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.cavall...@st.com>
---
drivers/mmc/core/debugfs.c | 2 ++
drivers/mmc/host/sdhci.c | 10 ++++++++++
include/linux/mmc/host.h | 2 ++
3 files changed, 14 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..6bfdec5 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1043,9 +1043,12 @@ 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;
+ host->mmc->actual_clock = 0;
+
if (clock == host->clock)
return;
@@ -1086,6 +1089,8 @@ 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 {
@@ -1099,6 +1104,7 @@ static void sdhci_set_clock(struct sdhci_host *host,
unsigned int clock)
break;
}
}
+ real_div = div;
div >>= 1;
}
} else {
@@ -1107,9 +1113,13 @@ static void sdhci_set_clock(struct sdhci_host *host,
unsigned int clock)
if ((host->max_clk / div) <= clock)
break;
}
+ real_div = div;
div >>= 1;
}
+ if (real_div)
+ host->mmc->actual_clock = (host->max_clk * clk_mul) / real_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;
};
--
1.7.4.4
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