[PATCH v4 09/15] media: rkvdec: Add RCB and SRAM support
Nicolas Dufresne
nicolas.dufresne at collabora.com
Wed Dec 10 12:32:47 PST 2025
Le mercredi 22 octobre 2025 à 13:45 -0400, Detlev Casanova a écrit :
> The RCB (Rows and Cols Buffers) are a set of buffers used by other
> variations of the decoder to store temporary data.
>
> Those variation come with a dedicated SRAM area used to store those
> buffers for better performances.
>
> The buffer sizes are either the width or height of the frame being
> decoded multiplied by a documented factor and can be stored either
> in SRAM or RAM.
> A fallback to RAM is provided if the SRAM is full (e.g.: multiple
> streams are being decoded at the same time).
>
> To manage the different kind of allocation, an enum is added to the
> rkvdec_aux_buf struct to specify how the buffer was allocated, and
> so, how to free it.
>
> This commit is in preparation of other variants support.
>
> Tested-by: Diederik de Haas <didi.debian at cknow.org> # Rock 5B
> Signed-off-by: Detlev Casanova <detlev.casanova at collabora.com>
> ---
> .../media/platform/rockchip/rkvdec/Makefile | 1 +
> .../platform/rockchip/rkvdec/rkvdec-rcb.c | 173 ++++++++++++++++++
> .../platform/rockchip/rkvdec/rkvdec-rcb.h | 29 +++
> .../media/platform/rockchip/rkvdec/rkvdec.c | 27 ++-
> .../media/platform/rockchip/rkvdec/rkvdec.h | 13 ++
> 5 files changed, 241 insertions(+), 2 deletions(-)
> create mode 100644 drivers/media/platform/rockchip/rkvdec/rkvdec-rcb.c
> create mode 100644 drivers/media/platform/rockchip/rkvdec/rkvdec-rcb.h
>
> diff --git a/drivers/media/platform/rockchip/rkvdec/Makefile b/drivers/media/platform/rockchip/rkvdec/Makefile
> index 1b4bc44be23e..3d75103e536d 100644
> --- a/drivers/media/platform/rockchip/rkvdec/Makefile
> +++ b/drivers/media/platform/rockchip/rkvdec/Makefile
> @@ -7,4 +7,5 @@ rockchip-vdec-y += \
> rkvdec-h264-common.o \
> rkvdec-hevc.o \
> rkvdec-hevc-common.o \
> + rkvdec-rcb.o \
> rkvdec-vp9.o
> diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec-rcb.c b/drivers/media/platform/rockchip/rkvdec/rkvdec-rcb.c
> new file mode 100644
> index 000000000000..5a4959c239e3
> --- /dev/null
> +++ b/drivers/media/platform/rockchip/rkvdec/rkvdec-rcb.c
> @@ -0,0 +1,173 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Rockchip video decoder Rows and Cols Buffers manager
> + *
> + * Copyright (C) 2025 Collabora, Ltd.
> + * Detlev Casanova <detlev.casanova at collabora.com>
> + */
> +
> +#include "rkvdec.h"
> +#include "rkvdec-rcb.h"
> +
> +#include <linux/types.h>
> +#include <linux/iommu.h>
> +#include <linux/genalloc.h>
> +
> +struct rkvdec_rcb_config {
> + struct rkvdec_aux_buf *rcb_bufs;
> + size_t rcb_count;
> +};
> +
> +static size_t rkvdec_rcb_size(const struct rcb_size_info *size_info,
> + unsigned int width, unsigned int height)
> +{
> + return size_info->multiplier * (size_info->axis == PIC_HEIGHT ? height : width);
> +}
> +
> +dma_addr_t rkvdec_rcb_buf_dma_addr(struct rkvdec_ctx *ctx, int id)
> +{
> + return ctx->rcb_config->rcb_bufs[id].dma;
> +}
> +
> +size_t rkvdec_rcb_buf_size(struct rkvdec_ctx *ctx, int id)
> +{
> + return ctx->rcb_config->rcb_bufs[id].size;
> +}
> +
> +int rkvdec_rcb_buf_count(struct rkvdec_ctx *ctx)
> +{
> + return ctx->rcb_config->rcb_count;
> +}
> +
> +void rkvdec_free_rcb(struct rkvdec_ctx *ctx)
> +{
> + struct rkvdec_dev *dev = ctx->dev;
> + struct rkvdec_rcb_config *cfg = ctx->rcb_config;
> + unsigned long virt_addr;
> + int i;
> +
> + if (!cfg)
> + return;
> +
> + for (i = 0; i < cfg->rcb_count; i++) {
> + size_t rcb_size = cfg->rcb_bufs[i].size;
> +
> + if (!cfg->rcb_bufs[i].cpu)
> + continue;
> +
> + switch (cfg->rcb_bufs[i].type) {
> + case RKVDEC_ALLOC_SRAM:
> + virt_addr = (unsigned long)cfg->rcb_bufs[i].cpu;
> +
> + if (dev->iommu_domain)
> + iommu_unmap(dev->iommu_domain, virt_addr, rcb_size);
> + gen_pool_free(dev->sram_pool, virt_addr, rcb_size);
> + break;
> + case RKVDEC_ALLOC_DMA:
> + dma_free_coherent(dev->dev,
> + rcb_size,
> + cfg->rcb_bufs[i].cpu,
> + cfg->rcb_bufs[i].dma);
> + break;
> + }
> + }
> +
> + if (cfg->rcb_bufs)
> + devm_kfree(dev->dev, cfg->rcb_bufs);
> +
> + devm_kfree(dev->dev, cfg);
> +}
> +
> +int rkvdec_allocate_rcb(struct rkvdec_ctx *ctx,
> + const struct rcb_size_info *size_info,
> + size_t rcb_count)
> +{
> + int ret, i;
> + u32 width, height;
> + struct rkvdec_dev *rkvdec = ctx->dev;
> + struct rkvdec_rcb_config *cfg;
> +
> + ctx->rcb_config = devm_kzalloc(rkvdec->dev, sizeof(*ctx->rcb_config), GFP_KERNEL);
> + if (!ctx->rcb_config)
> + return -ENOMEM;
> +
> + cfg = ctx->rcb_config;
> +
> + cfg->rcb_bufs = devm_kzalloc(rkvdec->dev, sizeof(*cfg->rcb_bufs) * rcb_count, GFP_KERNEL);
> + if (!cfg->rcb_bufs) {
> + ret = -ENOMEM;
> + goto err_alloc;
> + }
> +
> + width = ctx->decoded_fmt.fmt.pix_mp.width;
> + height = ctx->decoded_fmt.fmt.pix_mp.height;
> +
> + for (i = 0; i < rcb_count; i++) {
> + void *cpu = NULL;
> + dma_addr_t dma;
> + size_t rcb_size = rkvdec_rcb_size(&size_info[i], width, height);
> + enum rkvdec_alloc_type alloc_type = RKVDEC_ALLOC_SRAM;
> +
> + /* Try allocating an SRAM buffer */
> + if (ctx->dev->sram_pool) {
> + if (rkvdec->iommu_domain)
> + rcb_size = ALIGN(rcb_size, 0x1000);
> +
> + cpu = gen_pool_dma_zalloc_align(ctx->dev->sram_pool,
> + rcb_size,
> + &dma,
> + 0x1000);
> + }
> +
> + /* If an IOMMU is used, map the SRAM address through it */
> + if (cpu && rkvdec->iommu_domain) {
> + unsigned long virt_addr = (unsigned long)cpu;
> + phys_addr_t phys_addr = dma;
> +
> + ret = iommu_map(rkvdec->iommu_domain, virt_addr, phys_addr,
> + rcb_size, IOMMU_READ | IOMMU_WRITE, 0);
> + if (ret) {
> + gen_pool_free(ctx->dev->sram_pool,
> + (unsigned long)cpu,
> + rcb_size);
> + cpu = NULL;
> + goto ram_fallback;
> + }
> +
> + /*
> + * The registers will be configured with the virtual
> + * address so that it goes through the IOMMU
> + */
> + dma = virt_addr;
> + }
> +
> +ram_fallback:
> + /* Fallback to RAM */
> + if (!cpu) {
> + cpu = dma_alloc_coherent(ctx->dev->dev,
Some dev_dbg would be nice, looks like its going to run slower, so having a way
to detect it during integration would be helpful. Also, something to be checked
on RK3576, RK3566 and RK3568 were users seems to report that it runs fine, but
under perform.
> + rcb_size,
> + &dma,
> + GFP_KERNEL);
> + alloc_type = RKVDEC_ALLOC_DMA;
> + }
> +
> + if (!cpu) {
> + ret = -ENOMEM;
> + goto err_alloc;
> + }
> +
> + cfg->rcb_bufs[i].cpu = cpu;
> + cfg->rcb_bufs[i].dma = dma;
> + cfg->rcb_bufs[i].size = rcb_size;
> + cfg->rcb_bufs[i].type = alloc_type;
> +
> + cfg->rcb_count += 1;
> + }
> +
> + return 0;
> +
> +err_alloc:
> + rkvdec_free_rcb(ctx);
> +
> + return ret;
> +}
> diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec-rcb.h b/drivers/media/platform/rockchip/rkvdec/rkvdec-rcb.h
> new file mode 100644
> index 000000000000..30e8002555c8
> --- /dev/null
> +++ b/drivers/media/platform/rockchip/rkvdec/rkvdec-rcb.h
> @@ -0,0 +1,29 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Rockchip video decoder Rows and Cols Buffers manager
> + *
> + * Copyright (C) 2025 Collabora, Ltd.
> + * Detlev Casanova <detlev.casanova at collabora.com>
> + */
> +
> +#include <linux/types.h>
> +
> +struct rkvdec_ctx;
> +
> +enum rcb_axis {
> + PIC_WIDTH = 0,
> + PIC_HEIGHT = 1
> +};
> +
> +struct rcb_size_info {
> + u8 multiplier;
> + enum rcb_axis axis;
> +};
> +
> +int rkvdec_allocate_rcb(struct rkvdec_ctx *ctx,
> + const struct rcb_size_info *size_info,
> + size_t rcb_count);
> +dma_addr_t rkvdec_rcb_buf_dma_addr(struct rkvdec_ctx *ctx, int id);
> +size_t rkvdec_rcb_buf_size(struct rkvdec_ctx *ctx, int id);
> +int rkvdec_rcb_buf_count(struct rkvdec_ctx *ctx);
> +void rkvdec_free_rcb(struct rkvdec_ctx *ctx);
> diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec.c b/drivers/media/platform/rockchip/rkvdec/rkvdec.c
> index a7af1e3fdebd..5dd486edd64d 100644
> --- a/drivers/media/platform/rockchip/rkvdec/rkvdec.c
> +++ b/drivers/media/platform/rockchip/rkvdec/rkvdec.c
> @@ -10,6 +10,7 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/genalloc.h>
> #include <linux/interrupt.h>
> #include <linux/iommu.h>
> #include <linux/module.h>
> @@ -28,6 +29,7 @@
>
> #include "rkvdec.h"
> #include "rkvdec-regs.h"
> +#include "rkvdec-rcb.h"
>
> static bool rkvdec_image_fmt_match(enum rkvdec_image_fmt fmt1,
> enum rkvdec_image_fmt fmt2)
> @@ -771,6 +773,7 @@ static int rkvdec_start_streaming(struct vb2_queue *q, unsigned int count)
> {
> struct rkvdec_ctx *ctx = vb2_get_drv_priv(q);
> const struct rkvdec_coded_fmt_desc *desc;
> + const struct rkvdec_config *cfg = ctx->dev->variant->config;
> int ret;
>
> if (V4L2_TYPE_IS_CAPTURE(q->type))
> @@ -780,13 +783,22 @@ static int rkvdec_start_streaming(struct vb2_queue *q, unsigned int count)
> if (WARN_ON(!desc))
> return -EINVAL;
>
> + ret = rkvdec_allocate_rcb(ctx, cfg->rcb_size_info, cfg->rcb_num);
Shouldn't this be conditional ? I read your commit message as only new variants
needs that.
Nicolas
> + if (ret)
> + return ret;
> +
> if (desc->ops->start) {
> ret = desc->ops->start(ctx);
> if (ret)
> - return ret;
> + goto err_ops_start;
> }
>
> return 0;
> +
> +err_ops_start:
> + rkvdec_free_rcb(ctx);
> +
> + return ret;
> }
>
> static void rkvdec_queue_cleanup(struct vb2_queue *vq, u32 state)
> @@ -822,6 +834,8 @@ static void rkvdec_stop_streaming(struct vb2_queue *q)
>
> if (desc->ops->stop)
> desc->ops->stop(ctx);
> +
> + rkvdec_free_rcb(ctx);
> }
>
> rkvdec_queue_cleanup(q, VB2_BUF_STATE_ERROR);
> @@ -1350,6 +1364,10 @@ static int rkvdec_probe(struct platform_device *pdev)
> return ret;
> }
>
> + rkvdec->sram_pool = of_gen_pool_get(pdev->dev.of_node, "sram", 0);
> + if (!rkvdec->sram_pool && rkvdec->variant->config->rcb_num > 0)
> + dev_info(&pdev->dev, "No sram node, RCB will be stored in RAM\n");
> +
> pm_runtime_set_autosuspend_delay(&pdev->dev, 100);
> pm_runtime_use_autosuspend(&pdev->dev);
> pm_runtime_enable(&pdev->dev);
> @@ -1358,7 +1376,8 @@ static int rkvdec_probe(struct platform_device *pdev)
> if (ret)
> goto err_disable_runtime_pm;
>
> - if (iommu_get_domain_for_dev(&pdev->dev)) {
> + rkvdec->iommu_domain = iommu_get_domain_for_dev(&pdev->dev);
> + if (rkvdec->iommu_domain) {
> rkvdec->empty_domain = iommu_paging_domain_alloc(rkvdec->dev);
>
> if (IS_ERR(rkvdec->empty_domain)) {
> @@ -1372,6 +1391,10 @@ static int rkvdec_probe(struct platform_device *pdev)
> err_disable_runtime_pm:
> pm_runtime_dont_use_autosuspend(&pdev->dev);
> pm_runtime_disable(&pdev->dev);
> +
> + if (rkvdec->sram_pool)
> + gen_pool_destroy(rkvdec->sram_pool);
> +
> return ret;
> }
>
> diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec.h b/drivers/media/platform/rockchip/rkvdec/rkvdec.h
> index 3b1cc511412e..74f71542e031 100644
> --- a/drivers/media/platform/rockchip/rkvdec/rkvdec.h
> +++ b/drivers/media/platform/rockchip/rkvdec/rkvdec.h
> @@ -19,6 +19,7 @@
> #include <media/v4l2-ctrls.h>
> #include <media/v4l2-device.h>
> #include <media/v4l2-ioctl.h>
> +#include <media/v4l2-mem2mem.h>
> #include <media/videobuf2-core.h>
> #include <media/videobuf2-dma-contig.h>
>
> @@ -29,6 +30,7 @@
> #define RKVDEC_QUIRK_DISABLE_QOS BIT(0)
>
> struct rkvdec_ctx;
> +struct rkvdec_rcb_config;
>
> struct rkvdec_ctrl_desc {
> struct v4l2_ctrl_config cfg;
> @@ -117,6 +119,8 @@ struct rkvdec_coded_fmt_desc {
> struct rkvdec_config {
> const struct rkvdec_coded_fmt_desc *coded_fmts;
> size_t coded_fmts_num;
> + const struct rcb_size_info *rcb_size_info;
> + size_t rcb_num;
> };
>
> struct rkvdec_dev {
> @@ -129,6 +133,8 @@ struct rkvdec_dev {
> void __iomem *regs;
> struct mutex vdev_lock; /* serializes ioctls */
> struct delayed_work watchdog_work;
> + struct gen_pool *sram_pool;
> + struct iommu_domain *iommu_domain;
> struct iommu_domain *empty_domain;
> const struct rkvdec_variant *variant;
> };
> @@ -141,6 +147,7 @@ struct rkvdec_ctx {
> struct v4l2_ctrl_handler ctrl_hdl;
> struct rkvdec_dev *dev;
> enum rkvdec_image_fmt image_fmt;
> + struct rkvdec_rcb_config *rcb_config;
> void *priv;
> };
>
> @@ -149,10 +156,16 @@ static inline struct rkvdec_ctx *file_to_rkvdec_ctx(struct file *filp)
> return container_of(file_to_v4l2_fh(filp), struct rkvdec_ctx, fh);
> }
>
> +enum rkvdec_alloc_type {
> + RKVDEC_ALLOC_DMA = 0,
> + RKVDEC_ALLOC_SRAM = 1,
> +};
> +
> struct rkvdec_aux_buf {
> void *cpu;
> dma_addr_t dma;
> size_t size;
> + enum rkvdec_alloc_type type;
> };
>
> void rkvdec_run_preamble(struct rkvdec_ctx *ctx, struct rkvdec_run *run);
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