xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

EHCI: maintain the ehci->command value properly

Browse Source 
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>
This commit is contained in:
Alan Stern
2012-04-23 13:54:36 -04:00
committed by Greg Kroah-Hartman
parent 09091a4d5f
commit 3d9545cc37
5 changed files with 23 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/usb/host/ehci-sched.c
View File

@@ -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);