| Message ID | 20200130114220.23538-3-peter.ujfalusi@ti.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | dmaengine: Cleanups for symlink handling and debugfs support | expand |
Hi Peter, On Thu, Jan 30, 2020 at 12:41 PM Peter Ujfalusi <peter.ujfalusi@ti.com> 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> Thanks for your patch! On Salvator-XS with R-Car H3 ES2.0: dma0 (ec700000.dma-controller): number of channels: 15 dma1 (ec720000.dma-controller): number of channels: 15 dma2 (e65a0000.dma-controller): number of channels: 2 dma2chan0: e6590000.usb:ch0 dma2chan1: e6590000.usb:ch1 dma3 (e65b0000.dma-controller): number of channels: 2 dma3chan0: e6590000.usb:ch2 dma3chan1: e6590000.usb:ch3 dma4 (e6460000.dma-controller): number of channels: 2 dma4chan0: e659c000.usb:ch0 dma4chan1: e659c000.usb:ch1 dma5 (e6470000.dma-controller): number of channels: 2 dma5chan0: e659c000.usb:ch2 dma5chan1: e659c000.usb:ch3 dma6 (e6700000.dma-controller): number of channels: 15 dma7 (e7300000.dma-controller): number of channels: 15 dma7chan0: e6510000.i2c:tx dma8 (e7310000.dma-controller): number of channels: 15 dma8chan0: e6550000.serial:tx dma8chan1: e6550000.serial:rx > --- a/drivers/dma/dmaengine.c > +++ b/drivers/dma/dmaengine.c > @@ -760,6 +761,13 @@ 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->slave_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev), name); > + if (!chan->slave_name) > + dev_warn(dev, > + "Cannot allocate memory for slave name (debugfs)\n"); No need to print a message, as the memory allocation core already takes care of that. But, do you really need chan->slave_name? You already have chan->slave and chan->name. > +#endif > + > chan->name = kasprintf(GFP_KERNEL, "dma:%s", name); > if (!chan->name) { > dev_warn(dev, > @@ -1562,3 +1577,108 @@ static int __init dma_bus_init(void) > return class_register(&dma_devclass); > } > arch_initcall(dma_bus_init); > + > +#ifdef CONFIG_DEBUG_FS > +static void *dmaengine_seq_start(struct seq_file *s, loff_t *pos) > +{ > + struct dma_device *dma_dev = NULL; > + loff_t index = *pos; > + > + s->private = ""; > + > + mutex_lock(&dma_list_mutex); > + list_for_each_entry(dma_dev, &dma_device_list, global_node) > + if (index-- == 0) { > + mutex_unlock(&dma_list_mutex); > + return dma_dev; Can the dma_device go away after unlocking the list? Unlike dma_request_chan(), this doesn't increase a refcnt. > + } > + mutex_unlock(&dma_list_mutex); > + > + return NULL; > +} > + > +static void *dmaengine_seq_next(struct seq_file *s, void *v, loff_t *pos) > +{ > + struct dma_device *dma_dev = v; > + void *ret = NULL; > + > + mutex_lock(&dma_list_mutex); > + if (list_is_last(&dma_dev->global_node, &dma_device_list)) > + ret = NULL; > + else > + ret = list_entry(dma_dev->global_node.next, > + struct dma_device, global_node); > + mutex_unlock(&dma_list_mutex); Likewise. > + > + s->private = "\n"; > + ++*pos; > + > + return ret; > +} > + > +static void dmaengine_seq_stop(struct seq_file *s, void *v) > +{ > +} > + > +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, " dma%dchan%d:", dma_dev->dev_id, > + chan->chan_id); > + if (chan->slave_name) > + seq_printf(s, "\t\t%s\n", chan->slave_name); > + else > + seq_printf(s, "\t\t%s\n", "in-use"); The truncated ternary operator might help here: seq_printf(s, "\t\t%s\n", chan->slave_name ?: "in-use"); However, you might as well just use dev_name(chan->slave) and chan->name instead of chan->slave_name. > + } > + } > +} > + > +static int dmaengine_seq_show(struct seq_file *s, void *v) > +{ > + struct dma_device *dma_dev = v; > + > + seq_printf(s, "%sdma%d (%s): number of channels: %u\n", > + (char *)s->private, dma_dev->dev_id, dev_name(dma_dev->dev), > + dma_dev->chancnt); > + > + if (dma_dev->dbg_show) > + dma_dev->dbg_show(s, dma_dev); So providing a custom .dbg_show() means replacing the standard info, not augmenting it? > + else > + dmaengine_dbg_show(s, dma_dev); > + > + return 0; > +} Gr{oetje,eeting}s, Geert
Hi Geert, On 30/01/2020 17.42, Geert Uytterhoeven wrote: > Hi Peter, > > On Thu, Jan 30, 2020 at 12:41 PM Peter Ujfalusi <peter.ujfalusi@ti.com> 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> > > Thanks for your patch! > > On Salvator-XS with R-Car H3 ES2.0: > > dma0 (ec700000.dma-controller): number of channels: 15 > > dma1 (ec720000.dma-controller): number of channels: 15 > > dma2 (e65a0000.dma-controller): number of channels: 2 > dma2chan0: e6590000.usb:ch0 > dma2chan1: e6590000.usb:ch1 > > dma3 (e65b0000.dma-controller): number of channels: 2 > dma3chan0: e6590000.usb:ch2 > dma3chan1: e6590000.usb:ch3 > > dma4 (e6460000.dma-controller): number of channels: 2 > dma4chan0: e659c000.usb:ch0 > dma4chan1: e659c000.usb:ch1 > > dma5 (e6470000.dma-controller): number of channels: 2 > dma5chan0: e659c000.usb:ch2 > dma5chan1: e659c000.usb:ch3 > > dma6 (e6700000.dma-controller): number of channels: 15 > > dma7 (e7300000.dma-controller): number of channels: 15 > dma7chan0: e6510000.i2c:tx > > dma8 (e7310000.dma-controller): number of channels: 15 > dma8chan0: e6550000.serial:tx > dma8chan1: e6550000.serial:rx You have lots of DMAs over there ;) >> --- a/drivers/dma/dmaengine.c >> +++ b/drivers/dma/dmaengine.c >> @@ -760,6 +761,13 @@ 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->slave_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev), name); >> + if (!chan->slave_name) >> + dev_warn(dev, >> + "Cannot allocate memory for slave name (debugfs)\n"); > > No need to print a message, as the memory allocation core already takes > care of that. Right. > But, do you really need chan->slave_name? > You already have chan->slave and chan->name. The chan->name is prefixed with "dma:" it would not look right. In production this all go away as debugfs most likely disabled. But I will change the name to dbg_client_name. > >> +#endif >> + >> chan->name = kasprintf(GFP_KERNEL, "dma:%s", name); >> if (!chan->name) { >> dev_warn(dev, > >> @@ -1562,3 +1577,108 @@ static int __init dma_bus_init(void) >> return class_register(&dma_devclass); >> } >> arch_initcall(dma_bus_init); >> + >> +#ifdef CONFIG_DEBUG_FS >> +static void *dmaengine_seq_start(struct seq_file *s, loff_t *pos) >> +{ >> + struct dma_device *dma_dev = NULL; >> + loff_t index = *pos; >> + >> + s->private = ""; >> + >> + mutex_lock(&dma_list_mutex); >> + list_for_each_entry(dma_dev, &dma_device_list, global_node) >> + if (index-- == 0) { >> + mutex_unlock(&dma_list_mutex); >> + return dma_dev; > > Can the dma_device go away after unlocking the list? > Unlike dma_request_chan(), this doesn't increase a refcnt. It could, let me see what I can do. Probably locking the dma_device_list for the duration of the show. >> + } >> + mutex_unlock(&dma_list_mutex); >> + >> + return NULL; >> +} >> + >> +static void *dmaengine_seq_next(struct seq_file *s, void *v, loff_t *pos) >> +{ >> + struct dma_device *dma_dev = v; >> + void *ret = NULL; >> + >> + mutex_lock(&dma_list_mutex); >> + if (list_is_last(&dma_dev->global_node, &dma_device_list)) >> + ret = NULL; >> + else >> + ret = list_entry(dma_dev->global_node.next, >> + struct dma_device, global_node); >> + mutex_unlock(&dma_list_mutex); > > Likewise. > >> + >> + s->private = "\n"; >> + ++*pos; >> + >> + return ret; >> +} >> + >> +static void dmaengine_seq_stop(struct seq_file *s, void *v) >> +{ >> +} >> + >> +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, " dma%dchan%d:", dma_dev->dev_id, >> + chan->chan_id); >> + if (chan->slave_name) >> + seq_printf(s, "\t\t%s\n", chan->slave_name); >> + else >> + seq_printf(s, "\t\t%s\n", "in-use"); > > The truncated ternary operator might help here: > > seq_printf(s, "\t\t%s\n", chan->slave_name ?: "in-use"); > > However, you might as well just use dev_name(chan->slave) and chan->name > instead of chan->slave_name. "2b00000.mcasp" + "dma:tx" would be an awkward combination ;) > >> + } >> + } >> +} >> + >> +static int dmaengine_seq_show(struct seq_file *s, void *v) >> +{ >> + struct dma_device *dma_dev = v; >> + >> + seq_printf(s, "%sdma%d (%s): number of channels: %u\n", >> + (char *)s->private, dma_dev->dev_id, dev_name(dma_dev->dev), >> + dma_dev->chancnt); >> + >> + if (dma_dev->dbg_show) >> + dma_dev->dbg_show(s, dma_dev); > > So providing a custom .dbg_show() means replacing the standard info, not > augmenting it? Correct, if a DMA driver decides to implement it, then it is it's responsibility to show things after the "dma%d (%s): number of channels: %u\n" line. The standard infor is pretty minimal and not sure if it can be more verbose. Oh, I can add the router information if it is used. > >> + else >> + dmaengine_dbg_show(s, dma_dev); >> + >> + return 0; >> +} > > Gr{oetje,eeting}s, > > Geert > - Péter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 75516f9fbab4..7573a4d0f9d7 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 +761,13 @@ 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->slave_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev), name); + if (!chan->slave_name) + dev_warn(dev, + "Cannot allocate memory for slave name (debugfs)\n"); +#endif + chan->name = kasprintf(GFP_KERNEL, "dma:%s", name); if (!chan->name) { dev_warn(dev, @@ -840,6 +848,13 @@ void dma_release_channel(struct dma_chan *chan) chan->name = NULL; chan->slave = NULL; } + +#ifdef CONFIG_DEBUG_FS + if (chan->slave_name) { + kfree(chan->slave_name); + chan->slave_name = NULL; + } +#endif mutex_unlock(&dma_list_mutex); } EXPORT_SYMBOL_GPL(dma_release_channel); @@ -1562,3 +1577,108 @@ static int __init dma_bus_init(void) return class_register(&dma_devclass); } arch_initcall(dma_bus_init); + +#ifdef CONFIG_DEBUG_FS +static void *dmaengine_seq_start(struct seq_file *s, loff_t *pos) +{ + struct dma_device *dma_dev = NULL; + loff_t index = *pos; + + s->private = ""; + + mutex_lock(&dma_list_mutex); + list_for_each_entry(dma_dev, &dma_device_list, global_node) + if (index-- == 0) { + mutex_unlock(&dma_list_mutex); + return dma_dev; + } + mutex_unlock(&dma_list_mutex); + + return NULL; +} + +static void *dmaengine_seq_next(struct seq_file *s, void *v, loff_t *pos) +{ + struct dma_device *dma_dev = v; + void *ret = NULL; + + mutex_lock(&dma_list_mutex); + if (list_is_last(&dma_dev->global_node, &dma_device_list)) + ret = NULL; + else + ret = list_entry(dma_dev->global_node.next, + struct dma_device, global_node); + mutex_unlock(&dma_list_mutex); + + s->private = "\n"; + ++*pos; + + return ret; +} + +static void dmaengine_seq_stop(struct seq_file *s, void *v) +{ +} + +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, " dma%dchan%d:", dma_dev->dev_id, + chan->chan_id); + if (chan->slave_name) + seq_printf(s, "\t\t%s\n", chan->slave_name); + else + seq_printf(s, "\t\t%s\n", "in-use"); + } + } +} + +static int dmaengine_seq_show(struct seq_file *s, void *v) +{ + struct dma_device *dma_dev = v; + + seq_printf(s, "%sdma%d (%s): number of channels: %u\n", + (char *)s->private, 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); + + return 0; +} + +static const struct seq_operations dmaengine_seq_ops = { + .start = dmaengine_seq_start, + .next = dmaengine_seq_next, + .stop = dmaengine_seq_stop, + .show = dmaengine_seq_show, +}; + +static int dmaengine_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &dmaengine_seq_ops); +} + +static const struct file_operations dmaengine_operations = { + .owner = THIS_MODULE, + .open = dmaengine_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static int __init dmaengine_debugfs_init(void) +{ + /* /sys/kernel/debug/dmaengine */ + debugfs_create_file("dmaengine", S_IFREG | 0444, NULL, NULL, + &dmaengine_operations); + return 0; +} +subsys_initcall(dmaengine_debugfs_init); + +#endif /* DEBUG_FS */ diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 64461fc64e1b..5b9d6b1aa6e9 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 + * @slave_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 *slave_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,
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> --- drivers/dma/dmaengine.c | 120 ++++++++++++++++++++++++++++++++++++++ include/linux/dmaengine.h | 12 +++- 2 files changed, 131 insertions(+), 1 deletion(-)