[1/2] libcamera: software_isp: Add AllocCmaDmaBuffers constructor flag
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Message ID 20261025155233.113989-1-johannes.goede@oss.qualcomm.com
State New
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Series
  • [1/2] libcamera: software_isp: Add AllocCmaDmaBuffers constructor flag
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Commit Message

Hans de Goede Oct. 25, 2026, 3:52 p.m. UTC 
Allocating DMA buffers from the CMA pool is not necessary on platforms
where the expected consumers (GPU, video-encoder) support non contiguous
memory and allocating the buffers from the limited CMA pool may cause
starvation of that pool for other processes which do actually require CMA.

Add a new "SoftwareIspFlags flags" parameter to the SoftwareIsp()
constructor, implement a single AllocCmaDmaBuffers flag for now and only
request CmaHeap backed DmaBuffers when this flag is set.

The only SoftwareIsp() constructor caller is modified to pass the new flag
so this patch does not cause any behavior change.

Signed-off-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
---
 .../internal/software_isp/software_isp.h      | 13 +++++++++---
 src/libcamera/pipeline/simple/simple.cpp      |  4 +++-
 src/libcamera/software_isp/software_isp.cpp   | 21 ++++++++++++-------
 3 files changed, 27 insertions(+), 11 deletions(-)

Patch
diff mbox series 

diff --git a/include/libcamera/internal/software_isp/software_isp.h b/include/libcamera/internal/software_isp/software_isp.h
index b64910637..7d5eab3e3 100644
--- a/include/libcamera/internal/software_isp/software_isp.h
+++ b/include/libcamera/internal/software_isp/software_isp.h
@@ -17,6 +17,7 @@ 
 #include <vector>
 
 #include <libcamera/base/class.h>
+#include <libcamera/base/flags.h>
 #include <libcamera/base/log.h>
 #include <libcamera/base/object.h>
 #include <libcamera/base/signal.h>
@@ -29,7 +30,6 @@ 
 #include <libcamera/ipa/softisp_ipa_proxy.h>
 
 #include "libcamera/internal/camera_sensor.h"
-#include "libcamera/internal/dma_buf_allocator.h"
 #include "libcamera/internal/pipeline_handler.h"
 #include "libcamera/internal/shared_mem_object.h"
 #include "libcamera/internal/software_isp/debayer_params.h"
@@ -37,6 +37,7 @@ 
 namespace libcamera {
 
 class Debayer;
+class DmaBufAllocator;
 class FrameBuffer;
 class PixelFormat;
 class Stream;
@@ -47,8 +48,14 @@  LOG_DECLARE_CATEGORY(SoftwareIsp)
 class SoftwareIsp : public Object
 {
 public:
+	enum class SoftwareIspFlag {
+		AllocCmaDmaBuffers = 1 << 0,
+	};
+
+	using SoftwareIspFlags = Flags<SoftwareIspFlag>;
+
 	SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor,
-		    ControlInfoMap *ipaControls);
+		    SoftwareIspFlags flags, ControlInfoMap *ipaControls);
 	~SoftwareIsp();
 
 	int loadConfiguration([[maybe_unused]] const std::string &filename) { return 0; }
@@ -99,7 +106,7 @@  private:
 	Thread ispWorkerThread_;
 	SharedMemObject<DebayerParams> sharedParams_;
 	DebayerParams debayerParams_;
-	DmaBufAllocator dmaHeap_;
+	DmaBufAllocator *dmaHeap_;
 	bool ccmEnabled_;
 	bool lscEnabled_;
 
diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
index 35c29ceca..caab09b00 100644
--- a/src/libcamera/pipeline/simple/simple.cpp
+++ b/src/libcamera/pipeline/simple/simple.cpp
@@ -615,7 +615,9 @@  int SimpleCameraData::init()
 	 * Instantiate Soft ISP if this is enabled for the given driver and no converter is used.
 	 */
 	if (!converter_ && pipe->swIspEnabled()) {
-		swIsp_ = std::make_unique<SoftwareIsp>(pipe, sensor_.get(), &controlInfo_);
+		swIsp_ = std::make_unique<SoftwareIsp>(pipe, sensor_.get(),
+						       SoftwareIsp::SoftwareIspFlag::AllocCmaDmaBuffers,
+						       &controlInfo_);
 		if (!swIsp_->isValid()) {
 			LOG(SimplePipeline, Warning)
 				<< "Failed to create software ISP, disabling software debayering";
diff --git a/src/libcamera/software_isp/software_isp.cpp b/src/libcamera/software_isp/software_isp.cpp
index 627625b4f..1ef4211ca 100644
--- a/src/libcamera/software_isp/software_isp.cpp
+++ b/src/libcamera/software_isp/software_isp.cpp
@@ -24,6 +24,7 @@ 
 #include <libcamera/stream.h>
 
 #include "libcamera/internal/bayer_format.h"
+#include "libcamera/internal/dma_buf_allocator.h"
 #include "libcamera/internal/framebuffer.h"
 #include "libcamera/internal/software_isp/debayer_params.h"
 
@@ -76,16 +77,22 @@  LOG_DEFINE_CATEGORY(SoftwareIsp)
  * \brief Constructs SoftwareIsp object
  * \param[in] pipe The pipeline handler in use
  * \param[in] sensor Pointer to the CameraSensor instance owned by the pipeline handler
+ * \param[in] flags SoftwareIspFlags
  * \param[out] ipaControls The IPA controls to update
  */
 SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor,
-			 ControlInfoMap *ipaControls)
-	: ispWorkerThread_("SWIspWorker"),
-	  dmaHeap_(DmaBufAllocator::DmaBufAllocatorFlag::CmaHeap |
-		   DmaBufAllocator::DmaBufAllocatorFlag::SystemHeap |
-		   DmaBufAllocator::DmaBufAllocatorFlag::UDmaBuf)
+			 SoftwareIspFlags flags, ControlInfoMap *ipaControls)
+	: ispWorkerThread_("SWIspWorker")
 {
-	if (!dmaHeap_.isValid()) {
+	DmaBufAllocator::DmaBufAllocatorFlags types =
+		DmaBufAllocator::DmaBufAllocatorFlag::SystemHeap |
+		DmaBufAllocator::DmaBufAllocatorFlag::UDmaBuf;
+
+	if (flags & SoftwareIsp::SoftwareIspFlag::AllocCmaDmaBuffers)
+		types |= DmaBufAllocator::DmaBufAllocatorFlag::CmaHeap;
+
+	dmaHeap_ = new DmaBufAllocator(types);
+	if (!dmaHeap_->isValid()) {
 		LOG(SoftwareIsp, Error) << "Failed to create DmaBufAllocator object";
 		return;
 	}
@@ -323,7 +330,7 @@  int SoftwareIsp::exportBuffers(const Stream *stream, unsigned int count,
 	if (stream == nullptr)
 		return -EINVAL;
 
-	return dmaHeap_.exportBuffers(count, { debayer_->frameSize() }, buffers);
+	return dmaHeap_->exportBuffers(count, { debayer_->frameSize() }, buffers);
 }
 
 /**