Re: [PATCH] mmc: debugfs: expose the SDCLK frq in sys ios (V5)

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

On 04/11/11 09:16, Giuseppe CAVALLARO wrote:
> This patch is to expose the actual SDCLK frequency in
> /sys/kernel/debug/mmcX/ios entry.
> 
> For example, if the max clk for a normal speed card is 20MHz
> this is reported in /sys/kernel/debug/mmcX/ios.
> Unfortunately the actual SDCLK frequency (i.e. Baseclock / divisor)
> is not reported at all: for example, in that case, on Arasan HC,
> it should be 48/4=12 (MHz).
> 
> Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
> ---
>  drivers/mmc/core/debugfs.c |    2 ++
>  drivers/mmc/host/sdhci.c   |    9 +++++++++
>  include/linux/mmc/host.h   |    2 ++
>  3 files changed, 13 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
> index c3f24a7..688f4f8 100644
> --- a/drivers/mmc/core/debugfs.c
> +++ b/drivers/mmc/core/debugfs.c
> @@ -56,6 +56,8 @@ static int mmc_ios_show(struct seq_file *s, void *data)
>  	const char *str;
>  
>  	seq_printf(s, "clock:\t\t%u Hz\n", ios->clock);
> +	if (host->actual_clock)
> +		seq_printf(s, "actual clock:\t%u Hz\n", host->actual_clock);
>  	seq_printf(s, "vdd:\t\t%u ", ios->vdd);
>  	if ((1 << ios->vdd) & MMC_VDD_165_195)
>  		seq_printf(s, "(1.65 - 1.95 V)\n");
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 6d8eea3..f801609 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1066,12 +1066,15 @@ static void sdhci_finish_command(struct sdhci_host *host)
>  static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>  {
>  	int div = 0; /* Initialized for compiler warning */
> +	int real_div = div, clk_mul = 1;
>  	u16 clk = 0;
>  	unsigned long timeout;
>  
>  	if (clock == host->clock)
>  		return;
>  
> +	host->mmc->actual_clock = 0;
> +
>  	if (host->ops->set_clock) {
>  		host->ops->set_clock(host, clock);
>  		if (host->quirks & SDHCI_QUIRK_NONSTANDARD_CLOCK)
> @@ -1109,6 +1112,8 @@ static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>  				 * Control register.
>  				 */
>  				clk = SDHCI_PROG_CLOCK_MODE;
> +				real_div = div;
> +				clk_mul = host->clk_mul;
>  				div--;
>  			}
>  		} else {
> @@ -1122,6 +1127,7 @@ static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>  						break;
>  				}
>  			}
> +			real_div = div;
>  			div >>= 1;
>  		}
>  	} else {
> @@ -1130,9 +1136,12 @@ static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>  			if ((host->max_clk / div) <= clock)
>  				break;
>  		}
> +		real_div = div;
>  		div >>= 1;
>  	}
>  
> +	host->mmc->actual_clock = (host->max_clk * clk_mul) / real_div;

Still missing the "if (real_div)" from V3 but it is needed in one case
i.e. (ctrl & SDHCI_CTRL_PRESET_VAL_ENABLE)


> +
>  	clk |= (div & SDHCI_DIV_MASK) << SDHCI_DIVIDER_SHIFT;
>  	clk |= ((div & SDHCI_DIV_HI_MASK) >> SDHCI_DIV_MASK_LEN)
>  		<< SDHCI_DIVIDER_HI_SHIFT;
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index a3ac9c4..cea064f 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -323,6 +323,8 @@ struct mmc_host {
>  	struct fault_attr	fail_mmc_request;
>  #endif
>  
> +	unsigned int		actual_clock;	/* Actual HC clock rate */
> +
>  	unsigned long		private[0] ____cacheline_aligned;
>  };
>