From: Pete Zaitcev <zaitcev@redhat.com>
Date: Tue, 8 Dec 2009 16:16:30 -0500
Subject: [usb] add quirk for iso on amd sb800
Message-id: <20091208091630.26dd7c00@redhat.com>
Patchwork-id: 21746
O-Subject: [Patch RHEL5] Add quirk for ISO on AMD SB800
Bugzilla: 537433
RH-Acked-by: Stefan Assmann <sassmann@redhat.com>
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>

New SBx00, new quirk. This one is worked around by flipping magic bits in
the device itself, not in upstream bridge.

I built a test kernel in Brew and AMD tested it to confirm that it works.
The fix is properly limited to specific devices and I consider it safe.
It is in upstream (although depending on what gets into RHEL 6 we might
need it ported there too).

Please ack.

-- Pete

Signed-off-by: Don Zickus <dzickus@redhat.com>

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 72a6902..5e01963 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -138,6 +138,7 @@ static int ohci_reboot (struct notifier_block *, unsigned long , void *);
 #ifdef CONFIG_PCI
 static void quirk_amd_pll(int state);
 static void amd_iso_dev_put(void);
+static void sb800_prefetch(struct ohci_hcd *ohci, int on);
 #else
 static inline void quirk_amd_pll(int state)
 {
@@ -147,6 +148,10 @@ static inline void amd_iso_dev_put(void)
 {
 	return;
 }
+static inline void sb800_prefetch(struct ohci_hcd *ohci, int on)
+{
+	return;
+}
 #endif
 
 #include "ohci-hub.c"
diff --git a/drivers/usb/host/ohci-pci.c b/drivers/usb/host/ohci-pci.c
index 1ebc2ce..22ce63c 100644
--- a/drivers/usb/host/ohci-pci.c
+++ b/drivers/usb/host/ohci-pci.c
@@ -63,6 +63,13 @@ ohci_quirk_amd700(struct ohci_hcd *ohci)
 		return;
 
 	pci_read_config_byte(amd_smbus_dev, PCI_REVISION_ID, &rev);
+
+	/* SB800 needs pre-fetch fix */
+	if ((rev >= 0x40) && (rev <= 0x4f)) {
+		ohci->flags |= OHCI_QUIRK_AMD_PREFETCH;
+		ohci_dbg(ohci, "enabled AMD prefetch quirk\n");
+	}
+
 	if ((rev > 0x3b) || (rev < 0x30)) {
 		pci_dev_put(amd_smbus_dev);
 		amd_smbus_dev = NULL;
@@ -235,6 +242,19 @@ static void amd_iso_dev_put(void)
 	}
 }
 
+static void sb800_prefetch(struct ohci_hcd *ohci, int on)
+{
+	struct pci_dev *pdev;
+	u16 misc;
+
+	pdev = to_pci_dev(ohci_to_hcd(ohci)->self.controller);
+	pci_read_config_word(pdev, 0x50, &misc);
+	if (on == 0)
+		pci_write_config_word(pdev, 0x50, misc & 0xfcff);
+	else
+		pci_write_config_word(pdev, 0x50, misc | 0x0300);
+}
+
 #ifdef	CONFIG_PM
 
 static int ohci_pci_suspend (struct usb_hcd *hcd, pm_message_t message)
diff --git a/drivers/usb/host/ohci-q.c b/drivers/usb/host/ohci-q.c
index 2797ede..7902cda 100644
--- a/drivers/usb/host/ohci-q.c
+++ b/drivers/usb/host/ohci-q.c
@@ -61,9 +61,12 @@ __acquires(ohci->lock)
 	switch (usb_pipetype (urb->pipe)) {
 	case PIPE_ISOCHRONOUS:
 		ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs--;
-		if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0)
+		if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0) {
 			if (ohci->flags & OHCI_QUIRK_AMD_ISO)
 				quirk_amd_pll(1);
+			if (ohci->flags & OHCI_QUIRK_AMD_PREFETCH)
+				sb800_prefetch(ohci, 0);
+		}
 		break;
 	case PIPE_INTERRUPT:
 		ohci_to_hcd(ohci)->self.bandwidth_int_reqs--;
@@ -692,9 +695,12 @@ static void td_submit_urb (
 				data + urb->iso_frame_desc [cnt].offset,
 				urb->iso_frame_desc [cnt].length, urb, cnt);
 		}
-		if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0)
+		if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0) {
 			if (ohci->flags & OHCI_QUIRK_AMD_ISO)
 				quirk_amd_pll(0);
+			if (ohci->flags & OHCI_QUIRK_AMD_PREFETCH)
+				sb800_prefetch(ohci, 1);
+		}
 		periodic = ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs++ == 0
 			&& ohci_to_hcd(ohci)->self.bandwidth_int_reqs == 0;
 		break;
diff --git a/drivers/usb/host/ohci.h b/drivers/usb/host/ohci.h
index 2c39785..1e1c1e3 100644
--- a/drivers/usb/host/ohci.h
+++ b/drivers/usb/host/ohci.h
@@ -398,6 +398,7 @@ struct ohci_hcd {
 #define	OHCI_BIG_ENDIAN		0x08			/* big endian HC */
 #define	OHCI_QUIRK_ZFMICRO	0x10			/* Compaq ZFMicro chipset*/
 #define	OHCI_QUIRK_AMD_ISO	0x200			/* ISO transfers */
+#define	OHCI_QUIRK_AMD_PREFETCH	0x400			/* pre-fetch for ISO transfer */
 	// there are also chip quirks/bugs in init logic
 
 };