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Message-ID: <b5fd2dff-14a5-3ad8-9698-d1a50f4516fa@xs4all.nl>
Date:   Tue, 25 Jul 2023 12:15:03 +0200
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Subject: Re: [PATCH v5 5/7] media: mediatek: vcodec: Read HW active status
 from syscon
Content-Language: en-US
To:     =?UTF-8?B?TsOtY29sYXMgRi4gUi4gQS4gUHJhZG8=?= 
        <nfraprado@collabora.com>
Cc:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>, kernel@collabora.com,
        Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Tiffany Lin <tiffany.lin@mediatek.com>,
        Yunfei Dong <yunfei.dong@mediatek.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, linux-mediatek@lists.infradead.org,
        Matthias Brugger <matthias.bgg@gmail.com>
References: <20230630151436.155586-1-nfraprado@collabora.com>
 <20230630151436.155586-6-nfraprado@collabora.com>
From:   Hans Verkuil <hverkuil-cisco@xs4all.nl>
In-Reply-To: <20230630151436.155586-6-nfraprado@collabora.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hi Nicolas,

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@collabora.com>
> 
> ---
> 
> 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(-)

This patch introduced this new smatch error:

drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec_drv.c:143 mtk_vcodec_get_reg_bases() error: buffer overflow 'mtk_dec_reg_names' 11 <= 11

I think it is due to:

if (reg_num <= 0 || reg_num > NUM_MAX_VDEC_REG_BASE) {

in mtk_vcodec_get_reg_bases(): the '>' should probably be '>='.

Can you post a follow-up patch fixing this?

Regards,

	Hans

> 
> 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@mediatek.com>
>   */
>  
> +#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;
>  
>  	struct mtk_vcodec_fw *fw_handler;
>  
> diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_util.c b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_util.c
> index f214e6f67005..8aaa5eb45444 100644
> --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_util.c
> +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_util.c
> @@ -8,6 +8,7 @@
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> +#include <linux/regmap.h>
>  
>  #include "mtk_vcodec_dec_hw.h"
>  #include "mtk_vcodec_drv.h"
> @@ -34,6 +35,20 @@ void __iomem *mtk_vcodec_get_reg_addr(struct mtk_vcodec_ctx *data,
>  }
>  EXPORT_SYMBOL(mtk_vcodec_get_reg_addr);
>  
> +int mtk_vcodec_write_vdecsys(struct mtk_vcodec_ctx *ctx, unsigned int reg,
> +			     unsigned int val)
> +{
> +	struct mtk_vcodec_dev *dev = ctx->dev;
> +
> +	if (dev->vdecsys_regmap)
> +		return regmap_write(dev->vdecsys_regmap, reg, val);
> +
> +	writel(val, dev->reg_base[VDEC_SYS] + reg);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(mtk_vcodec_write_vdecsys);
> +
>  int mtk_vcodec_mem_alloc(struct mtk_vcodec_ctx *data,
>  			struct mtk_vcodec_mem *mem)
>  {
> diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_util.h b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_util.h
> index 88d389b65f13..c8bb4fc5153f 100644
> --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_util.h
> +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_util.h
> @@ -70,6 +70,8 @@ extern int mtk_vcodec_dbg;
>  
>  void __iomem *mtk_vcodec_get_reg_addr(struct mtk_vcodec_ctx *data,
>  				unsigned int reg_idx);
> +int mtk_vcodec_write_vdecsys(struct mtk_vcodec_ctx *ctx, unsigned int reg,
> +			     unsigned int val);
>  int mtk_vcodec_mem_alloc(struct mtk_vcodec_ctx *data,
>  				struct mtk_vcodec_mem *mem);
>  void mtk_vcodec_mem_free(struct mtk_vcodec_ctx *data,
> diff --git a/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp8_if.c b/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp8_if.c
> index 88c046731754..2592fa37b4c8 100644
> --- a/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp8_if.c
> +++ b/drivers/media/platform/mediatek/vcodec/vdec/vdec_vp8_if.c
> @@ -91,7 +91,6 @@ struct vdec_vp8_vsi {
>  
>  /**
>   * struct vdec_vp8_hw_reg_base - HW register base
> - * @sys		: base address for sys
>   * @misc	: base address for misc
>   * @ld		: base address for ld
>   * @top		: base address for top
> @@ -100,7 +99,6 @@ struct vdec_vp8_vsi {
>   * @hwb		: base address for hwb
>   */
>  struct vdec_vp8_hw_reg_base {
> -	void __iomem *sys;
>  	void __iomem *misc;
>  	void __iomem *ld;
>  	void __iomem *top;
> @@ -170,7 +168,6 @@ static void get_hw_reg_base(struct vdec_vp8_inst *inst)
>  	inst->reg_base.top = mtk_vcodec_get_reg_addr(inst->ctx, VDEC_TOP);
>  	inst->reg_base.cm = mtk_vcodec_get_reg_addr(inst->ctx, VDEC_CM);
>  	inst->reg_base.hwd = mtk_vcodec_get_reg_addr(inst->ctx, VDEC_HWD);
> -	inst->reg_base.sys = mtk_vcodec_get_reg_addr(inst->ctx, VDEC_SYS);
>  	inst->reg_base.misc = mtk_vcodec_get_reg_addr(inst->ctx, VDEC_MISC);
>  	inst->reg_base.ld = mtk_vcodec_get_reg_addr(inst->ctx, VDEC_LD);
>  	inst->reg_base.hwb = mtk_vcodec_get_reg_addr(inst->ctx, VDEC_HWB);
> @@ -222,17 +219,16 @@ static void read_hw_segmentation_data(struct vdec_vp8_inst *inst)
>  static void enable_hw_rw_function(struct vdec_vp8_inst *inst)
>  {
>  	u32 val = 0;
> -	void __iomem *sys = inst->reg_base.sys;
>  	void __iomem *misc = inst->reg_base.misc;
>  	void __iomem *ld = inst->reg_base.ld;
>  	void __iomem *hwb = inst->reg_base.hwb;
>  	void __iomem *hwd = inst->reg_base.hwd;
>  
> -	writel(0x1, sys + VP8_RW_CKEN_SET);
> +	mtk_vcodec_write_vdecsys(inst->ctx, VP8_RW_CKEN_SET, 0x1);
>  	writel(0x101, ld + VP8_WO_VLD_SRST);
>  	writel(0x101, hwb + VP8_WO_VLD_SRST);
>  
> -	writel(1, sys);
> +	mtk_vcodec_write_vdecsys(inst->ctx, 0, 0x1);
>  	val = readl(misc + VP8_RW_MISC_SRST);
>  	writel((val & 0xFFFFFFFE), misc + VP8_RW_MISC_SRST);
>  
> @@ -241,7 +237,7 @@ static void enable_hw_rw_function(struct vdec_vp8_inst *inst)
>  	writel(0x71201100, misc + VP8_RW_MISC_FUNC_CON);
>  	writel(0x0, ld + VP8_WO_VLD_SRST);
>  	writel(0x0, hwb + VP8_WO_VLD_SRST);
> -	writel(0x1, sys + VP8_RW_DCM_CON);
> +	mtk_vcodec_write_vdecsys(inst->ctx, VP8_RW_DCM_CON, 0x1);
>  	writel(0x1, misc + VP8_RW_MISC_DCM_CON);
>  	writel(0x1, hwd + VP8_RW_VP8_CTRL);
>  }