ehci-fsl: fix cache coherency problem on system with large memory

The patch fixes bug http://bugzilla.kernel.org/show_bug.cgi?id=7482.

It sets USB snooping on 4G space for PowerPC platforms without
CONFIG_NOT_COHERENT_CACHE defined.

Reported-by: Stefan Meyer <reyems@telkomsa.net>
Signed-off-by: Li Yang <leoli@freescale.com>
Cc: Greg KH <greg@kroah.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 14 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
index a52480505f78..c7a7c590426f 100644
--- a/drivers/usb/host/ehci-fsl.c
+++ b/drivers/usb/host/ehci-fsl.c
@@ -193,6 +193,19 @@ static void mpc83xx_usb_setup(struct usb_hcd *hcd)
         out_be32(non_ehci + FSL_SOC_USB_CTRL, 0x00000004);
         out_be32(non_ehci + FSL_SOC_USB_SNOOP1, 0x0000001b);
 
+#if defined(CONFIG_PPC32) && !defined(CONFIG_NOT_COHERENT_CACHE)
+        /*
+         * Turn on cache snooping hardware, since some PowerPC platforms
+         * wholly rely on hardware to deal with cache coherent
+         */
+
+        /* Setup Snooping for all the 4GB space */
+        /* SNOOP1 starts from 0x0, size 2G */
+        out_be32(non_ehci + FSL_SOC_USB_SNOOP1, 0x0 | SNOOP_SIZE_2GB);
+        /* SNOOP2 starts from 0x80000000, size 2G */
+        out_be32(non_ehci + FSL_SOC_USB_SNOOP2, 0x80000000 | SNOOP_SIZE_2GB);
+#endif
+
         if (pdata->operating_mode == FSL_USB2_DR_HOST)
                 mpc83xx_setup_phy(ehci, pdata->phy_mode, 0);
 
diff --git a/drivers/usb/host/ehci-fsl.h b/drivers/usb/host/ehci-fsl.h
index f28736a917e4..b5e59db53347 100644
--- a/drivers/usb/host/ehci-fsl.h
+++ b/drivers/usb/host/ehci-fsl.h
@@ -34,4 +34,5 @@
 #define FSL_SOC_USB_PRICTRL     0x40c   /* NOTE: big-endian */
 #define FSL_SOC_USB_SICTRL      0x410   /* NOTE: big-endian */
 #define FSL_SOC_USB_CTRL        0x500   /* NOTE: big-endian */
+#define SNOOP_SIZE_2GB          0x1e
 #endif                          /* _EHCI_FSL_H */