Hi,
On 11/15/2016 10:40 AM, Ritesh Harjani wrote:
Hi Stephen/Adrian,
On 11/15/2016 1:07 AM, Stephen Boyd wrote:
On 11/14, Ritesh Harjani wrote:
@@ -577,6 +578,90 @@ static unsigned int
sdhci_msm_get_min_clock(struct sdhci_host *host)
return SDHCI_MSM_MIN_CLOCK;
}
+/**
+ * __sdhci_msm_set_clock - sdhci_msm clock control.
+ *
+ * Description:
+ * Implement MSM version of sdhci_set_clock.
+ * This is required since MSM controller does not
+ * use internal divider and instead directly control
+ * the GCC clock as per HW recommendation.
+ **/
+void __sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+ u16 clk;
+ unsigned long timeout;
+
+ /*
+ * Keep actual_clock as zero -
+ * - since there is no divider used so no need of having
actual_clock.
+ * - MSM controller uses SDCLK for data timeout calculation. If
+ * actual_clock is zero, host->clock is taken for calculation.
+ */
+ host->mmc->actual_clock = 0;
+
+ sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
+
+ if (clock == 0)
+ return;
+
+ /*
+ * MSM controller do not use clock divider.
+ * Thus read SDHCI_CLOCK_CONTROL and only enable
+ * clock with no divider value programmed.
+ */
+ clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+
+ clk |= SDHCI_CLOCK_INT_EN;
+ sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
+
+ /* Wait max 20 ms */
+ timeout = 20;
+ while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
+ & SDHCI_CLOCK_INT_STABLE)) {
+ if (timeout == 0) {
+ pr_err("%s: Internal clock never stabilised\n",
+ mmc_hostname(host->mmc));
+ return;
+ }
+ timeout--;
+ mdelay(1);
+ }
+
+ clk |= SDHCI_CLOCK_CARD_EN;
+ sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
This is almost a copy/paste of sdhci_set_clock(). Can we make
sdhci_set_clock() call a __sdhci_set_clock() function that takes
unsigned int clock, and also a flag indicating if we want to set
the internal clock divider or not? Then we can call
__sdhci_set_clock() from sdhci_set_clock() with (clock, true) as
arguments and (clock, false).
Actually what you may be referring here is some sort of quirks which is
not entertained any more for sdhci driver.
sdhci is tending towards becoming a library and hence such changes are
restricted.
But I think we may do below changes to avoid duplication of code which
enables the sdhci internal clock and waits for internal clock to be stable.
Adrian, could you please tell if this should be ok?
Then we may be able to call for sdhci_set_clock_enable function from
sdhci_msm_set_clock.
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 42ef3eb..28e605c 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1343,19 +1343,8 @@ u16 sdhci_calc_clk(struct sdhci_host *host,
unsigned int clock,
}
EXPORT_SYMBOL_GPL(sdhci_calc_clk);
-void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
+void sdhci_set_clock_enable(struct sdhci_host *host, unsigned short clk)
{
- u16 clk;
- unsigned long timeout;
-
- host->mmc->actual_clock = 0;
-
- sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
-
- if (clock == 0)
- return;
-
- clk = sdhci_calc_clk(host, clock, &host->mmc->actual_clock);
clk |= SDHCI_CLOCK_INT_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
@@ -1377,6 +1366,24 @@ void sdhci_set_clock(struct sdhci_host *host,
unsigned int clock)
clk |= SDHCI_CLOCK_CARD_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
}
+EXPORT_SYMBOL_GPL(sdhci_set_clock_enable);
+
+void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+ u16 clk;
+ unsigned long timeout;
+
+ host->mmc->actual_clock = 0;
+
+ sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
+
+ if (clock == 0)
+ return;
+
+ clk = sdhci_calc_clk(host, clock, &host->mmc->actual_clock);
+
+ sdhci_set_clock_enable(host, clk);
+}
EXPORT_SYMBOL_GPL(sdhci_set_clock);
static void sdhci_set_power_reg(struct sdhci_host *host, unsigned char
mode,
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 766df17..43382e1 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -681,6 +681,7 @@ static inline bool sdhci_sdio_irq_enabled(struct
sdhci_host *host)
u16 sdhci_calc_clk(struct sdhci_host *host, unsigned int clock,
unsigned int *actual_clock);
void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
+void sdhci_set_clock_enable(struct sdhci_host *host, unsigned short clk);
void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
unsigned short vdd);
void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
Adrian,
Could you please comment here ?
+}
+
+/* sdhci_msm_set_clock - Called with (host->lock) spinlock held. */
+static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned
int clock)
+{
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+ int rc;
+
+ if (!clock) {
+ msm_host->clk_rate = clock;
+ goto out;
+ }
+
+ spin_unlock_irq(&host->lock);
+ if (clock != msm_host->clk_rate) {
Why do we need to check here? Can't we call clk_set_rate()
Unconditionally?
Since it may so happen that above layers may call for ->set_clock
function with same requested clock more than once, hence we cache the
host->clock here.
Also, since requested clock (host->clock) can be say 400Mhz but the
actual pltfm supported clock would be say 384MHz.
+ rc = clk_set_rate(msm_host->clk, clock);
+ if (rc) {
+ pr_err("%s: Failed to set clock at rate %u\n",
+ mmc_hostname(host->mmc), clock);
+ spin_lock_irq(&host->lock);
+ goto out;
Or replace the above two lines with goto err;
Ok, I will have another label out_lock instead of err.
+ }
+ msm_host->clk_rate = clock;
+ pr_debug("%s: Setting clock at rate %lu\n",
+ mmc_hostname(host->mmc), clk_get_rate(msm_host->clk));
+ }
And put an err label here.
will put the label here as out_lock;
+ spin_lock_irq(&host->lock);
+out:
+ __sdhci_msm_set_clock(host, clock);
+}
+
static const struct of_device_id sdhci_msm_dt_match[] = {
{ .compatible = "qcom,sdhci-msm-v4" },
{},
--
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