[PATCH v5 2/2] mmc: dw_mmc: force setup bus if active slots exist

Shawn Lin shawn.lin at rock-chips.com
Thu Jan 12 18:59:22 PST 2017

From: Ziyuan Xu <xzy.xu at rock-chips.com>

It's necessary to setup bus if any slots are present.
- update clock after ctrl reset
- if the host has genpd node, we can guarantee the clock is
  available before starting request. Otherwies, the clock register
  is reset once power off the pd, and host can't output the active
  clock during communication.

Fixes: e9ed8835e990 ("mmc: dw_mmc: add runtime PM callback")
Fixes: df9bcc2bc0a1 ("mmc: dw_mmc: add missing codes for runtime resume")
cc: <stable at vger.kernel.org>
Reported-by: Randy Li <randy.li at rock-chips.com>
Reported-by: S. Gilles <sgilles at math.umd.edu>
Signed-off-by: Ziyuan Xu <xzy.xu at rock-chips.com>
Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>


Changes in v5:
- rebase in order to skip spamming log

Changes in v4:
- update commit message
- fix SD host rpm resume can't work

Changes in v3:
- only reset host with active slot.

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

 drivers/mmc/host/dw_mmc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index dc58ec3..0914d53 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -3367,10 +3367,11 @@ int dw_mci_runtime_resume(struct device *dev)
 		if (!slot)
-		if (slot->mmc->pm_flags & MMC_PM_KEEP_POWER) {
+		if (slot->mmc->pm_flags & MMC_PM_KEEP_POWER)
 			dw_mci_set_ios(slot->mmc, &slot->mmc->ios);
-			dw_mci_setup_bus(slot, true, true);
-		}
+		/* Force setup bus to guarantee available clock output */
+		dw_mci_setup_bus(slot, true, true);
 	/* Now that slots are all setup, we can enable card detect */

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