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>

5 files changed, 23 insertions, 27 deletions

diff --git a/drivers/usb/host/ehci-dbg.c b/drivers/usb/host/ehci-dbg.c
index 680e1a31fb8..7561966fbdc 100644
--- a/drivers/usb/host/ehci-dbg.c
+++ b/drivers/usb/host/ehci-dbg.c
@@ -1025,10 +1025,8 @@ static ssize_t debug_lpm_write(struct file *file, const char __user *user_buf,
                 if (strict_strtoul(buf + 5, 16, &hird))
                         return -EINVAL;
                 printk(KERN_INFO "setting hird %s %lu\n", buf + 6, hird);
-                temp = ehci_readl(ehci, &ehci->regs->command);
-                temp &= ~CMD_HIRD;
-                temp |= hird << 24;
-                ehci_writel(ehci, temp, &ehci->regs->command);
+                ehci->command = (ehci->command & ~CMD_HIRD) | (hird << 24);
+                ehci_writel(ehci, ehci->command, &ehci->regs->command);
         } else if (strncmp(buf, "disable", 7) == 0) {
                 if (strict_strtoul(buf + 8, 10, &port))
                         return -EINVAL;
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index a87c0573c86..de1e689d3df 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -226,8 +226,13 @@ static int ehci_halt (struct ehci_hcd *ehci)
         if ((temp & STS_HALT) != 0)
                 return 0;
 
+        /*
+         * This routine gets called during probe before ehci->command
+         * has been initialized, so we can't rely on its value.
+         */
+        ehci->command &= ~CMD_RUN;
         temp = ehci_readl(ehci, &ehci->regs->command);
-        temp &= ~CMD_RUN;
+        temp &= ~(CMD_RUN | CMD_IAAD);
         ehci_writel(ehci, temp, &ehci->regs->command);
         return handshake (ehci, &ehci->regs->status,
                           STS_HALT, STS_HALT, 16 * 125);
@@ -347,6 +352,7 @@ static int ehci_reset (struct ehci_hcd *ehci)
         if (ehci->debug)
                 dbgp_external_startup();
 
+        ehci->command = ehci_readl(ehci, &ehci->regs->command);
         ehci->port_c_suspend = ehci->suspended_ports =
                         ehci->resuming_ports = 0;
         return retval;
@@ -363,16 +369,14 @@ static void ehci_quiesce (struct ehci_hcd *ehci)
 #endif
 
         /* wait for any schedule enables/disables to take effect */
-        temp = ehci_readl(ehci, &ehci->regs->command) << 10;
-        temp &= STS_ASS | STS_PSS;
+        temp = (ehci->command << 10) & (STS_ASS | STS_PSS);
         if (handshake_on_error_set_halt(ehci, &ehci->regs->status,
                                         STS_ASS | STS_PSS, temp, 16 * 125))
                 return;
 
         /* then disable anything that's still active */
-        temp = ehci_readl(ehci, &ehci->regs->command);
-        temp &= ~(CMD_ASE | CMD_IAAD | CMD_PSE);
-        ehci_writel(ehci, temp, &ehci->regs->command);
+        ehci->command &= ~(CMD_ASE | CMD_PSE);
+        ehci_writel(ehci, ehci->command, &ehci->regs->command);
 
         /* hardware can take 16 microframes to turn off ... */
         handshake_on_error_set_halt(ehci, &ehci->regs->status,
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 402e766df2f..fc9e7cc6ac9 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -233,7 +233,6 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
         /* stop schedules, clean any completed work */
         if (ehci->rh_state == EHCI_RH_RUNNING)
                 ehci_quiesce (ehci);
-        ehci->command = ehci_readl(ehci, &ehci->regs->command);
         ehci_work(ehci);
 
         /* Unlike other USB host controller types, EHCI doesn't have
@@ -374,6 +373,7 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
         ehci_writel(ehci, (u32) ehci->async->qh_dma, &ehci->regs->async_next);
 
         /* restore CMD_RUN, framelist size, and irq threshold */
+        ehci->command |= CMD_RUN;
         ehci_writel(ehci, ehci->command, &ehci->regs->command);
         ehci->rh_state = EHCI_RH_RUNNING;
 
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 36ca5077cdf..13f4f980841 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -981,14 +981,12 @@ static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
         head = ehci->async;
         timer_action_done (ehci, TIMER_ASYNC_OFF);
         if (!head->qh_next.qh) {
-                u32     cmd = ehci_readl(ehci, &ehci->regs->command);
-
-                if (!(cmd & CMD_ASE)) {
+                if (!(ehci->command & CMD_ASE)) {
                         /* in case a clear of CMD_ASE didn't take yet */
                         (void)handshake(ehci, &ehci->regs->status,
                                         STS_ASS, 0, 150);
-                        cmd |= CMD_ASE;
-                        ehci_writel(ehci, cmd, &ehci->regs->command);
+                        ehci->command |= CMD_ASE;
+                        ehci_writel(ehci, ehci->command, &ehci->regs->command);
                         /* posted write need not be known to HC yet ... */
                 }
         }
@@ -1204,7 +1202,6 @@ static void end_unlink_async (struct ehci_hcd *ehci)
 
 static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
 {
-        int             cmd = ehci_readl(ehci, &ehci->regs->command);
         struct ehci_qh  *prev;
 
 #ifdef DEBUG
@@ -1222,8 +1219,8 @@ static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
                 if (ehci->rh_state != EHCI_RH_HALTED
                                 && !ehci->reclaim) {
                         /* ... and CMD_IAAD clear */
-                        ehci_writel(ehci, cmd & ~CMD_ASE,
-                                    &ehci->regs->command);
+                        ehci->command &= ~CMD_ASE;
+                        ehci_writel(ehci, ehci->command, &ehci->regs->command);
                         wmb ();
                         // handshake later, if we need to
                         timer_action_done (ehci, TIMER_ASYNC_OFF);
@@ -1253,8 +1250,7 @@ static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
                 return;
         }
 
-        cmd |= CMD_IAAD;
-        ehci_writel(ehci, cmd, &ehci->regs->command);
+        ehci_writel(ehci, ehci->command | CMD_IAAD, &ehci->regs->command);
         (void)ehci_readl(ehci, &ehci->regs->command);
         iaa_watchdog_start(ehci);
 }
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index a60679cbbf8..ffe8fc3bc7e 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);