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usb: dwc2: Skip clock gating on Samsung SoCs

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Commit 0112b7ce68ea ("usb: dwc2: Update dwc2_handle_usb_suspend_intr
function.") changed the way the driver handles power down modes in a such
way that it uses clock gating when no other power down mode is available.

This however doesn't work well on the DWC2 implementation used on the
Samsung SoCs. When a clock gating is enabled, system hangs. It looks that
the proper clock gating requires some additional glue code in the shared
USB2 PHY and/or Samsung glue code for the DWC2. To restore driver
operation on the Samsung SoCs simply skip enabling clock gating mode
until one finds what is really needed to make it working reliably.

Fixes: 0112b7ce68ea ("usb: dwc2: Update dwc2_handle_usb_suspend_intr function.")
Cc: stable <stable@vger.kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20210716050127.4406-1-m.szyprowski@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Marek Szyprowski 2021-07-16 07:01:27 +02:00 committed by Greg Kroah-Hartman
parent 5719df243e
commit c4a0f7a6ab
4 changed files with 11 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/usb/dwc2/core.h
View File

@ -383,6 +383,9 @@ enum dwc2_ep0_state {
* 0 - No (default)
* 1 - Partial power down
* 2 - Hibernation
* @no_clock_gating: Specifies whether to avoid clock gating feature.
* 0 - No (use clock gating)
* 1 - Yes (avoid it)
* @lpm: Enable LPM support.
* 0 - No
* 1 - Yes
@ -480,6 +483,7 @@ struct dwc2_core_params {
#define DWC2_POWER_DOWN_PARAM_NONE 0
#define DWC2_POWER_DOWN_PARAM_PARTIAL 1
#define DWC2_POWER_DOWN_PARAM_HIBERNATION 2
bool no_clock_gating;
bool lpm;
bool lpm_clock_gating;

3
drivers/usb/dwc2/core_intr.c
View File

@ -556,7 +556,8 @@ static void dwc2_handle_usb_suspend_intr(struct dwc2_hsotg *hsotg)
* If neither hibernation nor partial power down are supported,
* clock gating is used to save power.
*/
dwc2_gadget_enter_clock_gating(hsotg);
if (!hsotg->params.no_clock_gating)
dwc2_gadget_enter_clock_gating(hsotg);
}
/*

6
drivers/usb/dwc2/hcd.c
View File

@ -3338,7 +3338,8 @@ int dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex)
* If not hibernation nor partial power down are supported,
* clock gating is used to save power.
*/
dwc2_host_enter_clock_gating(hsotg);
if (!hsotg->params.no_clock_gating)
dwc2_host_enter_clock_gating(hsotg);
break;
}
@ -4402,7 +4403,8 @@ static int _dwc2_hcd_suspend(struct usb_hcd *hcd)
* If not hibernation nor partial power down are supported,
* clock gating is used to save power.
*/
dwc2_host_enter_clock_gating(hsotg);
if (!hsotg->params.no_clock_gating)
dwc2_host_enter_clock_gating(hsotg);
/* After entering suspend, hardware is not accessible */
clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);

1
drivers/usb/dwc2/params.c
View File

@ -76,6 +76,7 @@ static void dwc2_set_s3c6400_params(struct dwc2_hsotg *hsotg)
struct dwc2_core_params *p = &hsotg->params;
p->power_down = DWC2_POWER_DOWN_PARAM_NONE;
p->no_clock_gating = true;
p->phy_utmi_width = 8;
}