[PATCH 1/2] coresight: etb10: Refactor etb_drvdata::mode handling
From: Mathieu Poirier <mathieu.poirier@linaro.org>
Date: 2018-08-14 22:14:32
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> --- drivers/hwtracing/coresight/coresight-etb10.c | 62 +++++++++++++++------------ 1 file 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);
--
2.7.4