[PATCH 4.19 199/280] dmaengine: usb-dmac: Make DMAC system sleep callbacks explicit

From: Greg Kroah-Hartman
Date: Fri Mar 22 2019 - 08:06:51 EST

4.19-stable review patch. If anyone has any objections, please let me know.


From: Phuong Nguyen <phuong.nguyen.xw@xxxxxxxxxxx>

commit d9140a0da4a230a03426d175145989667758aa6a upstream.

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

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

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.
suspended after and initialized before renesas_usbhs."

Signed-off-by: Phuong Nguyen <phuong.nguyen.xw@xxxxxxxxxxx>
Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@xxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.16+
[shimoda: revise the commit log and add Cc tag]
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/dma/sh/usb-dmac.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/dma/sh/usb-dmac.c
+++ b/drivers/dma/sh/usb-dmac.c
@@ -697,6 +697,8 @@ static int usb_dmac_runtime_resume(struc
#endif /* CONFIG_PM */

static const struct dev_pm_ops usb_dmac_pm = {
+ SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+ pm_runtime_force_resume)
SET_RUNTIME_PM_OPS(usb_dmac_runtime_suspend, usb_dmac_runtime_resume,