[PATCH] mmc: sdhci-msm: fix mutex while in spinlock

[PATCH] mmc: sdhci-msm: fix mutex while in spinlock

[Jorge Ramirez-Ortiz]

mutexes can sleep and therefore should not be taken while holding a
spinlock. move clk_get_rate (can sleep) outside the spinlock protected
region.

This regression was introduced with commit
     Date:   Mon Nov 21 12:07:16 2016 +0530
     mmc: sdhci-msm: Update DLL reset sequence

     SDCC core with minor version >= 0x42 introduced new 14lpp
     DLL. This has additional requirements in the reset sequence
     for DLL tuning. Make necessary changes as needed.

Fixes: 83736352e0ca ("mmc: sdhci-msm: Update DLL reset sequence")
Cc: stable@vger.kernel.org
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
---
 drivers/mmc/host/sdhci-msm.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 5fc76a1993d0..9cf14b359c14 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -575,11 +575,14 @@ static int msm_init_cm_dll(struct sdhci_host *host)
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
 	int wait_cnt = 50;
-	unsigned long flags;
+	unsigned long flags, xo_clk = 0;
 	u32 config;
 	const struct sdhci_msm_offset *msm_offset =
 					msm_host->offset;
 
+	if (msm_host->use_14lpp_dll_reset && !IS_ERR_OR_NULL(msm_host->xo_clk))
+		xo_clk = clk_get_rate(msm_host->xo_clk);
+
 	spin_lock_irqsave(&host->lock, flags);
 
 	/*
@@ -627,10 +630,10 @@ static int msm_init_cm_dll(struct sdhci_host *host)
 		config &= CORE_FLL_CYCLE_CNT;
 		if (config)
 			mclk_freq = DIV_ROUND_CLOSEST_ULL((host->clock * 8),
-					clk_get_rate(msm_host->xo_clk));
+					xo_clk);
 		else
 			mclk_freq = DIV_ROUND_CLOSEST_ULL((host->clock * 4),
-					clk_get_rate(msm_host->xo_clk));
+					xo_clk);
 
 		config = readl_relaxed(host->ioaddr +
 				msm_offset->core_dll_config_2);
-- 
2.21.0

Re: [PATCH] mmc: sdhci-msm: fix mutex while in spinlock

[Bjorn Andersson]

On Mon 01 Jul 03:53 PDT 2019, Jorge Ramirez-Ortiz wrote:

> mutexes can sleep and therefore should not be taken while holding a
> spinlock. move clk_get_rate (can sleep) outside the spinlock protected
> region.
> 
> This regression was introduced with commit
>      Date:   Mon Nov 21 12:07:16 2016 +0530
>      mmc: sdhci-msm: Update DLL reset sequence
> 
>      SDCC core with minor version >= 0x42 introduced new 14lpp
>      DLL. This has additional requirements in the reset sequence
>      for DLL tuning. Make necessary changes as needed.

Your Fixes: below already states this.

> 
> Fixes: 83736352e0ca ("mmc: sdhci-msm: Update DLL reset sequence")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>

Apart from that, your patch is good

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
>  drivers/mmc/host/sdhci-msm.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 5fc76a1993d0..9cf14b359c14 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -575,11 +575,14 @@ static int msm_init_cm_dll(struct sdhci_host *host)
>  	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>  	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
>  	int wait_cnt = 50;
> -	unsigned long flags;
> +	unsigned long flags, xo_clk = 0;
>  	u32 config;
>  	const struct sdhci_msm_offset *msm_offset =
>  					msm_host->offset;
>  
> +	if (msm_host->use_14lpp_dll_reset && !IS_ERR_OR_NULL(msm_host->xo_clk))
> +		xo_clk = clk_get_rate(msm_host->xo_clk);
> +
>  	spin_lock_irqsave(&host->lock, flags);
>  
>  	/*
> @@ -627,10 +630,10 @@ static int msm_init_cm_dll(struct sdhci_host *host)
>  		config &= CORE_FLL_CYCLE_CNT;
>  		if (config)
>  			mclk_freq = DIV_ROUND_CLOSEST_ULL((host->clock * 8),
> -					clk_get_rate(msm_host->xo_clk));
> +					xo_clk);
>  		else
>  			mclk_freq = DIV_ROUND_CLOSEST_ULL((host->clock * 4),
> -					clk_get_rate(msm_host->xo_clk));
> +					xo_clk);
>  
>  		config = readl_relaxed(host->ioaddr +
>  				msm_offset->core_dll_config_2);
> -- 
> 2.21.0
>