[PATCH] powerpc/usb: Fix 440EPx USBH_3 & USBH_5 EHCI errata

[- Reyneke]

Patch applies to 440EPx devices in USB EHCI host mode (USB 2.0).

>From the 440EPx errata:

USBH_3: Host hangs after underrun or overrun occurs
USBH_5: EHCI0_INSNREGxx registers are reset by a Soft or Light Host Controller Reset

Workround for USBH_3 is to enable Break Memory Transfer (BMT) in INSNREG3. But the controller is reset after this fix is applied, and thus the current workround is lost. The following short patch ensures INSNREG3 is correctly set after reset.


Signed-off-by: Jan Reyneke 
---
 ehci-hcd.c    |    7 +++++++
 ehci-ppc-of.c |   30 +++++++++++++++++++-----------
 ehci.h        |    5 +++++
 3 files changed, 31 insertions(+), 11 deletions(-)

diff -uprN a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
--- a/drivers/usb/host/ehci.h    2009-03-04 01:05:22.000000000 +0000
+++ b/drivers/usb/host/ehci.h    2009-03-06 10:52:53.000000000 +0000
@@ -137,6 +137,11 @@ struct ehci_hcd {            /* one per controlle
 
     u8            sbrn;        /* packed release number */
 
+#if defined(CONFIG_440EPX)
+    #define     PPC440EPX_EHCI0_INSREG_BMT    (0x1 << 0)
+    __iomem u32 *insn_regs;        /* INSNREGx device memory/io */
+#endif
+
     /* irq statistics */
 #ifdef EHCI_STATS
     struct ehci_stats    stats;
diff -uprN a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
--- a/drivers/usb/host/ehci-hcd.c    2009-03-04 01:05:22.000000000 +0000
+++ b/drivers/usb/host/ehci-hcd.c    2009-03-06 10:54:36.000000000 +0000
@@ -217,6 +217,13 @@ static int ehci_reset (struct ehci_hcd *
     if (ehci_is_TDI(ehci))
         tdi_reset (ehci);
 
+#if defined(CONFIG_440EPX)
+    /* USBH_5: INSN values are lost on reset -> redo USBH_3.
+       See also ppc44x_enable_bmt.*/
+    if (ehci->insn_regs)
+        out_be32(ehci->insn_regs + 3, PPC440EPX_EHCI0_INSREG_BMT);
+#endif
+
     return retval;
 }
 
diff -uprN a/drivers/usb/host/ehci-ppc-of.c b/drivers/usb/host/ehci-ppc-of.c
--- a/drivers/usb/host/ehci-ppc-of.c    2009-03-04 01:05:22.000000000 +0000
+++ b/drivers/usb/host/ehci-ppc-of.c    2009-03-06 10:56:08.000000000 +0000
@@ -82,23 +82,24 @@ static const struct hc_driver ehci_ppc_o
 
 
 /*
- * 440EPx Errata USBH_3
- * Fix: Enable Break Memory Transfer (BMT) in INSNREG3
- */
-#define PPC440EPX_EHCI0_INSREG_BMT    (0x1 << 0)
+ * 440EPx Errata USBH_3 & USBH_5
+ * Fix: Enable Break Memory Transfer (BMT) in INSNREG3. Also cache
+ * the registers so we can redo the USBH_3 fix on future resets */
 static int __devinit
-ppc44x_enable_bmt(struct device_node *dn)
+ppc44x_enable_bmt(struct device_node *dn, struct ehci_hcd* ehci)
 {
-    __iomem u32 *insreg_virt;
 
-    insreg_virt = of_iomap(dn, 1);
-    if (!insreg_virt)
+#if defined(CONFIG_440EPX)
+
+    ehci->insn_regs = of_iomap(dn, 1);
+    if (!ehci->insn_regs)
         return  -EINVAL;
 
-    out_be32(insreg_virt + 3, PPC440EPX_EHCI0_INSREG_BMT);
+    out_be32(ehci->insn_regs + 3, PPC440EPX_EHCI0_INSREG_BMT);
 
-    iounmap(insreg_virt);
+#endif
     return 0;
+
 }
 
 
@@ -183,7 +184,7 @@ ehci_hcd_ppc_of_probe(struct of_device *
     ehci->hcs_params = ehci_readl(ehci, &ehci->caps->hcs_params);
 
     if (of_device_is_compatible(dn, "ibm,usb-ehci-440epx")) {
-        rv = ppc44x_enable_bmt(dn);
+        rv = ppc44x_enable_bmt(dn, ehci);
         ehci_dbg(ehci, "Break Memory Transfer (BMT) is %senabled!\n",
                 rv ? "NOT ": "");
     }
@@ -221,6 +222,13 @@ static int ehci_hcd_ppc_of_remove(struct
 
     usb_remove_hcd(hcd);
 
+#if defined(CONFIG_440EPX)
+    if (ehci->insn_regs) {
+        iounmap(ehci->insn_regs);
+        ehci->insn_regs = 0;
+    }
+#endif
+
     iounmap(hcd->regs);
     irq_dispose_mapping(hcd->irq);
     release_mem_region(hcd->rsrc_start, hcd->rsrc_len);



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