Re: [PATCH v2] mmc: dw_mmc: revise the reset path in runtime resume

From: Ziyuan
Date: Wed Jan 04 2017 - 20:54:27 EST



On 01/05/2017 09:29 AM, Jaehoon Chung wrote:
On 01/05/2017 01:04 AM, ayaka wrote:

On 01/04/2017 08:51 PM, Ziyuan Xu wrote:
Immediately after reset, issue the command which sets
update_clock_register_only bit, the card clock will restart. Revise
dw_mci_ctrl_reset to dw_mci_reset, which has wrapped this sequence.

The patch fixes commit e9ed8835e990 ("mmc: dw_mmc: add runtime PM
callback"). MMC_PM_KEEP_POWEP is disabled for SD card and eMMC slots, so
that they have no chance to invoke dw_mci_setup_bus for update clock
behaviour. Let's consummate it.

Reported-by: Randy Li <randy.li@xxxxxxxxxxxxxx>
Signed-off-by: Ziyuan Xu <xzy.xu@xxxxxxxxxxxxxx>
Thank you Ziyuan, it works for me, but I capture those warning message in boot log
[ 5.943096] Unable to handle kernel NULL pointer dereference at virtual address 00000004
[ 5.951227] pgd = c0004000
[ 5.953958] [00000004] *pgd=00000000
[ 5.957563] Internal error: Oops: 5 [#1] SMP ARM
[ 5.962177] Modules linked in:
[ 5.965238] CPU: 0 PID: 117 Comm: kworker/0:3 Not tainted 4.9.0-next-20161224+ #122
[ 5.972875] Hardware name: Rockchip (Device Tree)
[ 5.977586] Workqueue: events_freezable mmc_rescan
[ 5.982377] task: ee186740 task.stack: ee1d2000
[ 5.986908] PC is at mci_send_cmd.constprop.5+0x20/0xb0
[ 5.992129] LR is at dw_mci_reset+0xdc/0x130
[ 5.996400] pc : [<c05cf464>] lr : [<c05d0308>] psr: 60000013
[ 5.996400] sp : ee1d3d38 ip : ee1d3d68 fp : ee1d3d64
[ 6.007862] r10: ee1d2000 r9 : c04fe918 r8 : c04fe918
[ 6.013083] r7 : c0c03d00 r6 : ee171780 r5 : c0c03d00 r4 : ee17e618
[ 6.019604] r3 : 00000201 r2 : f08e4000 r1 : 00200000 r0 : 00000000
[ 6.026127] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
[ 6.033253] Control: 10c5387d Table: 0000406a DAC: 00000051
[ 6.038994] Process kworker/0:3 (pid: 117, stack limit = 0xee1d2210)
[ 6.045340] Stack: (0xee1d3d38 to 0xee1d4000)
[ 6.049696] 3d20: c0495ed0 c0714e60
[ 6.057870] 3d40: ee17e618 00000001 ee171780 c0c03d00 c04fe918 c04fe918 ee1d3d7c ee1d3d68
[ 6.066043] 3d60: c05d0308 c05cf450 ee17e618 00000000 ee1d3da4 ee1d3d80 c05d07fc c05d0238
[ 6.074216] 3d80: 00000000 eeae5a10 00000000 c0c03d00 c04fe918 c04fe918 ee1d3db4 ee1d3da8
[ 6.082389] 3da0: c04fe954 c05d0718 ee1d3dec ee1d3db8 c0501c70 c04fe924 c0162310 c044f7b0
[ 6.090563] 3dc0: 00000000 eeae5a10 c0c62510 00000000 c0c03d00 c04fe918 c0175574 ee1d2000
[ 6.098737] 3de0: ee1d3e0c ee1d3df0 c0501df0 c0501b88 eeae5a10 c0c62510 00000000 c0c03d00
[ 6.106911] 3e00: ee1d3e5c ee1d3e10 c0501898 c0501dcc c0c0408c eeae5aa8 eeda0d00 00000000
[ 6.115085] 3e20: c0c04108 ee1867c0 ee1d3eac 00040900 c016e53c eeae5a10 00000004 eeae5a84
[ 6.123259] 3e40: 60000013 ee1d2000 c0c0408c ee160c00 ee1d3e7c ee1d3e60 c0501b5c c05013e4
[ 6.131433] 3e60: 00000000 ee160e1c 20000013 00000000 ee1d3ecc ee1d3e80 c05b0128 c0501af8
[ 6.139607] 3e80: ffffe000 ee160e80 00000000 ee186740 c0156324 00000100 00000200 00040900
[ 6.147781] 3ea0: ee1d3f14 ee160e94 ee160e1c ee160c00 60000013 eeda3e00 ee160e98 00000000
[ 6.155956] 3ec0: ee1d3ef4 ee1d3ed0 c05b3a68 c05aff80 ee160e94 ee176380 eeda0880 00000000
[ 6.164130] 3ee0: eeda3e00 ee160e98 ee1d3f2c ee1d3ef8 c0142374 c05b383c c0c03d00 eeda0898
[ 6.172303] 3f00: ee1d2000 eeda0880 ee176398 00000008 c0c03d00 eeda0898 ee1d2000 ee176380
[ 6.180477] 3f20: ee1d3f74 ee1d3f30 c014329c c01421d0 ee1d3f54 c0959c8c ee1d2000 00000000
[ 6.188650] 3f40: ee15a880 c0c20f1a ee1d1e7c eea00600 ee1d2000 00000000 ee15a880 ee176380
[ 6.196824] 3f60: ee1d1e7c eea0061c ee1d3fac ee1d3f78 c0148ed0 c0143248 00000000 c014323c
[ 6.204996] 3f80: ee1d3fac ee15a880 c0148da8 00000000 00000000 00000000 00000000 00000000
[ 6.213168] 3fa0: 00000000 ee1d3fb0 c0108e90 c0148db4 00000000 00000000 00000000 00000000
[ 6.221341] 3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 6.229514] 3fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff
[ 6.237696] [<c05cf464>] (mci_send_cmd.constprop.5) from [<c05d0308>] (dw_mci_reset+0xdc/0x130)
[ 6.246393] [<c05d0308>] (dw_mci_reset) from [<c05d07fc>] (dw_mci_runtime_resume+0xf0/0x1cc)
[ 6.254833] [<c05d07fc>] (dw_mci_runtime_resume) from [<c04fe954>] (pm_generic_runtime_resume+0x3c/0x48)
[ 6.264313] [<c04fe954>] (pm_generic_runtime_resume) from [<c0501c70>] (__rpm_callback+0xf4/0x244)
[ 6.273273] [<c0501c70>] (__rpm_callback) from [<c0501df0>] (rpm_callback+0x30/0x90)
[ 6.281017] [<c0501df0>] (rpm_callback) from [<c0501898>] (rpm_resume+0x4c0/0x714)
[ 6.288588] [<c0501898>] (rpm_resume) from [<c0501b5c>] (__pm_runtime_resume+0x70/0x90)
[ 6.296592] [<c0501b5c>] (__pm_runtime_resume) from [<c05b0128>] (__mmc_claim_host+0x1b4/0x1ec)
[ 6.305287] [<c05b0128>] (__mmc_claim_host) from [<c05b3a68>] (mmc_rescan+0x238/0x3f4)
[ 6.313206] [<c05b3a68>] (mmc_rescan) from [<c0142374>] (process_one_work+0x1b0/0x4c0)
[ 6.321125] [<c0142374>] (process_one_work) from [<c014329c>] (worker_thread+0x60/0x548)
[ 6.329215] [<c014329c>] (worker_thread) from [<c0148ed0>] (kthread+0x128/0x158)
[ 6.336614] [<c0148ed0>] (kthread) from [<c0108e90>] (ret_from_fork+0x14/0x24)
[ 6.343836] Code: e52de004 e8bd4000 e3035d00 e34c50c0 (e5909004)
[ 6.349974] ---[ end trace b2215a1ef671f11e ]---
It seems that cur_slot is NULL. Before calling the dw_mci_reset(),
need to assign cur_slot...I will check this.

Yes, I got this warning when insert sd card. We don't need to reset the host without active solt.
mmc_rescan will start a set_ios request once sd card insert. :-)
I send a v3 patch for fix this pitfall.

Best Regards,
Ziyuan Xu


Best Regards,
Jaehoon Chung

---

Changes in v2:
- update the commit message
- use dw_mci_reset instead of dw_mci_ctrl_reset

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 b44306b..ed63237 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -3324,7 +3324,7 @@ int dw_mci_runtime_resume(struct device *dev)
if (ret)
goto err;
- if (!dw_mci_ctrl_reset(host, SDMMC_CTRL_ALL_RESET_FLAGS)) {
+ if (!dw_mci_reset(host)) {
clk_disable_unprepare(host->ciu_clk);
ret = -ENODEV;
goto err;



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