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* [PATCH v3] dmaengine: Add basic debugfs support
@ 2020-02-05 11:15 Peter Ujfalusi
  2020-02-24 16:37 ` Vinod Koul
  0 siblings, 1 reply; 6+ messages in thread
From: Peter Ujfalusi @ 2020-02-05 11:15 UTC (permalink / raw)
  To: vkoul; +Cc: dmaengine, linux-kernel, dan.j.williams, geert

Via the /sys/kernel/debug/dmaengine users can get information about the
DMA devices and the used channels.

Example output on am654-evm with audio using two channels and after running
dmatest on 6 channels:

# cat /sys/kernel/debug/dmaengine
dma0 (285c0000.dma-controller): number of channels: 96

dma1 (31150000.dma-controller): number of channels: 267
 dma1chan0    | 2b00000.mcasp:tx
 dma1chan1    | 2b00000.mcasp:rx
 dma1chan2    | in-use
 dma1chan3    | in-use
 dma1chan4    | in-use
 dma1chan5    | in-use
 dma1chan6    | in-use
 dma1chan7    | in-use

For slave channels we can show the device and the channel name a given
channel is requested.
For non slave devices the only information we know is that the channel is
in use.

DMA drivers can implement the optional dbg_show callback to provide
controller specific information instead of the generic one.

It is easy to extend the generic dmaengine_dbg_show() to print additional
information about the used channels.

I have taken the idea from gpiolib.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
Hi,

Changes since v2:
- Use dma_chan_name() for printing the channel's name

Changes since v1:
- Use much more simplified fops for the debugfs file (via DEFINE_SHOW_ATTRIBUTE)
- do not allow modification to dma_device_list while the debugfs file is read
- rename the slave_name to dbg_client_name (it is only for debugging)
- print information about dma_router if it is used by the channel
- Formating of the output slightly changed

Regards,
Peter

 drivers/dma/dmaengine.c   | 65 +++++++++++++++++++++++++++++++++++++++
 include/linux/dmaengine.h | 12 +++++++-
 2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index c3b1283b6d31..37c3a4cd5b1a 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -32,6 +32,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/platform_device.h>
+#include <linux/debugfs.h>
 #include <linux/dma-mapping.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -760,6 +761,11 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name)
 		return chan ? chan : ERR_PTR(-EPROBE_DEFER);
 
 found:
+#ifdef CONFIG_DEBUG_FS
+	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
+					  name);
+#endif
+
 	chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
 	if (!chan->name)
 		return chan;
@@ -837,6 +843,11 @@ void dma_release_channel(struct dma_chan *chan)
 		chan->name = NULL;
 		chan->slave = NULL;
 	}
+
+#ifdef CONFIG_DEBUG_FS
+	kfree(chan->dbg_client_name);
+	chan->dbg_client_name = NULL;
+#endif
 	mutex_unlock(&dma_list_mutex);
 }
 EXPORT_SYMBOL_GPL(dma_release_channel);
@@ -1562,3 +1573,57 @@ static int __init dma_bus_init(void)
 	return class_register(&dma_devclass);
 }
 arch_initcall(dma_bus_init);
+
+#ifdef CONFIG_DEBUG_FS
+static void dmaengine_dbg_show(struct seq_file *s, struct dma_device *dma_dev)
+{
+	struct dma_chan *chan;
+
+	list_for_each_entry(chan, &dma_dev->channels, device_node) {
+		if (chan->client_count) {
+			seq_printf(s, " %-13s| %s", dma_chan_name(chan),
+				   chan->dbg_client_name ?: "in-use");
+
+			if (chan->router)
+				seq_printf(s, " (via router: %s)\n",
+					dev_name(chan->router->dev));
+			else
+				seq_puts(s, "\n");
+		}
+	}
+}
+
+static int dmaengine_debugfs_show(struct seq_file *s, void *data)
+{
+	struct dma_device *dma_dev = NULL;
+
+	mutex_lock(&dma_list_mutex);
+	list_for_each_entry(dma_dev, &dma_device_list, global_node) {
+		seq_printf(s, "dma%d (%s): number of channels: %u\n",
+			   dma_dev->dev_id, dev_name(dma_dev->dev),
+			   dma_dev->chancnt);
+
+		if (dma_dev->dbg_show)
+			dma_dev->dbg_show(s, dma_dev);
+		else
+			dmaengine_dbg_show(s, dma_dev);
+
+		if (!list_is_last(&dma_dev->global_node, &dma_device_list))
+			seq_puts(s, "\n");
+	}
+	mutex_unlock(&dma_list_mutex);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(dmaengine_debugfs);
+
+static int __init dmaengine_debugfs_init(void)
+{
+	/* /sys/kernel/debug/dmaengine */
+	debugfs_create_file("dmaengine", 0444, NULL, NULL,
+			    &dmaengine_debugfs_fops);
+	return 0;
+}
+late_initcall(dmaengine_debugfs_init);
+
+#endif	/* DEBUG_FS */
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 64461fc64e1b..9f232b7618f1 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -300,6 +300,8 @@ struct dma_router {
  * @chan_id: channel ID for sysfs
  * @dev: class device for sysfs
  * @name: backlink name for sysfs
+ * @dbg_client_name: slave name for debugfs in format:
+ *	dev_name(requester's dev):channel name, for example: "2b00000.mcasp:tx"
  * @device_node: used to add this to the device chan list
  * @local: per-cpu pointer to a struct dma_chan_percpu
  * @client_count: how many clients are using this channel
@@ -318,6 +320,9 @@ struct dma_chan {
 	int chan_id;
 	struct dma_chan_dev *dev;
 	const char *name;
+#ifdef CONFIG_DEBUG_FS
+	char *dbg_client_name;
+#endif
 
 	struct list_head device_node;
 	struct dma_chan_percpu __percpu *local;
@@ -805,7 +810,9 @@ struct dma_filter {
  *     called and there are no further references to this structure. This
  *     must be implemented to free resources however many existing drivers
  *     do not and are therefore not safe to unbind while in use.
- *
+ * @dbg_show: optional routine to show contents in debugfs; default code
+ *     will be used when this is omitted, but custom code can show extra,
+ *     controller specific information.
  */
 struct dma_device {
 	struct kref ref;
@@ -891,6 +898,9 @@ struct dma_device {
 					    struct dma_tx_state *txstate);
 	void (*device_issue_pending)(struct dma_chan *chan);
 	void (*device_release)(struct dma_device *dev);
+#ifdef CONFIG_DEBUG_FS
+	void (*dbg_show)(struct seq_file *s, struct dma_device *dev);
+#endif
 };
 
 static inline int dmaengine_slave_config(struct dma_chan *chan,
-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] dmaengine: Add basic debugfs support
  2020-02-05 11:15 [PATCH v3] dmaengine: Add basic debugfs support Peter Ujfalusi
@ 2020-02-24 16:37 ` Vinod Koul
  2020-02-26 12:10   ` Peter Ujfalusi
  0 siblings, 1 reply; 6+ messages in thread
From: Vinod Koul @ 2020-02-24 16:37 UTC (permalink / raw)
  To: Peter Ujfalusi; +Cc: dmaengine, linux-kernel, dan.j.williams, geert

On 05-02-20, 13:15, Peter Ujfalusi wrote:
> Via the /sys/kernel/debug/dmaengine users can get information about the
> DMA devices and the used channels.
> 
> Example output on am654-evm with audio using two channels and after running
> dmatest on 6 channels:
> 
> # cat /sys/kernel/debug/dmaengine
> dma0 (285c0000.dma-controller): number of channels: 96
> 
> dma1 (31150000.dma-controller): number of channels: 267
>  dma1chan0    | 2b00000.mcasp:tx
>  dma1chan1    | 2b00000.mcasp:rx
>  dma1chan2    | in-use
>  dma1chan3    | in-use
>  dma1chan4    | in-use
>  dma1chan5    | in-use
>  dma1chan6    | in-use
>  dma1chan7    | in-use
> 
> For slave channels we can show the device and the channel name a given
> channel is requested.
> For non slave devices the only information we know is that the channel is
> in use.
> 
> DMA drivers can implement the optional dbg_show callback to provide
> controller specific information instead of the generic one.
> 
> It is easy to extend the generic dmaengine_dbg_show() to print additional
> information about the used channels.
> 
> I have taken the idea from gpiolib.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
> Hi,
> 
> Changes since v2:
> - Use dma_chan_name() for printing the channel's name
> 
> Changes since v1:
> - Use much more simplified fops for the debugfs file (via DEFINE_SHOW_ATTRIBUTE)
> - do not allow modification to dma_device_list while the debugfs file is read
> - rename the slave_name to dbg_client_name (it is only for debugging)
> - print information about dma_router if it is used by the channel
> - Formating of the output slightly changed
> 
> Regards,
> Peter
> 
>  drivers/dma/dmaengine.c   | 65 +++++++++++++++++++++++++++++++++++++++
>  include/linux/dmaengine.h | 12 +++++++-
>  2 files changed, 76 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index c3b1283b6d31..37c3a4cd5b1a 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -32,6 +32,7 @@
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
>  #include <linux/platform_device.h>
> +#include <linux/debugfs.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/init.h>
>  #include <linux/module.h>
> @@ -760,6 +761,11 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name)
>  		return chan ? chan : ERR_PTR(-EPROBE_DEFER);
>  
>  found:
> +#ifdef CONFIG_DEBUG_FS
> +	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
> +					  name);
> +#endif
> +
>  	chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
>  	if (!chan->name)
>  		return chan;
> @@ -837,6 +843,11 @@ void dma_release_channel(struct dma_chan *chan)
>  		chan->name = NULL;
>  		chan->slave = NULL;
>  	}
> +
> +#ifdef CONFIG_DEBUG_FS
> +	kfree(chan->dbg_client_name);
> +	chan->dbg_client_name = NULL;
> +#endif
>  	mutex_unlock(&dma_list_mutex);
>  }
>  EXPORT_SYMBOL_GPL(dma_release_channel);
> @@ -1562,3 +1573,57 @@ static int __init dma_bus_init(void)
>  	return class_register(&dma_devclass);
>  }
>  arch_initcall(dma_bus_init);
> +
> +#ifdef CONFIG_DEBUG_FS
> +static void dmaengine_dbg_show(struct seq_file *s, struct dma_device *dma_dev)
> +{
> +	struct dma_chan *chan;
> +
> +	list_for_each_entry(chan, &dma_dev->channels, device_node) {
> +		if (chan->client_count) {
> +			seq_printf(s, " %-13s| %s", dma_chan_name(chan),
> +				   chan->dbg_client_name ?: "in-use");
> +
> +			if (chan->router)
> +				seq_printf(s, " (via router: %s)\n",
> +					dev_name(chan->router->dev));
> +			else
> +				seq_puts(s, "\n");
> +		}
> +	}
> +}
> +
> +static int dmaengine_debugfs_show(struct seq_file *s, void *data)
> +{
> +	struct dma_device *dma_dev = NULL;
> +
> +	mutex_lock(&dma_list_mutex);
> +	list_for_each_entry(dma_dev, &dma_device_list, global_node) {
> +		seq_printf(s, "dma%d (%s): number of channels: %u\n",
> +			   dma_dev->dev_id, dev_name(dma_dev->dev),
> +			   dma_dev->chancnt);
> +
> +		if (dma_dev->dbg_show)
> +			dma_dev->dbg_show(s, dma_dev);
 do we really want a custom dbg_show()..? Drivers can add their own
files...

> +		else
> +			dmaengine_dbg_show(s, dma_dev);
> +
> +		if (!list_is_last(&dma_dev->global_node, &dma_device_list))
> +			seq_puts(s, "\n");
> +	}
> +	mutex_unlock(&dma_list_mutex);
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(dmaengine_debugfs);
> +
> +static int __init dmaengine_debugfs_init(void)
> +{
> +	/* /sys/kernel/debug/dmaengine */
> +	debugfs_create_file("dmaengine", 0444, NULL, NULL,
> +			    &dmaengine_debugfs_fops);

Should we add a directory? That way we can keep adding stuff into that
one
-- 
~Vinod

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] dmaengine: Add basic debugfs support
  2020-02-24 16:37 ` Vinod Koul
@ 2020-02-26 12:10   ` Peter Ujfalusi
  2020-02-28  4:47     ` Vinod Koul
  0 siblings, 1 reply; 6+ messages in thread
From: Peter Ujfalusi @ 2020-02-26 12:10 UTC (permalink / raw)
  To: Vinod Koul; +Cc: dmaengine, linux-kernel, dan.j.williams, geert

Hi Vinod,

On 2/24/20 6:37 PM, Vinod Koul wrote:
> On 05-02-20, 13:15, Peter Ujfalusi wrote:
>> Via the /sys/kernel/debug/dmaengine users can get information about the
>> DMA devices and the used channels.
>>
>> Example output on am654-evm with audio using two channels and after running
>> dmatest on 6 channels:
>>
>> # cat /sys/kernel/debug/dmaengine
>> dma0 (285c0000.dma-controller): number of channels: 96
>>
>> dma1 (31150000.dma-controller): number of channels: 267
>>  dma1chan0    | 2b00000.mcasp:tx
>>  dma1chan1    | 2b00000.mcasp:rx
>>  dma1chan2    | in-use
>>  dma1chan3    | in-use
>>  dma1chan4    | in-use
>>  dma1chan5    | in-use
>>  dma1chan6    | in-use
>>  dma1chan7    | in-use
>>
>> For slave channels we can show the device and the channel name a given
>> channel is requested.
>> For non slave devices the only information we know is that the channel is
>> in use.
>>
>> DMA drivers can implement the optional dbg_show callback to provide
>> controller specific information instead of the generic one.
>>
>> It is easy to extend the generic dmaengine_dbg_show() to print additional
>> information about the used channels.
>>
>> I have taken the idea from gpiolib.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>> ---
>> Hi,
>>
>> Changes since v2:
>> - Use dma_chan_name() for printing the channel's name
>>
>> Changes since v1:
>> - Use much more simplified fops for the debugfs file (via DEFINE_SHOW_ATTRIBUTE)
>> - do not allow modification to dma_device_list while the debugfs file is read
>> - rename the slave_name to dbg_client_name (it is only for debugging)
>> - print information about dma_router if it is used by the channel
>> - Formating of the output slightly changed
>>
>> Regards,
>> Peter
>>
>>  drivers/dma/dmaengine.c   | 65 +++++++++++++++++++++++++++++++++++++++
>>  include/linux/dmaengine.h | 12 +++++++-
>>  2 files changed, 76 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
>> index c3b1283b6d31..37c3a4cd5b1a 100644
>> --- a/drivers/dma/dmaengine.c
>> +++ b/drivers/dma/dmaengine.c
>> @@ -32,6 +32,7 @@
>>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>  
>>  #include <linux/platform_device.h>
>> +#include <linux/debugfs.h>
>>  #include <linux/dma-mapping.h>
>>  #include <linux/init.h>
>>  #include <linux/module.h>
>> @@ -760,6 +761,11 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name)
>>  		return chan ? chan : ERR_PTR(-EPROBE_DEFER);
>>  
>>  found:
>> +#ifdef CONFIG_DEBUG_FS
>> +	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
>> +					  name);
>> +#endif
>> +
>>  	chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
>>  	if (!chan->name)
>>  		return chan;
>> @@ -837,6 +843,11 @@ void dma_release_channel(struct dma_chan *chan)
>>  		chan->name = NULL;
>>  		chan->slave = NULL;
>>  	}
>> +
>> +#ifdef CONFIG_DEBUG_FS
>> +	kfree(chan->dbg_client_name);
>> +	chan->dbg_client_name = NULL;
>> +#endif
>>  	mutex_unlock(&dma_list_mutex);
>>  }
>>  EXPORT_SYMBOL_GPL(dma_release_channel);
>> @@ -1562,3 +1573,57 @@ static int __init dma_bus_init(void)
>>  	return class_register(&dma_devclass);
>>  }
>>  arch_initcall(dma_bus_init);
>> +
>> +#ifdef CONFIG_DEBUG_FS
>> +static void dmaengine_dbg_show(struct seq_file *s, struct dma_device *dma_dev)
>> +{
>> +	struct dma_chan *chan;
>> +
>> +	list_for_each_entry(chan, &dma_dev->channels, device_node) {
>> +		if (chan->client_count) {
>> +			seq_printf(s, " %-13s| %s", dma_chan_name(chan),
>> +				   chan->dbg_client_name ?: "in-use");
>> +
>> +			if (chan->router)
>> +				seq_printf(s, " (via router: %s)\n",
>> +					dev_name(chan->router->dev));
>> +			else
>> +				seq_puts(s, "\n");
>> +		}
>> +	}
>> +}
>> +
>> +static int dmaengine_debugfs_show(struct seq_file *s, void *data)
>> +{
>> +	struct dma_device *dma_dev = NULL;
>> +
>> +	mutex_lock(&dma_list_mutex);
>> +	list_for_each_entry(dma_dev, &dma_device_list, global_node) {
>> +		seq_printf(s, "dma%d (%s): number of channels: %u\n",
>> +			   dma_dev->dev_id, dev_name(dma_dev->dev),
>> +			   dma_dev->chancnt);
>> +
>> +		if (dma_dev->dbg_show)
>> +			dma_dev->dbg_show(s, dma_dev);
>  do we really want a custom dbg_show()..? Drivers can add their own
> files...

They could do that already ;)

With the custom dbg_show() DMA drivers can save on the surrounding
code and just fill in the information regarding to their HW.
Again, on am654 the default information is:
# cat /sys/kernel/debug/dmaengine 
dma0 (285c0000.dma-controller): number of channels: 96

dma1 (31150000.dma-controller): number of channels: 267
 dma1chan0    | 2b00000.mcasp:tx
 dma1chan1    | 2b00000.mcasp:rx
 dma1chan2    | in-use
 dma1chan3    | in-use
 dma1chan4    | in-use
 dma1chan5    | in-use

With my current .dbg_show implementation for k3-udma:
# cat /sys/kernel/debug/dmaengine 
dma0 (285c0000.dma-controller): number of channels: 96

dma1 (31150000.dma-controller): number of channels: 267
 dma1chan0    | 2b00000.mcasp:tx (MEM_TO_DEV, tchan8 [0x1008 -> 0xc400], PDMA, TR mode)
 dma1chan1    | 2b00000.mcasp:rx (DEV_TO_MEM, rchan8 [0x4400 -> 0x9008], PDMA, TR mode)
 dma1chan2    | in-use (MEM_TO_MEM, chan2 pair [0x1002 -> 0x9002], PSI-L Native, TR mode)
 dma1chan3    | in-use (MEM_TO_MEM, chan3 pair [0x1003 -> 0x9003], PSI-L Native, TR mode)
 dma1chan4    | in-use (MEM_TO_MEM, chan4 pair [0x1004 -> 0x9004], PSI-L Native, TR mode)
 dma1chan5    | in-use (MEM_TO_MEM, chan5 pair [0x1005 -> 0x9005], PSI-L Native, TR mode)

For me this makes a huge difference.

> 
>> +		else
>> +			dmaengine_dbg_show(s, dma_dev);
>> +
>> +		if (!list_is_last(&dma_dev->global_node, &dma_device_list))
>> +			seq_puts(s, "\n");
>> +	}
>> +	mutex_unlock(&dma_list_mutex);
>> +
>> +	return 0;
>> +}
>> +DEFINE_SHOW_ATTRIBUTE(dmaengine_debugfs);
>> +
>> +static int __init dmaengine_debugfs_init(void)
>> +{
>> +	/* /sys/kernel/debug/dmaengine */
>> +	debugfs_create_file("dmaengine", 0444, NULL, NULL,
>> +			    &dmaengine_debugfs_fops);
> 
> Should we add a directory? That way we can keep adding stuff into that
> one

and have this file as 'summary' underneath?
I like the fact hat I can get all the information via one file.
Saves a lot of time (and explaining to users) on finding the correct
one to cat...
 - Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] dmaengine: Add basic debugfs support
  2020-02-26 12:10   ` Peter Ujfalusi
@ 2020-02-28  4:47     ` Vinod Koul
  2020-02-28 10:01       ` Peter Ujfalusi
  0 siblings, 1 reply; 6+ messages in thread
From: Vinod Koul @ 2020-02-28  4:47 UTC (permalink / raw)
  To: Peter Ujfalusi; +Cc: dmaengine, linux-kernel, dan.j.williams, geert

Hi Peter,

On 26-02-20, 14:10, Peter Ujfalusi wrote:

> >  do we really want a custom dbg_show()..? Drivers can add their own
> > files...
> 
> They could do that already ;)
> 
> With the custom dbg_show() DMA drivers can save on the surrounding
> code and just fill in the information regarding to their HW.
> Again, on am654 the default information is:
> # cat /sys/kernel/debug/dmaengine 
> dma0 (285c0000.dma-controller): number of channels: 96
> 
> dma1 (31150000.dma-controller): number of channels: 267
>  dma1chan0    | 2b00000.mcasp:tx
>  dma1chan1    | 2b00000.mcasp:rx
>  dma1chan2    | in-use
>  dma1chan3    | in-use
>  dma1chan4    | in-use
>  dma1chan5    | in-use
> 
> With my current .dbg_show implementation for k3-udma:
> # cat /sys/kernel/debug/dmaengine 
> dma0 (285c0000.dma-controller): number of channels: 96
> 
> dma1 (31150000.dma-controller): number of channels: 267
>  dma1chan0    | 2b00000.mcasp:tx (MEM_TO_DEV, tchan8 [0x1008 -> 0xc400], PDMA, TR mode)
>  dma1chan1    | 2b00000.mcasp:rx (DEV_TO_MEM, rchan8 [0x4400 -> 0x9008], PDMA, TR mode)
>  dma1chan2    | in-use (MEM_TO_MEM, chan2 pair [0x1002 -> 0x9002], PSI-L Native, TR mode)
>  dma1chan3    | in-use (MEM_TO_MEM, chan3 pair [0x1003 -> 0x9003], PSI-L Native, TR mode)
>  dma1chan4    | in-use (MEM_TO_MEM, chan4 pair [0x1004 -> 0x9004], PSI-L Native, TR mode)
>  dma1chan5    | in-use (MEM_TO_MEM, chan5 pair [0x1005 -> 0x9005], PSI-L Native, TR mode)
> 
> For me this makes a huge difference.

Ok

> >> +DEFINE_SHOW_ATTRIBUTE(dmaengine_debugfs);
> >> +
> >> +static int __init dmaengine_debugfs_init(void)
> >> +{
> >> +	/* /sys/kernel/debug/dmaengine */
> >> +	debugfs_create_file("dmaengine", 0444, NULL, NULL,
> >> +			    &dmaengine_debugfs_fops);
> > 
> > Should we add a directory? That way we can keep adding stuff into that
> > one
> 
> and have this file as 'summary' underneath?

Correct

> I like the fact hat I can get all the information via one file.
> Saves a lot of time (and explaining to users) on finding the correct
> one to cat...

But am sure we can come with more data to show, so having a directory
helps :)

-- 
~Vinod

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] dmaengine: Add basic debugfs support
  2020-02-28  4:47     ` Vinod Koul
@ 2020-02-28 10:01       ` Peter Ujfalusi
  2020-02-28 10:26         ` Vinod Koul
  0 siblings, 1 reply; 6+ messages in thread
From: Peter Ujfalusi @ 2020-02-28 10:01 UTC (permalink / raw)
  To: Vinod Koul; +Cc: dmaengine, linux-kernel, dan.j.williams, geert

Hi Vinod,

On 28/02/2020 6.47, Vinod Koul wrote:
> Hi Peter,
> 
> On 26-02-20, 14:10, Peter Ujfalusi wrote:
> 
>>>  do we really want a custom dbg_show()..? Drivers can add their own
>>> files...
>>
>> They could do that already ;)
>>
>> With the custom dbg_show() DMA drivers can save on the surrounding
>> code and just fill in the information regarding to their HW.
>> Again, on am654 the default information is:
>> # cat /sys/kernel/debug/dmaengine 
>> dma0 (285c0000.dma-controller): number of channels: 96
>>
>> dma1 (31150000.dma-controller): number of channels: 267
>>  dma1chan0    | 2b00000.mcasp:tx
>>  dma1chan1    | 2b00000.mcasp:rx
>>  dma1chan2    | in-use
>>  dma1chan3    | in-use
>>  dma1chan4    | in-use
>>  dma1chan5    | in-use
>>
>> With my current .dbg_show implementation for k3-udma:
>> # cat /sys/kernel/debug/dmaengine 
>> dma0 (285c0000.dma-controller): number of channels: 96
>>
>> dma1 (31150000.dma-controller): number of channels: 267
>>  dma1chan0    | 2b00000.mcasp:tx (MEM_TO_DEV, tchan8 [0x1008 -> 0xc400], PDMA, TR mode)
>>  dma1chan1    | 2b00000.mcasp:rx (DEV_TO_MEM, rchan8 [0x4400 -> 0x9008], PDMA, TR mode)
>>  dma1chan2    | in-use (MEM_TO_MEM, chan2 pair [0x1002 -> 0x9002], PSI-L Native, TR mode)
>>  dma1chan3    | in-use (MEM_TO_MEM, chan3 pair [0x1003 -> 0x9003], PSI-L Native, TR mode)
>>  dma1chan4    | in-use (MEM_TO_MEM, chan4 pair [0x1004 -> 0x9004], PSI-L Native, TR mode)
>>  dma1chan5    | in-use (MEM_TO_MEM, chan5 pair [0x1005 -> 0x9005], PSI-L Native, TR mode)
>>
>> For me this makes a huge difference.
> 
> Ok
> 
>>>> +DEFINE_SHOW_ATTRIBUTE(dmaengine_debugfs);
>>>> +
>>>> +static int __init dmaengine_debugfs_init(void)
>>>> +{
>>>> +	/* /sys/kernel/debug/dmaengine */
>>>> +	debugfs_create_file("dmaengine", 0444, NULL, NULL,
>>>> +			    &dmaengine_debugfs_fops);
>>>
>>> Should we add a directory? That way we can keep adding stuff into that
>>> one
>>
>> and have this file as 'summary' underneath?
> 
> Correct

/sys/kernel/debug/dmaengine/summary, right?

>> I like the fact hat I can get all the information via one file.
>> Saves a lot of time (and explaining to users) on finding the correct
>> one to cat...
> 
> But am sure we can come with more data to show, so having a directory
> helps :)

OK, so we need to store the dbgfs rootdir and add an API so DMA drivers
can get the dentry of it, so they can implement their custom
files/directories underneath.

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH v3] dmaengine: Add basic debugfs support
  2020-02-28 10:01       ` Peter Ujfalusi
@ 2020-02-28 10:26         ` Vinod Koul
  0 siblings, 0 replies; 6+ messages in thread
From: Vinod Koul @ 2020-02-28 10:26 UTC (permalink / raw)
  To: Peter Ujfalusi; +Cc: dmaengine, linux-kernel, dan.j.williams, geert

On 28-02-20, 12:01, Peter Ujfalusi wrote:
> Hi Vinod,
> 
> On 28/02/2020 6.47, Vinod Koul wrote:
> > Hi Peter,
> > 
> > On 26-02-20, 14:10, Peter Ujfalusi wrote:
> > 
> >>>  do we really want a custom dbg_show()..? Drivers can add their own
> >>> files...
> >>
> >> They could do that already ;)
> >>
> >> With the custom dbg_show() DMA drivers can save on the surrounding
> >> code and just fill in the information regarding to their HW.
> >> Again, on am654 the default information is:
> >> # cat /sys/kernel/debug/dmaengine 
> >> dma0 (285c0000.dma-controller): number of channels: 96
> >>
> >> dma1 (31150000.dma-controller): number of channels: 267
> >>  dma1chan0    | 2b00000.mcasp:tx
> >>  dma1chan1    | 2b00000.mcasp:rx
> >>  dma1chan2    | in-use
> >>  dma1chan3    | in-use
> >>  dma1chan4    | in-use
> >>  dma1chan5    | in-use
> >>
> >> With my current .dbg_show implementation for k3-udma:
> >> # cat /sys/kernel/debug/dmaengine 
> >> dma0 (285c0000.dma-controller): number of channels: 96
> >>
> >> dma1 (31150000.dma-controller): number of channels: 267
> >>  dma1chan0    | 2b00000.mcasp:tx (MEM_TO_DEV, tchan8 [0x1008 -> 0xc400], PDMA, TR mode)
> >>  dma1chan1    | 2b00000.mcasp:rx (DEV_TO_MEM, rchan8 [0x4400 -> 0x9008], PDMA, TR mode)
> >>  dma1chan2    | in-use (MEM_TO_MEM, chan2 pair [0x1002 -> 0x9002], PSI-L Native, TR mode)
> >>  dma1chan3    | in-use (MEM_TO_MEM, chan3 pair [0x1003 -> 0x9003], PSI-L Native, TR mode)
> >>  dma1chan4    | in-use (MEM_TO_MEM, chan4 pair [0x1004 -> 0x9004], PSI-L Native, TR mode)
> >>  dma1chan5    | in-use (MEM_TO_MEM, chan5 pair [0x1005 -> 0x9005], PSI-L Native, TR mode)
> >>
> >> For me this makes a huge difference.
> > 
> > Ok
> > 
> >>>> +DEFINE_SHOW_ATTRIBUTE(dmaengine_debugfs);
> >>>> +
> >>>> +static int __init dmaengine_debugfs_init(void)
> >>>> +{
> >>>> +	/* /sys/kernel/debug/dmaengine */
> >>>> +	debugfs_create_file("dmaengine", 0444, NULL, NULL,
> >>>> +			    &dmaengine_debugfs_fops);
> >>>
> >>> Should we add a directory? That way we can keep adding stuff into that
> >>> one
> >>
> >> and have this file as 'summary' underneath?
> > 
> > Correct
> 
> /sys/kernel/debug/dmaengine/summary, right?

Yup!

> 
> >> I like the fact hat I can get all the information via one file.
> >> Saves a lot of time (and explaining to users) on finding the correct
> >> one to cat...
> > 
> > But am sure we can come with more data to show, so having a directory
> > helps :)
> 
> OK, so we need to store the dbgfs rootdir and add an API so DMA drivers
> can get the dentry of it, so they can implement their custom
> files/directories underneath.

Correct

-- 
~Vinod

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, back to index

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-05 11:15 [PATCH v3] dmaengine: Add basic debugfs support Peter Ujfalusi
2020-02-24 16:37 ` Vinod Koul
2020-02-26 12:10   ` Peter Ujfalusi
2020-02-28  4:47     ` Vinod Koul
2020-02-28 10:01       ` Peter Ujfalusi
2020-02-28 10:26         ` Vinod Koul

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