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author | Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> | 2015-04-15 00:53:15 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2015-04-17 07:23:46 +0200 |
commit | ab3da15bc14cc5297b2da27eb3dcd8d70dac41df (patch) | |
tree | f25fad095cb149fefb5b216dc9fb37b43a0e2158 /drivers/base | |
parent | 11045f866dd3b924d025faa86c41bd4dd3a9236a (diff) | |
download | barebox-ab3da15bc14cc5297b2da27eb3dcd8d70dac41df.tar.gz barebox-ab3da15bc14cc5297b2da27eb3dcd8d70dac41df.tar.xz |
base: Introduce deferred probing
As expected, we would need deferred probing sooner or later. This is
a first approach to allow devices to return -EPROBE_DEFER and get
sorted into a list of deferred devices that will be re-probed later.
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/driver.c | 56 |
1 files changed, 53 insertions, 3 deletions
diff --git a/drivers/base/driver.c b/drivers/base/driver.c index 590c97c964..6112b4953b 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -29,6 +29,7 @@ #include <console.h> #include <linux/ctype.h> #include <errno.h> +#include <init.h> #include <fs.h> #include <of.h> #include <linux/list.h> @@ -43,6 +44,7 @@ LIST_HEAD(driver_list); EXPORT_SYMBOL(driver_list); static LIST_HEAD(active); +static LIST_HEAD(deferred); struct device_d *get_device_by_name(const char *name) { @@ -88,13 +90,20 @@ int device_probe(struct device_d *dev) list_add(&dev->active, &active); ret = dev->bus->probe(dev); - if (ret) { + if (ret == 0) + return 0; + + if (ret == -EPROBE_DEFER) { list_del(&dev->active); - dev_err(dev, "probe failed: %s\n", strerror(-ret)); + list_add(&dev->active, &deferred); + dev_dbg(dev, "probe deferred\n"); return ret; } - return 0; + list_del(&dev->active); + dev_err(dev, "probe failed: %s\n", strerror(-ret)); + + return ret; } int device_detect(struct device_d *dev) @@ -213,6 +222,47 @@ int unregister_device(struct device_d *old_dev) } EXPORT_SYMBOL(unregister_device); +/* + * Loop over list of deferred devices as long as at least one + * device is successfully probed. Devices that again request + * deferral are re-added to deferred list in device_probe(). + * For devices finally left in deferred list -EPROBE_DEFER + * becomes a fatal error. + */ +static int device_probe_deferred(void) +{ + struct device_d *dev, *tmp; + struct driver_d *drv; + bool success; + + do { + success = false; + + if (list_empty(&deferred)) + break; + + list_for_each_entry_safe(dev, tmp, &deferred, active) { + list_del(&dev->active); + dev_dbg(dev, "re-probe device\n"); + bus_for_each_driver(dev->bus, drv) { + if (match(drv, dev)) + continue; + success = true; + break; + } + } + } while (success); + + if (list_empty(&deferred)) + return 0; + + list_for_each_entry(dev, &deferred, active) + dev_err(dev, "probe permanently deferred\n"); + + return 0; +} +late_initcall(device_probe_deferred); + struct driver_d *get_driver_by_name(const char *name) { struct driver_d *drv; |