linux-kernel - [PATCH 4.4 198/230] dmaengine: usb-dmac: Make DMAC system sleep callbacks explicit

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Message-Id: <20190322111250.728983008@linuxfoundation.org>
Date:   Fri, 22 Mar 2019 12:15:36 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Phuong Nguyen <phuong.nguyen.xw@...esas.com>,
        Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@...esas.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Vinod Koul <vkoul@...nel.org>
Subject: [PATCH 4.4 198/230] dmaengine: usb-dmac: Make DMAC system sleep callbacks explicit

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

------------------

From: Phuong Nguyen <phuong.nguyen.xw@...esas.com>

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
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@...esas.com>
Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@...esas.com>
Cc: <stable@...r.kernel.org> # v4.16+
[shimoda: revise the commit log and add Cc tag]
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 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
@@ -700,6 +700,8 @@ 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,
 			   NULL)
 };