Re: [PATCH v2] mailbox: test: really ignore optional memory resources

[Geert Uytterhoeven]

Hi Wolfram,

On Mon, 23 Feb 2026 at 13:30, Wolfram Sang
<wsa+renesas@xxxxxxxxxxxxxxxxxxxx> wrote:
> Memory resources are optional but if the resource is empty
> devm_platform_get_and_ioremap_resource() prints an error nonetheless.
> Refactor the code to check the resources locally first and process them
> only if they are present. The -EBUSY error message of ioremap_resource()
> is still kept because it is correct. The comment which explains that a
> plain ioremap() is tried as a workaround is turned into a info message.
> So, a user will be informed about it, too.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>

Thanks for your patch!

> --- a/drivers/mailbox/mailbox-test.c
> +++ b/drivers/mailbox/mailbox-test.c
> @@ -355,11 +355,30 @@ mbox_test_request_channel(struct platform_device *pdev, const char *name)
>         return channel;
>  }
>
> -static int mbox_test_probe(struct platform_device *pdev)
> +static void *mbox_test_ioremap(struct platform_device *pdev, unsigned int res_num)
>  {
> -       struct mbox_test_device *tdev;
>         struct resource *res;
>         resource_size_t size;
> +       void *mmio = NULL;
> +
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, res_num);
> +       if (res) {

if (!res)
        return NULL;

> +               mmio = devm_ioremap_resource(&pdev->dev, res);
> +               if (PTR_ERR(mmio) == -EBUSY) {
> +                       dev_info(&pdev->dev, "trying workaround with plain ioremap\n");
> +                       size = resource_size(res);

With the reduced indentation, you don't need a temporary to avoid the
next line being too long.

> +                       mmio = devm_ioremap(&pdev->dev, res->start, size);

return devm_ioremap(...);

> +               } else if (IS_ERR(mmio)) {
> +                       mmio = NULL;
> +               }
> +       }
> +
> +       return mmio;

return IS_ERR(mmio) ? NULL : mmio;


> +}

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds