RE: [PATCH v2] usb: ehci: handshake CMD_RUN instead of STS_HALT

-----Original Message-----
From: Alan Stern <stern@rowland.harvard.edu>
Sent: Thursday, September 2, 2021 12:41 AM
To: Neal Liu <neal_liu@aspeedtech.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Tony Prisk
[off-list ref]; linux-usb@vger.kernel.org;
linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; Tao Ren
[off-list ref]; BMC-SW [off-list ref]
Subject: Re: [PATCH v2] usb: ehci: handshake CMD_RUN instead of STS_HALT

On Wed, Sep 01, 2021 at 11:50:41AM +0800, neal_liu wrote:

quoted

Retitle.

For Aspeed, HCHalted status depends on not only Run/Stop but also
ASS/PSS status.
Handshake CMD_RUN on startup instead.

Signed-off-by: neal_liu <neal_liu@aspeedtech.com>

I'm still a little doubtful about doing this, but if you guys say it works for your
hardware then I guess it's okay.

Acked-by: Alan Stern <stern@rowland.harvard.edu>

 
Thanks for your review.

quoted

---
 drivers/usb/host/ehci-hcd.c      | 11 ++++++++++-
 drivers/usb/host/ehci-platform.c |  6 ++++++
 drivers/usb/host/ehci.h          |  1 +
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 10b0365f3439..01c022e46aa2 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c

@@ -634,7 +634,16 @@ 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 = ehci_handshake(ehci, &ehci->regs->command, CMD_RUN,
+				    1, 100 * 1000);
+	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)

quoted

 					  "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