diff options
| author | Shawn Lin <shawn.lin@rock-chips.com> | 2026-01-28 21:26:15 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-02-06 18:44:20 +0300 |
| commit | 59b8a1ca6df4db2ca250e9eeab74e2b0068d69e9 (patch) | |
| tree | d12910bbfd5891588e30d633bc3f0e2157233a0e /drivers/mmc | |
| parent | 0d1ae48aaa1ac020e560dd4fb60c4ec5fd7963fe (diff) | |
| download | linux-59b8a1ca6df4db2ca250e9eeab74e2b0068d69e9.tar.xz | |
mmc: sdhci-of-dwcmshc: Prevent illegal clock reduction in HS200/HS400 mode
[ Upstream commit 3009738a855cf938bbfc9078bec725031ae623a4 ]
When operating in HS200 or HS400 timing modes, reducing the clock frequency
below 52MHz will lead to link broken as the Rockchip DWC MSHC controller
requires maintaining a minimum clock of 52MHz in these modes.
Add a check to prevent illegal clock reduction through debugfs:
root@debian:/# echo 50000000 > /sys/kernel/debug/mmc0/clock
root@debian:/# [ 30.090146] mmc0: running CQE recovery
mmc0: cqhci: Failed to halt
mmc0: cqhci: spurious TCN for tag 0
WARNING: drivers/mmc/host/cqhci-core.c:797 at cqhci_irq+0x254/0x818, CPU#1: kworker/1:0H/24
Modules linked in:
CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0H Not tainted 6.19.0-rc1-00001-g09db0998649d-dirty #204 PREEMPT
Hardware name: Rockchip RK3588 EVB1 V10 Board (DT)
Workqueue: kblockd blk_mq_run_work_fn
pstate: 604000c9 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : cqhci_irq+0x254/0x818
lr : cqhci_irq+0x254/0x818
...
Fixes: c6f361cba51c ("mmc: sdhci-of-dwcmshc: add support for rk3588")
Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Yifeng Zhao <yifeng.zhao@rock-chips.com>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/host/sdhci-of-dwcmshc.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c index 19376bee9ec1..aa68c63f7024 100644 --- a/drivers/mmc/host/sdhci-of-dwcmshc.c +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c @@ -236,6 +236,13 @@ static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock sdhci_writel(host, extra, reg); if (clock <= 52000000) { + if (host->mmc->ios.timing == MMC_TIMING_MMC_HS200 || + host->mmc->ios.timing == MMC_TIMING_MMC_HS400) { + dev_err(mmc_dev(host->mmc), + "Can't reduce the clock below 52MHz in HS200/HS400 mode"); + return; + } + /* * Disable DLL and reset both of sample and drive clock. * The bypass bit and start bit need to be set if DLL is not locked. |