USB: EHCI: EHCI 1.1 addendum: Enable Per-port change detect bits
This patch will enable Per-port event feature defined in EHCI 1.1
addendum. This feature addresses an issue where HCD is currently
required to read and parse PORTSC for all enabled root hub ports. With
this patch, the overhead will be reduced.
Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index baf9b64..8697ad19 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -584,6 +584,11 @@
if (log2_irq_thresh < 0 || log2_irq_thresh > 6)
log2_irq_thresh = 0;
temp = 1 << (16 + log2_irq_thresh);
+ if (HCC_PER_PORT_CHANGE_EVENT(hcc_params)) {
+ ehci->has_ppcd = 1;
+ ehci_dbg(ehci, "enable per-port change event\n");
+ temp |= CMD_PPCEE;
+ }
if (HCC_CANPARK(hcc_params)) {
/* HW default park == 3, on hardware that supports it (like
* NVidia and ALI silicon), maximizes throughput on the async
@@ -782,6 +787,7 @@
/* remote wakeup [4.3.1] */
if (status & STS_PCD) {
unsigned i = HCS_N_PORTS (ehci->hcs_params);
+ u32 ppcd = 0;
/* kick root hub later */
pcd_status = status;
@@ -790,9 +796,18 @@
if (!(cmd & CMD_RUN))
usb_hcd_resume_root_hub(hcd);
+ /* get per-port change detect bits */
+ if (ehci->has_ppcd)
+ ppcd = status >> 16;
+
while (i--) {
- int pstatus = ehci_readl(ehci,
- &ehci->regs->port_status [i]);
+ int pstatus;
+
+ /* leverage per-port change bits feature */
+ if (ehci->has_ppcd && !(ppcd & (1 << i)))
+ continue;
+ pstatus = ehci_readl(ehci,
+ &ehci->regs->port_status[i]);
if (pstatus & PORT_OWNER)
continue;
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 8a28dae..84e792d 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -603,6 +603,7 @@
u32 mask;
int ports, i, retval = 1;
unsigned long flags;
+ u32 ppcd = 0;
/* if !USB_SUSPEND, root hub timers won't get shut down ... */
if (!HC_IS_RUNNING(hcd->state))
@@ -632,7 +633,15 @@
/* port N changes (bit N)? */
spin_lock_irqsave (&ehci->lock, flags);
+
+ /* get per-port change detect bits */
+ if (ehci->has_ppcd)
+ ppcd = ehci_readl(ehci, &ehci->regs->status) >> 16;
+
for (i = 0; i < ports; i++) {
+ /* leverage per-port change bits feature */
+ if (ehci->has_ppcd && !(ppcd & (1 << i)))
+ continue;
temp = ehci_readl(ehci, &ehci->regs->port_status [i]);
/*
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 21f30a0..e6c57cc 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -141,6 +141,7 @@
__hc32 *ohci_hcctrl_reg;
unsigned has_hostpc:1;
unsigned has_lpm:1; /* support link power management */
+ unsigned has_ppcd:1; /* support per-port change bits */
u8 sbrn; /* packed release number */
/* irq statistics */