[PATCH] ARM: dts: hi6220: Reset the mmc hosts

[Daniel Lezcano]

The MMC hosts could be left in an unconsistent or uninitialized state from
the firmware. Instead of assuming, the firmware did the right things, let's
reset the host controllers.

This change fixes a bug when the mmc2/sdio is initialized leading to a hung
task:

[  242.704294] INFO: task kworker/7:1:675 blocked for more than 120 seconds.
[  242.711129]       Not tainted 4.9.0-rc8-00017-gcf0251f #3
[  242.716571] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  242.724435] kworker/7:1     D    0   675      2 0x00000000
[  242.729973] Workqueue: events_freezable mmc_rescan
[  242.734796] Call trace:
[  242.737269] [<ffff00000808611c>] __switch_to+0xa8/0xb4
[  242.742437] [<ffff000008d07c04>] __schedule+0x1c0/0x67c
[  242.747689] [<ffff000008d08254>] schedule+0x40/0xa0
[  242.752594] [<ffff000008d0b284>] schedule_timeout+0x1c4/0x35c
[  242.758366] [<ffff000008d08e38>] wait_for_common+0xd0/0x15c
[  242.763964] [<ffff000008d09008>] wait_for_completion+0x28/0x34
[  242.769825] [<ffff000008a1a9f4>] mmc_wait_for_req_done+0x40/0x124
[  242.775949] [<ffff000008a1ab98>] mmc_wait_for_req+0xc0/0xf8
[  242.781549] [<ffff000008a1ac3c>] mmc_wait_for_cmd+0x6c/0x84
[  242.787149] [<ffff000008a26610>] mmc_io_rw_direct_host+0x9c/0x114
[  242.793270] [<ffff000008a26aa0>] sdio_reset+0x34/0x7c
[  242.798347] [<ffff000008a1d46c>] mmc_rescan+0x2fc/0x360

[ ... ]

Cc: stable at vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano at linaro.org>
---
 arch/arm64/boot/dts/hisilicon/hi6220.dtsi | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
index 470461d..1e5129b 100644
--- a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
+++ b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
@@ -774,6 +774,7 @@
 			clocks = <&sys_ctrl 2>, <&sys_ctrl 1>;
 			clock-names = "ciu", "biu";
 			resets = <&sys_ctrl PERIPH_RSTDIS0_MMC0>;
+			reset-names = "reset";
 			bus-width = <0x8>;
 			vmmc-supply = <&ldo19>;
 			pinctrl-names = "default";
@@ -797,6 +798,7 @@
 			clocks = <&sys_ctrl 4>, <&sys_ctrl 3>;
 			clock-names = "ciu", "biu";
 			resets = <&sys_ctrl PERIPH_RSTDIS0_MMC1>;
+			reset-names = "reset";
 			vqmmc-supply = <&ldo7>;
 			vmmc-supply = <&ldo10>;
 			bus-width = <0x4>;
@@ -815,6 +817,7 @@
 			clocks = <&sys_ctrl HI6220_MMC2_CIUCLK>, <&sys_ctrl HI6220_MMC2_CLK>;
 			clock-names = "ciu", "biu";
 			resets = <&sys_ctrl PERIPH_RSTDIS0_MMC2>;
+			reset-names = "reset";
 			bus-width = <0x4>;
 			broken-cd;
 			pinctrl-names = "default", "idle";
-- 
1.9.1