[+ 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@xxxxxxxxxxxx>
Fixes: ARC STAR 9001306872 HSDK, sdio: board crashes when copying big files
Signed-off-by: Evgeniy Didin <Evgeniy.Didin@xxxxxxxxxxxx>
CC: Alexey Brodkin <abrodkin@xxxxxxxxxxxx>
CC: Eugeniy Paltsev <paltsev@xxxxxxxxxxxx>
CC: Douglas Anderson <dianders@xxxxxxxxxxxx>
CC: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
CC: linux-kernel@xxxxxxxxxxxxxxx
CC: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # 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@xxxxxxxxxxxxxxx>
Otherwise,
Reviewed-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
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 */
--
Best Regards
Shawn Lin