Re: [PATCH] mmc: sdhci-brcmstb: don't log an error for missing BOOT registers

[Gregor Herburger]

Hi, 

On Fri, Oct 09, 2026 at 02:32:01AM +0200, Karl Mehltretter wrote:
> The BOOT register range is optional: the probe function ignores a
> failure to map it and the suspend/resume code checks for NULL. It is
> mapped with devm_platform_get_and_ioremap_resource(), though, which
> calls dev_err_probe() when the resource does not exist. Every
> non-removable host without a third reg entry therefore logs an error
> at probe time and then works normally.
> 
> The binding only describes the "host" and "cfg" ranges, so this is the
> case for the in-tree users. On the Raspberry Pi 5 family (BCM2712),
> where the SDIO host of the Wi-Fi module is non-removable, each boot
> prints:
> 
>   sdhci-brcmstb 1001100000.mmc: error -EINVAL: invalid resource (null)
> 
> Look the resource up with platform_get_resource() first and map it only
> when it is present. Hosts that do have the range are mapped by the same
> two calls as before.
> 
> Fixes: b7e614802e3f ("mmc: sdhci-brcmstb: save and restore registers during PM")
> Assisted-by: LLM
> Signed-off-by: Karl Mehltretter <kmehltretter@xxxxxxxxx>
Reviewed-by: Gregor Herburger <gregor.herburger@xxxxxxxxxxxxx>
> ---
> Tested on a Raspberry Pi 500+ with v7.3-rc4: the message is gone, the
> SDIO card is detected as before and Wi-Fi works. Suspend/resume, the
> only user of these registers, was not tested.
I have seen this error a few times but newer looked into it. Thanks for the fix.
> 
>  drivers/mmc/host/sdhci-brcmstb.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-brcmstb.c b/drivers/mmc/host/sdhci-brcmstb.c
> index 1de2f05..7c17a3c 100644
> --- a/drivers/mmc/host/sdhci-brcmstb.c
> +++ b/drivers/mmc/host/sdhci-brcmstb.c
> @@ -491,6 +491,7 @@ static int sdhci_brcmstb_probe(struct platform_device *pdev)
>  	struct sdhci_brcmstb_priv *priv;
>  	u32 actual_clock_mhz;
>  	struct sdhci_host *host;
> +	struct resource *boot_res;
>  	struct clk *clk;
>  	struct clk *base_clk = NULL;
>  	int res;
> @@ -534,9 +535,13 @@ static int sdhci_brcmstb_probe(struct platform_device *pdev)
>  
>  	/* map non-standard BOOT registers if present */
>  	if (host->mmc->caps & MMC_CAP_NONREMOVABLE) {
> -		priv->boot_regs = devm_platform_get_and_ioremap_resource(pdev, 2, NULL);
> -		if (IS_ERR(priv->boot_regs))
> -			priv->boot_regs = NULL;
> +		boot_res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
> +		if (boot_res) {
> +			priv->boot_regs = devm_ioremap_resource(&pdev->dev,
> +								boot_res);
> +			if (IS_ERR(priv->boot_regs))
> +				priv->boot_regs = NULL;
> +		}
>  	}
>  
>  	/*
> 
> base-commit: 6c377d19d4a5116d9bec5203aa3c6c11523e7898

-- 
Gregor Herburger
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