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

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Date:   Thu, 2 Dec 2021 10:24:44 +0800
From:   "yunfei.dong@...iatek.com" <yunfei.dong@...iatek.com>
To:     Benjamin Gaignard <benjamin.gaignard@...labora.com>,
        Alexandre Courbot <acourbot@...omium.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        "Tzung-Bi Shih" <tzungbi@...omium.org>,
        Tiffany Lin <tiffany.lin@...iatek.com>,
        Andrew-CT Chen <andrew-ct.chen@...iatek.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Tomasz Figa <tfiga@...gle.com>
CC:     Hsin-Yi Wang <hsinyi@...omium.org>,
        Fritz Koenig <frkoenig@...omium.org>,
        Dafna Hirschfeld <dafna.hirschfeld@...labora.com>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Irui Wang <irui.wang@...iatek.com>,
        <linux-media@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>,
        <linux-mediatek@...ts.infradead.org>,
        <Project_Global_Chrome_Upstream_Group@...iatek.com>
Subject: Re: [PATCH v11, 01/19] media: mtk-vcodec: Get numbers of register
 bases from DT

Hi Benjamin,

Thanks for your suggestion.
On Tue, 2021-11-30 at 14:20 +0100, Benjamin Gaignard wrote:
> Le 29/11/2021 à 04:41, Yunfei Dong a écrit :
> > Different platform may has different numbers of register bases.
> > Gets the
> > numbers of register bases from DT (sizeof(u32) * 4 bytes for each).
> > 
> > Reviewed-by: Tzung-Bi Shih<tzungbi@...gle.com>
> > Signed-off-by: Yunfei Dong <yunfei.dong@...iatek.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)
> > +{
> > +	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);
> 
> It looks strange for me to have a "reg" size equal to sizeof(u32) *
> 4. Usually
> we more see reg size = sizeof(u32).
> 
For the definition of reg in dtsi is reg = <0 0x16000000 0 0x800>,
Need to using sizeof(u32) * 4, not sizeof(u32).
> > +	if (reg_num <= 0 || reg_num > NUM_MAX_VDEC_REG_BASE) {
> 
> If reg_num = NUM_MAX_VDEC_REG_BASE you will iterate out of bounds of
> dev->reg_base array.
> That never happens because dev->reg_base size equal
> NUM_MAX_VCODEC_REG_BASE.
> The question is what is the real needed size for dev->reg_base array
> ? NUM_MAX_VDEC_REG_BASE or
> NUM_MAX_VCODEC_REG_BASE ?
> 
> NUM_MAX_VDEC_REG_BASE is used for video decoder, and
> NUM_MAX_VCODEC_REG_BASE is used for encoder.

The max register number of video decoder is NUM_MAX_VDEC_REG_BASE, and
the ranges is 0 ~ NUM_MAX_VDEC_REG_BASE - 1.

> Regards,
> Benjamin
> 
Best Regards,
Yunfei Dong
> > +		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) {