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>

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 9fd77fd..6928716 100644 (file)
--- 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);