| Message ID | 1565909736-11379-1-git-send-email-thor.thayer@linux.intel.com |
|---|---|
| State | Accepted |
| Delegated to: | Ambarus Tudor |
| Headers | show |
| Series | [RESEND] mtd: spi-nor: Fix Cadence QSPI RCU Schedule Stall | expand |
Miquel, On 08/16/2019 01:55 AM, thor.thayer@linux.intel.com wrote: > External E-Mail > > > From: Thor Thayer <thor.thayer@linux.intel.com> > > The current Cadence QSPI driver sometimes caused a > "rcu_sched self-detected stall" while writing large files. > > Stall Report: > '# mtd_debug write /dev/mtd1 0 48816464 blob.img > [ 1815.454227] rcu: INFO: rcu_sched self-detected stall on CPU > [ 1815.459789] rcu: 0-....: (2099 ticks this GP) idle=8c6/1/0x40000002 > softirq=6492/6492 fqs=935 > [ 1815.468442] rcu: (t=2100 jiffies g=8749 q=247) > <snip> (abbreviated backtrace) > [ 1815.772086] [<c05a3ea0>] (cqspi_exec_flash_cmd) (cqspi_read_reg) > [ 1815.786203] [<c05a5488>] (cqspi_read_reg) from (read_sr) > [ 1815.803790] [<c05a0330>] (read_sr) from > (spi_nor_wait_till_ready_with_timeout) > [ 1815.816610] [<c05a182c>] (spi_nor_wait_till_ready_with_timeout) from > (spi_nor_write+0x104/0x1d0) > [ 1815.836791] [<c05a1a44>] (spi_nor_write) from (part_write+0x50/0x58) > <snip> > [ 1815.997961] cadence-qspi ff809000.spi: Flash command execution timed out. > [ 1816.004733] error -110 reading SR > file_to_flash: write, size 0x2e8e150, n 0x2e8e150 > write(): Connection timed out > > This was caused by a tight loop in cqspi_wait_for_bit(). Fix by using > readl_relaxed_poll_timeout() which sleeps 10us while polling a register. > > Fit onto 80 character line by truncating the bool clear parameter > > Fixes: 140623410536 ("mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller") > Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com> Probably this is a good candidate for mtd/fixes. Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com> > --- > drivers/mtd/spi-nor/cadence-quadspi.c | 19 +++++-------------- > 1 file changed, 5 insertions(+), 14 deletions(-) > > diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c > index 67f15a1f16fd..7bef63947b29 100644 > --- a/drivers/mtd/spi-nor/cadence-quadspi.c > +++ b/drivers/mtd/spi-nor/cadence-quadspi.c > @@ -13,6 +13,7 @@ > #include <linux/errno.h> > #include <linux/interrupt.h> > #include <linux/io.h> > +#include <linux/iopoll.h> > #include <linux/jiffies.h> > #include <linux/kernel.h> > #include <linux/module.h> > @@ -241,23 +242,13 @@ struct cqspi_driver_platdata { > > #define CQSPI_IRQ_STATUS_MASK 0x1FFFF > > -static int cqspi_wait_for_bit(void __iomem *reg, const u32 mask, bool clear) > +static int cqspi_wait_for_bit(void __iomem *reg, const u32 mask, bool clr) > { > - unsigned long end = jiffies + msecs_to_jiffies(CQSPI_TIMEOUT_MS); > u32 val; > > - while (1) { > - val = readl(reg); > - if (clear) > - val = ~val; > - val &= mask; > - > - if (val == mask) > - return 0; > - > - if (time_after(jiffies, end)) > - return -ETIMEDOUT; > - } > + return readl_relaxed_poll_timeout(reg, val, > + (((clr ? ~val : val) & mask) == mask), > + 10, CQSPI_TIMEOUT_MS * 1000); > } > > static bool cqspi_is_idle(struct cqspi_st *cqspi) >
On 08/16/2019 01:55 AM, thor.thayer@linux.intel.com wrote: > External E-Mail > > > From: Thor Thayer <thor.thayer@linux.intel.com> > > The current Cadence QSPI driver sometimes caused a > "rcu_sched self-detected stall" while writing large files. > > Stall Report: > '# mtd_debug write /dev/mtd1 0 48816464 blob.img > [ 1815.454227] rcu: INFO: rcu_sched self-detected stall on CPU > [ 1815.459789] rcu: 0-....: (2099 ticks this GP) idle=8c6/1/0x40000002 > softirq=6492/6492 fqs=935 > [ 1815.468442] rcu: (t=2100 jiffies g=8749 q=247) > <snip> (abbreviated backtrace) > [ 1815.772086] [<c05a3ea0>] (cqspi_exec_flash_cmd) (cqspi_read_reg) > [ 1815.786203] [<c05a5488>] (cqspi_read_reg) from (read_sr) > [ 1815.803790] [<c05a0330>] (read_sr) from > (spi_nor_wait_till_ready_with_timeout) > [ 1815.816610] [<c05a182c>] (spi_nor_wait_till_ready_with_timeout) from > (spi_nor_write+0x104/0x1d0) > [ 1815.836791] [<c05a1a44>] (spi_nor_write) from (part_write+0x50/0x58) > <snip> > [ 1815.997961] cadence-qspi ff809000.spi: Flash command execution timed out. > [ 1816.004733] error -110 reading SR > file_to_flash: write, size 0x2e8e150, n 0x2e8e150 > write(): Connection timed out > > This was caused by a tight loop in cqspi_wait_for_bit(). Fix by using > readl_relaxed_poll_timeout() which sleeps 10us while polling a register. > > Fit onto 80 character line by truncating the bool clear parameter > > Fixes: 140623410536 ("mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller") > Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com> > --- > drivers/mtd/spi-nor/cadence-quadspi.c | 19 +++++-------------- > 1 file changed, 5 insertions(+), 14 deletions(-) > Since the bug was not introduced in the previous release and we are quite late for mtd/fixes, Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git, spi-nor/next branch. Thanks, ta
diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c index 67f15a1f16fd..7bef63947b29 100644 --- a/drivers/mtd/spi-nor/cadence-quadspi.c +++ b/drivers/mtd/spi-nor/cadence-quadspi.c @@ -13,6 +13,7 @@ #include <linux/errno.h> #include <linux/interrupt.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/jiffies.h> #include <linux/kernel.h> #include <linux/module.h> @@ -241,23 +242,13 @@ struct cqspi_driver_platdata { #define CQSPI_IRQ_STATUS_MASK 0x1FFFF -static int cqspi_wait_for_bit(void __iomem *reg, const u32 mask, bool clear) +static int cqspi_wait_for_bit(void __iomem *reg, const u32 mask, bool clr) { - unsigned long end = jiffies + msecs_to_jiffies(CQSPI_TIMEOUT_MS); u32 val; - while (1) { - val = readl(reg); - if (clear) - val = ~val; - val &= mask; - - if (val == mask) - return 0; - - if (time_after(jiffies, end)) - return -ETIMEDOUT; - } + return readl_relaxed_poll_timeout(reg, val, + (((clr ? ~val : val) & mask) == mask), + 10, CQSPI_TIMEOUT_MS * 1000); } static bool cqspi_is_idle(struct cqspi_st *cqspi)