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Message-ID: <ff5674b3-6536-4f37-92e7-0c114645cd49@quicinc.com>
Date: Fri, 13 Oct 2023 09:26:34 +0530
From: Krishna Kurapati PSSNV <quic_kriskura@...cinc.com>
To: Wesley Cheng <quic_wcheng@...cinc.com>,
Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC: <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<quic_ppratap@...cinc.com>, <quic_jackp@...cinc.com>,
<quic_ugoswami@...cinc.com>
Subject: Re: [RFC] usb: dwc3: core: Fix RAM interface getting stuck during
enumeration
On 10/13/2023 12:55 AM, Wesley Cheng wrote:
> Hi Krishna,
>
> On 10/11/2023 3:02 AM, Krishna Kurapati wrote:
>> This implementation is to fix RAM interface getting stuck during
>> Synopsys confirmed that the issue is present on all USB3 devices and
>> as a workaround, suggested to re-initialize device mode.
>>
>> Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.com>
>> ---
>> drivers/usb/dwc3/core.c | 20 ++++++++++++++++++++
>> drivers/usb/dwc3/core.h | 4 ++++
>> drivers/usb/dwc3/drd.c | 5 +++++
>> drivers/usb/dwc3/gadget.c | 6 ++++--
>> 4 files changed, 33 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 44ee8526dc28..d18b81cccdc5 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -122,6 +122,7 @@ static void __dwc3_set_mode(struct work_struct *work)
>> unsigned long flags;
>> int ret;
>> u32 reg;
>> + u8 timeout = 100;
>> u32 desired_dr_role;
>> mutex_lock(&dwc->mutex);
>> @@ -137,6 +138,25 @@ static void __dwc3_set_mode(struct work_struct
>> *work)
>> if (!desired_dr_role)
>> goto out;
>> + /*
>> + * STAR 5001544 - If cable disconnect doesn't generate
>> + * disconnect event in device mode, then re-initialize the
>> + * controller.
>> + */
>> + if ((dwc->cable_disconnected == true) &&
>> + (dwc->current_dr_role == DWC3_GCTL_PRTCAP_DEVICE)) {
>> + while (dwc->connected == true && timeout != 0) {
>> + mdelay(10);
>> + timeout--;
>> + }
>> +
>> + if (timeout == 0) {
>> + dwc3_gadget_soft_disconnect(dwc);
>> + udelay(100);
>> + dwc3_gadget_soft_connect(dwc);
>> + }
>> + }
>> +
>> if (desired_dr_role == dwc->current_dr_role)
>> goto out;
>> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
>> index c6c87acbd376..7642330cf608 100644
>> --- a/drivers/usb/dwc3/core.h
>> +++ b/drivers/usb/dwc3/core.h
>> @@ -1355,6 +1355,7 @@ struct dwc3 {
>> int last_fifo_depth;
>> int num_ep_resized;
>> struct dentry *debug_root;
>> + bool cable_disconnected;
>> };
>> #define INCRX_BURST_MODE 0
>> @@ -1568,6 +1569,9 @@ void dwc3_event_buffers_cleanup(struct dwc3 *dwc);
>> int dwc3_core_soft_reset(struct dwc3 *dwc);
>> +int dwc3_gadget_soft_disconnect(struct dwc3 *dwc);
>> +int dwc3_gadget_soft_connect(struct dwc3 *dwc);
>> +
>> #if IS_ENABLED(CONFIG_USB_DWC3_HOST) ||
>> IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
>> int dwc3_host_init(struct dwc3 *dwc);
>> void dwc3_host_exit(struct dwc3 *dwc);
>> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
>> index 039bf241769a..593c023fc39a 100644
>> --- a/drivers/usb/dwc3/drd.c
>> +++ b/drivers/usb/dwc3/drd.c
>> @@ -446,6 +446,8 @@ static int dwc3_usb_role_switch_set(struct
>> usb_role_switch *sw,
>> struct dwc3 *dwc = usb_role_switch_get_drvdata(sw);
>> u32 mode;
>> + dwc->cable_disconnected = false;
>> +
>> switch (role) {
>> case USB_ROLE_HOST:
>> mode = DWC3_GCTL_PRTCAP_HOST;
>> @@ -454,6 +456,9 @@ static int dwc3_usb_role_switch_set(struct
>> usb_role_switch *sw,
>> mode = DWC3_GCTL_PRTCAP_DEVICE;
>> break;
>> default:
>> + if (role == USB_ROLE_NONE)
>> + dwc->cable_disconnected = true;
>> +
>
> How do we handle cases where role switch isn't used? (ie extcon or maybe
> no cable connection notification at all)
>
Hi Wesley,
Since I was considering fixing it during disconnect, I made it in role
switch. So no cable connection notification case has been ruled out in
this patch. But yes, extcon is a valid case. Will need to account for it.
Regards,
Krishna,
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