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

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Message-ID:
 <PH7PR07MB95384A1319F64B5DA9F04190DD852@PH7PR07MB9538.namprd07.prod.outlook.com>
Date: Thu, 24 Apr 2025 09:01:31 +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?
>
>> +	__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