2016-10-21 15:45:18

by Sriram Dash

[permalink] [raw]
Subject: [PATCH] usb: xhci: Workaround for erratum-A010129

For the USB3.0 controller, USB 2.0 reset not driven while
port is in Resume state. So, do not program the USB 2.0 reset
(PORTSC[PR]=1) while in Resume state.

Signed-off-by: Rajat Srivastava <[email protected]>
Signed-off-by: Sriram Dash <[email protected]>
Signed-off-by: Rajesh Bhagat <[email protected]>
---
drivers/usb/host/xhci-hub.c | 28 +++++++++++++++++++++++++++-
drivers/usb/host/xhci.h | 1 +
2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 730b9fd..3def0dd 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -878,7 +878,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
struct xhci_hcd *xhci = hcd_to_xhci(hcd);
int max_ports;
unsigned long flags;
- u32 temp, status;
+ u32 temp, status, tmp_status = 0;
int retval = 0;
__le32 __iomem **port_array;
int slot_id;
@@ -1098,6 +1098,32 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
spin_lock_irqsave(&xhci->lock, flags);
break;
case USB_PORT_FEAT_RESET:
+ /*
+ * Erratum : A010129
+ * Synopsys STAR 9000962562.
+ * USB 2.0 Reset Not Driven While Port in Resume
+ * While in USB 2.0 resume state (the PORTSC.PLS
+ * register bit is set to 4'd15), if the xHCI driver
+ * programs the PORTSC.PR register bit to 1, the
+ * controller does not drive a USB 2.0 reset
+ * and it does not generate a PORTSC.PRC=1 interrupt.
+ * So, The xHCI driver should not program a USB
+ * 2.0 reset (PORTSC.PR=1) while in resume
+ * (PORTSC.PLS=4'd15).
+ */
+ if (xhci->quirks & XHCI_PORT_RST_ON_RESUME) {
+ tmp_status = readl(port_array[wIndex]);
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ if (!DEV_SUPERSPEED(tmp_status)
+ && (tmp_status & PORT_PLS_MASK)
+ == XDEV_RESUME) {
+ xhci_err(xhci, "skip port reset\n");
+ spin_lock_irqsave(&xhci->lock, flags);
+ break;
+ }
+ spin_lock_irqsave(&xhci->lock, flags);
+ }
+
temp = (temp | PORT_RESET);
writel(temp, port_array[wIndex]);

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index b2c1dc5..c07e267 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1653,6 +1653,7 @@ struct xhci_hcd {
#define XHCI_MTK_HOST (1 << 21)
#define XHCI_SSIC_PORT_UNUSED (1 << 22)
#define XHCI_NO_64BIT_SUPPORT (1 << 23)
+#define XHCI_PORT_RST_ON_RESUME (1 << 24)
unsigned int num_active_eps;
unsigned int limit_active_eps;
/* There are two roothubs to keep track of bus suspend info for */
--
2.1.0


2016-10-21 16:44:29

by Alan Stern

[permalink] [raw]
Subject: Re: [PATCH] usb: xhci: Workaround for erratum-A010129

On Fri, 21 Oct 2016, Sriram Dash wrote:

> For the USB3.0 controller, USB 2.0 reset not driven while
> port is in Resume state. So, do not program the USB 2.0 reset
> (PORTSC[PR]=1) while in Resume state.
>
> Signed-off-by: Rajat Srivastava <[email protected]>
> Signed-off-by: Sriram Dash <[email protected]>
> Signed-off-by: Rajesh Bhagat <[email protected]>
> ---
> drivers/usb/host/xhci-hub.c | 28 +++++++++++++++++++++++++++-
> drivers/usb/host/xhci.h | 1 +
> 2 files changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
> index 730b9fd..3def0dd 100644
> --- a/drivers/usb/host/xhci-hub.c
> +++ b/drivers/usb/host/xhci-hub.c
> @@ -878,7 +878,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
> struct xhci_hcd *xhci = hcd_to_xhci(hcd);
> int max_ports;
> unsigned long flags;
> - u32 temp, status;
> + u32 temp, status, tmp_status = 0;
> int retval = 0;
> __le32 __iomem **port_array;
> int slot_id;
> @@ -1098,6 +1098,32 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
> spin_lock_irqsave(&xhci->lock, flags);
> break;
> case USB_PORT_FEAT_RESET:
> + /*
> + * Erratum : A010129
> + * Synopsys STAR 9000962562.
> + * USB 2.0 Reset Not Driven While Port in Resume
> + * While in USB 2.0 resume state (the PORTSC.PLS
> + * register bit is set to 4'd15), if the xHCI driver
> + * programs the PORTSC.PR register bit to 1, the
> + * controller does not drive a USB 2.0 reset
> + * and it does not generate a PORTSC.PRC=1 interrupt.
> + * So, The xHCI driver should not program a USB
> + * 2.0 reset (PORTSC.PR=1) while in resume
> + * (PORTSC.PLS=4'd15).
> + */
> + if (xhci->quirks & XHCI_PORT_RST_ON_RESUME) {

It's always a bad idea to drive a reset signal while a port is
resuming. We don't need a quirk flag for this. The HCD should never
do it, and the USB core should never tell the HCD to do it.

Alan Stern

2016-10-23 11:19:51

by Sriram Dash

[permalink] [raw]
Subject: RE: [PATCH] usb: xhci: Workaround for erratum-A010129

>From: Alan Stern [mailto:[email protected]]
>On Fri, 21 Oct 2016, Sriram Dash wrote:
>
>> For the USB3.0 controller, USB 2.0 reset not driven while port is in
>> Resume state. So, do not program the USB 2.0 reset
>> (PORTSC[PR]=1) while in Resume state.
>>
>> Signed-off-by: Rajat Srivastava <[email protected]>
>> Signed-off-by: Sriram Dash <[email protected]>
>> Signed-off-by: Rajesh Bhagat <[email protected]>
>> ---
>> drivers/usb/host/xhci-hub.c | 28 +++++++++++++++++++++++++++-
>> drivers/usb/host/xhci.h | 1 +
>> 2 files changed, 28 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
>> index 730b9fd..3def0dd 100644
>> --- a/drivers/usb/host/xhci-hub.c
>> +++ b/drivers/usb/host/xhci-hub.c
>> @@ -878,7 +878,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq,
>u16 wValue,
>> struct xhci_hcd *xhci = hcd_to_xhci(hcd);
>> int max_ports;
>> unsigned long flags;
>> - u32 temp, status;
>> + u32 temp, status, tmp_status = 0;
>> int retval = 0;
>> __le32 __iomem **port_array;
>> int slot_id;
>> @@ -1098,6 +1098,32 @@ int xhci_hub_control(struct usb_hcd *hcd, u16
>typeReq, u16 wValue,
>> spin_lock_irqsave(&xhci->lock, flags);
>> break;
>> case USB_PORT_FEAT_RESET:
>> + /*
>> + * Erratum : A010129
>> + * Synopsys STAR 9000962562.
>> + * USB 2.0 Reset Not Driven While Port in Resume
>> + * While in USB 2.0 resume state (the PORTSC.PLS
>> + * register bit is set to 4'd15), if the xHCI driver
>> + * programs the PORTSC.PR register bit to 1, the
>> + * controller does not drive a USB 2.0 reset
>> + * and it does not generate a PORTSC.PRC=1 interrupt.
>> + * So, The xHCI driver should not program a USB
>> + * 2.0 reset (PORTSC.PR=1) while in resume
>> + * (PORTSC.PLS=4'd15).
>> + */
>> + if (xhci->quirks & XHCI_PORT_RST_ON_RESUME) {
>
>It's always a bad idea to drive a reset signal while a port is resuming. We don't
>need a quirk flag for this.

Hi Alan,

Ok. Then I will make it generic for xhci in the next version.

>The HCD should never do it, and the USB core should
>never tell the HCD to do it.
>
>Alan Stern