| Message ID | 20181206092459.26202-1-alek.du@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mmc: sdhci: fix the timeout check window for clock and reset | expand |
On Thu, 6 Dec 2018 at 10:25, <alek.du@intel.com> wrote: > > From: Alek Du <alek.du@intel.com> > > 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> Yes, now it works better! Applied for fixes and by adding Adrian's ack, thanks! Kind regards Uffe > --- > drivers/mmc/host/sdhci.c | 18 +++++++++++++----- > 1 file changed, 13 insertions(+), 5 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 99bdae53fa2e..451b08a818a9 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); > -- > 2.17.1 >
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 99bdae53fa2e..451b08a818a9 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);