> > +
> > +DmaHeap::~DmaHeap()
> > +{
> > +	if (dmaHeapHandle_)
> > +		::close(dmaHeapHandle_);
> > +}
> > +
> > +FileDescriptor DmaHeap::alloc(const char *name, std::size_t size)
> > +{
> > +	unsigned int pageSize = getpagesize();
> 
> The getpagesize() man page states that "Portable applications should
> employ sysconf(_SC_PAGESIZE) instead of getpagesize()". But do we need
> this ? The dma-heap implementation rounds up the requested size to a
> multiple of PAGE_SIZE internally. Of course none of the userspace API is
> documented, so whether this is an implementation detail or an API
> guarantee is not known :-@ How can we seriously merge an API these days
> without documentation ?
> 
> > +	int ret;
> > +
> > +	if (!name)
> > +		return FileDescriptor();
> > +
> > +	/* Ask for page aligned allocation. */
> > +	size = (size + pageSize - 1) & ~(pageSize - 1);
> > +
> > +	struct dma_heap_allocation_data alloc = {};
> > +
> > +	alloc.len = size;
> > +	alloc.fd_flags = O_CLOEXEC | O_RDWR;
> > +
> > +	ret = ::ioctl(dmaHeapHandle_, DMA_HEAP_IOCTL_ALLOC, &alloc);
> > +
> > +	if (ret < 0) {
> > +		LOG(RPI, Error) << "dmaHeap allocation failure for "
> > +				<< name;
> > +		return FileDescriptor();
> > +	}
> > +
> > +	ret = ::ioctl(alloc.fd, DMA_BUF_SET_NAME, name);
> > +	if (ret < 0) {
> > +		LOG(RPI, Error) << "dmaHeap naming failure for "
> > +				<< name;
> > +		::close(alloc.fd);
> > +		return FileDescriptor();
> > +	}
> > +
> > +	return FileDescriptor(std::move(alloc.fd));
> > +}
> > +
> > +} /* namespace RPi */
> > +
> > +} /* namespace libcamera */
> > diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.h b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> > new file mode 100644
> > index 00000000..80892fd4
> > --- /dev/null
> > +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> > @@ -0,0 +1,43 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2020, Raspberry Pi (Trading) Limited
> > + *
> > + * dma_heaps.h - Helper class for dma-heap allocations.
> > + */
> > +#ifndef __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__
> > +#define __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__
> > +
> > +#include <libcamera/file_descriptor.h>
> > +
> > +namespace libcamera {
> > +
> > +LOG_DECLARE_CATEGORY(RPI)
> > +
> > +namespace RPi {
> > +
> > +/*
> > + * /dev/dma-heap/linux,cma is the dma-heap allocator, which allows dmaheap-cma to
> > + * only have to worry about importing.
> > + *
> > + * Annoyingly, should the cma heap size be specified on the kernel command line
> > + * instead of DT, the heap gets named "reserved" instead.
> > + */
> > +#define DMA_HEAP_CMA_NAME "/dev/dma_heap/linux,cma"
> > +#define DMA_HEAP_CMA_ALT_NAME "/dev/dma_heap/reserved"
> 
> I would move this to the .cpp file.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> Please let me know if you would like me to make those small
> modifications when applying the series, or if you would like to send a
> v3.
> 
> > +
> > +class DmaHeap
> > +{
> > +public:
> > +	DmaHeap();
> > +	~DmaHeap();
> > +	FileDescriptor alloc(const char *name, std::size_t size);
> > +
> > +private:
> > +	int dmaHeapHandle_;
> > +};
> > +
> > +} /* namespace RPi */
> > +
> > +} /* namespace libcamera */
> > +
> > +#endif /* __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__ */
> > diff --git a/src/libcamera/pipeline/raspberrypi/meson.build b/src/libcamera/pipeline/raspberrypi/meson.build
> > index dcfe07c5..ae0aed3b 100644
> > --- a/src/libcamera/pipeline/raspberrypi/meson.build
> > +++ b/src/libcamera/pipeline/raspberrypi/meson.build
> > @@ -1,6 +1,7 @@
> >  # SPDX-License-Identifier: CC0-1.0
> >  
> >  libcamera_sources += files([
> > +    'dma_heaps.cpp',
> >      'raspberrypi.cpp',
> >      'staggered_ctrl.cpp',
> >  ])
> > diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > index 7450062f..431de44d 100644
> > --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > @@ -13,6 +13,7 @@
> >  
> >  #include <libcamera/camera.h>
> >  #include <libcamera/control_ids.h>
> > +#include <libcamera/file_descriptor.h>
> >  #include <libcamera/formats.h>
> >  #include <libcamera/ipa/raspberrypi.h>
> >  #include <libcamera/logging.h>
> > @@ -30,8 +31,8 @@
> >  #include "libcamera/internal/v4l2_controls.h"
> >  #include "libcamera/internal/v4l2_videodevice.h"
> >  
> > +#include "dma_heaps.h"
> >  #include "staggered_ctrl.h"
> > -#include "vcsm.h"
> >  
> >  namespace libcamera {
> >  
> > @@ -285,23 +286,13 @@ class RPiCameraData : public CameraData
> >  {
> >  public:
> >  	RPiCameraData(PipelineHandler *pipe)
> > -		: CameraData(pipe), sensor_(nullptr), lsTable_(nullptr),
> > -		  state_(State::Stopped), dropFrame_(false), ispOutputCount_(0)
> > +		: CameraData(pipe), sensor_(nullptr), state_(State::Stopped),
> > +		  dropFrame_(false), ispOutputCount_(0)
> >  	{
> >  	}
> >  
> >  	~RPiCameraData()
> >  	{
> > -		/*
> > -		 * Free the LS table if we have allocated one. Another
> > -		 * allocation will occur in applyLS() with the appropriate
> > -		 * size.
> > -		 */
> > -		if (lsTable_) {
> > -			vcsm_.free(lsTable_);
> > -			lsTable_ = nullptr;
> > -		}
> > -
> >  		/* Stop the IPA proxy thread. */
> >  		if (ipa_)
> >  			ipa_->stop();
> > @@ -330,9 +321,9 @@ public:
> >  	/* Buffers passed to the IPA. */
> >  	std::vector<IPABuffer> ipaBuffers_;
> >  
> > -	/* VCSM allocation helper. */
> > -	::RPi::Vcsm vcsm_;
> > -	void *lsTable_;
> > +	/* DMAHEAP allocation helper. */
> > +	RPi::DmaHeap dmaHeap_;
> > +	FileDescriptor lsTable_;
> >  
> >  	RPi::StaggeredCtrl staggeredCtrl_;
> >  	uint32_t expectedSequence_;
> > @@ -1006,27 +997,16 @@ int PipelineHandlerRPi::configureIPA(Camera *camera)
> >  	entityControls.emplace(0, data->unicam_[Unicam::Image].dev()->controls());
> >  	entityControls.emplace(1, data->isp_[Isp::Input].dev()->controls());
> >  
> > -	/* Allocate the lens shading table via vcsm and pass to the IPA. */
> > -	if (!data->lsTable_) {
> > -		data->lsTable_ = data->vcsm_.alloc("ls_grid", MAX_LS_GRID_SIZE);
> > -		uintptr_t ptr = reinterpret_cast<uintptr_t>(data->lsTable_);
> > -
> > -		if (!data->lsTable_)
> > +	/* Allocate the lens shading table via dmaHeap and pass to the IPA. */
> > +	if (!data->lsTable_.isValid()) {
> > +		data->lsTable_ = data->dmaHeap_.alloc("ls_grid", MAX_LS_GRID_SIZE);
> > +		if (!data->lsTable_.isValid())
> >  			return -ENOMEM;
> >  
> > -		/*
> > -		 * The vcsm allocation will always be in the memory region
> > -		 * < 32-bits to allow Videocore to access the memory.
> > -		 *
> > -		 * \todo Sending a pointer to the IPA is a workaround for
> > -		 * vc_sm_cma not yet supporting dmabuf. This will not work with
> > -		 * IPA module isolation and should be reworked when vc_sma_cma
> > -		 * will permit.
> > -		 */
> > +		/* Allow the IPA to mmap the LS table via the file descriptor. */
> >  		IPAOperationData op;
> >  		op.operation = RPI_IPA_EVENT_LS_TABLE_ALLOCATION;
> > -		op.data = { static_cast<uint32_t>(ptr & 0xffffffff),
> > -			    data->vcsm_.getVCHandle(data->lsTable_) };
> > +		op.data = { static_cast<unsigned int>(data->lsTable_.fd()) };
> >  		data->ipa_->processEvent(op);
> >  	}
> >  
> > diff --git a/src/libcamera/pipeline/raspberrypi/vcsm.h b/src/libcamera/pipeline/raspberrypi/vcsm.h
> > deleted file mode 100644
> > index bebe86a7..00000000
> > --- a/src/libcamera/pipeline/raspberrypi/vcsm.h
> > +++ /dev/null
> > @@ -1,149 +0,0 @@
> > -/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > -/*
> > - * Copyright (C) 2019, Raspberry Pi (Trading) Limited
> > - *
> > - * vcsm.h - Helper class for vcsm allocations.
> > - */
> > -#ifndef __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__
> > -#define __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__
> > -
> > -#include <iostream>
> > -#include <mutex>
> > -
> > -#include <fcntl.h>
> > -#include <linux/vc_sm_cma_ioctl.h>
> > -#include <sys/ioctl.h>
> > -#include <sys/mman.h>
> > -#include <unistd.h>
> > -
> > -namespace RPi {
> > -
> > -#define VCSM_CMA_DEVICE_NAME "/dev/vcsm-cma"
> > -
> > -class Vcsm
> > -{
> > -public:
> > -	Vcsm()
> > -	{
> > -		vcsmHandle_ = ::open(VCSM_CMA_DEVICE_NAME, O_RDWR, 0);
> > -		if (vcsmHandle_ == -1) {
> > -			std::cerr << "Could not open vcsm device: "
> > -				  << VCSM_CMA_DEVICE_NAME;
> > -		}
> > -	}
> > -
> > -	~Vcsm()
> > -	{
> > -		/* Free all existing allocations. */
> > -		auto it = allocMap_.begin();
> > -		while (it != allocMap_.end())
> > -			it = remove(it->first);
> > -
> > -		if (vcsmHandle_)
> > -			::close(vcsmHandle_);
> > -	}
> > -
> > -	void *alloc(const char *name, unsigned int size,
> > -		    vc_sm_cma_cache_e cache = VC_SM_CMA_CACHE_NONE)
> > -	{
> > -		unsigned int pageSize = getpagesize();
> > -		void *user_ptr;
> > -		int ret;
> > -
> > -		if (!name)
> > -			return nullptr;
> > -
> > -		/* Ask for page aligned allocation. */
> > -		size = (size + pageSize - 1) & ~(pageSize - 1);
> > -
> > -		struct vc_sm_cma_ioctl_alloc alloc;
> > -		memset(&alloc, 0, sizeof(alloc));
> > -		alloc.size = size;
> > -		alloc.num = 1;
> > -		alloc.cached = cache;
> > -		alloc.handle = 0;
> > -		memcpy(alloc.name, name, 32);
> > -
> > -		ret = ::ioctl(vcsmHandle_, VC_SM_CMA_IOCTL_MEM_ALLOC, &alloc);
> > -
> > -		if (ret < 0 || alloc.handle < 0) {
> > -			std::cerr << "vcsm allocation failure for "
> > -				  << name << std::endl;
> > -			return nullptr;
> > -		}
> > -
> > -		/* Map the buffer into user space. */
> > -		user_ptr = ::mmap(0, alloc.size, PROT_READ | PROT_WRITE,
> > -				  MAP_SHARED, alloc.handle, 0);
> > -
> > -		if (user_ptr == MAP_FAILED) {
> > -			std::cerr << "vcsm mmap failure for " << name << std::endl;
> > -			::close(alloc.handle);
> > -			return nullptr;
> > -		}
> > -
> > -		std::lock_guard<std::mutex> lock(lock_);
> > -		allocMap_.emplace(user_ptr, AllocInfo(alloc.handle,
> > -						      alloc.size, alloc.vc_handle));
> > -
> > -		return user_ptr;
> > -	}
> > -
> > -	void free(void *user_ptr)
> > -	{
> > -		std::lock_guard<std::mutex> lock(lock_);
> > -		remove(user_ptr);
> > -	}
> > -
> > -	unsigned int getVCHandle(void *user_ptr)
> > -	{
> > -		std::lock_guard<std::mutex> lock(lock_);
> > -		auto it = allocMap_.find(user_ptr);
> > -		if (it != allocMap_.end())
> > -			return it->second.vcHandle;
> > -
> > -		return 0;
> > -	}
> > -
> > -private:
> > -	struct AllocInfo {
> > -		AllocInfo(int handle_, int size_, int vcHandle_)
> > -			: handle(handle_), size(size_), vcHandle(vcHandle_)
> > -		{
> > -		}
> > -
> > -		int handle;
> > -		int size;
> > -		uint32_t vcHandle;
> > -	};
> > -
> > -	/* Map of all allocations that have been requested. */
> > -	using AllocMap = std::map<void *, AllocInfo>;
> > -
> > -	AllocMap::iterator remove(void *user_ptr)
> > -	{
> > -		auto it = allocMap_.find(user_ptr);
> > -		if (it != allocMap_.end()) {
> > -			int handle = it->second.handle;
> > -			int size = it->second.size;
> > -			::munmap(user_ptr, size);
> > -			::close(handle);
> > -			/*
> > -			 * Remove the allocation from the map. This returns
> > -			 * an iterator to the next element.
> > -			 */
> > -			it = allocMap_.erase(it);
> > -		}
> > -
> > -		/* Returns an iterator to the next element. */
> > -		return it;
> > -	}
> > -
> > -	AllocMap allocMap_;
> > -	int vcsmHandle_;
> > -	std::mutex lock_;
> > -};
> > -
> > -} /* namespace RPi */
> > -
> > -#endif /* __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__ */

Hi Laurent,

Thanks for the comments.

On Thu, 16 Jul 2020 at 00:20, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Naush,
>
> Thank you for the patch.
>
> On Wed, Jul 15, 2020 at 10:39:11AM +0100, Naushir Patuck wrote:
> > Remove use of vcsm allocations and replace with dma heap allocations.
> > The pipeline handler now passes the fd of the allocation over to the IPA
> > instead of the raw pointer.
> >
> > Also use libcamera::FileDescriptor for fd lifetime management.
> >
> > This commit must be built alongside the accompanying BCM2835 ISP kernel
> > driver changes at https://github.com/raspberrypi/linux/pull/3715.
> > Otherwise a mismatch will cause undefined behavior.
> >
> > Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
> > ---
> >  include/linux/bcm2835-isp.h                   |   4 +-
> >  include/linux/vc_sm_cma_ioctl.h               | 135 ----------------
> >  src/ipa/raspberrypi/raspberrypi.cpp           |  29 +++-
> >  .../pipeline/raspberrypi/dma_heaps.cpp        |  77 +++++++++
> >  .../pipeline/raspberrypi/dma_heaps.h          |  43 +++++
> >  .../pipeline/raspberrypi/meson.build          |   1 +
> >  .../pipeline/raspberrypi/raspberrypi.cpp      |  46 ++----
> >  src/libcamera/pipeline/raspberrypi/vcsm.h     | 149 ------------------
> >  8 files changed, 160 insertions(+), 324 deletions(-)
> >  delete mode 100644 include/linux/vc_sm_cma_ioctl.h
> >  create mode 100644 src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> >  create mode 100644 src/libcamera/pipeline/raspberrypi/dma_heaps.h
> >  delete mode 100644 src/libcamera/pipeline/raspberrypi/vcsm.h
> >
> > diff --git a/include/linux/bcm2835-isp.h b/include/linux/bcm2835-isp.h
> > index e7afc367..45abb681 100644
> > --- a/include/linux/bcm2835-isp.h
> > +++ b/include/linux/bcm2835-isp.h
> > @@ -108,7 +108,7 @@ enum bcm2835_isp_gain_format {
> >   * @grid_stride:     Row to row distance (in grid cells) between grid cells
> >   *                   in the same horizontal location.
> >   * @grid_height:     Height of lens shading tables in grid cells.
> > - * @mem_handle_table:        Memory handle to the tables.
> > + * @dmabuf:          dmabuf file handle containing the table.
> >   * @ref_transform:   Reference transform - unsupported, please pass zero.
> >   * @corner_sampled:  Whether the gains are sampled at the corner points
> >   *                   of the grid cells or in the cell centres.
> > @@ -120,7 +120,7 @@ struct bcm2835_isp_lens_shading {
> >       __u32 grid_width;
> >       __u32 grid_stride;
> >       __u32 grid_height;
> > -     __u32 mem_handle_table;
> > +     __s32 dmabuf;
> >       __u32 ref_transform;
> >       __u32 corner_sampled;
> >       __u32 gain_format;
> > diff --git a/include/linux/vc_sm_cma_ioctl.h b/include/linux/vc_sm_cma_ioctl.h
> > deleted file mode 100644
> > index 21b8758e..00000000
> > --- a/include/linux/vc_sm_cma_ioctl.h
> > +++ /dev/null
> > @@ -1,135 +0,0 @@
> > -/*
> > -Copyright (c) 2012, Broadcom Europe Ltd
> > -All rights reserved.
> > -
> > -Redistribution and use in source and binary forms, with or without
> > -modification, are permitted provided that the following conditions are met:
> > -    * Redistributions of source code must retain the above copyright
> > -      notice, this list of conditions and the following disclaimer.
> > -    * Redistributions in binary form must reproduce the above copyright
> > -      notice, this list of conditions and the following disclaimer in the
> > -      documentation and/or other materials provided with the distribution.
> > -    * Neither the name of the copyright holder nor the
> > -      names of its contributors may be used to endorse or promote products
> > -      derived from this software without specific prior written permission.
> > -
> > -THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
> > -ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
> > -WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
> > -DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
> > -DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
> > -(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
> > -LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
> > -ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> > -(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
> > -SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> > -*/
> > -
> > -/*
> > - * Copyright 2019 Raspberry Pi (Trading) Ltd.  All rights reserved.
> > - *
> > - * Based on vmcs_sm_ioctl.h Copyright Broadcom Corporation.
> > - */
> > -
> > -#ifndef __VC_SM_CMA_IOCTL_H
> > -#define __VC_SM_CMA_IOCTL_H
> > -
> > -/* ---- Include Files ---------------------------------------------------- */
> > -
> > -#include <linux/types.h>     /* Needed for standard types */
> > -
> > -#include <linux/ioctl.h>
> > -
> > -/* ---- Constants and Types ---------------------------------------------- */
> > -
> > -#define VC_SM_CMA_RESOURCE_NAME               32
> > -#define VC_SM_CMA_RESOURCE_NAME_DEFAULT       "sm-host-resource"
> > -
> > -/* Type define used to create unique IOCTL number */
> > -#define VC_SM_CMA_MAGIC_TYPE                  'J'
> > -
> > -/* IOCTL commands on /dev/vc-sm-cma */
> > -enum vc_sm_cma_cmd_e {
> > -     VC_SM_CMA_CMD_ALLOC = 0x5A,     /* Start at 0x5A arbitrarily */
> > -
> > -     VC_SM_CMA_CMD_IMPORT_DMABUF,
> > -
> > -     VC_SM_CMA_CMD_CLEAN_INVALID2,
> > -
> > -     VC_SM_CMA_CMD_LAST      /* Do not delete */
> > -};
> > -
> > -/* Cache type supported, conveniently matches the user space definition in
> > - * user-vcsm.h.
> > - */
> > -enum vc_sm_cma_cache_e {
> > -     VC_SM_CMA_CACHE_NONE,
> > -     VC_SM_CMA_CACHE_HOST,
> > -     VC_SM_CMA_CACHE_VC,
> > -     VC_SM_CMA_CACHE_BOTH,
> > -};
> > -
> > -/* IOCTL Data structures */
> > -struct vc_sm_cma_ioctl_alloc {
> > -     /* user -> kernel */
> > -     __u32 size;
> > -     __u32 num;
> > -     __u32 cached;           /* enum vc_sm_cma_cache_e */
> > -     __u32 pad;
> > -     __u8 name[VC_SM_CMA_RESOURCE_NAME];
> > -
> > -     /* kernel -> user */
> > -     __s32 handle;
> > -     __u32 vc_handle;
> > -     __u64 dma_addr;
> > -};
> > -
> > -struct vc_sm_cma_ioctl_import_dmabuf {
> > -     /* user -> kernel */
> > -     __s32 dmabuf_fd;
> > -     __u32 cached;           /* enum vc_sm_cma_cache_e */
> > -     __u8 name[VC_SM_CMA_RESOURCE_NAME];
> > -
> > -     /* kernel -> user */
> > -     __s32 handle;
> > -     __u32 vc_handle;
> > -     __u32 size;
> > -     __u32 pad;
> > -     __u64 dma_addr;
> > -};
> > -
> > -/*
> > - * Cache functions to be set to struct vc_sm_cma_ioctl_clean_invalid2
> > - * invalidate_mode.
> > - */
> > -#define VC_SM_CACHE_OP_NOP       0x00
> > -#define VC_SM_CACHE_OP_INV       0x01
> > -#define VC_SM_CACHE_OP_CLEAN     0x02
> > -#define VC_SM_CACHE_OP_FLUSH     0x03
> > -
> > -struct vc_sm_cma_ioctl_clean_invalid2 {
> > -     __u32 op_count;
> > -     __u32 pad;
> > -     struct vc_sm_cma_ioctl_clean_invalid_block {
> > -             __u32 invalidate_mode;
> > -             __u32 block_count;
> > -             void *  /*__user */start_address;
> > -             __u32 block_size;
> > -             __u32 inter_block_stride;
> > -     } s[0];
> > -};
> > -
> > -/* IOCTL numbers */
> > -#define VC_SM_CMA_IOCTL_MEM_ALLOC\
> > -     _IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_ALLOC,\
> > -      struct vc_sm_cma_ioctl_alloc)
> > -
> > -#define VC_SM_CMA_IOCTL_MEM_IMPORT_DMABUF\
> > -     _IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_IMPORT_DMABUF,\
> > -      struct vc_sm_cma_ioctl_import_dmabuf)
> > -
> > -#define VC_SM_CMA_IOCTL_MEM_CLEAN_INVALID2\
> > -     _IOR(VC_SM_CMA_MAGIC_TYPE, VC_SM_CMA_CMD_CLEAN_INVALID2,\
> > -      struct vc_sm_cma_ioctl_clean_invalid2)
> > -
> > -#endif /* __VC_SM_CMA_IOCTL_H */
> > diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
> > index b1f27861..8efc9aa5 100644
> > --- a/src/ipa/raspberrypi/raspberrypi.cpp
> > +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> > @@ -15,6 +15,7 @@
> >  #include <libcamera/buffer.h>
> >  #include <libcamera/control_ids.h>
> >  #include <libcamera/controls.h>
> > +#include <libcamera/file_descriptor.h>
> >  #include <libcamera/ipa/ipa_interface.h>
> >  #include <libcamera/ipa/ipa_module_info.h>
> >  #include <libcamera/ipa/raspberrypi.h>
> > @@ -65,12 +66,14 @@ public:
> >       IPARPi()
> >               : lastMode_({}), controller_(), controllerInit_(false),
> >                 frame_count_(0), check_count_(0), hide_count_(0),
> > -               mistrust_count_(0), lsTableHandle_(0), lsTable_(nullptr)
> > +               mistrust_count_(0), lsTable_(nullptr)
> >       {
> >       }
> >
> >       ~IPARPi()
> >       {
> > +             if (lsTable_)
> > +                     munmap(lsTable_, MAX_LS_GRID_SIZE);
> >       }
> >
> >       int init(const IPASettings &settings) override;
> > @@ -137,7 +140,7 @@ private:
> >       /* How many frames we should avoid running control algos on. */
> >       unsigned int mistrust_count_;
> >       /* LS table allocation passed in from the pipeline handler. */
> > -     uint32_t lsTableHandle_;
> > +     FileDescriptor lsTableHandle_;
> >       void *lsTable_;
> >  };
> >
> > @@ -357,8 +360,24 @@ void IPARPi::processEvent(const IPAOperationData &event)
> >       }
> >
> >       case RPI_IPA_EVENT_LS_TABLE_ALLOCATION: {
> > -             lsTable_ = reinterpret_cast<void *>(event.data[0]);
> > -             lsTableHandle_ = event.data[1];
> > +             /* Remove any previous table, if there was one. */
> > +             if (lsTable_)
> > +                     munmap(lsTable_, MAX_LS_GRID_SIZE);
> > +
> > +             lsTable_ = nullptr;
>
> Not that it matters much, but I would have but the assignment inside the
> if block, it seems logical to me to group it with munmap.
>
> > +
> > +             /* Map the LS table buffer into user space. */
> > +             lsTableHandle_ = FileDescriptor(event.data[0]);
> > +             if (lsTableHandle_.isValid()) {
> > +                     lsTable_ = mmap(nullptr, MAX_LS_GRID_SIZE, PROT_READ | PROT_WRITE,
> > +                                     MAP_SHARED, lsTableHandle_.fd(), 0);
> > +
> > +                     if (lsTable_ == MAP_FAILED) {
> > +                             LOG(IPARPI, Error) << "dmaHeap mmap failure for LS table.";
> > +                             lsTable_ = nullptr;
> > +                     }
> > +             }
> > +
> >               break;
> >       }
> >
> > @@ -1026,7 +1045,7 @@ void IPARPi::applyLS(const struct AlscStatus *lsStatus, ControlList &ctrls)
> >               .grid_width = w,
> >               .grid_stride = w,
> >               .grid_height = h,
> > -             .mem_handle_table = lsTableHandle_,
> > +             .dmabuf = lsTableHandle_.fd(),
> >               .ref_transform = 0,
> >               .corner_sampled = 1,
> >               .gain_format = GAIN_FORMAT_U4P10
> > diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> > new file mode 100644
> > index 00000000..c29a1a25
> > --- /dev/null
> > +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> > @@ -0,0 +1,77 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2020, Raspberry Pi (Trading) Limited
> > + *
> > + * dma_heaps.h - Helper class for dma-heap allocations.
> > + */
> > +#include <fcntl.h>
> > +#include <linux/dma-buf.h>
> > +#include <linux/dma-heap.h>
> > +#include <sys/ioctl.h>
> > +#include <unistd.h>
> > +
> > +#include "libcamera/internal/log.h"
> > +
> > +#include "dma_heaps.h"
>
> This should be the very first header to be included, to test that it can
> be compiled self-contained. This helps avoiding future compilation
> breakages when other headers are reworked.
>
> > +
> > +namespace libcamera {
> > +
> > +LOG_DECLARE_CATEGORY(RPI)
> > +
> > +namespace RPi {
> > +
> > +DmaHeap::DmaHeap()
> > +{
> > +     dmaHeapHandle_ = ::open(DMA_HEAP_CMA_NAME, O_RDWR, 0);
> > +     if (dmaHeapHandle_ == -1) {
> > +             dmaHeapHandle_ = ::open(DMA_HEAP_CMA_ALT_NAME, O_RDWR, 0);
> > +             if (dmaHeapHandle_ == -1) {
> > +                     LOG(RPI, Error) << "Could not open dmaHeap device";
> > +             }
> > +     }
> > +}
> > +
> > +DmaHeap::~DmaHeap()
> > +{
> > +     if (dmaHeapHandle_)
> > +             ::close(dmaHeapHandle_);
> > +}
> > +
> > +FileDescriptor DmaHeap::alloc(const char *name, std::size_t size)
> > +{
> > +     unsigned int pageSize = getpagesize();
>
> The getpagesize() man page states that "Portable applications should
> employ sysconf(_SC_PAGESIZE) instead of getpagesize()". But do we need
> this ? The dma-heap implementation rounds up the requested size to a
> multiple of PAGE_SIZE internally. Of course none of the userspace API is
> documented, so whether this is an implementation detail or an API
> guarantee is not known :-@ How can we seriously merge an API these days
> without documentation ?

I think we can probably get rid of the getpagesize() usage and
alignment in that case.

>
> > +     int ret;
> > +
> > +     if (!name)
> > +             return FileDescriptor();
> > +
> > +     /* Ask for page aligned allocation. */
> > +     size = (size + pageSize - 1) & ~(pageSize - 1);
> > +
> > +     struct dma_heap_allocation_data alloc = {};
> > +
> > +     alloc.len = size;
> > +     alloc.fd_flags = O_CLOEXEC | O_RDWR;
> > +
> > +     ret = ::ioctl(dmaHeapHandle_, DMA_HEAP_IOCTL_ALLOC, &alloc);
> > +
> > +     if (ret < 0) {
> > +             LOG(RPI, Error) << "dmaHeap allocation failure for "
> > +                             << name;
> > +             return FileDescriptor();
> > +     }
> > +
> > +     ret = ::ioctl(alloc.fd, DMA_BUF_SET_NAME, name);
> > +     if (ret < 0) {
> > +             LOG(RPI, Error) << "dmaHeap naming failure for "
> > +                             << name;
> > +             ::close(alloc.fd);
> > +             return FileDescriptor();
> > +     }
> > +
> > +     return FileDescriptor(std::move(alloc.fd));
> > +}
> > +
> > +} /* namespace RPi */
> > +
> > +} /* namespace libcamera */
> > diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.h b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> > new file mode 100644
> > index 00000000..80892fd4
> > --- /dev/null
> > +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.h
> > @@ -0,0 +1,43 @@
> > +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > +/*
> > + * Copyright (C) 2020, Raspberry Pi (Trading) Limited
> > + *
> > + * dma_heaps.h - Helper class for dma-heap allocations.
> > + */
> > +#ifndef __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__
> > +#define __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__
> > +
> > +#include <libcamera/file_descriptor.h>
> > +
> > +namespace libcamera {
> > +
> > +LOG_DECLARE_CATEGORY(RPI)
> > +
> > +namespace RPi {
> > +
> > +/*
> > + * /dev/dma-heap/linux,cma is the dma-heap allocator, which allows dmaheap-cma to
> > + * only have to worry about importing.
> > + *
> > + * Annoyingly, should the cma heap size be specified on the kernel command line
> > + * instead of DT, the heap gets named "reserved" instead.
> > + */
> > +#define DMA_HEAP_CMA_NAME "/dev/dma_heap/linux,cma"
> > +#define DMA_HEAP_CMA_ALT_NAME "/dev/dma_heap/reserved"
>
> I would move this to the .cpp file.
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> Please let me know if you would like me to make those small
> modifications when applying the series, or if you would like to send a
> v3.

Happy for you to go ahead and make the modifications before
submitting.  Could you give me a quick email before merging, so I can
get Phil to merge the kernel changes at around the same time please?


>
> > +
> > +class DmaHeap
> > +{
> > +public:
> > +     DmaHeap();
> > +     ~DmaHeap();
> > +     FileDescriptor alloc(const char *name, std::size_t size);
> > +
> > +private:
> > +     int dmaHeapHandle_;
> > +};
> > +
> > +} /* namespace RPi */
> > +
> > +} /* namespace libcamera */
> > +
> > +#endif /* __LIBCAMERA_PIPELINE_RASPBERRYPI_DMA_HEAPS_H__ */
> > diff --git a/src/libcamera/pipeline/raspberrypi/meson.build b/src/libcamera/pipeline/raspberrypi/meson.build
> > index dcfe07c5..ae0aed3b 100644
> > --- a/src/libcamera/pipeline/raspberrypi/meson.build
> > +++ b/src/libcamera/pipeline/raspberrypi/meson.build
> > @@ -1,6 +1,7 @@
> >  # SPDX-License-Identifier: CC0-1.0
> >
> >  libcamera_sources += files([
> > +    'dma_heaps.cpp',
> >      'raspberrypi.cpp',
> >      'staggered_ctrl.cpp',
> >  ])
> > diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > index 7450062f..431de44d 100644
> > --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> > @@ -13,6 +13,7 @@
> >
> >  #include <libcamera/camera.h>
> >  #include <libcamera/control_ids.h>
> > +#include <libcamera/file_descriptor.h>
> >  #include <libcamera/formats.h>
> >  #include <libcamera/ipa/raspberrypi.h>
> >  #include <libcamera/logging.h>
> > @@ -30,8 +31,8 @@
> >  #include "libcamera/internal/v4l2_controls.h"
> >  #include "libcamera/internal/v4l2_videodevice.h"
> >
> > +#include "dma_heaps.h"
> >  #include "staggered_ctrl.h"
> > -#include "vcsm.h"
> >
> >  namespace libcamera {
> >
> > @@ -285,23 +286,13 @@ class RPiCameraData : public CameraData
> >  {
> >  public:
> >       RPiCameraData(PipelineHandler *pipe)
> > -             : CameraData(pipe), sensor_(nullptr), lsTable_(nullptr),
> > -               state_(State::Stopped), dropFrame_(false), ispOutputCount_(0)
> > +             : CameraData(pipe), sensor_(nullptr), state_(State::Stopped),
> > +               dropFrame_(false), ispOutputCount_(0)
> >       {
> >       }
> >
> >       ~RPiCameraData()
> >       {
> > -             /*
> > -              * Free the LS table if we have allocated one. Another
> > -              * allocation will occur in applyLS() with the appropriate
> > -              * size.
> > -              */
> > -             if (lsTable_) {
> > -                     vcsm_.free(lsTable_);
> > -                     lsTable_ = nullptr;
> > -             }
> > -
> >               /* Stop the IPA proxy thread. */
> >               if (ipa_)
> >                       ipa_->stop();
> > @@ -330,9 +321,9 @@ public:
> >       /* Buffers passed to the IPA. */
> >       std::vector<IPABuffer> ipaBuffers_;
> >
> > -     /* VCSM allocation helper. */
> > -     ::RPi::Vcsm vcsm_;
> > -     void *lsTable_;
> > +     /* DMAHEAP allocation helper. */
> > +     RPi::DmaHeap dmaHeap_;
> > +     FileDescriptor lsTable_;
> >
> >       RPi::StaggeredCtrl staggeredCtrl_;
> >       uint32_t expectedSequence_;
> > @@ -1006,27 +997,16 @@ int PipelineHandlerRPi::configureIPA(Camera *camera)
> >       entityControls.emplace(0, data->unicam_[Unicam::Image].dev()->controls());
> >       entityControls.emplace(1, data->isp_[Isp::Input].dev()->controls());
> >
> > -     /* Allocate the lens shading table via vcsm and pass to the IPA. */
> > -     if (!data->lsTable_) {
> > -             data->lsTable_ = data->vcsm_.alloc("ls_grid", MAX_LS_GRID_SIZE);
> > -             uintptr_t ptr = reinterpret_cast<uintptr_t>(data->lsTable_);
> > -
> > -             if (!data->lsTable_)
> > +     /* Allocate the lens shading table via dmaHeap and pass to the IPA. */
> > +     if (!data->lsTable_.isValid()) {
> > +             data->lsTable_ = data->dmaHeap_.alloc("ls_grid", MAX_LS_GRID_SIZE);
> > +             if (!data->lsTable_.isValid())
> >                       return -ENOMEM;
> >
> > -             /*
> > -              * The vcsm allocation will always be in the memory region
> > -              * < 32-bits to allow Videocore to access the memory.
> > -              *
> > -              * \todo Sending a pointer to the IPA is a workaround for
> > -              * vc_sm_cma not yet supporting dmabuf. This will not work with
> > -              * IPA module isolation and should be reworked when vc_sma_cma
> > -              * will permit.
> > -              */
> > +             /* Allow the IPA to mmap the LS table via the file descriptor. */
> >               IPAOperationData op;
> >               op.operation = RPI_IPA_EVENT_LS_TABLE_ALLOCATION;
> > -             op.data = { static_cast<uint32_t>(ptr & 0xffffffff),
> > -                         data->vcsm_.getVCHandle(data->lsTable_) };
> > +             op.data = { static_cast<unsigned int>(data->lsTable_.fd()) };
> >               data->ipa_->processEvent(op);
> >       }
> >
> > diff --git a/src/libcamera/pipeline/raspberrypi/vcsm.h b/src/libcamera/pipeline/raspberrypi/vcsm.h
> > deleted file mode 100644
> > index bebe86a7..00000000
> > --- a/src/libcamera/pipeline/raspberrypi/vcsm.h
> > +++ /dev/null
> > @@ -1,149 +0,0 @@
> > -/* SPDX-License-Identifier: LGPL-2.1-or-later */
> > -/*
> > - * Copyright (C) 2019, Raspberry Pi (Trading) Limited
> > - *
> > - * vcsm.h - Helper class for vcsm allocations.
> > - */
> > -#ifndef __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__
> > -#define __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__
> > -
> > -#include <iostream>
> > -#include <mutex>
> > -
> > -#include <fcntl.h>
> > -#include <linux/vc_sm_cma_ioctl.h>
> > -#include <sys/ioctl.h>
> > -#include <sys/mman.h>
> > -#include <unistd.h>
> > -
> > -namespace RPi {
> > -
> > -#define VCSM_CMA_DEVICE_NAME "/dev/vcsm-cma"
> > -
> > -class Vcsm
> > -{
> > -public:
> > -     Vcsm()
> > -     {
> > -             vcsmHandle_ = ::open(VCSM_CMA_DEVICE_NAME, O_RDWR, 0);
> > -             if (vcsmHandle_ == -1) {
> > -                     std::cerr << "Could not open vcsm device: "
> > -                               << VCSM_CMA_DEVICE_NAME;
> > -             }
> > -     }
> > -
> > -     ~Vcsm()
> > -     {
> > -             /* Free all existing allocations. */
> > -             auto it = allocMap_.begin();
> > -             while (it != allocMap_.end())
> > -                     it = remove(it->first);
> > -
> > -             if (vcsmHandle_)
> > -                     ::close(vcsmHandle_);
> > -     }
> > -
> > -     void *alloc(const char *name, unsigned int size,
> > -                 vc_sm_cma_cache_e cache = VC_SM_CMA_CACHE_NONE)
> > -     {
> > -             unsigned int pageSize = getpagesize();
> > -             void *user_ptr;
> > -             int ret;
> > -
> > -             if (!name)
> > -                     return nullptr;
> > -
> > -             /* Ask for page aligned allocation. */
> > -             size = (size + pageSize - 1) & ~(pageSize - 1);
> > -
> > -             struct vc_sm_cma_ioctl_alloc alloc;
> > -             memset(&alloc, 0, sizeof(alloc));
> > -             alloc.size = size;
> > -             alloc.num = 1;
> > -             alloc.cached = cache;
> > -             alloc.handle = 0;
> > -             memcpy(alloc.name, name, 32);
> > -
> > -             ret = ::ioctl(vcsmHandle_, VC_SM_CMA_IOCTL_MEM_ALLOC, &alloc);
> > -
> > -             if (ret < 0 || alloc.handle < 0) {
> > -                     std::cerr << "vcsm allocation failure for "
> > -                               << name << std::endl;
> > -                     return nullptr;
> > -             }
> > -
> > -             /* Map the buffer into user space. */
> > -             user_ptr = ::mmap(0, alloc.size, PROT_READ | PROT_WRITE,
> > -                               MAP_SHARED, alloc.handle, 0);
> > -
> > -             if (user_ptr == MAP_FAILED) {
> > -                     std::cerr << "vcsm mmap failure for " << name << std::endl;
> > -                     ::close(alloc.handle);
> > -                     return nullptr;
> > -             }
> > -
> > -             std::lock_guard<std::mutex> lock(lock_);
> > -             allocMap_.emplace(user_ptr, AllocInfo(alloc.handle,
> > -                                                   alloc.size, alloc.vc_handle));
> > -
> > -             return user_ptr;
> > -     }
> > -
> > -     void free(void *user_ptr)
> > -     {
> > -             std::lock_guard<std::mutex> lock(lock_);
> > -             remove(user_ptr);
> > -     }
> > -
> > -     unsigned int getVCHandle(void *user_ptr)
> > -     {
> > -             std::lock_guard<std::mutex> lock(lock_);
> > -             auto it = allocMap_.find(user_ptr);
> > -             if (it != allocMap_.end())
> > -                     return it->second.vcHandle;
> > -
> > -             return 0;
> > -     }
> > -
> > -private:
> > -     struct AllocInfo {
> > -             AllocInfo(int handle_, int size_, int vcHandle_)
> > -                     : handle(handle_), size(size_), vcHandle(vcHandle_)
> > -             {
> > -             }
> > -
> > -             int handle;
> > -             int size;
> > -             uint32_t vcHandle;
> > -     };
> > -
> > -     /* Map of all allocations that have been requested. */
> > -     using AllocMap = std::map<void *, AllocInfo>;
> > -
> > -     AllocMap::iterator remove(void *user_ptr)
> > -     {
> > -             auto it = allocMap_.find(user_ptr);
> > -             if (it != allocMap_.end()) {
> > -                     int handle = it->second.handle;
> > -                     int size = it->second.size;
> > -                     ::munmap(user_ptr, size);
> > -                     ::close(handle);
> > -                     /*
> > -                      * Remove the allocation from the map. This returns
> > -                      * an iterator to the next element.
> > -                      */
> > -                     it = allocMap_.erase(it);
> > -             }
> > -
> > -             /* Returns an iterator to the next element. */
> > -             return it;
> > -     }
> > -
> > -     AllocMap allocMap_;
> > -     int vcsmHandle_;
> > -     std::mutex lock_;
> > -};
> > -
> > -} /* namespace RPi */
> > -
> > -#endif /* __LIBCAMERA_PIPELINE_RASPBERRYPI_VCSM_H__ */
>
> --
> Regards,
>
> Laurent Pinchart

Regards,
Naush