4 files changed, 46 insertions, 6 deletions

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 78bb7710f36d..24eb74781919 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -87,6 +87,7 @@ static int ohci_restart (struct ohci_hcd *ohci);
 #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)
 {
@@ -96,6 +97,10 @@ static inline void amd_iso_dev_put(void)
 {
         return;
 }
+static inline void sb800_prefetch(struct ohci_hcd *ohci, int on)
+{
+        return;
+}
 #endif
 
 
diff --git a/drivers/usb/host/ohci-pci.c b/drivers/usb/host/ohci-pci.c
index d2ba04dd785e..b8a1148f248e 100644
--- a/drivers/usb/host/ohci-pci.c
+++ b/drivers/usb/host/ohci-pci.c
@@ -177,6 +177,13 @@ static int ohci_quirk_amd700(struct usb_hcd *hcd)
                 return 0;
 
         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;
@@ -262,6 +269,19 @@ 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);
+}
+
 /* List of quirks for OHCI */
 static const struct pci_device_id ohci_pci_quirks[] = {
         {
diff --git a/drivers/usb/host/ohci-q.c b/drivers/usb/host/ohci-q.c
index 16fecb8ecc39..35288bcae0db 100644
--- a/drivers/usb/host/ohci-q.c
+++ b/drivers/usb/host/ohci-q.c
@@ -49,9 +49,12 @@ __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
-                                && quirk_amdiso(ohci))
-                        quirk_amd_pll(1);
+                if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0) {
+                        if (quirk_amdiso(ohci))
+                                quirk_amd_pll(1);
+                        if (quirk_amdprefetch(ohci))
+                                sb800_prefetch(ohci, 0);
+                }
                 break;
         case PIPE_INTERRUPT:
                 ohci_to_hcd(ohci)->self.bandwidth_int_reqs--;
@@ -680,9 +683,12 @@ 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
-                                && quirk_amdiso(ohci))
-                        quirk_amd_pll(0);
+                if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0) {
+                        if (quirk_amdiso(ohci))
+                                quirk_amd_pll(0);
+                        if (quirk_amdprefetch(ohci))
+                                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 222011f6172c..5bf15fed0d9f 100644
--- a/drivers/usb/host/ohci.h
+++ b/drivers/usb/host/ohci.h
@@ -402,6 +402,7 @@ struct ohci_hcd {
 #define OHCI_QUIRK_FRAME_NO     0x80                    /* no big endian frame_no shift */
 #define OHCI_QUIRK_HUB_POWER    0x100                   /* distrust firmware power/oc setup */
 #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
 
         struct work_struct      nec_work;       /* Worker for NEC quirk */
@@ -433,6 +434,10 @@ static inline int quirk_amdiso(struct ohci_hcd *ohci)
 {
         return ohci->flags & OHCI_QUIRK_AMD_ISO;
 }
+static inline int quirk_amdprefetch(struct ohci_hcd *ohci)
+{
+        return ohci->flags & OHCI_QUIRK_AMD_PREFETCH;
+}
 #else
 static inline int quirk_nec(struct ohci_hcd *ohci)
 {
@@ -446,6 +451,10 @@ static inline int quirk_amdiso(struct ohci_hcd *ohci)
 {
         return 0;
 }
+static inline int quirk_amdprefetch(struct ohci_hcd *ohci)
+{
+        return 0;
+}
 #endif
 
 /* convert between an hcd pointer and the corresponding ohci_hcd */