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mmc: sdhci-of-arasan: Add quirk for unstable clocks

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Some controllers immediately report SDHCI_CLOCK_INT_STABLE after
enabling the clock even when the clock is not stable. When used in
conjunction with older/slower cards, this can result in:

    mmc0: error -84 whilst initialising SD card

When the stable reporting is known to be broken, we simply wait for the
maximum stabilization period.

Signed-off-by: Helmut Grohne <h.grohne@intenta.de>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Helmut Grohne 2018-06-20 13:33:00 +02:00 committed by Ulf Hansson
parent 26c3122813
commit 3f2c7d5d15
1 changed files with 16 additions and 0 deletions
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16
drivers/mmc/host/sdhci-of-arasan.c
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@ -102,6 +102,9 @@ struct sdhci_arasan_data {
/* Controller does not have CD wired and will not function normally without */
#define SDHCI_ARASAN_QUIRK_FORCE_CDTEST BIT(0)
/* Controller immediately reports SDHCI_CLOCK_INT_STABLE after enabling the
* internal clock even when the clock isn't stable */
#define SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE BIT(1)
};
static const struct sdhci_arasan_soc_ctl_map rk3399_soc_ctl_map = {
@ -207,6 +210,16 @@ static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
sdhci_set_clock(host, clock);
if (sdhci_arasan->quirks & SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE)
/*
* Some controllers immediately report SDHCI_CLOCK_INT_STABLE
* after enabling the clock even though the clock is not
* stable. Trying to use a clock without waiting here results
* in EILSEQ while detecting some older/slower cards. The
* chosen delay is the maximum delay from sdhci_set_clock.
*/
msleep(20);
if (ctrl_phy) {
phy_power_on(sdhci_arasan->phy);
sdhci_arasan->is_phy_on = true;
@ -758,6 +771,9 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
if (of_property_read_bool(np, "xlnx,fails-without-test-cd"))
sdhci_arasan->quirks |= SDHCI_ARASAN_QUIRK_FORCE_CDTEST;
if (of_property_read_bool(np, "xlnx,int-clock-stable-broken"))
sdhci_arasan->quirks |= SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE;
pltfm_host->clk = clk_xin;
if (of_device_is_compatible(pdev->dev.of_node,