Re: [PATCH V3] mmc: sdhci: Fix regression setting power on Trats2 board

[Jaehoon Chung <jh80.chung@samsung.com>]

On 03/29/2016 06:45 PM, Adrian Hunter wrote:
> Several commits relating to setting power have been introducing
> problems by putting driver-specific rules into generic SDHCI code.
> 
> Krzysztof Kozlowski reported that after commit 918f4cbd4340 ("mmc:
> sdhci: restore behavior when setting VDD via external regulator")
> on Trats2 board there are warnings for invalid VDD  value (2.8V):
> 
> [    3.119656] ------------[ cut here ]------------
> [    3.119666] WARNING: CPU: 3 PID: 90 at
> ../drivers/mmc/host/sdhci.c:1234 sdhci_do_set_ios+0x4cc/0x5e0
> [    3.119669] mmc0: Invalid vdd 0x10
> [    3.119673] Modules linked in:
> [    3.119679] CPU: 3 PID: 90 Comm: kworker/3:1 Tainted: G        W
>    4.5.0-next-20160324 #23
> [    3.119681] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
> [    3.119690] Workqueue: events_freezable mmc_rescan
> [    3.119708] [<c010e0ac>] (unwind_backtrace) from [<c010ae10>]
> (show_stack+0x10/0x14)
> [    3.119719] [<c010ae10>] (show_stack) from [<c0323260>]
> (dump_stack+0x88/0x9c)
> [    3.119728] [<c0323260>] (dump_stack) from [<c011b754>] (__warn+0xe8/0x100)
> [    3.119734] [<c011b754>] (__warn) from [<c011b7a4>]
> (warn_slowpath_fmt+0x38/0x48)
> [    3.119740] [<c011b7a4>] (warn_slowpath_fmt) from [<c0527d28>]
> (sdhci_do_set_ios+0x4cc/0x5e0)
> [    3.119748] [<c0527d28>] (sdhci_do_set_ios) from [<c0528018>]
> (sdhci_runtime_resume_host+0x60/0x114)
> [    3.119758] [<c0528018>] (sdhci_runtime_resume_host) from
> [<c0402570>] (__rpm_callback+0x2c/0x60)
> [    3.119767] [<c0402570>] (__rpm_callback) from [<c04025c4>]
> (rpm_callback+0x20/0x80)
> [    3.119773] [<c04025c4>] (rpm_callback) from [<c04034b8>]
> (rpm_resume+0x36c/0x558)
> [    3.119780] [<c04034b8>] (rpm_resume) from [<c04036f0>]
> (__pm_runtime_resume+0x4c/0x64)
> [    3.119788] [<c04036f0>] (__pm_runtime_resume) from [<c0512728>]
> (__mmc_claim_host+0x170/0x1b0)
> [    3.119795] [<c0512728>] (__mmc_claim_host) from [<c0514e2c>]
> (mmc_rescan+0x54/0x348)
> [    3.119807] [<c0514e2c>] (mmc_rescan) from [<c0130dac>]
> (process_one_work+0x120/0x3f4)
> [    3.119815] [<c0130dac>] (process_one_work) from [<c01310b8>]
> (worker_thread+0x38/0x554)
> [    3.119823] [<c01310b8>] (worker_thread) from [<c01365a4>]
> (kthread+0xdc/0xf4)
> [    3.119831] [<c01365a4>] (kthread) from [<c0107878>]
> (ret_from_fork+0x14/0x3c)
> [    3.119834] ---[ end trace a22d652aa3276886 ]---
> 
> Fix by adding a 'set_power' callback and restoring the default
> behaviour prior to commit 918f4cbd4340 ("mmc: sdhci: restore
> behavior when setting VDD via external regulator").  The desired
> behaviour of that commit is gotten by having sdhci-pxav3 provide
> its own set_power callback.
> 
> Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Link: http://lkml.kernel.org/r/CAJKOXPcGDnPm-Ykh6wHqV1YxfTaov5E8iVqBoBn4OJc7BnhgEQ@mail.gmail.com
> Fixes: 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD...)
> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> Cc: stable@vger.kernel.org # v4.5+
> ---
> 

Tested-by: Jaehoon Chung <jh80.chung@samsung.com>

With trats2 board.

> 
> Changes in V3:
> 
> 	Expanded commit message.
> 
> 	Removed redundant vdd = 0 from sdhci_set_power()
> 
> 	Make pxav3_set_power() check the regulator was created successfully
> 	before using it, and ensure vdd is 0 when pwr is 0.
> 
> 
>  drivers/mmc/host/sdhci-pxav3.c | 22 ++++++++++++++++++++++
>  drivers/mmc/host/sdhci.c       | 39 ++++++++++++++++++++++++++++++---------
>  drivers/mmc/host/sdhci.h       |  4 ++++
>  3 files changed, 56 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
> index f5edf9d3a18a..0535827b02ee 100644
> --- a/drivers/mmc/host/sdhci-pxav3.c
> +++ b/drivers/mmc/host/sdhci-pxav3.c
> @@ -307,8 +307,30 @@ static void pxav3_set_uhs_signaling(struct sdhci_host *host, unsigned int uhs)
>  		__func__, uhs, ctrl_2);
>  }
>  
> +static void pxav3_set_power(struct sdhci_host *host, unsigned char mode,
> +			    unsigned short vdd)
> +{
> +	struct mmc_host *mmc = host->mmc;
> +	u8 pwr = host->pwr;
> +
> +	sdhci_set_power(host, mode, vdd);
> +
> +	if (host->pwr == pwr)
> +		return;
> +
> +	if (host->pwr == 0)
> +		vdd = 0;
> +
> +	if (!IS_ERR(mmc->supply.vmmc)) {
> +		spin_unlock_irq(&host->lock);
> +		mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
> +		spin_lock_irq(&host->lock);
> +	}
> +}
> +
>  static const struct sdhci_ops pxav3_sdhci_ops = {
>  	.set_clock = sdhci_set_clock,
> +	.set_power = pxav3_set_power,
>  	.platform_send_init_74_clocks = pxav3_gen_init_74_clocks,
>  	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
>  	.set_bus_width = sdhci_set_bus_width,
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index add9fdfd1d8f..f5b52b4308cc 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1269,10 +1269,24 @@ clock_set:
>  }
>  EXPORT_SYMBOL_GPL(sdhci_set_clock);
>  
> -static void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> -			    unsigned short vdd)
> +static void sdhci_set_power_reg(struct sdhci_host *host, unsigned char mode,
> +				unsigned short vdd)
>  {
>  	struct mmc_host *mmc = host->mmc;
> +
> +	spin_unlock_irq(&host->lock);
> +	mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
> +	spin_lock_irq(&host->lock);
> +
> +	if (mode != MMC_POWER_OFF)
> +		sdhci_writeb(host, SDHCI_POWER_ON, SDHCI_POWER_CONTROL);
> +	else
> +		sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
> +}
> +
> +void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> +		     unsigned short vdd)
> +{
>  	u8 pwr = 0;
>  
>  	if (mode != MMC_POWER_OFF) {
> @@ -1304,7 +1318,6 @@ static void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>  		sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
>  		if (host->quirks2 & SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON)
>  			sdhci_runtime_pm_bus_off(host);
> -		vdd = 0;
>  	} else {
>  		/*
>  		 * Spec says that we should clear the power reg before setting
> @@ -1335,12 +1348,20 @@ static void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>  		if (host->quirks & SDHCI_QUIRK_DELAY_AFTER_POWER)
>  			mdelay(10);
>  	}
> +}
> +EXPORT_SYMBOL_GPL(sdhci_set_power);
>  
> -	if (!IS_ERR(mmc->supply.vmmc)) {
> -		spin_unlock_irq(&host->lock);
> -		mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
> -		spin_lock_irq(&host->lock);
> -	}
> +static void __sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> +			      unsigned short vdd)
> +{
> +	struct mmc_host *mmc = host->mmc;
> +
> +	if (host->ops->set_power)
> +		host->ops->set_power(host, mode, vdd);
> +	else if (!IS_ERR(mmc->supply.vmmc))
> +		sdhci_set_power_reg(host, mode, vdd);
> +	else
> +		sdhci_set_power(host, mode, vdd);
>  }
>  
>  /*****************************************************************************\
> @@ -1490,7 +1511,7 @@ static void sdhci_do_set_ios(struct sdhci_host *host, struct mmc_ios *ios)
>  		}
>  	}
>  
> -	sdhci_set_power(host, ios->power_mode, ios->vdd);
> +	__sdhci_set_power(host, ios->power_mode, ios->vdd);
>  
>  	if (host->ops->platform_send_init_74_clocks)
>  		host->ops->platform_send_init_74_clocks(host, ios->power_mode);
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 0115e9907bf8..033d72b5bbd5 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -529,6 +529,8 @@ struct sdhci_ops {
>  #endif
>  
>  	void	(*set_clock)(struct sdhci_host *host, unsigned int clock);
> +	void	(*set_power)(struct sdhci_host *host, unsigned char mode,
> +			     unsigned short vdd);
>  
>  	int		(*enable_dma)(struct sdhci_host *host);
>  	unsigned int	(*get_max_clock)(struct sdhci_host *host);
> @@ -660,6 +662,8 @@ static inline bool sdhci_sdio_irq_enabled(struct sdhci_host *host)
>  }
>  
>  void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
> +void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
> +		     unsigned short vdd);
>  void sdhci_set_bus_width(struct sdhci_host *host, int width);
>  void sdhci_reset(struct sdhci_host *host, u8 mask);
>  void sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned timing);
>