Hi Fabrice,
>On 3/16/2023 12:41 PM, Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx> wrote:
>From: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
>Sent: Thursday, March 16, 2023 12:41 PM
>To: Minas Harutyunyan <hminas@xxxxxxxxxxxx>; gregkh@xxxxxxxxxxxxxxxxxxx;
>maz@xxxxxxxxxx; m.szyprowski@xxxxxxxxxxx
>Cc: linux-usb@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-stm32@st-
>md-mailman.stormreply.com; amelie.delaunay@xxxxxxxxxxx;
>alexandre.torgue@xxxxxxxxxxx; fabrice.gasnier@xxxxxxxxxxx
>Subject: [PATCH v2] usb: dwc2: fix a devres leak in hw_enable upon suspend
>resume
>
>Each time the platform goes to low power, PM suspend / resume routines
>call: __dwc2_lowlevel_hw_enable -> devm_add_action_or_reset().
>This adds a new devres each time.
>This may also happen at runtime, as dwc2_lowlevel_hw_enable() can be called
>from udc_start().
>
>This can be seen with tracing:
>- echo 1 > /sys/kernel/debug/tracing/events/dev/devres_log/enable
>- go to low power
>- cat /sys/kernel/debug/tracing/trace
>
>A new "ADD" entry is found upon each low power cycle:
>... devres_log: 49000000.usb-otg ADD 82a13bba devm_action_release (8 bytes)
>... devres_log: 49000000.usb-otg ADD 49889daf devm_action_release (8 bytes)
>...
>
>A second issue is addressed here:
>- regulator_bulk_enable() is called upon each PM cycle (suspend/resume).
>- regulator_bulk_disable() never gets called.
>
>So the reference count for these regulators constantly increase, by one upon
>each low power cycle, due to missing regulator_bulk_disable() call in
>__dwc2_lowlevel_hw_disable().
>
>The original fix that introduced the devm_add_action_or_reset() call, fixed
>an issue during probe, that happens due to other errors in
>dwc2_driver_probe() -> dwc2_core_reset(). Then the probe fails without
>disabling regulators, when dr_mode == USB_DR_MODE_PERIPHERAL.
>
>Rather fix the error path: disable all the low level hardware in the error
>path, by using the "hsotg->ll_hw_enabled" flag. Checking dr_mode has been
>introduced to avoid a dual call to dwc2_lowlevel_hw_disable().
>"ll_hw_enabled" should achieve the same (and is used currently in the
>remove() routine).
>
>Fixes: 54c196060510 ("usb: dwc2: Always disable regulators on driver
>teardown")
>Fixes: 33a06f1300a7 ("usb: dwc2: Fix error path in gadget registration")
>Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
Reviewed-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxxxxx>
Tested-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxxxxx>
Acked-by: Minas Harutyunyan <hminas@xxxxxxxxxxxx>
>---
>Changes in v2: commit message updated to remove useless tags
>---
> drivers/usb/dwc2/platform.c | 16 ++--------------
> 1 file changed, 2 insertions(+), 14 deletions(-)
>
>diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c index
>262c13b6362a..d1589ba7d322 100644
>--- a/drivers/usb/dwc2/platform.c
>+++ b/drivers/usb/dwc2/platform.c
>@@ -91,13 +91,6 @@ static int dwc2_get_dr_mode(struct dwc2_hsotg *hsotg)
> return 0;
> }
>
>-static void __dwc2_disable_regulators(void *data) -{
>- struct dwc2_hsotg *hsotg = data;
>-
>- regulator_bulk_disable(ARRAY_SIZE(hsotg->supplies), hsotg->supplies);
>-}
>-
> static int __dwc2_lowlevel_hw_enable(struct dwc2_hsotg *hsotg) {
> struct platform_device *pdev = to_platform_device(hsotg->dev); @@ -
>108,11 +101,6 @@ static int __dwc2_lowlevel_hw_enable(struct dwc2_hsotg
>*hsotg)
> if (ret)
> return ret;
>
>- ret = devm_add_action_or_reset(&pdev->dev,
>- __dwc2_disable_regulators, hsotg);
>- if (ret)
>- return ret;
>-
> if (hsotg->clk) {
> ret = clk_prepare_enable(hsotg->clk);
> if (ret)
>@@ -168,7 +156,7 @@ static int __dwc2_lowlevel_hw_disable(struct dwc2_hsotg
>*hsotg)
> if (hsotg->clk)
> clk_disable_unprepare(hsotg->clk);
>
>- return 0;
>+ return regulator_bulk_disable(ARRAY_SIZE(hsotg->supplies),
>+hsotg->supplies);
> }
>
> /**
>@@ -607,7 +595,7 @@ static int dwc2_driver_probe(struct platform_device
>*dev)
> if (hsotg->params.activate_stm_id_vb_detection)
> regulator_disable(hsotg->usb33d);
> error:
>- if (hsotg->dr_mode != USB_DR_MODE_PERIPHERAL)
>+ if (hsotg->ll_hw_enabled)
> dwc2_lowlevel_hw_disable(hsotg);
> return retval;
> }
>--
>2.25.1
