[+ Jaehoon]
On 2018/2/22 21:34, Evgeniy Didin wrote:
In commit 9d9491a7da2a ("mmc: dw_mmc: Fix the DTO timeout calculation") have been made changes which cause multiply overflow for 32-bit systems. The broken timeout calculations caused false interrupt latency warnings and stacktrace splat (such as below) when accessing the SD Card.
| Running : 4M-check-reassembly-tcp-cmykw2-rotatew2.out -v0 -w1 | - Info: Finished target initialization. | mmcblk0: error -110 transferring data, sector 320544, nr 2048, cmd response | 0x900, card status 0x0 | mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 400000Hz, actual | 396825HZ div = 63) | mmc_host mmc0: Bus speed (slot 0) = 50000000Hz (slot req 25000000Hz, actual | 25000000HZ div = 1) | ------------[ cut here ]------------ | softirq: huh, entered softirq 6 TASKLET 6f6a9412 with preempt_count 00000101, | exited with 00000100? | WARNING: CPU: 2 PID: 0 at ../lib/scatterlist.c:652 sg_miter_next+0x28/0x20c | Modules linked in: | CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.15.0 #57 | | Stack Trace: | arc_unwind_core.constprop.1+0xd0/0xf4 | dump_stack+0x68/0x80 | warn_slowpath_null+0x4e/0xec | sg_miter_next+0x28/0x20c | dw_mci_read_data_pio+0x44/0x190 | dw_mmc f000a000.mmc: Unexpected interrupt latency
I think we tested SD cards but the main reason we missed this is that we don't use pio mode since dw_mmc decides the transfer mode via HCON register but we don't have one platform at hand then to do that. Given the data-transfer-over interrupt should come after the data hit the RAM, so pio mode could probably consume more time than IDMAC.
| dw_mci_interrupt+0x3ee/0x530 | __handle_irq_event_percpu+0x56/0x150 | handle_irq_event+0x34/0x78 | handle_level_irq+0x8e/0x120 | generic_handle_irq+0x1c/0x2c | idu_cascade_isr+0x30/0x6c | __handle_domain_irq+0x72/0xc8 | ret_from_exception+0x0/0x8 |---[ end trace 2a58c9af6c25fe51 ]---
Lets cast this multiply to u64 type which prevents overflow.
Tested-by: Vineet Gupta Vineet.Gupta1@synopsys.com Fixes: ARC STAR 9001306872 HSDK, sdio: board crashes when copying big files
Signed-off-by: Evgeniy Didin Evgeniy.Didin@synopsys.com
CC: Alexey Brodkin abrodkin@synopsys.com CC: Eugeniy Paltsev paltsev@synopsys.com CC: Douglas Anderson dianders@chromium.org CC: Ulf Hansson ulf.hansson@linaro.org CC: linux-kernel@vger.kernel.org CC: linux-snps-arc@lists.infradead.org Cc: stable@vger.kernel.org # 9d9491a7da2a mmc: dw_mmc: Fix the DTO timeout calculation
The fix looks good to me, but the tags should be improved a bit:
Fixes: 9d9491a7da2a ("mmc: dw_mmc: Fix the DTO timeout calculation") Cc: stable@vger.kernel.org
Otherwise, Reviewed-by: Shawn Lin shawn.lin@rock-chips.com
BTW, would you mind cooking another patch for fixing cto_ms case?
Changes since v1: -uint64_t switched to u64 -changed commit message drivers/mmc/host/dw_mmc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 0aa39975f33b..1a0b9751c67c 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -1944,7 +1944,7 @@ static void dw_mci_set_drto(struct dw_mci *host) drto_div = (mci_readl(host, CLKDIV) & 0xff) * 2; if (drto_div == 0) drto_div = 1;
- drto_ms = DIV_ROUND_UP(MSEC_PER_SEC * drto_clks * drto_div,
- drto_ms = DIV_ROUND_UP((u64)MSEC_PER_SEC * drto_clks * drto_div, host->bus_hz);
/* add a bit spare time */