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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2010-05-24 16:25:15 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2010-06-04 16:16:18 -0400
commit2d62f3eea98354d61f90d6b115eecf9be5f4bdfe (patch)
treebd42be1731bab339ad0376fb389f9dc5a64f04ac /drivers
parent0c8a32dff4f9ebed3e067e52e12842d7d7e047a0 (diff)
USB: xhci: Wait for controller to be ready after reset.
After software resets an xHCI host controller, it must wait for the "Controller Not Ready" (CNR) bit in the status register to be cleared. Software is not supposed to ring any doorbells or write to any registers except the status register until this bit is cleared. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/usb/host/xhci.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 40e0a0c221b8..79ccfe5f8ad0 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -116,6 +116,7 @@ int xhci_reset(struct xhci_hcd *xhci)
116{ 116{
117 u32 command; 117 u32 command;
118 u32 state; 118 u32 state;
119 int ret;
119 120
120 state = xhci_readl(xhci, &xhci->op_regs->status); 121 state = xhci_readl(xhci, &xhci->op_regs->status);
121 if ((state & STS_HALT) == 0) { 122 if ((state & STS_HALT) == 0) {
@@ -130,7 +131,17 @@ int xhci_reset(struct xhci_hcd *xhci)
130 /* XXX: Why does EHCI set this here? Shouldn't other code do this? */ 131 /* XXX: Why does EHCI set this here? Shouldn't other code do this? */
131 xhci_to_hcd(xhci)->state = HC_STATE_HALT; 132 xhci_to_hcd(xhci)->state = HC_STATE_HALT;
132 133
133 return handshake(xhci, &xhci->op_regs->command, CMD_RESET, 0, 250 * 1000); 134 ret = handshake(xhci, &xhci->op_regs->command,
135 CMD_RESET, 0, 250 * 1000);
136 if (ret)
137 return ret;
138
139 xhci_dbg(xhci, "Wait for controller to be ready for doorbell rings\n");
140 /*
141 * xHCI cannot write to any doorbells or operational registers other
142 * than status until the "Controller Not Ready" flag is cleared.
143 */
144 return handshake(xhci, &xhci->op_regs->status, STS_CNR, 0, 250 * 1000);
134} 145}
135 146
136 147