Messages in this thread | | | Date | Wed, 10 Sep 2014 07:43:40 -0700 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] PM / Domains: add debugfs listing of struct generic_pm_domain-s |
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On Wed, Sep 10, 2014 at 01:28:56PM +0200, Maciej Matraszek wrote: > Add /sys/kernel/debug/pm_genpd/pm_genpd_summary file, which > lists power domains in the system, their statuses and attached devices, > resembling /sys/kernel/debug/clk/clk_summary. > > Currently it is impossible to inspect (from userland) whether > a power domain is on or off. And, if it is on, which device blocks it > from powering down. This change allows developers working on > embedded devices power efficiency to list all necessary information > about generic power domains in one place. > > The content of pm_genpd/pm_genpd_summary file is generated by iterating > over all generic power domain in the system, and, for each, > over registered devices. > > Example output: > $ cat /sys/kernel/debug/pm_genpd/pm_genpd_summary > domain status slaves > /device runtime status > ---------------------------------------------------------------------- > isp-power-domain off > /devices/soc/12180000.fimc-is suspended > /devices/soc/12180000.fimc-is/120a0000.fimc-lite suspended > lcd0-power-domain on > /devices/soc/11c80000.dsi active > /devices/soc/11c00000.fimd active > /devices/soc/11e20000.sysmmu suspended > g3d-power-domain off > /devices/soc/13001000.gpu suspended > mfc-power-domain off > /devices/soc/13400000.mfc-codec suspended > /devices/soc/13620000.sysmmu suspended > cam-power-domain off > /devices/soc/11830000.jpeg-codec suspended > /devices/soc/11a60000.sysmmu suspended > /devices/soc/12180000.fimc-is/120c0000.csis suspended > > To enable this feature, compile the kernel with debugfs > and CONFIG_PM_ADVANCED_DEBUG enabled. > > Signed-off-by: Maciej Matraszek <m.matraszek@samsung.com> > --- > drivers/base/power/domain.c | 153 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 153 insertions(+) > > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c > index eee55c1e5fde..d1aa731ba0db 100644 > --- a/drivers/base/power/domain.c > +++ b/drivers/base/power/domain.c > @@ -2189,3 +2189,156 @@ void pm_genpd_init(struct generic_pm_domain *genpd, > list_add(&genpd->gpd_list_node, &gpd_list); > mutex_unlock(&gpd_list_lock); > } > + > + > +/*** debugfs support ***/ > + > +#ifdef CONFIG_PM_ADVANCED_DEBUG > +#include <linux/pm.h> > +#include <linux/device.h> > +#include <linux/debugfs.h> > +#include <linux/kobject.h> > +static struct dentry *pm_genpd_debugfs_dir; > + > +/* > + * TODO: This function is a slightly modified version of rtpm_status_show > + * from sysfs.c, but dependencies between PM_GENERIC_DOMAINS and PM_RUNTIME > + * are too loose to generalize it. > + */ > +#ifdef CONFIG_PM_RUNTIME > +static void rtpm_status_str(struct seq_file *s, struct device *dev) > +{ > + static const char * const status_lookup[] = { > + [RPM_ACTIVE] = "active", > + [RPM_RESUMING] = "resuming", > + [RPM_SUSPENDED] = "suspended", > + [RPM_SUSPENDING] = "suspending" > + }; > + const char *p = ""; > + > + if (dev->power.runtime_error) > + p = "error"; > + else if (dev->power.disable_depth) > + p = "unsupported"; > + else if (dev->power.runtime_status < ARRAY_SIZE(status_lookup)) > + p = status_lookup[dev->power.runtime_status]; > + else > + WARN_ON(1); > + > + seq_puts(s, p); > +} > +#else > +static void rtpm_status_str(struct seq_file *s, struct device *dev) > +{ > + seq_puts(s, "active"); > +} > +#endif > + > +static int pm_genpd_summary_one(struct seq_file *s, > + struct generic_pm_domain *gpd) > +{ > + static const char * const status_lookup[] = { > + [GPD_STATE_ACTIVE] = "on", > + [GPD_STATE_WAIT_MASTER] = "wait-master", > + [GPD_STATE_BUSY] = "busy", > + [GPD_STATE_REPEAT] = "off-in-progress", > + [GPD_STATE_POWER_OFF] = "off" > + }; > + struct pm_domain_data *pm_data; > + const char *kobj_path; > + struct gpd_link *link; > + int ret; > + > + ret = mutex_lock_interruptible(&gpd->lock); > + if (ret) > + return -ERESTARTSYS; > + > + if (WARN_ON(gpd->status >= ARRAY_SIZE(status_lookup))) > + goto exit; > + seq_printf(s, "%-30s %-15s ", gpd->name, status_lookup[gpd->status]); > + > + /* > + * Modifications on the list require holding locks on both > + * master and slave, so we are safe. > + * Also gpd->name is immutable. > + */ > + list_for_each_entry(link, &gpd->master_links, master_node) { > + seq_printf(s, "%s", link->slave->name); > + if (!list_is_last(&link->master_node, &gpd->master_links)) > + seq_puts(s, ", "); > + } > + > + list_for_each_entry(pm_data, &gpd->dev_list, list_node) { > + kobj_path = kobject_get_path(&pm_data->dev->kobj, GFP_KERNEL); > + if (kobj_path == NULL) > + continue; > + > + seq_printf(s, "\n %-50s ", kobj_path); > + rtpm_status_str(s, pm_data->dev); > + kfree(kobj_path); > + } > + > + seq_puts(s, "\n"); > +exit: > + mutex_unlock(&gpd->lock); > + > + return 0; > +} > + > +static int pm_genpd_summary_show(struct seq_file *s, void *data) > +{ > + struct generic_pm_domain *gpd; > + int ret = 0; > + > + seq_puts(s, " domain status slaves\n"); > + seq_puts(s, " /device runtime status\n"); > + seq_puts(s, "----------------------------------------------------------------------\n"); > + > + ret = mutex_lock_interruptible(&gpd_list_lock); > + if (ret) > + return -ERESTARTSYS; > + > + list_for_each_entry(gpd, &gpd_list, gpd_list_node) { > + ret = pm_genpd_summary_one(s, gpd); > + if (ret) > + break; > + } > + mutex_unlock(&gpd_list_lock); > + > + return ret; > +} > + > +static int pm_genpd_summary_open(struct inode *inode, struct file *file) > +{ > + return single_open(file, pm_genpd_summary_show, inode->i_private); > +} > + > +static const struct file_operations pm_genpd_summary_fops = { > + .open = pm_genpd_summary_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = single_release, > +}; > + > +static int __init pm_genpd_debug_init(void) > +{ > + struct dentry *d; > + > + pm_genpd_debugfs_dir = debugfs_create_dir("pm_genpd", NULL); > + > + /* No debugfs */ > + if (IS_ERR(pm_genpd_debugfs_dir)) > + return PTR_ERR(pm_genpd_debugfs_dir);
You shouldn't care at all, just do this check:
> + if (!pm_genpd_debugfs_dir) > + return -ENOMEM;
And all will be fine, because:
> + d = debugfs_create_file("pm_genpd_summary", S_IRUGO, > + pm_genpd_debugfs_dir, NULL, &pm_genpd_summary_fops);
That call will resolve away to nothing if debugfs is not enabled, and it doesn't make much sense to do anything with an "error" of no debugfs.
> + if (!d) > + return -ENOMEM; > + > + return 0; > +} > +late_initcall(pm_genpd_debug_init); > +#endif /* CONFIG_PM_ADVANCED_DEBUG */
No tear-down of the debugfs files on shutdown?
thanks,
greg k-h
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