usb: ehci-fsl: set INCR8 mode for system bus interface on MPC512x

Use INCR8 mode for system bus interface of the USB controller
on MPC512x. This is a work-around for the AHB bus lock up
problem observed on MPC512x when there is heavy simultaneous
PATA write or network (FEC) activity.

See also "12.4 The USB controller can issue transactions that lock
up the AHB bus under certain conditions" in MPC5121e (M36P) Errata.

Signed-off-by: Anatolij Gustschin <[e-mail]>
Tested-by: Matthias Fuchs <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/ehci-fsl.c

···
 	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
 	int retval;
 	struct fsl_usb2_platform_data *pdata;
+	struct device *dev;
 
+	dev = hcd->self.controller;
 	pdata = hcd->self.controller->platform_data;
 	ehci->big_endian_desc = pdata->big_endian_desc;
 	ehci->big_endian_mmio = pdata->big_endian_mmio;
···
 	ehci->sbrn = 0x20;
 
 	ehci_reset(ehci);
+
+	if (of_device_is_compatible(dev->parent->of_node,
+				    "fsl,mpc5121-usb2-dr")) {
+		/*
+		 * set SBUSCFG:AHBBRST so that control msgs don't
+		 * fail when doing heavy PATA writes.
+		 */
+		ehci_writel(ehci, SBUSCFG_INCR8,
+			    hcd->regs + FSL_SOC_USB_SBUSCFG);
+	}
 
 	retval = ehci_fsl_reinit(ehci);
 	return retval;
···
 		    hcd->regs + FSL_SOC_USB_USBGENCTRL);
 	ehci_writel(ehci, ISIPHYCTRL_PXE | ISIPHYCTRL_PHYE,
 		    hcd->regs + FSL_SOC_USB_ISIPHYCTRL);
+
+	ehci_writel(ehci, SBUSCFG_INCR8, hcd->regs + FSL_SOC_USB_SBUSCFG);
 
 	/* restore EHCI registers */
 	ehci_writel(ehci, pdata->pm_command, &ehci->regs->command);

drivers/usb/host/ehci-fsl.h

···
 #define _EHCI_FSL_H
 
 /* offsets for the non-ehci registers in the FSL SOC USB controller */
+#define FSL_SOC_USB_SBUSCFG	0x90
+#define SBUSCFG_INCR8		0x02	/* INCR8, specified */
 #define FSL_SOC_USB_ULPIVP	0x170
 #define FSL_SOC_USB_PORTSC1	0x184
 #define PORT_PTS_MSK		(3<<30)