USB: powerpc: Workaround for the PPC440EPX USBH_23 errata [take 3]

[pandora-kernel.git] / drivers / usb / host / ohci-ppc-of.c

diff --git a/drivers/usb/host/ohci-ppc-of.c b/drivers/usb/host/ohci-ppc-of.c
index 7ac5326..68a3017 100644 (file)
--- a/drivers/usb/host/ohci-ppc-of.c
+++ b/drivers/usb/host/ohci-ppc-of.c
@@ -91,6 +91,7 @@ ohci_hcd_ppc_of_probe(struct of_device *op, const struct of_device_id *match)
 
        int rv;
        int is_bigendian;
+       struct device_node *np;
 
        if (usb_disabled())
                return -ENODEV;
@@ -147,6 +148,30 @@ ohci_hcd_ppc_of_probe(struct of_device *op, const struct of_device_id *match)
        if (rv == 0)
                return 0;
 
+       /* by now, 440epx is known to show usb_23 erratum */
+       np = of_find_compatible_node(NULL, NULL, "ibm,usb-ehci-440epx");
+
+       /* Work around - At this point ohci_run has executed, the
+       * controller is running, everything, the root ports, etc., is
+       * set up.  If the ehci driver is loaded, put the ohci core in
+       * the suspended state.  The ehci driver will bring it out of
+       * suspended state when / if a non-high speed USB device is
+       * attached to the USB Host port.  If the ehci driver is not
+       * loaded, do nothing. request_mem_region is used to test if
+       * the ehci driver is loaded.
+       */
+       if (np !=  NULL) {
+               if (!of_address_to_resource(np, 0, &res)) {
+                       if (!request_mem_region(res.start, 0x4, hcd_name)) {
+                               writel_be((readl_be(&ohci->regs->control) |
+                                       OHCI_USB_SUSPEND), &ohci->regs->control);
+                                       (void) readl_be(&ohci->regs->control);
+                       } else
+                               release_mem_region(res.start, 0x4);
+               } else
+                   pr_debug(__FILE__ ": cannot get ehci offset from fdt\n");
+       }
+
        iounmap(hcd->regs);
 err_ioremap:
        irq_dispose_mapping(irq);