linux-kernel - RE: [PATCH] usb: cdnsp: fix L1 resume issue for RTL_REVISION_NEW

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Message-ID:
 <PH7PR07MB9538A65E135543B23202757BDD852@PH7PR07MB9538.namprd07.prod.outlook.com>
Date: Thu, 24 Apr 2025 11:36:22 +0000
From: Pawel Laszczak <pawell@...ence.com>
To: "Peter Chen (CIX)" <peter.chen@...nel.org>
CC: "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: RE: [PATCH] usb: cdnsp: fix L1 resume issue for RTL_REVISION_NEW_LPM
 version

>>
>>On 25-04-23 11:43:03, Pawel Laszczak wrote:
>>> The controllers with rtl version greeter than
>>less than?
>>
>>> RTL_REVISION_NEW_LPM (0x00002700) has bug which causes that
>>> controller doesn't resume from L1 state. It happens if after
>>> receiving LPM packet controller starts transitioning to L1 and in
>>> this moment the driver force resuming by write operation to PORTSC.PLS.
>>> It's corner case and happens when write operation to PORTSC occurs
>>> during device delay before transitioning to L1 after transmitting ACK
>>> time (TL1TokenRetry).
>>>
>>> Forcing transition from L1->L0 by driver for revision greeter than
>>
>>%s/greeter/larger
>>
>>> RTL_REVISION_NEW_LPM is not needed, so driver can simply fix this
>>> issue through block call of cdnsp_force_l0_go function.
>>>
>>> Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence
>>> USBSSP DRD Driver")
>>> cc: stable@...r.kernel.org
>>> Signed-off-by: Pawel Laszczak <pawell@...ence.com>
>>> ---
>>>  drivers/usb/cdns3/cdnsp-gadget.c | 2 ++
>>> drivers/usb/cdns3/cdnsp-gadget.h | 3 +++
>>>  drivers/usb/cdns3/cdnsp-ring.c   | 3 ++-
>>>  3 files changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/cdns3/cdnsp-gadget.c
>>> b/drivers/usb/cdns3/cdnsp-gadget.c
>>> index 7f5534db2086..4824a10df07e 100644
>>> --- a/drivers/usb/cdns3/cdnsp-gadget.c
>>> +++ b/drivers/usb/cdns3/cdnsp-gadget.c
>>> @@ -1793,6 +1793,8 @@ static void cdnsp_get_rev_cap(struct
>>> cdnsp_device
>>*pdev)
>>>  	reg += cdnsp_find_next_ext_cap(reg, 0, RTL_REV_CAP);
>>>  	pdev->rev_cap  = reg;
>>>
>>> +	pdev->rtl_revision = readl(&pdev->rev_cap->rtl_revision);
>>> +
>>>  	dev_info(pdev->dev, "Rev: %08x/%08x, eps: %08x, buff: %08x/%08x\n",
>>>  		 readl(&pdev->rev_cap->ctrl_revision),
>>>  		 readl(&pdev->rev_cap->rtl_revision),
>>> diff --git a/drivers/usb/cdns3/cdnsp-gadget.h
>>> b/drivers/usb/cdns3/cdnsp-gadget.h
>>> index 87ac0cd113e7..fa02f861217f 100644
>>> --- a/drivers/usb/cdns3/cdnsp-gadget.h
>>> +++ b/drivers/usb/cdns3/cdnsp-gadget.h
>>> @@ -1360,6 +1360,7 @@ struct cdnsp_port {
>>>   * @rev_cap: Controller Capabilities Registers.
>>>   * @hcs_params1: Cached register copies of read-only HCSPARAMS1
>>>   * @hcc_params: Cached register copies of read-only HCCPARAMS1
>>> + * @rtl_revision: Cached controller rtl revision.
>>>   * @setup: Temporary buffer for setup packet.
>>>   * @ep0_preq: Internal allocated request used during enumeration.
>>>   * @ep0_stage: ep0 stage during enumeration process.
>>> @@ -1414,6 +1415,8 @@ struct cdnsp_device {
>>>  	__u32 hcs_params1;
>>>  	__u32 hcs_params3;
>>>  	__u32 hcc_params;
>>> +	#define RTL_REVISION_NEW_LPM 0x00002701
>>
>>0x2700?

It does no matter -  0x2700 has not been part of any delivery package.
I will change it to 0x2700. 
This issue will be fixed in  RTL_REVISION >= 0x276E

>>
>>> +	__u32 rtl_revision;
>>>  	/* Lock used in interrupt thread context. */
>>>  	spinlock_t lock;
>>>  	struct usb_ctrlrequest setup;
>>> diff --git a/drivers/usb/cdns3/cdnsp-ring.c
>>> b/drivers/usb/cdns3/cdnsp-ring.c index 46852529499d..fd06cb85c4ea
>>> 100644
>>> --- a/drivers/usb/cdns3/cdnsp-ring.c
>>> +++ b/drivers/usb/cdns3/cdnsp-ring.c
>>> @@ -308,7 +308,8 @@ static bool cdnsp_ring_ep_doorbell(struct
>>> cdnsp_device *pdev,
>>>
>>>  	writel(db_value, reg_addr);
>>>
>>> -	cdnsp_force_l0_go(pdev);
>>> +	if (pdev->rtl_revision < RTL_REVISION_NEW_LPM)
>>> +		cdnsp_force_l0_go(pdev);
>>
>>Pawel, it may not solve all issues for controllers which RTL version is
>>less than 0x2700, do you have any other patches for it?
>
>At this moment, it's the last patch for LPM issues which we was able to debug
>and make fix in driver.
>
>Thanks,
>Pawel
>
>>
>>--
>>
>>Best regards,
>>Peter