On 21/10/11 11:16, 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 <[email protected]>
> ---
> drivers/mmc/core/debugfs.c | 2 ++
> drivers/mmc/host/sdhci.c | 7 +++++++
> include/linux/mmc/host.h | 2 ++
> 3 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
> index 998797e..0b9a4aa 100644
> --- a/drivers/mmc/core/debugfs.c
> +++ b/drivers/mmc/core/debugfs.c
> @@ -46,6 +46,8 @@ 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 0e02cc1..a0d61b0 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1043,6 +1043,7 @@ 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 actual_div = 0;
> u16 clk = 0;
> unsigned long timeout;
What if the clock is gated i.e. zero? Maybe add
host->mmc->actual_clock = 0;
>
> @@ -1088,6 +1089,7 @@ static void sdhci_set_clock(struct sdhci_host *host,
> unsigned int clock)
> clk = SDHCI_PROG_CLOCK_MODE;
> div--;
> }
> + actual_div = div;
What about the clock multiplier?
> } else {
> /* Version 3.00 divisors must be a multiple of 2. */
> if (host->max_clk <= clock)
> @@ -1099,6 +1101,7 @@ static void sdhci_set_clock(struct sdhci_host *host,
> unsigned int clock)
> break;
> }
> }
> + actual_div = div;
> div >>= 1;
> }
> } else {
> @@ -1107,9 +1110,13 @@ static void sdhci_set_clock(struct sdhci_host *host,
> unsigned int clock)
> if ((host->max_clk / div) <= clock)
> break;
> }
> + actual_div = div;
> div >>= 1;
> }
>
> + if (actual_div)
> + host->mmc->actual_clock = host->max_clk / actual_div;
> +
> 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 1d09562..d815311 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -302,6 +302,8 @@ struct mmc_host {
>
> struct mmc_async_req *areq; /* active async req */
>
> + unsigned int actual_clock; /* Actual HC clock rate */
> +
> unsigned long private[0] ____cacheline_aligned;
> };
>
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