USB: EHCI: AMD periodic frame list table quirk
On AMD SB700/SB800/Hudson-2/3 platforms, USB EHCI controller may read/write
to memory space not allocated to USB controller if there is longer than
normal latency on DMA read encountered. In this condition the exposure will
be encountered only if the driver has following format of Periodic Frame
List link pointer structure:
For any idle periodic schedule, the Frame List link pointers that have the
T-bit set to 1 intending to terminate the use of frame list link pointer
as a physical memory pointer.
Idle periodic schedule Frame List Link pointer shoule be in the following
format to avoid the issue:
Frame list link pointer should be always contains a valid pointer to a
inactive QHead with T-bit set to 0.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index bde823f..ba8eab3 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -73,6 +73,7 @@
/* async schedule support */
struct ehci_qh *async;
+ struct ehci_qh *dummy; /* For AMD quirk use */
struct ehci_qh *reclaim;
unsigned scanning : 1;
@@ -131,6 +132,7 @@
unsigned need_io_watchdog:1;
unsigned broken_periodic:1;
unsigned fs_i_thresh:1; /* Intel iso scheduling */
+ unsigned use_dummy_qh:1; /* AMD Frame List table quirk*/
/* required for usb32 quirk */
#define OHCI_CTRL_HCFS (3 << 6)