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usb: dwc2: fix a devres leak in hw_enable upon suspend resume 

commit f747313249 upstream.

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: 54c1960605 ("usb: dwc2: Always disable regulators on driver teardown")
Fixes: 33a06f1300 ("usb: dwc2: Fix error path in gadget registration")
Cc: stable <stable@kernel.org>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20230316084127.126084-1-fabrice.gasnier@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Fabrice Gasnier 2023-03-16 09:41:27 +01:00 committed by Greg Kroah-Hartman
parent 4e6b558907
commit 6485fc381b
1 changed files with 2 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/usb/dwc2/platform.c
View File

@ -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 @@ error_init:
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;
}