linux-kernel - Re: [PATCH 3/5] drm/msm/dp: Refactor ioremap wrapper

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Date:   Thu, 22 Jul 2021 20:09:20 +0000
From:   Stephen Boyd <swboyd@...omium.org>
To:     Abhinav Kumar <abhinavk@...eaurora.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Rob Clark <robdclark@...il.com>,
        Rob Herring <robh+dt@...nel.org>, Sean Paul <sean@...rly.run>
Cc:     Kuogee Hsieh <khsieh@...eaurora.org>,
        Tanmay Shah <tanmay@...eaurora.org>,
        Chandan Uddaraju <chandanu@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5] drm/msm/dp: Refactor ioremap wrapper

Quoting Bjorn Andersson (2021-07-21 19:42:25)
> In order to deal with multiple memory ranges in the following commit
> change the ioremap wrapper to not poke directly into the dss_io_data
> struct.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
>  drivers/gpu/drm/msm/dp/dp_parser.c | 28 ++++++++++++++--------------
>  drivers/gpu/drm/msm/dp/dp_parser.h |  2 +-
>  2 files changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_parser.c b/drivers/gpu/drm/msm/dp/dp_parser.c
> index c064ced78278..e68dacef547c 100644
> --- a/drivers/gpu/drm/msm/dp/dp_parser.c
> +++ b/drivers/gpu/drm/msm/dp/dp_parser.c
> @@ -19,39 +19,39 @@ static const struct dp_regulator_cfg sdm845_dp_reg_cfg = {
>         },
>  };
>
> -static int msm_dss_ioremap(struct platform_device *pdev,
> -                               struct dss_io_data *io_data)
> +static void __iomem *dp_ioremap(struct platform_device *pdev, int idx, size_t *len)
>  {
>         struct resource *res = NULL;

Can we drop assignment to NULL too?

> +       void __iomem *base;
>
> -       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, idx);
>         if (!res) {
>                 DRM_ERROR("%pS->%s: msm_dss_get_res failed\n",
>                         __builtin_return_address(0), __func__);
> -               return -ENODEV;
> +               return ERR_PTR(-ENODEV);
>         }
>
> -       io_data->len = (u32)resource_size(res);
> -       io_data->base = devm_ioremap(&pdev->dev, res->start, io_data->len);
> -       if (!io_data->base) {
> +       base = devm_ioremap_resource(&pdev->dev, res);
> +       if (!base) {

devm_ioremap_resource() returns an ERR_PTR on failure, not NULL.

>                 DRM_ERROR("%pS->%s: ioremap failed\n",
>                         __builtin_return_address(0), __func__);
> -               return -EIO;
> +               return ERR_PTR(-EIO);
>         }
>
> -       return 0;
> +       *len = resource_size(res);
> +       return base;
>  }
>
>  static int dp_parser_ctrl_res(struct dp_parser *parser)
>  {
> -       int rc = 0;
>         struct platform_device *pdev = parser->pdev;
>         struct dp_io *io = &parser->io;
> +       struct dss_io_data *dss = &io->dp_controller;
>
> -       rc = msm_dss_ioremap(pdev, &io->dp_controller);
> -       if (rc) {
> -               DRM_ERROR("unable to remap dp io resources, rc=%d\n", rc);
> -               return rc;
> +       dss->base = dp_ioremap(pdev, 0, &dss->len);
> +       if (IS_ERR(dss->base)) {
> +               DRM_ERROR("unable to remap dp io region: %pe\n", dss->base);
> +               return PTR_ERR(dss->base);
>         }
>
>         io->phy = devm_phy_get(&pdev->dev, "dp");