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| author | Alek Du <alek.du@intel.com> | 2018-12-06 17:24:59 +0800 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2018-12-06 11:22:00 +0100 |
| commit | b704441e38f645dcfba1348ca3cc1ba43d1a9f31 (patch) | |
| tree | a6f1a837a5bacca8394309b99fe94e219424b5f2 | |
| parent | db2039fcfd5754d15986340152e4503737f68f8d (diff) | |
| download | linux-b704441e38f645dcfba1348ca3cc1ba43d1a9f31.tar.gz | |
mmc: sdhci: fix the timeout check window for clock and reset
We observed some premature timeouts on a virtualization platform, the log
is like this:
case 1:
[159525.255629] mmc1: Internal clock never stabilised.
[159525.255818] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
[159525.256049] mmc1: sdhci: Sys addr: 0x00000000 | Version: 0x00001002
...
[159525.257205] mmc1: sdhci: Wake-up: 0x00000000 | Clock: 0x0000fa03
From the clock control register dump, we are pretty sure the clock was
stablized.
case 2:
[ 914.550127] mmc1: Reset 0x2 never completed.
[ 914.550321] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
[ 914.550608] mmc1: sdhci: Sys addr: 0x00000010 | Version: 0x00001002
After checking the sdhci code, we found the timeout check actually has a
little window that the CPU can be scheduled out and when it comes back,
the original time set or check is not valid.
Fixes: 5a436cc0af62 ("mmc: sdhci: Optimize delay loops")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Alek Du <alek.du@intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
| -rw-r--r-- | drivers/mmc/host/sdhci.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 99bdae53fa2e08..451b08a818a9d6 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -216,8 +216,12 @@ void sdhci_reset(struct sdhci_host *host, u8 mask) timeout = ktime_add_ms(ktime_get(), 100); /* hw clears the bit when it's done */ - while (sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask) { - if (ktime_after(ktime_get(), timeout)) { + while (1) { + bool timedout = ktime_after(ktime_get(), timeout); + + if (!(sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask)) + break; + if (timedout) { pr_err("%s: Reset 0x%x never completed.\n", mmc_hostname(host->mmc), (int)mask); sdhci_dumpregs(host); @@ -1608,9 +1612,13 @@ void sdhci_enable_clk(struct sdhci_host *host, u16 clk) /* Wait max 20 ms */ timeout = ktime_add_ms(ktime_get(), 20); - while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL)) - & SDHCI_CLOCK_INT_STABLE)) { - if (ktime_after(ktime_get(), timeout)) { + while (1) { + bool timedout = ktime_after(ktime_get(), timeout); + + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL); + if (clk & SDHCI_CLOCK_INT_STABLE) + break; + if (timedout) { pr_err("%s: Internal clock never stabilised.\n", mmc_hostname(host->mmc)); sdhci_dumpregs(host); |