From: "Du, Alek" <alek.du@intel.com> To: Adrian Hunter <adrian.hunter@intel.com> Cc: <linux-mmc@vger.kernel.org>, <ulf.hansson@linaro.org>, <linux-kernel@vger.kernel.org> Subject: [PATCH V3] sdhci: fix the timeout check window for clock and reset Date: Wed, 5 Dec 2018 11:14:50 +0800 [thread overview] Message-ID: <20181205111450.300e0478@xdu1-mobl> (raw) In-Reply-To: <229dc468-1155-b81f-9fda-b71402387e3f@intel.com> From bcb38577961823b4f8f2cc0aec7dd450a81b6ddc Mon Sep 17 00:00:00 2001 From: Alek Du <alek.du@intel.com> Date: Fri, 30 Nov 2018 14:02:28 +0800 Subject: [PATCH] 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") Signed-off-by: Alek Du <alek.du@intel.com> Cc: stable@vger.kernel.org # v4.12+ --- 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
WARNING: multiple messages have this Message-ID (diff)
From: "Du, Alek" <alek.du@intel.com> To: Adrian Hunter <adrian.hunter@intel.com> Cc: linux-mmc@vger.kernel.org, ulf.hansson@linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH V3] sdhci: fix the timeout check window for clock and reset Date: Wed, 5 Dec 2018 11:14:50 +0800 [thread overview] Message-ID: <20181205111450.300e0478@xdu1-mobl> (raw) In-Reply-To: <229dc468-1155-b81f-9fda-b71402387e3f@intel.com> >From bcb38577961823b4f8f2cc0aec7dd450a81b6ddc Mon Sep 17 00:00:00 2001 From: Alek Du <alek.du@intel.com> Date: Fri, 30 Nov 2018 14:02:28 +0800 Subject: [PATCH] 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") Signed-off-by: Alek Du <alek.du@intel.com> Cc: stable@vger.kernel.org # v4.12+ --- 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
next prev parent reply other threads:[~2018-12-05 3:14 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-11-30 7:00 [PATCH] sdhci: fix the fake timeout bug Du, Alek 2018-11-30 7:00 ` Du, Alek 2018-11-30 9:19 ` Adrian Hunter 2018-11-30 14:13 ` Du, Alek 2018-11-30 14:13 ` Du, Alek 2018-11-30 14:40 ` Adrian Hunter 2018-12-01 5:42 ` Du, Alek 2018-12-01 5:42 ` Du, Alek 2018-12-04 1:01 ` [PATCH V2] sdhci: fix the timeout check window for clock and reset Du, Alek 2018-12-04 1:01 ` Du, Alek 2018-12-04 12:24 ` Adrian Hunter 2018-12-05 3:14 ` Du, Alek [this message] 2018-12-05 3:14 ` [PATCH V3] " Du, Alek 2018-12-05 11:16 ` Adrian Hunter 2018-12-05 14:20 ` Ulf Hansson 2018-12-05 23:33 ` [PATCH V3 rebase] mmc: " Du, Alek 2018-12-05 23:33 ` Du, Alek 2018-12-06 7:55 ` Ulf Hansson 2018-12-06 9:28 ` Du, Alek 2018-12-04 12:47 ` [PATCH] sdhci: fix the fake timeout bug Adrian Hunter
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