EHCI: maintain the ehci->command value properly

The ehci-hcd driver is a little haphazard about keeping track of the
state of the USBCMD register.  The ehci->command field is supposed to
hold the register's value (apart from a few special bits) at all
times, but it isn't maintained properly.

This patch (as1543) cleans up the situation.  It keeps ehci->command
up-to-date, and uses that value rather than reading the register from
the hardware whenever possible.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 6 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index a60679cbbf85..ffe8fc3bc7ef 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -481,7 +481,6 @@ static int tt_no_collision (
 
 static int enable_periodic (struct ehci_hcd *ehci)
 {
-        u32     cmd;
         int     status;
 
         if (ehci->periodic_sched++)
@@ -497,8 +496,8 @@ static int enable_periodic (struct ehci_hcd *ehci)
                 return status;
         }
 
-        cmd = ehci_readl(ehci, &ehci->regs->command) | CMD_PSE;
-        ehci_writel(ehci, cmd, &ehci->regs->command);
+        ehci->command |= CMD_PSE;
+        ehci_writel(ehci, ehci->command, &ehci->regs->command);
         /* posted write ... PSS happens later */
 
         /* make sure ehci_work scans these */
@@ -511,7 +510,6 @@ static int enable_periodic (struct ehci_hcd *ehci)
 
 static int disable_periodic (struct ehci_hcd *ehci)
 {
-        u32     cmd;
         int     status;
 
         if (--ehci->periodic_sched)
@@ -537,8 +535,8 @@ static int disable_periodic (struct ehci_hcd *ehci)
                 return status;
         }
 
-        cmd = ehci_readl(ehci, &ehci->regs->command) & ~CMD_PSE;
-        ehci_writel(ehci, cmd, &ehci->regs->command);
+        ehci->command &= ~CMD_PSE;
+        ehci_writel(ehci, ehci->command, &ehci->regs->command);
         /* posted write ... */
 
         free_cached_lists(ehci);