| Message ID | 1486973622-1072-1-git-send-email-der.herr@hofr.at |
|---|---|
| State | Accepted |
| Delegated to: | Boris Brezillon |
| Headers | show |
On Mon, Feb 13, 2017 at 09:13:42AM +0100, Nicholas Mc Guire wrote: > The overall poll time here is INTEL_SPI_TIMEOUT * 1000 which is > 5000 * 1000 - so 5seconds and it is coded as a tight loop here delay_us > to readl_poll_timeout() is set to 0. As this is never called in an atomic > context sleeping should be no issue and there is no reasons for the > tight-loop here. > > Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
On Tue, 14 Feb 2017 11:47:24 +0200 Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > On Mon, Feb 13, 2017 at 09:13:42AM +0100, Nicholas Mc Guire wrote: > > The overall poll time here is INTEL_SPI_TIMEOUT * 1000 which is > > 5000 * 1000 - so 5seconds and it is coded as a tight loop here delay_us > > to readl_poll_timeout() is set to 0. As this is never called in an atomic > > context sleeping should be no issue and there is no reasons for the > > tight-loop here. > > > > Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at> > > Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> Queued to spi-nor/next. Thanks, Boris > > ______________________________________________________ > Linux MTD discussion mailing list > http://lists.infradead.org/mailman/listinfo/linux-mtd/
diff --git a/drivers/mtd/spi-nor/intel-spi.c b/drivers/mtd/spi-nor/intel-spi.c index a10f602..4630716 100644 --- a/drivers/mtd/spi-nor/intel-spi.c +++ b/drivers/mtd/spi-nor/intel-spi.c @@ -263,7 +263,7 @@ static int intel_spi_wait_hw_busy(struct intel_spi *ispi) u32 val; return readl_poll_timeout(ispi->base + HSFSTS_CTL, val, - !(val & HSFSTS_CTL_SCIP), 0, + !(val & HSFSTS_CTL_SCIP), 40, INTEL_SPI_TIMEOUT * 1000); } @@ -272,7 +272,7 @@ static int intel_spi_wait_sw_busy(struct intel_spi *ispi) u32 val; return readl_poll_timeout(ispi->sregs + SSFSTS_CTL, val, - !(val & SSFSTS_CTL_SCIP), 0, + !(val & SSFSTS_CTL_SCIP), 40, INTEL_SPI_TIMEOUT * 1000); }
The overall poll time here is INTEL_SPI_TIMEOUT * 1000 which is 5000 * 1000 - so 5seconds and it is coded as a tight loop here delay_us to readl_poll_timeout() is set to 0. As this is never called in an atomic context sleeping should be no issue and there is no reasons for the tight-loop here. Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at> --- V2: fixed prefix as pointed out by Boris Brezillon <boris.brezillon@free-electrons.com> Problem located by experimental coccinelle script: ./drivers/mtd/spi-nor/intel-spi.c:265:8-26: WARNING: usleep_range min=0 for delay INTEL_SPI_TIMEOUT * 1000 ./drivers/mtd/spi-nor/intel-spi.c:274:8-26: WARNING: usleep_range min=0 for delay INTEL_SPI_TIMEOUT * 1000 The rational for setting the delay_us here to 40 is that readx_poll_timeout() will take delay_us >> 2 + 1 as min value and that should be at least 10us (see Documentation/timers/timers-howto.txt). Ideally the delay would be made even larger to keep the load on the hrtimer subsystem low as these delays here do not seem to be critical. Someone that knows the details of this device would need to check if a larger delay would be ok here. Patch was compile tested with: multi_v7_defconfig (implies CONFIG_MTD_SPI_NOR=y) one coccicheck finding reported and one spars finding (in separate patches) Patch is against 4.10-rc7 (localversion-next is next-20170213) drivers/mtd/spi-nor/intel-spi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)