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
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
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
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
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
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