dmaengine: usb-dmac: Make DMAC system sleep callbacks explicit
authorPhuong Nguyen <phuong.nguyen.xw@renesas.com>
Thu, 17 Jan 2019 08:44:17 +0000 (17:44 +0900)
committerVinod Koul <vkoul@kernel.org>
Sun, 20 Jan 2019 10:59:52 +0000 (16:29 +0530)
commitd9140a0da4a230a03426d175145989667758aa6a
tree734e503e39c72e0c5e24b66e070f6769b4afdd03
parentbfeffd155283772bbe78c6a05dec7c0128ee500c
dmaengine: usb-dmac: Make DMAC system sleep callbacks explicit

This commit fixes the issue that USB-DMAC hangs silently after system
resumes on R-Car Gen3 hence renesas_usbhs will not work correctly
when using USB-DMAC for bulk transfer e.g. ethernet or serial
gadgets.

The issue can be reproduced by these steps:
 1. modprobe g_serial
 2. Suspend and resume system.
 3. connect a usb cable to host side
 4. Transfer data from Host to Target
 5. cat /dev/ttyGS0 (Target side)
 6. echo "test" > /dev/ttyACM0 (Host side)

The 'cat' will not result anything. However, system still can work
normally.

Currently, USB-DMAC driver does not have system sleep callbacks hence
this driver relies on the PM core to force runtime suspend/resume to
suspend and reinitialize USB-DMAC during system resume. After
the commit 17218e0092f8 ("PM / genpd: Stop/start devices without
pm_runtime_force_suspend/resume()"), PM core will not force
runtime suspend/resume anymore so this issue happens.

To solve this, make system suspend resume explicit by using
pm_runtime_force_{suspend,resume}() as the system sleep callbacks.
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS() is used to make sure USB-DMAC
suspended after and initialized before renesas_usbhs."

Signed-off-by: Phuong Nguyen <phuong.nguyen.xw@renesas.com>
Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Cc: <stable@vger.kernel.org> # v4.16+
[shimoda: revise the commit log and add Cc tag]
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
drivers/dma/sh/usb-dmac.c