From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wi0-x234.google.com ([2a00:1450:400c:c05::234]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Yi9iH-00079z-Qq for barebox@lists.infradead.org; Tue, 14 Apr 2015 22:53:53 +0000 Received: by wizk4 with SMTP id k4so132619485wiz.1 for ; Tue, 14 Apr 2015 15:53:26 -0700 (PDT) From: Sebastian Hesselbarth Date: Wed, 15 Apr 2015 00:53:15 +0200 Message-Id: <1429052000-20647-2-git-send-email-sebastian.hesselbarth@gmail.com> In-Reply-To: <1429052000-20647-1-git-send-email-sebastian.hesselbarth@gmail.com> References: <1429052000-20647-1-git-send-email-sebastian.hesselbarth@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH v2 1/6] base: Introduce deferred probing To: Sebastian Hesselbarth Cc: barebox@lists.infradead.org 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 --- Changelog: v1->v2: - Rework deferred probing to loop until no previously deferred device probing succeeds. (Suggested by Sascha Hauer) - Print an error message for devices stuck in deferred list. - Add a comment how deferred probing and re-assignment to deferred list works. Cc: barebox@lists.infradead.org --- drivers/base/driver.c | 56 ++++++++++++++++++++++++++++++++++++++++++--- include/asm-generic/errno.h | 1 + 2 files changed, 54 insertions(+), 3 deletions(-) diff --git a/drivers/base/driver.c b/drivers/base/driver.c index 590c97c96424..6112b4953ba6 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -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; diff --git a/include/asm-generic/errno.h b/include/asm-generic/errno.h index bbf493c373ae..6072f7b605bb 100644 --- a/include/asm-generic/errno.h +++ b/include/asm-generic/errno.h @@ -132,6 +132,7 @@ #define ERESTARTNOINTR 513 #define ERESTARTNOHAND 514 /* restart if no handler.. */ #define ENOIOCTLCMD 515 /* No ioctl command */ +#define EPROBE_DEFER 517 /* Driver requests probe retry */ #define ENOTSUPP 524 /* Operation is not supported */ -- 2.1.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox