Re: [PATCH v3] usb: dwc3: core: Fix system suspend on TI AM62 platforms

Roger Quadros
2024-11-02T11:50:18Z

Hi William,

On 02/11/2024 01:08, William McVicker wrote:
> +linux-arm-msm@vger.kernel.org
>
> Hi Roger,
>
> On 10/11/2024, Roger Quadros wrote:
>> Since commit 6d735722063a ("usb: dwc3: core: Prevent phy suspend during init"),
>> system suspend is broken on AM62 TI platforms.
>>
>> Before that commit, both DWC3_GUSB3PIPECTL_SUSPHY and DWC3_GUSB2PHYCFG_SUSPHY
>> bits (hence forth called 2 SUSPHY bits) were being set during core
>> initialization and even during core re-initialization after a system
>> suspend/resume.
>>
>> These bits are required to be set for system suspend/resume to work correctly
>> on AM62 platforms.
>>
>> Since that commit, the 2 SUSPHY bits are not set for DEVICE/OTG mode if gadget
>> driver is not loaded and started.
>> For Host mode, the 2 SUSPHY bits are set before the first system suspend but
>> get cleared at system resume during core re-init and are never set again.
>>
>> This patch resovles these two issues by ensuring the 2 SUSPHY bits are set
>> before system suspend and restored to the original state during system resume.
>>
>> Cc: stable@vger.kernel.org # v6.9+
>> Fixes: 6d735722063a ("usb: dwc3: core: Prevent phy suspend during init")
>> Link: https://lore.kernel.org/all/1519dbe7-73b6-4afc-bfe3-23f4f75d772f@kernel.org/
>> Signed-off-by: Roger Quadros <rogerq@kernel.org>
>> Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
>> ---
>> Changes in v3:
>> - Fix single line comment style
>> - add DWC3_GUSB3PIPECTL_SUSPHY to documentation of susphy_state
>> - Added Acked-by tag
>> - Link to v2: https://lore.kernel.org/r/20241009-am62-lpm-usb-v2-1-da26c0cd2b1e@kernel.org
>>
>> Changes in v2:
>> - Fix comment style
>> - Use both USB3 and USB2 SUSPHY bits to determine susphy_state during system suspend/resume.
>> - Restore SUSPHY bits at system resume regardless if it was set or cleared before system suspend.
>> - Link to v1: https://lore.kernel.org/r/20241001-am62-lpm-usb-v1-1-9916b71165f7@kernel.org
>> ---
>> drivers/usb/dwc3/core.c | 19 +++++++++++++++++++
>> drivers/usb/dwc3/core.h | 3 +++
>> 2 files changed, 22 insertions(+)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 9eb085f359ce..ca77f0b186c4 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -2336,6 +2336,11 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
>> u32 reg;
>> int i;
>>
>> + dwc->susphy_state = (dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0)) &
>> + DWC3_GUSB2PHYCFG_SUSPHY) ||
>> + (dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0)) &
>> + DWC3_GUSB3PIPECTL_SUSPHY);
>> +
>
> I'm running into an issue on my Pixel 6 device with this change when the
> dwc3-exynos device has runtime PM enabled. Basically, after the device boots up
> and I disconnect USB, the dwc3-exynos device enters runtime suspend followed by
> system suspend 15 seconds later. On system suspend, the clocks powering these
> dwc3 registers are off which results in an SError. I have verified that
> reverting this change fixes the issue.
>
> I noticed that dwc3-qcom.c also supports runtime PM for their dwc3 device and
> most likely is affected by this as well. It would be great if someone with a
> Qualcomm device could test out dwc3 suspend as well.

Chris was facing another issue with this patch on Rockchip RK3566 [1]

Looks like we totally missed the runtime suspended case
I'll think about a solution and send something by today.

[1] - https://lore.kernel.org/all/671bef75.050a0220.e4bcd.1821@mx.google.com/

>
> Here is the crash stack:
>
> SError Interrupt on CPU7, code 0x00000000be000011 -- SError
> CPU: 7 UID: 1000 PID: 5661 Comm: binder:477_1 Tainted: G W OE 6.12.0-rc3-android16-0-maybe-dirty-4k #1 0439eacb3cff642033630df7ee2e250e0625f2f0
> 96 irq, BUS_DATA0 group, 0x0
> Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
> Hardware name: Raven DVT (DT)
> pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : readl+0x40/0x80
> lr : readl+0x38/0x80
> sp : ffffffc08baa39a0
> x29: ffffffc08baa39a0 x28: ffffffd4dd140000 x27: ffffffd4dd140d70
> x26: ffffffd4dd2b2000 x25: ffffff800cef2410 x24: ffffff800cef24c0
> x23: ffffffd4dd24e000 x22: ffffff887df59440 x21: ffffffc085298100
> x20: ffffffd4db8acf60 x19: ffffffc085298200 x18: ffffffc091b730b0
> x17: 000000002a703c0b x16: 000000002a703c0b x15: 0000000000953000
> x14: 0000000000000000 x13: 0000000000000030 x12: 0101010101010101
> x11: 7f7f7f7f7f7fffff x10: 0000000000000000 x9 : ffffffd4dc0d7d48
> x8 : 0000000000000000 x7 : 0000000000008000 x6 : 0000000000000000
> x5 : 500020737562ffff x4 : 500020737562ffff x3 : ffffffd4db8acf60
> x2 : ffffffd4db8a7bac x1 : ffffffc085298200 x0 : 0000000000000020
> Kernel panic - not syncing: Asynchronous SError Interrupt
> CPU: 7 UID: 1000 PID: 5661 Comm: binder:477_1 Tainted: G W OE 6.12.0-rc3-android16-0-maybe-dirty-4k #1 0439eacb3cff642033630df7ee2e250e0625f2f0
> Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
> Hardware name: Raven DVT (DT)
> Call trace:
> dump_backtrace+0xec/0x128
> show_stack+0x18/0x28
> dump_stack_lvl+0x40/0x88
> dump_stack+0x18/0x24
> panic+0x134/0x45c
> nmi_panic+0x3c/0x88
> arm64_serror_panic+0x64/0x8c
> do_serror+0xc4/0xc8
> el1h_64_error_handler+0x34/0x48
> el1h_64_error+0x68/0x6c
> readl+0x40/0x80
> dwc3_suspend_common+0x34/0x454
> dwc3_suspend+0x20/0x40
> platform_pm_suspend+0x40/0x90
> dpm_run_callback+0x60/0x250
> device_suspend+0x334/0x614
> dpm_suspend+0xc4/0x368
> dpm_suspend_start+0x90/0x100
> suspend_devices_and_enter+0x128/0xad0
> pm_suspend+0x354/0x650
> state_store+0x104/0x144
> kobj_attr_store+0x30/0x48
> sysfs_kf_write+0x54/0x6c
> kernfs_fop_write_iter+0x104/0x1e4
> vfs_write+0x3bc/0x50c
> ksys_write+0x78/0xe8
> __arm64_sys_write+0x1c/0x2c
> invoke_syscall+0x58/0x10c
> el0_svc_common+0xa8/0xdc
> do_el0_svc+0x1c/0x28
> el0_svc+0x38/0x6c
> el0t_64_sync_handler+0x70/0xbc
> el0t_64_sync+0x1a8/0x1ac
>
> Thanks,
> Will
>
> <snip>
>

--
cheers,
-roger