coresight-etm4x: Controls pertaining to the selection of resources

Adding sysfs entries to control the selection of the resources the
trace unit will use as triggers to perform a trace run.

Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
index 104f3951c998df75a952967ad36f546297132b6c..5c7391d4e33a08ae289c9d9956ea391899e9822b 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
@@ -230,3 +230,15 @@ Date:              April 2015
 KernelVersion: 4.01
 Contact:       Mathieu Poirier <mathieu.poirier@linaro.org>
 Description:   (RW) Controls the operation of the selected counter.
+
+What:          /sys/bus/coresight/devices/<memory_map>.etm/res_idx
+Date:          April 2015
+KernelVersion: 4.01
+Contact:       Mathieu Poirier <mathieu.poirier@linaro.org>
+Description:   (RW) Select which resource selection unit to work with.
+
+What:          /sys/bus/coresight/devices/<memory_map>.etm/res_ctrl
+Date:          April 2015
+KernelVersion: 4.01
+Contact:       Mathieu Poirier <mathieu.poirier@linaro.org>
+Description:   (RW) Controls the selection of the resources in the trace unit.

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 2c394e41b0c8ccc6ba010edecda19f425a310328..308a48df4338156d859573f67de19fca59b10797 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -1707,6 +1707,79 @@ static ssize_t cntr_ctrl_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(cntr_ctrl);
 
+static ssize_t res_idx_show(struct device *dev,
+                           struct device_attribute *attr,
+                           char *buf)
+{
+       unsigned long val;
+       struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+       val = drvdata->res_idx;
+       return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
+}
+
+static ssize_t res_idx_store(struct device *dev,
+                            struct device_attribute *attr,
+                            const char *buf, size_t size)
+{
+       unsigned long val;
+       struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+       if (kstrtoul(buf, 16, &val))
+               return -EINVAL;
+       /* Resource selector pair 0 is always implemented and reserved */
+       if ((val == 0) || (val >= drvdata->nr_resource))
+               return -EINVAL;
+
+       /*
+        * Use spinlock to ensure index doesn't change while it gets
+        * dereferenced multiple times within a spinlock block elsewhere.
+        */
+       spin_lock(&drvdata->spinlock);
+       drvdata->res_idx = val;
+       spin_unlock(&drvdata->spinlock);
+       return size;
+}
+static DEVICE_ATTR_RW(res_idx);
+
+static ssize_t res_ctrl_show(struct device *dev,
+                            struct device_attribute *attr,
+                            char *buf)
+{
+       u8 idx;
+       unsigned long val;
+       struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+       spin_lock(&drvdata->spinlock);
+       idx = drvdata->res_idx;
+       val = drvdata->res_ctrl[idx];
+       spin_unlock(&drvdata->spinlock);
+       return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
+}
+
+static ssize_t res_ctrl_store(struct device *dev,
+                             struct device_attribute *attr,
+                             const char *buf, size_t size)
+{
+       u8 idx;
+       unsigned long val;
+       struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+       if (kstrtoul(buf, 16, &val))
+               return -EINVAL;
+
+       spin_lock(&drvdata->spinlock);
+       idx = drvdata->res_idx;
+       /* For odd idx pair inversal bit is RES0 */
+       if (idx % 2 != 0)
+               /* PAIRINV, bit[21] */
+               val &= ~BIT(21);
+       drvdata->res_ctrl[idx] = val;
+       spin_unlock(&drvdata->spinlock);
+       return size;
+}
+static DEVICE_ATTR_RW(res_ctrl);
+
 static ssize_t cpu_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
 {
@@ -1757,6 +1830,8 @@ static struct attribute *coresight_etmv4_attrs[] = {
        &dev_attr_cntrldvr.attr,
        &dev_attr_cntr_val.attr,
        &dev_attr_cntr_ctrl.attr,
+       &dev_attr_res_idx.attr,
+       &dev_attr_res_ctrl.attr,
        &dev_attr_cpu.attr,
        NULL,
 };