Re: [PATCH v5 5/7] media: mediatek: vcodec: Read HW active status from syscon

[Hans Verkuil]

On 30/06/2023 17:14, Nícolas F. R. A. Prado wrote:
> Remove the requirement of a VDEC_SYS reg iospace for both MT8173 and
> MT8183. To achieve that, rely on a vdecsys syscon to be passed through
> the DT, and use it to directly read the VDEC_HW_ACTIVE bit during IRQ
> handling to check whether the HW is active. Also update the VP8 stateful
> decoder to use the syscon, if present, for writes to VDEC_SYS.
> 
> The old behavior is still present when reg-names aren't supplied, as
> to keep backward compatibility.
> 
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>
> 
> ---
> 
> Changes in v5:
> - Added explicit linux/bitfield.h include for FIELD_GET(), following
>   0day report
> 
> Changes in v4:
> - Added new helper and updated VP8 stateful decoder to use it, so the
>   syscon can also be used by mt8173
> - Made handling cleaner
> - Reworded commit
> 
> Changes in v3:
> - Switched handling of VDEC_HW_ACTIVE to use a syscon instead of the
>   'active' clock
> - Reworded commit
> - Removed changes to subdev part of driver, since they aren't used by
>   MT8183
> 
>  .../mediatek/vcodec/mtk_vcodec_dec_drv.c      | 77 ++++++++++++++++---
>  .../platform/mediatek/vcodec/mtk_vcodec_drv.h |  1 +
>  .../mediatek/vcodec/mtk_vcodec_util.c         | 15 ++++
>  .../mediatek/vcodec/mtk_vcodec_util.h         |  2 +
>  .../mediatek/vcodec/vdec/vdec_vp8_if.c        | 10 +--
>  5 files changed, 87 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec_drv.c b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec_drv.c
> index 83780d29a9cf..742b6903d030 100644
> --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec_drv.c
> +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec_drv.c
> @@ -5,13 +5,16 @@
>   *         Tiffany Lin <tiffany.lin@xxxxxxxxxxxx>
>   */
>  
> +#include <linux/bitfield.h>
>  #include <linux/slab.h>
>  #include <linux/interrupt.h>
>  #include <linux/irq.h>
> +#include <linux/mfd/syscon.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
>  #include <linux/of.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
>  #include <media/v4l2-event.h>
>  #include <media/v4l2-mem2mem.h>
>  #include <media/videobuf2-dma-contig.h>
> @@ -38,22 +41,30 @@ static int mtk_vcodec_get_hw_count(struct mtk_vcodec_dev *dev)
>  	}
>  }
>  
> +static bool mtk_vcodec_is_hw_active(struct mtk_vcodec_dev *dev)
> +{
> +	u32 cg_status;
> +
> +	if (dev->vdecsys_regmap)
> +		return !regmap_test_bits(dev->vdecsys_regmap, VDEC_HW_ACTIVE_ADDR,
> +					 VDEC_HW_ACTIVE_MASK);
> +
> +	cg_status = readl(dev->reg_base[VDEC_SYS] + VDEC_HW_ACTIVE_ADDR);
> +	return !FIELD_GET(VDEC_HW_ACTIVE_MASK, cg_status);
> +}
> +
>  static irqreturn_t mtk_vcodec_dec_irq_handler(int irq, void *priv)
>  {
>  	struct mtk_vcodec_dev *dev = priv;
>  	struct mtk_vcodec_ctx *ctx;
> -	u32 cg_status = 0;
>  	unsigned int dec_done_status = 0;
>  	void __iomem *vdec_misc_addr = dev->reg_base[VDEC_MISC] +
>  					VDEC_IRQ_CFG_REG;
>  
>  	ctx = mtk_vcodec_get_curr_ctx(dev, MTK_VDEC_CORE);
>  
> -	/* check if HW active or not */
> -	cg_status = readl(dev->reg_base[0] + VDEC_HW_ACTIVE_ADDR);
> -	if ((cg_status & VDEC_HW_ACTIVE_MASK) != 0) {
> -		mtk_v4l2_err("DEC ISR, VDEC active is not 0x0 (0x%08x)",
> -			     cg_status);
> +	if (!mtk_vcodec_is_hw_active(dev)) {
> +		mtk_v4l2_err("DEC ISR, VDEC active is not 0x0");
>  		return IRQ_HANDLED;
>  	}
>  
> @@ -82,6 +93,33 @@ static int mtk_vcodec_get_reg_bases(struct mtk_vcodec_dev *dev)
>  {
>  	struct platform_device *pdev = dev->plat_dev;
>  	int reg_num, i;
> +	struct resource *res;
> +	bool has_vdecsys_reg;
> +	static const char * const mtk_dec_reg_names[] = {
> +		"misc",
> +		"ld",
> +		"top",
> +		"cm",
> +		"ad",
> +		"av",
> +		"pp",
> +		"hwd",
> +		"hwq",
> +		"hwb",
> +		"hwg"
> +	};
> +
> +	/*
> +	 * If we have reg-names in devicetree, this means that we're on a new
> +	 * register organization, which implies that the VDEC_SYS iospace gets
> +	 * R/W through a syscon (regmap).
> +	 * Here we try to get the "misc" iostart only to check if we have reg-names
> +	 */
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "misc");
> +	if (res)
> +		has_vdecsys_reg = false;
> +	else
> +		has_vdecsys_reg = true;
>  
>  	/* Sizeof(u32) * 4 bytes for each register base. */
>  	reg_num = of_property_count_elems_of_size(pdev->dev.of_node, "reg",
> @@ -91,12 +129,29 @@ static int mtk_vcodec_get_reg_bases(struct mtk_vcodec_dev *dev)
>  		return -EINVAL;
>  	}
>  
> -	for (i = 0; i < reg_num; i++) {
> -		dev->reg_base[i] = devm_platform_ioremap_resource(pdev, i);
> -		if (IS_ERR(dev->reg_base[i]))
> -			return PTR_ERR(dev->reg_base[i]);
> +	if (has_vdecsys_reg) {
> +		for (i = 0; i < reg_num; i++) {
> +			dev->reg_base[i] = devm_platform_ioremap_resource(pdev, i);
> +			if (IS_ERR(dev->reg_base[i]))
> +				return PTR_ERR(dev->reg_base[i]);
> +
> +			mtk_v4l2_debug(2, "reg[%d] base=%p", i, dev->reg_base[i]);
> +		}
> +	} else {
> +		for (i = 0; i < reg_num; i++) {
> +			dev->reg_base[i+1] = devm_platform_ioremap_resource_byname(pdev, mtk_dec_reg_names[i]);
> +			if (IS_ERR(dev->reg_base[i+1]))
> +				return PTR_ERR(dev->reg_base[i+1]);
>  
> -		mtk_v4l2_debug(2, "reg[%d] base=%p", i, dev->reg_base[i]);
> +			mtk_v4l2_debug(2, "reg[%d] base=%p", i+1, dev->reg_base[i+1]);
> +		}
> +
> +		dev->vdecsys_regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
> +								      "mediatek,vdecsys");
> +		if (IS_ERR(dev->vdecsys_regmap)) {
> +			dev_err(&pdev->dev, "Missing mediatek,vdecsys property");
> +			return PTR_ERR(dev->vdecsys_regmap);
> +		}
>  	}
>  
>  	return 0;
> diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_drv.h b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_drv.h
> index f17d67e781c9..0b430936f67d 100644
> --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_drv.h
> +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_drv.h
> @@ -489,6 +489,7 @@ struct mtk_vcodec_dev {
>  	void __iomem *reg_base[NUM_MAX_VCODEC_REG_BASE];
>  	const struct mtk_vcodec_dec_pdata *vdec_pdata;
>  	const struct mtk_vcodec_enc_pdata *venc_pdata;
> +	struct regmap *vdecsys_regmap;

You forgot to add the kerneldoc documentation for this new field.

If you just give me the documentation of this field then I can modify the
patch. That's actually easier for me.

Regards,

	Hans