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

[Roger Quadros]

Hi William & Chris,

On 02/11/2024 13:50, Roger Quadros wrote:
> Hi William,
> 
> On 02/11/2024 01:08, William McVicker wrote:
>> +linux-arm-msm@xxxxxxxxxxxxxxx
>>
>> 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@xxxxxxxxxxxxxxx # v6.9+
>>> Fixes: 6d735722063a ("usb: dwc3: core: Prevent phy suspend during init")
>>> Link: https://lore.kernel.org/all/1519dbe7-73b6-4afc-bfe3-23f4f75d772f@xxxxxxxxxx/
>>> Signed-off-by: Roger Quadros <rogerq@xxxxxxxxxx>
>>> Acked-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
>>> ---
>>> 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@xxxxxxxxxx
>>>
>>> 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@xxxxxxxxxx
>>> ---
>>>  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@xxxxxxxxxxxxx/
> 
>>
>> 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
>>

Does this patch fix it for you?