On Fri Oct 17 17:58:38 2025 +0200, Marek Vasut wrote:
> Add support for optional allocation of bitstream descriptors from SRAM
> instead of DRAM. In case the encoder/decoder DT node contains 'sram'
> property which points to 'mmio-sram', the driver will attempt to use
> the SRAM instead of DRAM for descriptor allocation, which might improve
> performance.
>
> This also helps on i.MX95 rev.A with sporadic SLOTn_STATUS IMG_RD_ERR
> bit 11 being triggered during JPEG encoding, which is caused by a bug
> fixed on later SoC revisions. The bug occurs less often when using the
> SRAM for descriptor storage, but is not entirely mitigated. The following
> pipeline triggers the bug when descriptors get allocated from DRAM, the
> pipeline often hangs after a few seconds and the encoder driver indicates
> "timeout, cancel it":
>
> gst-launch-1.0 videotestsrc ! \
> video/x-raw,width=256,height=256,format=YUY2 ! \
> queue ! v4l2jpegenc ! queue ! fakesink
>
> Tested-by: Ming Qian <[email protected]>
> Signed-off-by: Marek Vasut <[email protected]>
> Signed-off-by: Nicolas Dufresne <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Patch committed.
Thanks,
Hans Verkuil
drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c | 70 +++++++++++++++-----------
drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h | 1 +
2 files changed, 43 insertions(+), 28 deletions(-)
---
diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
index 9e4a813489c0..b558700d1d96 100644
--- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
+++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c
@@ -44,6 +44,7 @@
#include <linux/module.h>
#include <linux/io.h>
#include <linux/clk.h>
+#include <linux/genalloc.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
@@ -783,32 +784,40 @@ static int mxc_get_free_slot(struct mxc_jpeg_slot_data
*slot_data)
return -1;
}
+static void mxc_jpeg_free(struct mxc_jpeg_dev *jpeg, size_t size, void *addr,
dma_addr_t handle)
+{
+ if (jpeg->sram_pool)
+ gen_pool_free(jpeg->sram_pool, (unsigned long)addr, size);
+ else
+ dma_free_coherent(jpeg->dev, size, addr, handle);
+}
+
static void mxc_jpeg_free_slot_data(struct mxc_jpeg_dev *jpeg)
{
/* free descriptor for decoding/encoding phase */
- dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
- jpeg->slot_data.desc,
- jpeg->slot_data.desc_handle);
+ mxc_jpeg_free(jpeg, sizeof(struct mxc_jpeg_desc),
+ jpeg->slot_data.desc,
+ jpeg->slot_data.desc_handle);
jpeg->slot_data.desc = NULL;
jpeg->slot_data.desc_handle = 0;
/* free descriptor for encoder configuration phase / decoder DHT */
- dma_free_coherent(jpeg->dev, sizeof(struct mxc_jpeg_desc),
- jpeg->slot_data.cfg_desc,
- jpeg->slot_data.cfg_desc_handle);
+ mxc_jpeg_free(jpeg, sizeof(struct mxc_jpeg_desc),
+ jpeg->slot_data.cfg_desc,
+ jpeg->slot_data.cfg_desc_handle);
jpeg->slot_data.cfg_desc_handle = 0;
jpeg->slot_data.cfg_desc = NULL;
/* free configuration stream */
- dma_free_coherent(jpeg->dev, MXC_JPEG_MAX_CFG_STREAM,
- jpeg->slot_data.cfg_stream_vaddr,
- jpeg->slot_data.cfg_stream_handle);
+ mxc_jpeg_free(jpeg, MXC_JPEG_MAX_CFG_STREAM,
+ jpeg->slot_data.cfg_stream_vaddr,
+ jpeg->slot_data.cfg_stream_handle);
jpeg->slot_data.cfg_stream_vaddr = NULL;
jpeg->slot_data.cfg_stream_handle = 0;
- dma_free_coherent(jpeg->dev, jpeg->slot_data.cfg_dec_size,
- jpeg->slot_data.cfg_dec_vaddr,
- jpeg->slot_data.cfg_dec_daddr);
+ mxc_jpeg_free(jpeg, jpeg->slot_data.cfg_dec_size,
+ jpeg->slot_data.cfg_dec_vaddr,
+ jpeg->slot_data.cfg_dec_daddr);
jpeg->slot_data.cfg_dec_size = 0;
jpeg->slot_data.cfg_dec_vaddr = NULL;
jpeg->slot_data.cfg_dec_daddr = 0;
@@ -816,6 +825,15 @@ static void mxc_jpeg_free_slot_data(struct mxc_jpeg_dev
*jpeg)
jpeg->slot_data.used = false;
}
+static struct mxc_jpeg_desc *mxc_jpeg_alloc(struct mxc_jpeg_dev *jpeg, size_t
size,
+ dma_addr_t *handle)
+{
+ if (jpeg->sram_pool)
+ return gen_pool_dma_zalloc(jpeg->sram_pool, size, handle);
+ else
+ return dma_alloc_coherent(jpeg->dev, size, handle, GFP_ATOMIC);
+}
+
static bool mxc_jpeg_alloc_slot_data(struct mxc_jpeg_dev *jpeg)
{
struct mxc_jpeg_desc *desc;
@@ -826,37 +844,29 @@ static bool mxc_jpeg_alloc_slot_data(struct mxc_jpeg_dev
*jpeg)
goto skip_alloc; /* already allocated, reuse it */
/* allocate descriptor for decoding/encoding phase */
- desc = dma_alloc_coherent(jpeg->dev,
- sizeof(struct mxc_jpeg_desc),
- &jpeg->slot_data.desc_handle,
- GFP_ATOMIC);
+ desc = mxc_jpeg_alloc(jpeg, sizeof(struct mxc_jpeg_desc),
+ &jpeg->slot_data.desc_handle);
if (!desc)
goto err;
jpeg->slot_data.desc = desc;
/* allocate descriptor for configuration phase (encoder only) */
- cfg_desc = dma_alloc_coherent(jpeg->dev,
- sizeof(struct mxc_jpeg_desc),
- &jpeg->slot_data.cfg_desc_handle,
- GFP_ATOMIC);
+ cfg_desc = mxc_jpeg_alloc(jpeg, sizeof(struct mxc_jpeg_desc),
+ &jpeg->slot_data.cfg_desc_handle);
if (!cfg_desc)
goto err;
jpeg->slot_data.cfg_desc = cfg_desc;
/* allocate configuration stream */
- cfg_stm = dma_alloc_coherent(jpeg->dev,
- MXC_JPEG_MAX_CFG_STREAM,
- &jpeg->slot_data.cfg_stream_handle,
- GFP_ATOMIC);
+ cfg_stm = mxc_jpeg_alloc(jpeg, MXC_JPEG_MAX_CFG_STREAM,
+ &jpeg->slot_data.cfg_stream_handle);
if (!cfg_stm)
goto err;
jpeg->slot_data.cfg_stream_vaddr = cfg_stm;
jpeg->slot_data.cfg_dec_size = MXC_JPEG_PATTERN_WIDTH *
MXC_JPEG_PATTERN_HEIGHT * 2;
- jpeg->slot_data.cfg_dec_vaddr = dma_alloc_coherent(jpeg->dev,
-
jpeg->slot_data.cfg_dec_size,
-
&jpeg->slot_data.cfg_dec_daddr,
- GFP_ATOMIC);
+ jpeg->slot_data.cfg_dec_vaddr = mxc_jpeg_alloc(jpeg,
jpeg->slot_data.cfg_dec_size,
+
&jpeg->slot_data.cfg_dec_daddr);
if (!jpeg->slot_data.cfg_dec_vaddr)
goto err;
@@ -2884,6 +2894,10 @@ static int mxc_jpeg_probe(struct platform_device *pdev)
jpeg->dev = dev;
jpeg->mode = mode;
+ /* SRAM pool is optional */
+ jpeg->sram_pool = of_gen_pool_get(pdev->dev.of_node, "sram", 0);
+ dev_info(dev, "Using DMA descriptor pool in %cRAM\n", jpeg->sram_pool ?
'S' : 'D');
+
/* Get clocks */
ret = devm_clk_bulk_get_all(&pdev->dev, &jpeg->clks);
if (ret < 0) {
diff --git a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h
b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h
index 44e46face6d1..9c5b4f053ded 100644
--- a/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h
+++ b/drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.h
@@ -141,6 +141,7 @@ struct mxc_jpeg_dev {
int num_domains;
struct device **pd_dev;
struct device_link **pd_link;
+ struct gen_pool *sram_pool;
};
/**
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