Re: [PATCH V16 12/23] mmc: sdhci-uhs2: add reset function function

[Adrian Hunter <adrian.hunter@intel.com>]

On 22/05/24 14:08, Victor Shih wrote:
> From: Victor Shih <victor.shih@genesyslogic.com.tw>
> 
> Sdhci_uhs2_reset() does a UHS-II specific reset operation.
> 
> Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> Signed-off-by: Victor Shih <victor.shih@genesyslogic.com.tw>
> ---
> 
> Updates in V15:
>  - Refer the SD Host Controller Standard Specification Section 3.10
>    to add reset command data mechanism.
> 
> Updates in V14:
>  - Since mmc_card_uhs2() is the same as sdhci_uhs2_mode(), so drop
>    sdhci_uhs2_mode() and use mmc_card_uhs2() instead of sdhci_uhs2_mode().
> 
> Updates in V13:
>  - Use ios timing to stead MMC_UHS2_SUPPORT for indicate the UHS2 mode.
> 
> Updates in V8:
>  - Adjust the position of matching brackets.
> 
> Updates in V6:
>  - Remove unnecessary functions and simplify code.
> 
> ---
> 
>  drivers/mmc/host/sdhci-uhs2.c | 57 +++++++++++++++++++++++++++++++++++
>  drivers/mmc/host/sdhci-uhs2.h |  1 +
>  drivers/mmc/host/sdhci.c      |  3 +-
>  drivers/mmc/host/sdhci.h      |  1 +
>  4 files changed, 61 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> index 9cb0f1b2a37d..7652158ea151 100644
> --- a/drivers/mmc/host/sdhci-uhs2.c
> +++ b/drivers/mmc/host/sdhci-uhs2.c
> @@ -10,7 +10,9 @@
>   *  Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
>   */
>  
> +#include <linux/delay.h>
>  #include <linux/module.h>
> +#include <linux/iopoll.h>
>  
>  #include "sdhci.h"
>  #include "sdhci-uhs2.h"
> @@ -21,6 +23,8 @@
>  #define SDHCI_UHS2_DUMP(f, x...) \
>  	pr_err("%s: " DRIVER_NAME ": " f, mmc_hostname(host->mmc), ## x)
>  
> +#define UHS2_RESET_TIMEOUT_100MS		100000
> +
>  void sdhci_uhs2_dump_regs(struct sdhci_host *host)
>  {
>  	if (!(mmc_card_uhs2(host->mmc)))
> @@ -49,6 +53,57 @@ void sdhci_uhs2_dump_regs(struct sdhci_host *host)
>  }
>  EXPORT_SYMBOL_GPL(sdhci_uhs2_dump_regs);
>  
> +/*****************************************************************************\
> + *                                                                           *
> + * Low level functions                                                       *
> + *                                                                           *
> +\*****************************************************************************/
> +
> +/**
> + * sdhci_uhs2_reset - invoke SW reset
> + * @host: SDHCI host
> + * @mask: Control mask
> + *
> + * Invoke SW reset, depending on a bit in @mask and wait for completion.
> + */
> +void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask)
> +{
> +	u32 val;
> +
> +	sdhci_writew(host, mask, SDHCI_UHS2_SW_RESET);
> +
> +	if (mask & SDHCI_UHS2_SW_RESET_FULL)
> +		host->clock = 0;
> +
> +	/* hw clears the bit when it's done */
> +	if (read_poll_timeout_atomic(sdhci_readw, val, !(val & mask), 10,
> +				     UHS2_RESET_TIMEOUT_100MS, true, host, SDHCI_UHS2_SW_RESET)) {
> +		pr_warn("%s: %s: Reset 0x%x never completed. %s: clean reset bit.\n", __func__,
> +			mmc_hostname(host->mmc), (int)mask, mmc_hostname(host->mmc));
> +		sdhci_writeb(host, 0, SDHCI_UHS2_SW_RESET);
> +		return;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(sdhci_uhs2_reset);
> +
> +static void sdhci_uhs2_reset_cmd_data(struct mmc_host *mmc)
> +{
> +	struct sdhci_host *host = mmc_priv(mmc);
> +
> +	sdhci_do_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA);
> +
> +	if (host->mmc->ios.timing == MMC_TIMING_UHS2_SPEED_A ||
> +	    host->mmc->ios.timing == MMC_TIMING_UHS2_SPEED_A_HD ||
> +	    host->mmc->ios.timing == MMC_TIMING_UHS2_SPEED_B ||
> +	    host->mmc->ios.timing == MMC_TIMING_UHS2_SPEED_B_HD) {

Please use mmc_card_uhs2()

> +		sdhci_uhs2_reset(host, SDHCI_UHS2_SW_RESET_SD);
> +
> +		sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
> +		sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
> +		sdhci_uhs2_clear_set_irqs(host, SDHCI_INT_ALL_MASK, SDHCI_UHS2_INT_ERROR_MASK);
> +	}
> +}
> +
>  /*****************************************************************************\
>   *                                                                           *
>   * Driver init/exit                                                          *
> @@ -57,6 +112,8 @@ EXPORT_SYMBOL_GPL(sdhci_uhs2_dump_regs);
>  
>  static int sdhci_uhs2_host_ops_init(struct sdhci_host *host)
>  {
> +	host->mmc_host_ops.uhs2_reset_cmd_data = sdhci_uhs2_reset_cmd_data;

As noted for patch 8, any host controller resets needed
should be done before completing the request, so a call
back function should not be needed.

> +
>  	return 0;
>  }
>  
> diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
> index 2bfe18d29bca..caaf9fba4975 100644
> --- a/drivers/mmc/host/sdhci-uhs2.h
> +++ b/drivers/mmc/host/sdhci-uhs2.h
> @@ -177,5 +177,6 @@
>  struct sdhci_host;
>  
>  void sdhci_uhs2_dump_regs(struct sdhci_host *host);
> +void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
>  
>  #endif /* __SDHCI_UHS2_H */
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 8fc3e001db74..f212da6dc2aa 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -236,7 +236,7 @@ void sdhci_reset(struct sdhci_host *host, u8 mask)
>  }
>  EXPORT_SYMBOL_GPL(sdhci_reset);
>  
> -static bool sdhci_do_reset(struct sdhci_host *host, u8 mask)
> +bool sdhci_do_reset(struct sdhci_host *host, u8 mask)
>  {
>  	if (host->quirks & SDHCI_QUIRK_NO_CARD_NO_RESET) {
>  		struct mmc_host *mmc = host->mmc;
> @@ -249,6 +249,7 @@ static bool sdhci_do_reset(struct sdhci_host *host, u8 mask)
>  
>  	return true;
>  }
> +EXPORT_SYMBOL_GPL(sdhci_do_reset);
>  
>  static void sdhci_reset_for_all(struct sdhci_host *host)
>  {
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 13703f1a3710..83d994c8d89e 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -845,6 +845,7 @@ void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq);
>  int sdhci_request_atomic(struct mmc_host *mmc, struct mmc_request *mrq);
>  void sdhci_set_bus_width(struct sdhci_host *host, int width);
>  void sdhci_reset(struct sdhci_host *host, u8 mask);
> +bool sdhci_do_reset(struct sdhci_host *host, u8 mask);
>  void sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned timing);
>  int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode);
>  int __sdhci_execute_tuning(struct sdhci_host *host, u32 opcode);