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

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

[Karl Mehltretter]

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@gmail.com>
---
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.

 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

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@gmail.com>
Reviewed-by: Gregor Herburger <gregor.herburger@linutronix.de>
> ---
> 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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Re: [PATCH] mmc: sdhci-brcmstb: don't log an error for missing BOOT registers

[Markus Elfring]

…
> +++ 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;
…

I suggest to reduce the scope for this local variable because you would like to use it only
within a selected if branch.
https://elixir.bootlin.com/linux/v7.3-rc6/source/drivers/mmc/host/sdhci-brcmstb.c#L535-L540

Regards,
Markus