Re: [PATCH v11, 01/19] media: mtk-vcodec: Get numbers of register bases from DT

From: Steve Cho <stevecho@google.com>
To: "yunfei.dong@mediatek.com" <yunfei.dong@mediatek.com>
Cc: Andrew-CT Chen <andrew-ct.chen@mediatek.com>,
	Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Irui Wang <irui.wang@mediatek.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Benjamin Gaignard <benjamin.gaignard@collabora.com>,
	Project_Global_Chrome_Upstream_Group@mediatek.com,
	Fritz Koenig <frkoenig@chromium.org>,
	linux-media@vger.kernel.org, devicetree@vger.kernel.org,
	Tzung-Bi Shih <tzungbi@chromium.org>,
	Tomasz Figa <tfiga@google.com>, Rob Herring <robh+dt@kernel.org>,
	linux-mediatek@lists.infradead.org,
	Hsin-Yi Wang <hsinyi@chromium.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Tiffany Lin <tiffany.lin@mediatek.com>,
	linux-arm-kernel@lists.infradead.org,
	Alexandre Courbot <acourbot@chromium.org>,
	srv_heupstream@mediatek.com, linux-kernel@vger.kernel.org,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>
Subject: Re: [PATCH v11, 01/19] media: mtk-vcodec: Get numbers of register bases from DT
Date: Thu, 2 Dec 2021 08:38:58 -0800	[thread overview]
Message-ID: <CAN0yncFnrea=FHc8O4YLopXxN8WksrEDN1Z-X7VUOfcv_Y5n=Q@mail.gmail.com> (raw)
In-Reply-To: <90950d579c6613fa52500ff5f2e7602b483dcb3d.camel@mediatek.com>

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Thanks,
Steve

On Wed, Dec 1, 2021 at 6:38 PM yunfei.dong@mediatek.com <
yunfei.dong@mediatek.com> wrote:

> Hi Steve,
>
> Thanks for your suggestion.
> On Wed, 2021-12-01 at 15:36 -0800, Steve Cho wrote:
>
> LGTM with few nits.
>
> Thanks,
> Steve
>
> On Sun, Nov 28, 2021 at 7:44 PM Yunfei Dong <yunfei.dong@mediatek.com>
> wrote:
>
> Different platform may has different numbers of register bases. Gets the
> numbers of register bases from DT (sizeof(u32) * 4 bytes for each)
>
> Few nits.
> s/platform/platforms/
> s/has/have/
>
> Fix, DT is dts.
> Btw, what is DT?
>
>
> Reviewed-by: Tzung-Bi Shih<tzungbi@google.com>
> Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
> ---
>  .../platform/mtk-vcodec/mtk_vcodec_dec_drv.c  | 37 ++++++++++++++-----
>  1 file changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c
> b/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c
> index e6e6a8203eeb..59caf2163349 100644
> --- a/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c
> +++ b/drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_drv.c
> @@ -78,6 +78,30 @@ static irqreturn_t mtk_vcodec_dec_irq_handler(int irq,
> void *priv)
>         return IRQ_HANDLED;
>  }
>
> +static int mtk_vcodec_get_reg_bases(struct mtk_vcodec_dev *dev)
> +{
>
> I see that dev is already checked before entering into this function, but
> null check for dev would still be nice.
>
>
> Dev is never null in this function, whether it looks not very reasonable?
>
That is correct with current code. In Chromium world, reviewers still
suggest to null check in similar situations.
Up to you. It is fine with me as it is.


> Best Regards,
> Yunfei Dong
>
> +       struct platform_device *pdev = dev->plat_dev;
> +       int reg_num, i;
> +
> +       /* Sizeof(u32) * 4 bytes for each register base. */
> +       reg_num = of_property_count_elems_of_size(pdev->dev.of_node, "reg",
> +               sizeof(u32) * 4);
> +       if (reg_num <= 0 || reg_num > NUM_MAX_VDEC_REG_BASE) {
> +               dev_err(&pdev->dev, "Invalid register property size:
> %d\n", reg_num);
> +               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]);
> +
> +               mtk_v4l2_debug(2, "reg[%d] base=%p", i, dev->reg_base[i]);
> +       }
> +
> +       return 0;
> +}
> +
>  static int fops_vcodec_open(struct file *file)
>  {
>         struct mtk_vcodec_dev *dev = video_drvdata(file);
> @@ -206,7 +230,7 @@ static int mtk_vcodec_probe(struct platform_device
> *pdev)
>         struct resource *res;
>         phandle rproc_phandle;
>         enum mtk_vcodec_fw_type fw_type;
> -       int i, ret;
> +       int ret;
>
>         dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
>         if (!dev)
> @@ -238,14 +262,9 @@ static int mtk_vcodec_probe(struct platform_device
> *pdev)
>                 goto err_dec_pm;
>         }
>
> -       for (i = 0; i < NUM_MAX_VDEC_REG_BASE; i++) {
> -               dev->reg_base[i] = devm_platform_ioremap_resource(pdev, i);
> -               if (IS_ERR((__force void *)dev->reg_base[i])) {
> -                       ret = PTR_ERR((__force void *)dev->reg_base[i]);
> -                       goto err_res;
> -               }
> -               mtk_v4l2_debug(2, "reg[%d] base=%p", i, dev->reg_base[i]);
> -       }
> +       ret = mtk_vcodec_get_reg_bases(dev);
> +       if (ret)
> +               goto err_res;
>
>         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
>         if (res == NULL) {
>
>

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