linux-kernel - Re: [PATCH] Revert "mmc: dw_mmc-rockchip: add runtime PM support"

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Date:   Mon, 23 Jan 2017 11:24:32 +0000
From:   John Keeping <john@...anate.com>
To:     Jaehoon Chung <jh80.chung@...sung.com>
Cc:     Romain Perier <romain.perier@...labora.com>,
        Romain Perier <romain.perier@...il.com>,
        ulf.hansson@...aro.org, xzy.xu@...k-chips.com,
        Jaehoon Chung <jh80.chung@...il.com>,
        Heiko Stübner <heiko@...ech.de>,
        Randy Li <randy.li@...k-chips.com>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        ayaka <ayaka@...lik.info>, linux-mmc@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] Revert "mmc: dw_mmc-rockchip: add runtime PM support"

Hi,

On Fri, 20 Jan 2017 15:08:57 +0900, Jaehoon Chung wrote:
> On 01/17/2017 10:38 PM, Romain Perier wrote:
> > In my case I can reproduce the issue on the rock2 and the firefly-rk3288. A workaround is to
> > 
> > comment the line ".pm = <&pm_ops_foo>" .  
> 
> Sorry for late. I'm checking runtime PM for this. 
> After that, i will decide whether revert or not.

I hit this problem on Rock2 when trying 4.10-rc4.  The following patch
fixes it for me.

I'm not sure if this is safe in general or whether it should be guarded
by a quirk that is enabled for RK3288.

-- >8 --
Subject: [PATCH] mmc: dw_mmc: restore CIU state on resume

At least on RK3288, asserting SDMMC_CTRL_RESET causes the CIU to reset
and disable the clock.  We need to send SDMMC_CMD_UPD_CLK after doing
this in order to avoid the MMC host hanging.

Signed-off-by: John Keeping <john@...anate.com>
---
 drivers/mmc/host/dw_mmc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index b44306b886cb..e7504dabcfb6 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -3311,6 +3311,7 @@ int dw_mci_runtime_resume(struct device *dev)
 {
 	int i, ret = 0;
 	struct dw_mci *host = dev_get_drvdata(dev);
+	u32 sdmmc_cmd_bits = SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT;
 
 	if (host->cur_slot &&
 	    (mmc_can_gpio_cd(host->cur_slot->mmc) ||
@@ -3357,6 +3358,9 @@ int dw_mci_runtime_resume(struct device *dev)
 		if (slot->mmc->pm_flags & MMC_PM_KEEP_POWER) {
 			dw_mci_set_ios(slot->mmc, &slot->mmc->ios);
 			dw_mci_setup_bus(slot, true);
+		} else {
+			/* restore CIU */
+			mci_send_cmd(slot, sdmmc_cmd_bits, 0);
 		}
 	}
 
-- 
2.11.0.197.gb556de5.dirty