coresight: etb10: Refactor etb_drvdata::mode handling

This patch moves the etb_drvdata::mode from a locat_t to a simple u32,
as it is for the ETF and ETR drivers.  This streamlines the code and adds
commonality with the other drivers when dealing with similar operations.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 34 insertions, 28 deletions

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 9fd77fdc1244..69287163ce4e 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -5,7 +5,6 @@
  * Description: CoreSight Embedded Trace Buffer driver
  */
 
-#include <asm/local.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/types.h>
@@ -72,8 +71,8 @@
  * @miscdev:    specifics to handle "/dev/xyz.etb" entry.
  * @spinlock:   only one at a time pls.
  * @reading:    synchronise user space access to etb buffer.
- * @mode:       this ETB is being used.
  * @buf:        area of memory where ETB buffer content gets sent.
+ * @mode:       this ETB is being used.
  * @buffer_depth: size of @buf.
  * @trigger_cntr: amount of words to store after a trigger.
  */
@@ -85,8 +84,8 @@ struct etb_drvdata {
         struct miscdevice       miscdev;
         spinlock_t              spinlock;
         local_t                 reading;
-        local_t                 mode;
         u8                      *buf;
+        u32                     mode;
         u32                     buffer_depth;
         u32                     trigger_cntr;
 };
@@ -138,44 +137,48 @@ static void etb_enable_hw(struct etb_drvdata *drvdata)
 static int etb_enable(struct coresight_device *csdev, u32 mode, void *data)
 {
         int ret = 0;
-        u32 val;
         unsigned long flags;
         struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 
-        /*
-         * We don't have an internal state to clean up if we fail to setup
-         * the perf buffer. So we can perform the step before we turn the
-         * ETB on and leave without cleaning up.
-         */
-        if (mode == CS_MODE_PERF) {
-                ret = etb_set_buffer(csdev, (struct perf_output_handle *)data);
-                if (ret)
-                        goto out;
-        }
+        spin_lock_irqsave(&drvdata->spinlock, flags);
 
-        val = local_cmpxchg(&drvdata->mode,
-                            CS_MODE_DISABLED, mode);
         /*
          * When accessing from Perf, a HW buffer can be handled
          * by a single trace entity.  In sysFS mode many tracers
          * can be logging to the same HW buffer.
          */
-        if (val == CS_MODE_PERF)
-                return -EBUSY;
+        if (drvdata->mode == CS_MODE_PERF) {
+                ret = -EBUSY;
+                goto out;
+        }
 
         /* Don't let perf disturb sysFS sessions */
-        if (val == CS_MODE_SYSFS && mode == CS_MODE_PERF)
-                return -EBUSY;
+        if (drvdata->mode == CS_MODE_SYSFS && mode == CS_MODE_PERF) {
+                ret = -EBUSY;
+                goto out;
+        }
 
         /* Nothing to do, the tracer is already enabled. */
-        if (val == CS_MODE_SYSFS)
+        if (drvdata->mode == CS_MODE_SYSFS && mode == CS_MODE_SYSFS)
                 goto out;
 
-        spin_lock_irqsave(&drvdata->spinlock, flags);
+        /*
+         * We don't have an internal state to clean up if we fail to setup
+         * the perf buffer. So we can perform the step before we turn the
+         * ETB on and leave without cleaning up.
+         */
+        if (mode == CS_MODE_PERF) {
+                ret = etb_set_buffer(csdev, (struct perf_output_handle *)data);
+                if (ret)
+                        goto out;
+        }
+
+        drvdata->mode = mode;
         etb_enable_hw(drvdata);
-        spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 out:
+        spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
         if (!ret)
                 dev_dbg(drvdata->dev, "ETB enabled\n");
         return ret;
@@ -277,11 +280,14 @@ static void etb_disable(struct coresight_device *csdev)
         unsigned long flags;
 
         spin_lock_irqsave(&drvdata->spinlock, flags);
-        etb_disable_hw(drvdata);
-        etb_dump_hw(drvdata);
-        spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
-        local_set(&drvdata->mode, CS_MODE_DISABLED);
+        /* Disable the ETB only if it needs to */
+        if (drvdata->mode != CS_MODE_DISABLED) {
+                etb_disable_hw(drvdata);
+                etb_dump_hw(drvdata);
+                drvdata->mode = CS_MODE_DISABLED;
+        }
+        spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
         dev_dbg(drvdata->dev, "ETB disabled\n");
 }
@@ -488,7 +494,7 @@ static void etb_dump(struct etb_drvdata *drvdata)
         unsigned long flags;
 
         spin_lock_irqsave(&drvdata->spinlock, flags);
-        if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
+        if (drvdata->mode == CS_MODE_SYSFS) {
                 etb_disable_hw(drvdata);
                 etb_dump_hw(drvdata);
                 etb_enable_hw(drvdata);