[PATCH v2] usb: dwc3: core: Add shutdown callback for dwc3

[Sandeep Maheswaram <sanm@codeaurora.org>]

This patch adds a shutdown callback to USB DWC core driver to ensure that
it is properly shutdown in reboot/shutdown path. This is required
where SMMU address translation is enabled like on SC7180
SoC and few others. If the hardware is still accessing memory after
SMMU translation is disabled as part of SMMU shutdown callback in
system reboot or shutdown path, then IOVAs(I/O virtual address)
which it was using will go on the bus as the physical addresses which
might result in unknown crashes (NoC/interconnect errors).

Signed-off-by: Sandeep Maheswaram <sanm@codeaurora.org>
---
Changes in v2:
        - As per Stephen's comment, calling dwc3_remove in dwc3_shutdown.

 drivers/usb/dwc3/core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 05e2e54c..2022d90 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1658,6 +1658,11 @@ static int dwc3_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void dwc3_shutdown(struct platform_device *pdev)
+{
+	dwc3_remove(pdev);
+}
+
 #ifdef CONFIG_PM
 static int dwc3_core_init_for_resume(struct dwc3 *dwc)
 {
@@ -1975,6 +1980,7 @@ MODULE_DEVICE_TABLE(acpi, dwc3_acpi_match);
 static struct platform_driver dwc3_driver = {
 	.probe		= dwc3_probe,
 	.remove		= dwc3_remove,
+	.shutdown   = dwc3_shutdown,
 	.driver		= {
 		.name	= "dwc3",
 		.of_match_table	= of_match_ptr(of_dwc3_match),
-- 
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