[PATCH] usb: host: ehci: skip STS_HALT check for aspeed platform

[PATCH] usb: host: ehci: skip STS_HALT check for aspeed platform

[neal_liu]

STS_HALT also depends on ASS/PSS status for apseed.
Skip this check on startup.

Signed-off-by: neal_liu <neal_liu@aspeedtech.com>
---
 drivers/usb/host/ehci-hcd.c      | 10 +++++++++-
 drivers/usb/host/ehci-platform.c |  6 ++++++
 drivers/usb/host/ehci.h          |  1 +
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 10b0365f3439..a539e11502ef 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -634,7 +634,15 @@ static int ehci_run (struct usb_hcd *hcd)
 	/* Wait until HC become operational */
 	ehci_readl(ehci, &ehci->regs->command);	/* unblock posted writes */
 	msleep(5);
-	rc = ehci_handshake(ehci, &ehci->regs->status, STS_HALT, 0, 100 * 1000);
+
+	/* For Aspeed, STS_HALT also depends on ASS/PSS status.
+	 * Skip this check on startup.
+	 */
+	if (ehci->is_aspeed)
+		rc = 0;
+	else
+		rc = ehci_handshake(ehci, &ehci->regs->status, STS_HALT,
+				    0, 100 * 1000);
 
 	up_write(&ehci_cf_port_reset_rwsem);
 
diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
index c70f2d0b4aaf..c3dc906274d9 100644
--- a/drivers/usb/host/ehci-platform.c
+++ b/drivers/usb/host/ehci-platform.c
@@ -297,6 +297,12 @@ static int ehci_platform_probe(struct platform_device *dev)
 					  "has-transaction-translator"))
 			hcd->has_tt = 1;
 
+		if (of_device_is_compatible(dev->dev.of_node,
+					    "aspeed,ast2500-ehci") ||
+		    of_device_is_compatible(dev->dev.of_node,
+					    "aspeed,ast2600-ehci"))
+			ehci->is_aspeed = 1;
+
 		if (soc_device_match(quirk_poll_match))
 			priv->quirk_poll = true;
 
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 80bb823aa9fe..fdd073cc053b 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -219,6 +219,7 @@ struct ehci_hcd {			/* one per controller */
 	unsigned		need_oc_pp_cycle:1; /* MPC834X port power */
 	unsigned		imx28_write_fix:1; /* For Freescale i.MX28 */
 	unsigned		spurious_oc:1;
+	unsigned		is_aspeed:1;
 
 	/* required for usb32 quirk */
 	#define OHCI_CTRL_HCFS          (3 << 6)
-- 
2.17.1

Re: [PATCH] usb: host: ehci: skip STS_HALT check for aspeed platform

[Greg Kroah-Hartman]

On Thu, Aug 26, 2021 at 03:15:25PM +0800, neal_liu wrote:
> STS_HALT also depends on ASS/PSS status for apseed.
> Skip this check on startup.
> 
> Signed-off-by: neal_liu <neal_liu@aspeedtech.com>
> ---
>  drivers/usb/host/ehci-hcd.c      | 10 +++++++++-
>  drivers/usb/host/ehci-platform.c |  6 ++++++
>  drivers/usb/host/ehci.h          |  1 +
>  3 files changed, 16 insertions(+), 1 deletion(-)
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- Your patch contains warnings and/or errors noticed by the
  scripts/checkpatch.pl tool.

- You did not specify a description of why the patch is needed, or
  possibly, any description at all, in the email body.  Please read the
  section entitled "The canonical patch format" in the kernel file,
  Documentation/SubmittingPatches for what is needed in order to
  properly describe the change.

- It looks like you did not use your "real" name for the patch on either
  the Signed-off-by: line, or the From: line (both of which have to
  match).  Please read the kernel file, Documentation/SubmittingPatches
  for how to do this correctly.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot

Re: [PATCH] usb: host: ehci: skip STS_HALT check for aspeed platform

[Alan Stern]

On Thu, Aug 26, 2021 at 03:15:25PM +0800, neal_liu wrote:
> STS_HALT also depends on ASS/PSS status for apseed.
> Skip this check on startup.
> 
> Signed-off-by: neal_liu <neal_liu@aspeedtech.com>
> ---
>  drivers/usb/host/ehci-hcd.c      | 10 +++++++++-
>  drivers/usb/host/ehci-platform.c |  6 ++++++
>  drivers/usb/host/ehci.h          |  1 +
>  3 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> index 10b0365f3439..a539e11502ef 100644
> --- a/drivers/usb/host/ehci-hcd.c
> +++ b/drivers/usb/host/ehci-hcd.c
> @@ -634,7 +634,15 @@ static int ehci_run (struct usb_hcd *hcd)
>  	/* Wait until HC become operational */
>  	ehci_readl(ehci, &ehci->regs->command);	/* unblock posted writes */
>  	msleep(5);
> -	rc = ehci_handshake(ehci, &ehci->regs->status, STS_HALT, 0, 100 * 1000);
> +
> +	/* For Aspeed, STS_HALT also depends on ASS/PSS status.
> +	 * Skip this check on startup.
> +	 */
> +	if (ehci->is_aspeed)
> +		rc = 0;
> +	else
> +		rc = ehci_handshake(ehci, &ehci->regs->status, STS_HALT,
> +				    0, 100 * 1000);

You must not do this.  You are assuming the controller will always begin 
operating within 5 ms of the time it is told to start.  What happens if you are 
wrong?

There must be some way for the aspeed controller's host computer to tell when 
the controller has started running.  Find out what it is and use it.

Alan Stern

RE: [PATCH] usb: host: ehci: skip STS_HALT check for aspeed platform

[Neal Liu]

> -----Original Message-----
> From: Alan Stern <stern@rowland.harvard.edu>
> Sent: Thursday, August 26, 2021 11:28 PM
> To: Neal Liu <neal_liu@aspeedtech.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Tony Prisk
> <linux@prisktech.co.nz>; linux-usb@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; Tao Ren
> <rentao.bupt@gmail.com>; BMC-SW <BMC-SW@aspeedtech.com>
> Subject: Re: [PATCH] usb: host: ehci: skip STS_HALT check for aspeed platform
> 
> On Thu, Aug 26, 2021 at 03:15:25PM +0800, neal_liu wrote:
> > STS_HALT also depends on ASS/PSS status for apseed.
> > Skip this check on startup.
> >
> > Signed-off-by: neal_liu <neal_liu@aspeedtech.com>
> > ---
> >  drivers/usb/host/ehci-hcd.c      | 10 +++++++++-
> >  drivers/usb/host/ehci-platform.c |  6 ++++++
> >  drivers/usb/host/ehci.h          |  1 +
> >  3 files changed, 16 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> > index 10b0365f3439..a539e11502ef 100644
> > --- a/drivers/usb/host/ehci-hcd.c
> > +++ b/drivers/usb/host/ehci-hcd.c
> > @@ -634,7 +634,15 @@ static int ehci_run (struct usb_hcd *hcd)
> >  	/* Wait until HC become operational */
> >  	ehci_readl(ehci, &ehci->regs->command);	/* unblock posted writes */
> >  	msleep(5);
> > -	rc = ehci_handshake(ehci, &ehci->regs->status, STS_HALT, 0, 100 * 1000);
> > +
> > +	/* For Aspeed, STS_HALT also depends on ASS/PSS status.
> > +	 * Skip this check on startup.
> > +	 */
> > +	if (ehci->is_aspeed)
> > +		rc = 0;
> > +	else
> > +		rc = ehci_handshake(ehci, &ehci->regs->status, STS_HALT,
> > +				    0, 100 * 1000);
> 
> You must not do this.  You are assuming the controller will always begin
> operating within 5 ms of the time it is told to start.  What happens if you are
> wrong?
> 
> There must be some way for the aspeed controller's host computer to tell
> when the controller has started running.  Find out what it is and use it.
> 
> Alan Stern

We can check the command RS bit to tell the controller has started running.
I'll sent next patch within this change.
Thanks

-Neal Liu