On 3/24/2021 9:01 AM, Stephen Boyd wrote:
Quoting Sandeep Maheswaram (2021-03-23 12:27:32)
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).
Previously this was added in dwc3 qcom glue driver.
https://patchwork.kernel.org/project/linux-arm-msm/list/?series=382449
But observed kernel panic as glue driver shutdown getting called after
iommu shutdown. As we are adding iommu nodes in dwc core node
in device tree adding shutdown callback in core driver seems correct.
Signed-off-by: Sandeep Maheswaram <sanm@xxxxxxxxxxxxxx>
---
drivers/usb/dwc3/core.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 94fdbe5..777b2b5 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1634,11 +1634,9 @@ static int dwc3_probe(struct platform_device *pdev)
return ret;
}
-static int dwc3_remove(struct platform_device *pdev)
+static void __dwc3_teardown(struct dwc3 *dwc)
{
- struct dwc3 *dwc = platform_get_drvdata(pdev);
-
- pm_runtime_get_sync(&pdev->dev);
+ pm_runtime_get_sync(dwc->dev);
dwc3_debugfs_exit(dwc);
dwc3_core_exit_mode(dwc);
@@ -1646,19 +1644,32 @@ static int dwc3_remove(struct platform_device *pdev)
dwc3_core_exit(dwc);
dwc3_ulpi_exit(dwc);
- pm_runtime_disable(&pdev->dev);
- pm_runtime_put_noidle(&pdev->dev);
- pm_runtime_set_suspended(&pdev->dev);
+ pm_runtime_disable(dwc->dev);
+ pm_runtime_put_noidle(dwc->dev);
+ pm_runtime_set_suspended(dwc->dev);
dwc3_free_event_buffers(dwc);
dwc3_free_scratch_buffers(dwc);
if (dwc->usb_psy)
power_supply_put(dwc->usb_psy);
+}
+
+static int dwc3_remove(struct platform_device *pdev)
+{
+ struct dwc3 *dwc = platform_get_drvdata(pdev);
+
+ __dwc3_teardown(dwc);
return 0;
}
+static void dwc3_shutdown(struct platform_device *pdev)
+{
+ struct dwc3 *dwc = platform_get_drvdata(pdev);
+
+ __dwc3_teardown(dwc);
+}
Can't this be
static void dwc3_shutdown(struct platform_device *pdev)
{
dwc3_remove(pdev);
}
and then there's nothing else to change? Basically ignore return value
of dwc3_remove() to make shutdown and remove harmonize. I also wonder if
this is more common than we think and a struct driver flag could be set
to say "call remove for shutdown" and then have driver core swizzle on
that and save some duplicate functions.
I was referring to similar patch
https://patchwork.kernel.org/project/linux-usb/patch/20190817174140.6394-1-vicencb@xxxxxxxxx/
#ifdef CONFIG_PM
static int dwc3_core_init_for_resume(struct dwc3 *dwc)
{
@@ -1976,6 +1987,7 @@ MODULE_DEVICE_TABLE(acpi, dwc3_acpi_match);
static struct platform_driver dwc3_driver = {
.probe = dwc3_probe,
.remove = dwc3_remove,
+ .shutdown = dwc3_shutdown,
