USB: octeon2-common: Don't reinitialize the clocks.

The UCTL clock initialization will cause the ehci and ohci blocks to
become inoperable if the clocks are reinitialized.

Check to see if the clocks have already been initialized.

Also use a mutex to protect the clock initialization code so that
there can be no attempt to use the clocks before they are fully
configured.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/octeon2-common.c

@@ -3,18 +3,19 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2010 Cavium Networks
+ * Copyright (C) 2010, 2011 Cavium Networks
  */
 
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/delay.h>
 
-#include <asm/atomic.h>
-
 #include <asm/octeon/octeon.h>
 #include <asm/octeon/cvmx-uctlx-defs.h>
 
-static atomic_t  octeon2_usb_clock_start_cnt = ATOMIC_INIT(0);
+static DEFINE_MUTEX(octeon2_usb_clocks_mutex);
+
+static int octeon2_usb_clock_start_cnt;
 
 void octeon2_usb_clocks_start(void)
 {
@@ -26,8 +27,12 @@ void octeon2_usb_clocks_start(void)
 	int i;
 	unsigned long io_clk_64_to_ns;
 
-	if (atomic_inc_return(&octeon2_usb_clock_start_cnt) != 1)
-		return;
+
+	mutex_lock(&octeon2_usb_clocks_mutex);
+
+	octeon2_usb_clock_start_cnt++;
+	if (octeon2_usb_clock_start_cnt != 1)
+		goto exit;
 
 	io_clk_64_to_ns = 64000000000ull / octeon_get_io_clock_rate();
 
@@ -43,6 +48,13 @@ void octeon2_usb_clocks_start(void)
 
 	/* Step 3: Configure the reference clock, PHY, and HCLK */
 	clk_rst_ctl.u64 = cvmx_read_csr(CVMX_UCTLX_CLK_RST_CTL(0));
+
+	/*
+	 * If the UCTL looks like it has already been started, skip
+	 * the initialization, otherwise bus errors are obtained.
+	 */
+	if (clk_rst_ctl.s.hrst)
+		goto end_clock;
 	/* 3a */
 	clk_rst_ctl.s.p_por = 1;
 	clk_rst_ctl.s.hrst = 0;
@@ -158,6 +170,7 @@ void octeon2_usb_clocks_start(void)
 	clk_rst_ctl.s.hrst = 1;
 	cvmx_write_csr(CVMX_UCTLX_CLK_RST_CTL(0), clk_rst_ctl.u64);
 
+end_clock:
 	/* Now we can set some other registers.  */
 
 	for (i = 0; i <= 1; i++) {
@@ -168,18 +181,15 @@ void octeon2_usb_clocks_start(void)
 		cvmx_write_csr(CVMX_UCTLX_UPHY_PORTX_CTL_STATUS(i, 0),
 			       port_ctl_status.u64);
 	}
+exit:
+	mutex_unlock(&octeon2_usb_clocks_mutex);
 }
 EXPORT_SYMBOL(octeon2_usb_clocks_start);
 
 void octeon2_usb_clocks_stop(void)
 {
-	union cvmx_uctlx_if_ena if_ena;
-
-	if (atomic_dec_return(&octeon2_usb_clock_start_cnt) != 0)
-		return;
-
-	if_ena.u64 = 0;
-	if_ena.s.en = 0;
-	cvmx_write_csr(CVMX_UCTLX_IF_ENA(0), if_ena.u64);
+	mutex_lock(&octeon2_usb_clocks_mutex);
+	octeon2_usb_clock_start_cnt--;
+	mutex_unlock(&octeon2_usb_clocks_mutex);
 }
 EXPORT_SYMBOL(octeon2_usb_clocks_stop);