Hello Adrian
On 10/25/2011 10:40 AM, Adrian Hunter wrote:
> 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;
ok
>
>
>>
>> @@ -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?
I hadn't the SDHCI 3.0 spec. I'm looking at it now and I'll provide a
new patch asap.
>
>> } 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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