diff mbox

[10/11] coresight-etm4x: Controls pertaining to the context ID functions

Message ID 1429742451-11465-11-git-send-email-mathieu.poirier@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Mathieu Poirier April 22, 2015, 10:40 p.m. UTC 
From: Pratik Patel <pratikp@codeaurora.org>

Adding sysfs entries to access and configure specifics about the
context ID comparator functions.

Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 .../ABI/testing/sysfs-bus-coresight-devices-etm4x  |  19 +++
 drivers/hwtracing/coresight/coresight-etm4x.c      | 187 +++++++++++++++++++++
 2 files changed, 206 insertions(+)

Comments

Christopher Covington April 23, 2015, 3:08 p.m. UTC | #1 
Hi Mathieu,

On 04/22/2015 06:40 PM, Mathieu Poirier wrote:
> From: Pratik Patel <pratikp@codeaurora.org>
> 
> Adding sysfs entries to access and configure specifics about the
> context ID comparator functions.
> 
> Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> ---
>  .../ABI/testing/sysfs-bus-coresight-devices-etm4x  |  19 +++
>  drivers/hwtracing/coresight/coresight-etm4x.c      | 187 +++++++++++++++++++++
>  2 files changed, 206 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> index b5c0456290ab..8b32cb7b9723 100644
> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> @@ -254,3 +254,22 @@ 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.
> +
> +What:		/sys/bus/coresight/devices/<memory_map>.etm/ctxid_idx
> +Date:		April 2015
> +KernelVersion:	4.01
> +Contact:	Mathieu Poirier <mathieu.poirier@linaro.org>
> +Description:	(RW) Select which context ID comparator to work with.
> +
> +What:		/sys/bus/coresight/devices/<memory_map>.etm/ctxid_val
> +Date:		April 2015
> +KernelVersion:	4.01
> +Contact:	Mathieu Poirier <mathieu.poirier@linaro.org>
> +Description:	(RW) Get/Set the context ID comparator value to trigger on.

If I'm understanding this correctly, ctxid_val is multiplexed using ctxid_idx.
Why not just have ctxid_val0, ctxid_val1, ...?

Thanks,
Chris
Mathieu Poirier April 23, 2015, 3:16 p.m. UTC | #2 
On 23 April 2015 at 09:08, Christopher Covington <cov@codeaurora.org> wrote:
> Hi Mathieu,
>
> On 04/22/2015 06:40 PM, Mathieu Poirier wrote:
>> From: Pratik Patel <pratikp@codeaurora.org>
>>
>> Adding sysfs entries to access and configure specifics about the
>> context ID comparator functions.
>>
>> Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
>> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>> ---
>>  .../ABI/testing/sysfs-bus-coresight-devices-etm4x  |  19 +++
>>  drivers/hwtracing/coresight/coresight-etm4x.c      | 187 +++++++++++++++++++++
>>  2 files changed, 206 insertions(+)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
>> index b5c0456290ab..8b32cb7b9723 100644
>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
>> @@ -254,3 +254,22 @@ 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.
>> +
>> +What:                /sys/bus/coresight/devices/<memory_map>.etm/ctxid_idx
>> +Date:                April 2015
>> +KernelVersion:       4.01
>> +Contact:     Mathieu Poirier <mathieu.poirier@linaro.org>
>> +Description: (RW) Select which context ID comparator to work with.
>> +
>> +What:                /sys/bus/coresight/devices/<memory_map>.etm/ctxid_val
>> +Date:                April 2015
>> +KernelVersion:       4.01
>> +Contact:     Mathieu Poirier <mathieu.poirier@linaro.org>
>> +Description: (RW) Get/Set the context ID comparator value to trigger on.
>
> If I'm understanding this correctly, ctxid_val is multiplexed using ctxid_idx.
> Why not just have ctxid_val0, ctxid_val1, ...?

There can be up to 8 of them on the current implementation and who
knows how many more in the future.  To me using and index to select
the context ID to work on scaled better and is introducing less
clutter in sysfs.

Thanks for the review,
Mathieu

>
> Thanks,
> Chris
>
> --
> Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
Christopher Covington April 23, 2015, 4:59 p.m. UTC | #3 
On 04/23/2015 11:16 AM, Mathieu Poirier wrote:
> On 23 April 2015 at 09:08, Christopher Covington <cov@codeaurora.org> wrote:
>> Hi Mathieu,
>>
>> On 04/22/2015 06:40 PM, Mathieu Poirier wrote:
>>> From: Pratik Patel <pratikp@codeaurora.org>
>>>
>>> Adding sysfs entries to access and configure specifics about the
>>> context ID comparator functions.
>>>
>>> Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
>>> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>>> ---
>>>  .../ABI/testing/sysfs-bus-coresight-devices-etm4x  |  19 +++
>>>  drivers/hwtracing/coresight/coresight-etm4x.c      | 187 +++++++++++++++++++++
>>>  2 files changed, 206 insertions(+)
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
>>> index b5c0456290ab..8b32cb7b9723 100644
>>> --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
>>> +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
>>> @@ -254,3 +254,22 @@ 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.
>>> +
>>> +What:                /sys/bus/coresight/devices/<memory_map>.etm/ctxid_idx
>>> +Date:                April 2015
>>> +KernelVersion:       4.01
>>> +Contact:     Mathieu Poirier <mathieu.poirier@linaro.org>
>>> +Description: (RW) Select which context ID comparator to work with.
>>> +
>>> +What:                /sys/bus/coresight/devices/<memory_map>.etm/ctxid_val
>>> +Date:                April 2015
>>> +KernelVersion:       4.01
>>> +Contact:     Mathieu Poirier <mathieu.poirier@linaro.org>
>>> +Description: (RW) Get/Set the context ID comparator value to trigger on.
>>
>> If I'm understanding this correctly, ctxid_val is multiplexed using ctxid_idx.
>> Why not just have ctxid_val0, ctxid_val1, ...?
> 
> There can be up to 8 of them on the current implementation and who
> knows how many more in the future.  To me using and index to select
> the context ID to work on scaled better and is introducing less
> clutter in sysfs.

In theory there's a race condition if two tasks are trying to set the index
and then the value, which having individually addressable values solves, but I
don't anticipate trying to use more than one task to configure tracing.

Chris
diff mbox

Patch

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
index b5c0456290ab..8b32cb7b9723 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
@@ -254,3 +254,22 @@  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.
+
+What:		/sys/bus/coresight/devices/<memory_map>.etm/ctxid_idx
+Date:		April 2015
+KernelVersion:	4.01
+Contact:	Mathieu Poirier <mathieu.poirier@linaro.org>
+Description:	(RW) Select which context ID comparator to work with.
+
+What:		/sys/bus/coresight/devices/<memory_map>.etm/ctxid_val
+Date:		April 2015
+KernelVersion:	4.01
+Contact:	Mathieu Poirier <mathieu.poirier@linaro.org>
+Description:	(RW) Get/Set the context ID comparator value to trigger on.
+
+What:		/sys/bus/coresight/devices/<memory_map>.etm/ctxid_masks
+Date:		April 2015
+KernelVersion:	4.01
+Contact:	Mathieu Poirier <mathieu.poirier@linaro.org>
+Description:	(RW) Mask for all 8 context ID comparator value
+		registers (if implemented).
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 67f3b71ea8dc..9bae7b158b20 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -1780,6 +1780,190 @@  static ssize_t res_ctrl_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(res_ctrl);
 
+static ssize_t ctxid_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->ctxid_idx;
+	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
+}
+
+static ssize_t ctxid_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;
+	if (val >= drvdata->numcidc)
+		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->ctxid_idx = val;
+	spin_unlock(&drvdata->spinlock);
+	return size;
+}
+static DEVICE_ATTR_RW(ctxid_idx);
+
+static ssize_t ctxid_val_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->ctxid_idx;
+	val = (unsigned long)drvdata->ctxid_val[idx];
+	spin_unlock(&drvdata->spinlock);
+	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
+}
+
+static ssize_t ctxid_val_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);
+
+	/*
+	 * only implemented when ctxid tracing is enabled, i.e. at least one
+	 * ctxid comparator is implemented and ctxid is greater than 0 bits
+	 * in length
+	 */
+	if (!drvdata->ctxid_size || !drvdata->numcidc)
+		return -EINVAL;
+	if (kstrtoul(buf, 16, &val))
+		return -EINVAL;
+
+	spin_lock(&drvdata->spinlock);
+	idx = drvdata->ctxid_idx;
+	drvdata->ctxid_val[idx] = (u64)val;
+	spin_unlock(&drvdata->spinlock);
+	return size;
+}
+static DEVICE_ATTR_RW(ctxid_val);
+
+static ssize_t ctxid_masks_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	unsigned long val1, val2;
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	spin_lock(&drvdata->spinlock);
+	val1 = drvdata->ctxid_mask0;
+	val2 = drvdata->ctxid_mask1;
+	spin_unlock(&drvdata->spinlock);
+	return scnprintf(buf, PAGE_SIZE, "%#lx %#lx\n", val1, val2);
+}
+
+static ssize_t ctxid_masks_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t size)
+{
+	u8 i, j, maskbyte;
+	unsigned long val1, val2, mask;
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	/*
+	 * only implemented when ctxid tracing is enabled, i.e. at least one
+	 * ctxid comparator is implemented and ctxid is greater than 0 bits
+	 * in length
+	 */
+	if (!drvdata->ctxid_size || !drvdata->numcidc)
+		return -EINVAL;
+	if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
+		return -EINVAL;
+
+	spin_lock(&drvdata->spinlock);
+	/*
+	 * each byte[0..3] controls mask value applied to ctxid
+	 * comparator[0..3]
+	 */
+	switch (drvdata->numcidc) {
+	case 0x1:
+		/* COMP0, bits[7:0] */
+		drvdata->ctxid_mask0 = val1 & 0xFF;
+		break;
+	case 0x2:
+		/* COMP1, bits[15:8] */
+		drvdata->ctxid_mask0 = val1 & 0xFFFF;
+		break;
+	case 0x3:
+		/* COMP2, bits[23:16] */
+		drvdata->ctxid_mask0 = val1 & 0xFFFFFF;
+		break;
+	case 0x4:
+		 /* COMP3, bits[31:24] */
+		drvdata->ctxid_mask0 = val1;
+		break;
+	case 0x5:
+		/* COMP4, bits[7:0] */
+		drvdata->ctxid_mask0 = val1;
+		drvdata->ctxid_mask1 = val2 & 0xFF;
+		break;
+	case 0x6:
+		/* COMP5, bits[15:8] */
+		drvdata->ctxid_mask0 = val1;
+		drvdata->ctxid_mask1 = val2 & 0xFFFF;
+		break;
+	case 0x7:
+		/* COMP6, bits[23:16] */
+		drvdata->ctxid_mask0 = val1;
+		drvdata->ctxid_mask1 = val2 & 0xFFFFFF;
+		break;
+	case 0x8:
+		/* COMP7, bits[31:24] */
+		drvdata->ctxid_mask0 = val1;
+		drvdata->ctxid_mask1 = val2;
+		break;
+	default:
+		break;
+	}
+	/*
+	 * If software sets a mask bit to 1, it must program relevant byte
+	 * of ctxid comparator value 0x0, otherwise behavior is unpredictable.
+	 * For example, if bit[3] of ctxid_mask0 is 1, we must clear bits[31:24]
+	 * of ctxid comparator0 value (corresponding to byte 0) register.
+	 */
+	mask = drvdata->ctxid_mask0;
+	for (i = 0; i < drvdata->numcidc; i++) {
+		/* mask value of corresponding ctxid comparator */
+		maskbyte = mask & ETMv4_EVENT_MASK;
+		/*
+		 * each bit corresponds to a byte of respective ctxid comparator
+		 * value register
+		 */
+		for (j = 0; j < 8; j++) {
+			if (maskbyte & 1)
+				drvdata->ctxid_val[i] &= ~(0xFF << (j * 8));
+			maskbyte >>= 1;
+		}
+		/* Select the next ctxid comparator mask value */
+		if (i == 3)
+			/* ctxid comparators[4-7] */
+			mask = drvdata->ctxid_mask1;
+		else
+			mask >>= 0x8;
+	}
+
+	spin_unlock(&drvdata->spinlock);
+	return size;
+}
+static DEVICE_ATTR_RW(ctxid_masks);
+
 static ssize_t status_show(struct device *dev,
 			   struct device_attribute *attr, char *buf)
 {
@@ -1962,6 +2146,9 @@  static struct attribute *coresight_etmv4_attrs[] = {
 	&dev_attr_cntr_ctrl.attr,
 	&dev_attr_res_idx.attr,
 	&dev_attr_res_ctrl.attr,
+	&dev_attr_ctxid_idx.attr,
+	&dev_attr_ctxid_val.attr,
+	&dev_attr_ctxid_masks.attr,
 	&dev_attr_status.attr,
 	&dev_attr_mgmt.attr,
 	&dev_attr_trcidr.attr,