From 2b31594a9523449b168946725689d039c80204de Mon Sep 17 00:00:00 2001 From: Jonghwan Choi Date: Sat, 14 Jan 2012 11:06:03 +0900 Subject: driver-core: Fix possible null reference in subsys_interface_unregister Check if the sif is not NULL before de-referencing it Signed-off-by: Jonghwan Choi Signed-off-by: Greg Kroah-Hartman --- drivers/base/bus.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 99dc5921e1d..4ddb38b696f 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -1193,13 +1193,15 @@ EXPORT_SYMBOL_GPL(subsys_interface_register); void subsys_interface_unregister(struct subsys_interface *sif) { - struct bus_type *subsys = sif->subsys; + struct bus_type *subsys; struct subsys_dev_iter iter; struct device *dev; - if (!sif) + if (!sif || !sif->subsys) return; + subsys = sif->subsys; + mutex_lock(&subsys->p->mutex); list_del_init(&sif->node); if (sif->remove_dev) { -- cgit v1.2.3-70-g09d2 From fde25a9b63b9a3dc91365c394a426ebe64cfc2da Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 24 Jan 2012 13:34:24 -0500 Subject: Driver core: driver_find() drops reference before returning As part of the removal of get_driver()/put_driver(), this patch (as1510) changes driver_find(); it now drops the reference it acquires before returning. The patch also adjusts all the callers of driver_find() to remove the now unnecessary calls to put_driver(). In addition, the patch adds a warning to driver_find(): Callers must make sure the driver they are searching for does not get unloaded while they are using it. This has always been the case; driver_find() has never prevented a driver from being unregistered or unloaded. Hence the patch will not introduce any new bugs. The existing callers all seem to be okay in this respect, however I don't understand the video drivers well enough to be certain about them. Signed-off-by: Alan Stern CC: Dmitry Torokhov CC: Kyungmin Park CC: Andy Walls CC: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- drivers/base/driver.c | 7 +++++-- drivers/input/gameport/gameport.c | 1 - drivers/input/serio/serio.c | 1 - drivers/media/video/cx18/cx18-alsa-main.c | 1 - drivers/media/video/ivtv/ivtvfb.c | 2 -- drivers/media/video/s5p-fimc/fimc-mdevice.c | 5 +---- drivers/media/video/s5p-tv/mixer_video.c | 1 - drivers/s390/net/smsgiucv_app.c | 9 ++++----- 8 files changed, 10 insertions(+), 17 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/driver.c b/drivers/base/driver.c index b631f7c5945..e979cad75c6 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -234,7 +234,6 @@ int driver_register(struct device_driver *drv) other = driver_find(drv->name, drv->bus); if (other) { - put_driver(other); printk(KERN_ERR "Error: Driver '%s' is already registered, " "aborting...\n", drv->name); return -EBUSY; @@ -275,7 +274,9 @@ EXPORT_SYMBOL_GPL(driver_unregister); * Call kset_find_obj() to iterate over list of drivers on * a bus to find driver by name. Return driver if found. * - * Note that kset_find_obj increments driver's reference count. + * This routine provides no locking to prevent the driver it returns + * from being unregistered or unloaded while the caller is using it. + * The caller is responsible for preventing this. */ struct device_driver *driver_find(const char *name, struct bus_type *bus) { @@ -283,6 +284,8 @@ struct device_driver *driver_find(const char *name, struct bus_type *bus) struct driver_private *priv; if (k) { + /* Drop reference added by kset_find_obj() */ + kobject_put(k); priv = to_driver(k); return priv->driver; } diff --git a/drivers/input/gameport/gameport.c b/drivers/input/gameport/gameport.c index c351aa421f8..da739d9d190 100644 --- a/drivers/input/gameport/gameport.c +++ b/drivers/input/gameport/gameport.c @@ -449,7 +449,6 @@ static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribut } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) { gameport_disconnect_port(gameport); error = gameport_bind_driver(gameport, to_gameport_driver(drv)); - put_driver(drv); } else { error = -EINVAL; } diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c index ba70058e2be..d0f7533dbf8 100644 --- a/drivers/input/serio/serio.c +++ b/drivers/input/serio/serio.c @@ -441,7 +441,6 @@ static ssize_t serio_rebind_driver(struct device *dev, struct device_attribute * } else if ((drv = driver_find(buf, &serio_bus)) != NULL) { serio_disconnect_port(serio); error = serio_bind_driver(serio, to_serio_driver(drv)); - put_driver(drv); serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT); } else { error = -EINVAL; diff --git a/drivers/media/video/cx18/cx18-alsa-main.c b/drivers/media/video/cx18/cx18-alsa-main.c index a1e6c2a3247..e118361c2e7 100644 --- a/drivers/media/video/cx18/cx18-alsa-main.c +++ b/drivers/media/video/cx18/cx18-alsa-main.c @@ -285,7 +285,6 @@ static void __exit cx18_alsa_exit(void) drv = driver_find("cx18", &pci_bus_type); ret = driver_for_each_device(drv, NULL, NULL, cx18_alsa_exit_callback); - put_driver(drv); cx18_ext_init = NULL; printk(KERN_INFO "cx18-alsa: module unload complete\n"); diff --git a/drivers/media/video/ivtv/ivtvfb.c b/drivers/media/video/ivtv/ivtvfb.c index d0fbfcf7133..e5e7fa9e737 100644 --- a/drivers/media/video/ivtv/ivtvfb.c +++ b/drivers/media/video/ivtv/ivtvfb.c @@ -1293,7 +1293,6 @@ static int __init ivtvfb_init(void) drv = driver_find("ivtv", &pci_bus_type); err = driver_for_each_device(drv, NULL, ®istered, ivtvfb_callback_init); - put_driver(drv); if (!registered) { printk(KERN_ERR "ivtvfb: no cards found\n"); return -ENODEV; @@ -1310,7 +1309,6 @@ static void ivtvfb_cleanup(void) drv = driver_find("ivtv", &pci_bus_type); err = driver_for_each_device(drv, NULL, NULL, ivtvfb_callback_cleanup); - put_driver(drv); } module_init(ivtvfb_init); diff --git a/drivers/media/video/s5p-fimc/fimc-mdevice.c b/drivers/media/video/s5p-fimc/fimc-mdevice.c index 8ea4ee116e4..63eccb55728 100644 --- a/drivers/media/video/s5p-fimc/fimc-mdevice.c +++ b/drivers/media/video/s5p-fimc/fimc-mdevice.c @@ -344,16 +344,13 @@ static int fimc_md_register_platform_entities(struct fimc_md *fmd) return -ENODEV; ret = driver_for_each_device(driver, NULL, fmd, fimc_register_callback); - put_driver(driver); if (ret) return ret; driver = driver_find(CSIS_DRIVER_NAME, &platform_bus_type); - if (driver) { + if (driver) ret = driver_for_each_device(driver, NULL, fmd, csis_register_callback); - put_driver(driver); - } return ret; } diff --git a/drivers/media/video/s5p-tv/mixer_video.c b/drivers/media/video/s5p-tv/mixer_video.c index 7884baeff76..f7ca5cc143c 100644 --- a/drivers/media/video/s5p-tv/mixer_video.c +++ b/drivers/media/video/s5p-tv/mixer_video.c @@ -58,7 +58,6 @@ static struct v4l2_subdev *find_and_register_subdev( } done: - put_driver(drv); return sd; } diff --git a/drivers/s390/net/smsgiucv_app.c b/drivers/s390/net/smsgiucv_app.c index 4d2ea400042..32515a201bb 100644 --- a/drivers/s390/net/smsgiucv_app.c +++ b/drivers/s390/net/smsgiucv_app.c @@ -168,7 +168,7 @@ static int __init smsgiucv_app_init(void) rc = dev_set_name(smsg_app_dev, KMSG_COMPONENT); if (rc) { kfree(smsg_app_dev); - goto fail_put_driver; + goto fail; } smsg_app_dev->bus = &iucv_bus; smsg_app_dev->parent = iucv_root; @@ -177,7 +177,7 @@ static int __init smsgiucv_app_init(void) rc = device_register(smsg_app_dev); if (rc) { put_device(smsg_app_dev); - goto fail_put_driver; + goto fail; } /* convert sender to uppercase characters */ @@ -191,12 +191,11 @@ static int __init smsgiucv_app_init(void) rc = smsg_register_callback(SMSG_PREFIX, smsg_app_callback); if (rc) { device_unregister(smsg_app_dev); - goto fail_put_driver; + goto fail; } rc = 0; -fail_put_driver: - put_driver(smsgiucv_drv); +fail: return rc; } module_init(smsgiucv_app_init); -- cgit v1.2.3-70-g09d2 From 9875bb480cc89d9b690f7028aadf7e58454f0dae Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 24 Jan 2012 13:35:37 -0500 Subject: Eliminate get_driver() and put_driver() Now that there are no users of get_driver() or put_driver(), this patch (as1513) removes those routines completely. Signed-off-by: Alan Stern CC: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman --- drivers/base/driver.c | 28 ---------------------------- include/linux/device.h | 2 -- 2 files changed, 30 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/driver.c b/drivers/base/driver.c index e979cad75c6..60e4f77ca66 100644 --- a/drivers/base/driver.c +++ b/drivers/base/driver.c @@ -153,34 +153,6 @@ int driver_add_kobj(struct device_driver *drv, struct kobject *kobj, } EXPORT_SYMBOL_GPL(driver_add_kobj); -/** - * get_driver - increment driver reference count. - * @drv: driver. - */ -struct device_driver *get_driver(struct device_driver *drv) -{ - if (drv) { - struct driver_private *priv; - struct kobject *kobj; - - kobj = kobject_get(&drv->p->kobj); - priv = to_driver(kobj); - return priv->driver; - } - return NULL; -} -EXPORT_SYMBOL_GPL(get_driver); - -/** - * put_driver - decrement driver's refcount. - * @drv: driver. - */ -void put_driver(struct device_driver *drv) -{ - kobject_put(&drv->p->kobj); -} -EXPORT_SYMBOL_GPL(put_driver); - static int driver_add_groups(struct device_driver *drv, const struct attribute_group **groups) { diff --git a/include/linux/device.h b/include/linux/device.h index a782d7ff9e8..d28bd829567 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -238,8 +238,6 @@ struct device_driver { extern int __must_check driver_register(struct device_driver *drv); extern void driver_unregister(struct device_driver *drv); -extern struct device_driver *get_driver(struct device_driver *drv); -extern void put_driver(struct device_driver *drv); extern struct device_driver *driver_find(const char *name, struct bus_type *bus); extern int driver_probe_done(void); -- cgit v1.2.3-70-g09d2 From fad12ac8c8c2591c7f4e61d19b6a9d76cd49fafa Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Thu, 26 Jan 2012 00:09:14 +0100 Subject: CPU: Introduce ARCH_HAS_CPU_AUTOPROBE and X86 parts This patch is based on Andi Kleen's work: Implement autoprobing/loading of modules serving CPU specific features (x86cpu autoloading). And Kay Siever's work to get rid of sysdev cpu structures and making use of struct device instead. Before, the cpuid driver had to be loaded to get the x86cpu autoloading feature. With this patch autoloading works through the /sys/devices/system/cpu object Cc: Kay Sievers Cc: Dave Jones Cc: Jens Axboe Cc: Herbert Xu Cc: Huang Ying Cc: Len Brown Acked-by: Andi Kleen Signed-off-by: Thomas Renninger Acked-by: H. Peter Anvin Signed-off-by: Greg Kroah-Hartman --- arch/x86/Kconfig | 3 +++ arch/x86/kernel/cpu/match.c | 44 +++++++++++++++++++++++++++++++++ arch/x86/kernel/cpuid.c | 59 +-------------------------------------------- drivers/base/cpu.c | 11 +++++++++ include/linux/cpu.h | 7 ++++++ 5 files changed, 66 insertions(+), 58 deletions(-) (limited to 'drivers/base') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 864cc6e6ac8..6baa1e66e1b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -179,6 +179,9 @@ config ARCH_HAS_DEFAULT_IDLE config ARCH_HAS_CACHE_LINE_SIZE def_bool y +config ARCH_HAS_CPU_AUTOPROBE + def_bool y + config HAVE_SETUP_PER_CPU_AREA def_bool y diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c index 7acc961422e..940e2d48307 100644 --- a/arch/x86/kernel/cpu/match.c +++ b/arch/x86/kernel/cpu/match.c @@ -2,6 +2,7 @@ #include #include #include +#include /** * x86_match_cpu - match current CPU again an array of x86_cpu_ids @@ -46,3 +47,46 @@ const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match) return NULL; } EXPORT_SYMBOL(x86_match_cpu); + +ssize_t arch_print_cpu_modalias(struct device *dev, + struct device_attribute *attr, + char *bufptr) +{ + int size = PAGE_SIZE; + int i, n; + char *buf = bufptr; + + n = snprintf(buf, size, "x86cpu:vendor:%04X:family:%04X:" + "model:%04X:feature:", + boot_cpu_data.x86_vendor, + boot_cpu_data.x86, + boot_cpu_data.x86_model); + size -= n; + buf += n; + size -= 2; + for (i = 0; i < NCAPINTS*32; i++) { + if (boot_cpu_has(i)) { + n = snprintf(buf, size, ",%04X", i); + if (n < 0) { + WARN(1, "x86 features overflow page\n"); + break; + } + size -= n; + buf += n; + } + } + *buf++ = ','; + *buf++ = '\n'; + return buf - bufptr; +} + +int arch_cpu_uevent(struct device *dev, struct kobj_uevent_env *env) +{ + char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL); + if (buf) { + arch_print_cpu_modalias(NULL, NULL, buf); + add_uevent_var(env, "MODALIAS=%s", buf); + kfree(buf); + } + return 0; +} diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c index 7c89880eefd..a524353d93f 100644 --- a/arch/x86/kernel/cpuid.c +++ b/arch/x86/kernel/cpuid.c @@ -40,7 +40,6 @@ #include #include #include -#include #include #include @@ -139,57 +138,13 @@ static const struct file_operations cpuid_fops = { .open = cpuid_open, }; -static ssize_t print_cpu_modalias(struct device *dev, - struct device_attribute *attr, - char *bufptr) -{ - int size = PAGE_SIZE; - int i, n; - char *buf = bufptr; - - n = snprintf(buf, size, "x86cpu:vendor:%04X:family:" - "%04X:model:%04X:feature:", - boot_cpu_data.x86_vendor, - boot_cpu_data.x86, - boot_cpu_data.x86_model); - size -= n; - buf += n; - size -= 2; - for (i = 0; i < NCAPINTS*32; i++) { - if (boot_cpu_has(i)) { - n = snprintf(buf, size, ",%04X", i); - if (n < 0) { - WARN(1, "x86 features overflow page\n"); - break; - } - size -= n; - buf += n; - } - } - *buf++ = ','; - *buf++ = '\n'; - return buf - bufptr; -} - -static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL); - static __cpuinit int cpuid_device_create(int cpu) { struct device *dev; - int err; dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL, "cpu%d", cpu); - if (IS_ERR(dev)) - return PTR_ERR(dev); - - err = device_create_file(dev, &dev_attr_modalias); - if (err) { - /* keep device around on error. attribute is optional. */ - err = 0; - } - - return 0; + return IS_ERR(dev) ? PTR_ERR(dev) : 0; } static void cpuid_device_destroy(int cpu) @@ -227,17 +182,6 @@ static char *cpuid_devnode(struct device *dev, umode_t *mode) return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt)); } -static int cpuid_dev_uevent(struct device *dev, struct kobj_uevent_env *env) -{ - char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL); - if (buf) { - print_cpu_modalias(NULL, NULL, buf); - add_uevent_var(env, "MODALIAS=%s", buf); - kfree(buf); - } - return 0; -} - static int __init cpuid_init(void) { int i, err = 0; @@ -256,7 +200,6 @@ static int __init cpuid_init(void) goto out_chrdev; } cpuid_class->devnode = cpuid_devnode; - cpuid_class->dev_uevent = cpuid_dev_uevent; for_each_online_cpu(i) { err = cpuid_device_create(i); if (err != 0) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index db87e78d745..2a0c670c281 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include "base.h" @@ -223,6 +224,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num) cpu->node_id = cpu_to_node(num); cpu->dev.id = num; cpu->dev.bus = &cpu_subsys; +#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE + cpu->dev.bus->uevent = arch_cpu_uevent; +#endif error = device_register(&cpu->dev); if (!error && cpu->hotpluggable) register_cpu_control(cpu); @@ -247,6 +251,10 @@ struct device *get_cpu_device(unsigned cpu) } EXPORT_SYMBOL_GPL(get_cpu_device); +#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE +static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL); +#endif + static struct attribute *cpu_root_attrs[] = { #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE &dev_attr_probe.attr, @@ -257,6 +265,9 @@ static struct attribute *cpu_root_attrs[] = { &cpu_attrs[2].attr.attr, &dev_attr_kernel_max.attr, &dev_attr_offline.attr, +#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE + &dev_attr_modalias.attr, +#endif NULL }; diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 1f6587590a1..6e53b4823d7 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -44,6 +44,13 @@ extern ssize_t arch_cpu_release(const char *, size_t); #endif struct notifier_block; +#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE +extern int arch_cpu_uevent(struct device *dev, struct kobj_uevent_env *env); +extern ssize_t arch_print_cpu_modalias(struct device *dev, + struct device_attribute *attr, + char *bufptr); +#endif + /* * CPU notifier priorities. */ -- cgit v1.2.3-70-g09d2 From 74d1d82cdaaec727f5072eb1c9f49b7e920e076f Mon Sep 17 00:00:00 2001 From: Lee Jones Date: Mon, 6 Feb 2012 11:22:22 -0800 Subject: drivers/base: add bus for System-on-Chip devices Traditionally, any System-on-Chip based platform creates a flat list of platform_devices directly under /sys/devices/platform. In order to give these some better structure, this introduces a new bus type for soc_devices that are registered with the new soc_device_register() function. All devices that are on the same chip should then be registered as child devices of the soc device. The soc bus also exports a few standardised device attributes which allow user space to query the specific type of soc. Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman --- drivers/base/Kconfig | 3 + drivers/base/Makefile | 1 + drivers/base/soc.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/sys_soc.h | 37 ++++++++++ 4 files changed, 224 insertions(+) create mode 100644 drivers/base/soc.c create mode 100644 include/linux/sys_soc.h (limited to 'drivers/base') diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index 7be9f79018e..9aa618acfe9 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -176,6 +176,9 @@ config GENERIC_CPU_DEVICES bool default n +config SOC_BUS + bool + source "drivers/base/regmap/Kconfig" config DMA_SHARED_BUFFER diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 610f9997a40..b6d1b9c4200 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -19,6 +19,7 @@ obj-$(CONFIG_MODULES) += module.o endif obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o obj-$(CONFIG_REGMAP) += regmap/ +obj-$(CONFIG_SOC_BUS) += soc.o ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG diff --git a/drivers/base/soc.c b/drivers/base/soc.c new file mode 100644 index 00000000000..05f150382da --- /dev/null +++ b/drivers/base/soc.c @@ -0,0 +1,183 @@ +/* + * Copyright (C) ST-Ericsson SA 2011 + * + * Author: Lee Jones for ST-Ericsson. + * License terms: GNU General Public License (GPL), version 2 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_IDR(soc_ida); +static DEFINE_SPINLOCK(soc_lock); + +static ssize_t soc_info_get(struct device *dev, + struct device_attribute *attr, + char *buf); + +struct soc_device { + struct device dev; + struct soc_device_attribute *attr; + int soc_dev_num; +}; + +static struct bus_type soc_bus_type = { + .name = "soc", +}; + +static DEVICE_ATTR(machine, S_IRUGO, soc_info_get, NULL); +static DEVICE_ATTR(family, S_IRUGO, soc_info_get, NULL); +static DEVICE_ATTR(soc_id, S_IRUGO, soc_info_get, NULL); +static DEVICE_ATTR(revision, S_IRUGO, soc_info_get, NULL); + +struct device *soc_device_to_device(struct soc_device *soc_dev) +{ + return &soc_dev->dev; +} + +static mode_t soc_attribute_mode(struct kobject *kobj, + struct attribute *attr, + int index) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); + + if ((attr == &dev_attr_machine.attr) + && (soc_dev->attr->machine != NULL)) + return attr->mode; + if ((attr == &dev_attr_family.attr) + && (soc_dev->attr->family != NULL)) + return attr->mode; + if ((attr == &dev_attr_revision.attr) + && (soc_dev->attr->revision != NULL)) + return attr->mode; + if ((attr == &dev_attr_soc_id.attr) + && (soc_dev->attr->soc_id != NULL)) + return attr->mode; + + /* Unknown or unfilled attribute. */ + return 0; +} + +static ssize_t soc_info_get(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); + + if (attr == &dev_attr_machine) + return sprintf(buf, "%s\n", soc_dev->attr->machine); + if (attr == &dev_attr_family) + return sprintf(buf, "%s\n", soc_dev->attr->family); + if (attr == &dev_attr_revision) + return sprintf(buf, "%s\n", soc_dev->attr->revision); + if (attr == &dev_attr_soc_id) + return sprintf(buf, "%s\n", soc_dev->attr->soc_id); + + return -EINVAL; + +} + +static struct attribute *soc_attr[] = { + &dev_attr_machine.attr, + &dev_attr_family.attr, + &dev_attr_soc_id.attr, + &dev_attr_revision.attr, + NULL, +}; + +static const struct attribute_group soc_attr_group = { + .attrs = soc_attr, + .is_visible = soc_attribute_mode, +}; + +static const struct attribute_group *soc_attr_groups[] = { + &soc_attr_group, + NULL, +}; + +static void soc_release(struct device *dev) +{ + struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); + + kfree(soc_dev); +} + +struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr) +{ + struct soc_device *soc_dev; + int ret; + + soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL); + if (!soc_dev) { + ret = -ENOMEM; + goto out1; + } + + /* Fetch a unique (reclaimable) SOC ID. */ + do { + if (!ida_pre_get(&soc_ida, GFP_KERNEL)) { + ret = -ENOMEM; + goto out2; + } + + spin_lock(&soc_lock); + ret = ida_get_new(&soc_ida, &soc_dev->soc_dev_num); + spin_unlock(&soc_lock); + + } while (ret == -EAGAIN); + + if (ret) + goto out2; + + soc_dev->attr = soc_dev_attr; + soc_dev->dev.bus = &soc_bus_type; + soc_dev->dev.groups = soc_attr_groups; + soc_dev->dev.release = soc_release; + + dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num); + + ret = device_register(&soc_dev->dev); + if (ret) + goto out3; + + return soc_dev; + +out3: + ida_remove(&soc_ida, soc_dev->soc_dev_num); +out2: + kfree(soc_dev); +out1: + return ERR_PTR(ret); +} + +/* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */ +void soc_device_unregister(struct soc_device *soc_dev) +{ + ida_remove(&soc_ida, soc_dev->soc_dev_num); + + device_unregister(&soc_dev->dev); +} + +static int __init soc_bus_register(void) +{ + spin_lock_init(&soc_lock); + + return bus_register(&soc_bus_type); +} +core_initcall(soc_bus_register); + +static void __exit soc_bus_unregister(void) +{ + ida_destroy(&soc_ida); + + bus_unregister(&soc_bus_type); +} +module_exit(soc_bus_unregister); diff --git a/include/linux/sys_soc.h b/include/linux/sys_soc.h new file mode 100644 index 00000000000..2739ccb6957 --- /dev/null +++ b/include/linux/sys_soc.h @@ -0,0 +1,37 @@ +/* + * Copyright (C) ST-Ericsson SA 2011 + * Author: Lee Jones for ST-Ericsson. + * License terms: GNU General Public License (GPL), version 2 + */ +#ifndef __SOC_BUS_H +#define __SOC_BUS_H + +#include + +struct soc_device_attribute { + const char *machine; + const char *family; + const char *revision; + const char *soc_id; +}; + +/** + * soc_device_register - register SoC as a device + * @soc_plat_dev_attr: Attributes passed from platform to be attributed to a SoC + */ +struct soc_device *soc_device_register( + struct soc_device_attribute *soc_plat_dev_attr); + +/** + * soc_device_unregister - unregister SoC device + * @dev: SoC device to be unregistered + */ +void soc_device_unregister(struct soc_device *soc_dev); + +/** + * soc_device_to_device - helper function to fetch struct device + * @soc: Previously registered SoC device container + */ +struct device *soc_device_to_device(struct soc_device *soc); + +#endif /* __SOC_BUS_H */ -- cgit v1.2.3-70-g09d2 From d1c3414c2a9d10ef7f0f7665f5d2947cd088c093 Mon Sep 17 00:00:00 2001 From: Grant Likely Date: Mon, 5 Mar 2012 08:47:41 -0700 Subject: drivercore: Add driver probe deferral mechanism Allow drivers to report at probe time that they cannot get all the resources required by the device, and should be retried at a later time. This should completely solve the problem of getting devices initialized in the right order. Right now this is mostly handled by mucking about with initcall ordering which is a complete hack, and doesn't even remotely handle the case where device drivers are in modules. This approach completely sidesteps the issues by allowing driver registration to occur in any order, and any driver can request to be retried after a few more other drivers get probed. v4: - Integrate Manjunath's addition of a separate workqueue - Change -EAGAIN to -EPROBE_DEFER for drivers to trigger deferral - Update comment blocks to reflect how the code really works v3: - Hold off workqueue scheduling until late_initcall so that the bulk of driver probes are complete before we start retrying deferred devices. - Tested with simple use cases. Still needs more testing though. Using it to get rid of the gpio early_initcall madness, or to replace the ASoC internal probe deferral code would be ideal. v2: - added locking so it should no longer be utterly broken in that regard - remove device from deferred list at device_del time. - Still completely untested with any real use case, but has been boot tested. Signed-off-by: Grant Likely Cc: Mark Brown Cc: Arnd Bergmann Cc: Dilan Lee Cc: Manjunath GKondaiah Cc: Alan Stern Cc: Tony Lindgren Cc: Alan Cox Reviewed-by: Mark Brown Acked-by: David Daney Reviewed-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman --- drivers/base/base.h | 1 + drivers/base/core.c | 2 + drivers/base/dd.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++- include/linux/device.h | 5 ++ include/linux/errno.h | 1 + 5 files changed, 146 insertions(+), 1 deletion(-) (limited to 'drivers/base') diff --git a/drivers/base/base.h b/drivers/base/base.h index b858dfd9a37..2c13deae5f8 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -105,6 +105,7 @@ extern void bus_remove_driver(struct device_driver *drv); extern void driver_detach(struct device_driver *drv); extern int driver_probe_device(struct device_driver *drv, struct device *dev); +extern void driver_deferred_probe_del(struct device *dev); static inline int driver_match_device(struct device_driver *drv, struct device *dev) { diff --git a/drivers/base/core.c b/drivers/base/core.c index 74dda4f697f..d4ff7adce38 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -644,6 +644,7 @@ void device_initialize(struct device *dev) { dev->kobj.kset = devices_kset; kobject_init(&dev->kobj, &device_ktype); + INIT_LIST_HEAD(&dev->deferred_probe); INIT_LIST_HEAD(&dev->dma_pools); mutex_init(&dev->mutex); lockdep_set_novalidate_class(&dev->mutex); @@ -1188,6 +1189,7 @@ void device_del(struct device *dev) device_remove_file(dev, &uevent_attr); device_remove_attrs(dev); bus_remove_device(dev); + driver_deferred_probe_del(dev); /* * Some platform devices are driven without driver attached diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 142e3d600f1..442b7641a08 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -28,6 +28,133 @@ #include "base.h" #include "power/power.h" +/* + * Deferred Probe infrastructure. + * + * Sometimes driver probe order matters, but the kernel doesn't always have + * dependency information which means some drivers will get probed before a + * resource it depends on is available. For example, an SDHCI driver may + * first need a GPIO line from an i2c GPIO controller before it can be + * initialized. If a required resource is not available yet, a driver can + * request probing to be deferred by returning -EPROBE_DEFER from its probe hook + * + * Deferred probe maintains two lists of devices, a pending list and an active + * list. A driver returning -EPROBE_DEFER causes the device to be added to the + * pending list. A successful driver probe will trigger moving all devices + * from the pending to the active list so that the workqueue will eventually + * retry them. + * + * The deferred_probe_mutex must be held any time the deferred_probe_*_list + * of the (struct device*)->deferred_probe pointers are manipulated + */ +static DEFINE_MUTEX(deferred_probe_mutex); +static LIST_HEAD(deferred_probe_pending_list); +static LIST_HEAD(deferred_probe_active_list); +static struct workqueue_struct *deferred_wq; + +/** + * deferred_probe_work_func() - Retry probing devices in the active list. + */ +static void deferred_probe_work_func(struct work_struct *work) +{ + struct device *dev; + /* + * This block processes every device in the deferred 'active' list. + * Each device is removed from the active list and passed to + * bus_probe_device() to re-attempt the probe. The loop continues + * until every device in the active list is removed and retried. + * + * Note: Once the device is removed from the list and the mutex is + * released, it is possible for the device get freed by another thread + * and cause a illegal pointer dereference. This code uses + * get/put_device() to ensure the device structure cannot disappear + * from under our feet. + */ + mutex_lock(&deferred_probe_mutex); + while (!list_empty(&deferred_probe_active_list)) { + dev = list_first_entry(&deferred_probe_active_list, + typeof(*dev), deferred_probe); + list_del_init(&dev->deferred_probe); + + get_device(dev); + + /* Drop the mutex while probing each device; the probe path + * may manipulate the deferred list */ + mutex_unlock(&deferred_probe_mutex); + dev_dbg(dev, "Retrying from deferred list\n"); + bus_probe_device(dev); + mutex_lock(&deferred_probe_mutex); + + put_device(dev); + } + mutex_unlock(&deferred_probe_mutex); +} +static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); + +static void driver_deferred_probe_add(struct device *dev) +{ + mutex_lock(&deferred_probe_mutex); + if (list_empty(&dev->deferred_probe)) { + dev_dbg(dev, "Added to deferred list\n"); + list_add(&dev->deferred_probe, &deferred_probe_pending_list); + } + mutex_unlock(&deferred_probe_mutex); +} + +void driver_deferred_probe_del(struct device *dev) +{ + mutex_lock(&deferred_probe_mutex); + if (!list_empty(&dev->deferred_probe)) { + dev_dbg(dev, "Removed from deferred list\n"); + list_del_init(&dev->deferred_probe); + } + mutex_unlock(&deferred_probe_mutex); +} + +static bool driver_deferred_probe_enable = false; +/** + * driver_deferred_probe_trigger() - Kick off re-probing deferred devices + * + * This functions moves all devices from the pending list to the active + * list and schedules the deferred probe workqueue to process them. It + * should be called anytime a driver is successfully bound to a device. + */ +static void driver_deferred_probe_trigger(void) +{ + if (!driver_deferred_probe_enable) + return; + + /* A successful probe means that all the devices in the pending list + * should be triggered to be reprobed. Move all the deferred devices + * into the active list so they can be retried by the workqueue */ + mutex_lock(&deferred_probe_mutex); + list_splice_tail_init(&deferred_probe_pending_list, + &deferred_probe_active_list); + mutex_unlock(&deferred_probe_mutex); + + /* Kick the re-probe thread. It may already be scheduled, but + * it is safe to kick it again. */ + queue_work(deferred_wq, &deferred_probe_work); +} + +/** + * deferred_probe_initcall() - Enable probing of deferred devices + * + * We don't want to get in the way when the bulk of drivers are getting probed. + * Instead, this initcall makes sure that deferred probing is delayed until + * late_initcall time. + */ +static int deferred_probe_initcall(void) +{ + deferred_wq = create_singlethread_workqueue("deferwq"); + if (WARN_ON(!deferred_wq)) + return -ENOMEM; + + driver_deferred_probe_enable = true; + driver_deferred_probe_trigger(); + return 0; +} +late_initcall(deferred_probe_initcall); static void driver_bound(struct device *dev) { @@ -42,6 +169,11 @@ static void driver_bound(struct device *dev) klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices); + /* Make sure the device is no longer in one of the deferred lists + * and kick off retrying all pending devices */ + driver_deferred_probe_del(dev); + driver_deferred_probe_trigger(); + if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_BOUND_DRIVER, dev); @@ -142,7 +274,11 @@ probe_failed: driver_sysfs_remove(dev); dev->driver = NULL; - if (ret != -ENODEV && ret != -ENXIO) { + if (ret == -EPROBE_DEFER) { + /* Driver requested deferred probing */ + dev_info(dev, "Driver %s requests probe deferral\n", drv->name); + driver_deferred_probe_add(dev); + } else if (ret != -ENODEV && ret != -ENXIO) { /* driver matched but the probe failed */ printk(KERN_WARNING "%s: probe of %s failed with error %d\n", diff --git a/include/linux/device.h b/include/linux/device.h index f62e21689fd..22d6938ddbb 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -585,6 +585,10 @@ struct device_dma_parameters { * @mutex: Mutex to synchronize calls to its driver. * @bus: Type of bus device is on. * @driver: Which driver has allocated this + * @deferred_probe: entry in deferred_probe_list which is used to retry the + * binding of drivers which were unable to get all the resources + * needed by the device; typically because it depends on another + * driver getting probed first. * @platform_data: Platform data specific to the device. * Example: For devices on custom boards, as typical of embedded * and SOC based hardware, Linux often uses platform_data to point @@ -644,6 +648,7 @@ struct device { struct bus_type *bus; /* type of bus device is on */ struct device_driver *driver; /* which driver has allocated this device */ + struct list_head deferred_probe; void *platform_data; /* Platform specific data, device core doesn't touch it */ struct dev_pm_info power; diff --git a/include/linux/errno.h b/include/linux/errno.h index 46685832ed9..2d09bfa5c26 100644 --- a/include/linux/errno.h +++ b/include/linux/errno.h @@ -16,6 +16,7 @@ #define ERESTARTNOHAND 514 /* restart if no handler.. */ #define ENOIOCTLCMD 515 /* No ioctl command */ #define ERESTART_RESTARTBLOCK 516 /* restart by calling sys_restart_syscall */ +#define EPROBE_DEFER 517 /* Driver requests probe retry */ /* Defined for the NFSv3 protocol */ #define EBADHANDLE 521 /* Illegal NFS file handle */ -- cgit v1.2.3-70-g09d2 From ef8a3fd6e5e12e8989dae97ba5491c2e39369af9 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 8 Mar 2012 12:17:22 -0800 Subject: driver core: move the deferred probe pointer into the private area Nothing outside of the driver core needs to get to the deferred probe pointer, so move it inside the private area of 'struct device' so no one tries to mess around with it. Cc: Grant Likely Signed-off-by: Greg Kroah-Hartman --- drivers/base/base.h | 5 +++++ drivers/base/core.c | 2 +- drivers/base/dd.c | 18 ++++++++++-------- include/linux/device.h | 5 ----- 4 files changed, 16 insertions(+), 14 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/base.h b/drivers/base/base.h index 2c13deae5f8..6ee17bb391a 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -59,6 +59,10 @@ struct driver_private { * @knode_parent - node in sibling list * @knode_driver - node in driver list * @knode_bus - node in bus list + * @deferred_probe - entry in deferred_probe_list which is used to retry the + * binding of drivers which were unable to get all the resources needed by + * the device; typically because it depends on another driver getting + * probed first. * @driver_data - private pointer for driver specific info. Will turn into a * list soon. * @device - pointer back to the struct class that this structure is @@ -71,6 +75,7 @@ struct device_private { struct klist_node knode_parent; struct klist_node knode_driver; struct klist_node knode_bus; + struct list_head deferred_probe; void *driver_data; struct device *device; }; diff --git a/drivers/base/core.c b/drivers/base/core.c index d4ff7adce38..7050a75dde3 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -644,7 +644,6 @@ void device_initialize(struct device *dev) { dev->kobj.kset = devices_kset; kobject_init(&dev->kobj, &device_ktype); - INIT_LIST_HEAD(&dev->deferred_probe); INIT_LIST_HEAD(&dev->dma_pools); mutex_init(&dev->mutex); lockdep_set_novalidate_class(&dev->mutex); @@ -922,6 +921,7 @@ int device_private_init(struct device *dev) dev->p->device = dev; klist_init(&dev->p->klist_children, klist_children_get, klist_children_put); + INIT_LIST_HEAD(&dev->p->deferred_probe); return 0; } diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 442b7641a08..9fa888e0805 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -45,7 +45,7 @@ * retry them. * * The deferred_probe_mutex must be held any time the deferred_probe_*_list - * of the (struct device*)->deferred_probe pointers are manipulated + * of the (struct device*)->p->deferred_probe pointers are manipulated */ static DEFINE_MUTEX(deferred_probe_mutex); static LIST_HEAD(deferred_probe_pending_list); @@ -58,6 +58,7 @@ static struct workqueue_struct *deferred_wq; static void deferred_probe_work_func(struct work_struct *work) { struct device *dev; + struct device_private *private; /* * This block processes every device in the deferred 'active' list. * Each device is removed from the active list and passed to @@ -72,9 +73,10 @@ static void deferred_probe_work_func(struct work_struct *work) */ mutex_lock(&deferred_probe_mutex); while (!list_empty(&deferred_probe_active_list)) { - dev = list_first_entry(&deferred_probe_active_list, - typeof(*dev), deferred_probe); - list_del_init(&dev->deferred_probe); + private = list_first_entry(&deferred_probe_active_list, + typeof(*dev->p), deferred_probe); + dev = private->device; + list_del_init(&private->deferred_probe); get_device(dev); @@ -94,9 +96,9 @@ static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func); static void driver_deferred_probe_add(struct device *dev) { mutex_lock(&deferred_probe_mutex); - if (list_empty(&dev->deferred_probe)) { + if (list_empty(&dev->p->deferred_probe)) { dev_dbg(dev, "Added to deferred list\n"); - list_add(&dev->deferred_probe, &deferred_probe_pending_list); + list_add(&dev->p->deferred_probe, &deferred_probe_pending_list); } mutex_unlock(&deferred_probe_mutex); } @@ -104,9 +106,9 @@ static void driver_deferred_probe_add(struct device *dev) void driver_deferred_probe_del(struct device *dev) { mutex_lock(&deferred_probe_mutex); - if (!list_empty(&dev->deferred_probe)) { + if (!list_empty(&dev->p->deferred_probe)) { dev_dbg(dev, "Removed from deferred list\n"); - list_del_init(&dev->deferred_probe); + list_del_init(&dev->p->deferred_probe); } mutex_unlock(&deferred_probe_mutex); } diff --git a/include/linux/device.h b/include/linux/device.h index 22d6938ddbb..f62e21689fd 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -585,10 +585,6 @@ struct device_dma_parameters { * @mutex: Mutex to synchronize calls to its driver. * @bus: Type of bus device is on. * @driver: Which driver has allocated this - * @deferred_probe: entry in deferred_probe_list which is used to retry the - * binding of drivers which were unable to get all the resources - * needed by the device; typically because it depends on another - * driver getting probed first. * @platform_data: Platform data specific to the device. * Example: For devices on custom boards, as typical of embedded * and SOC based hardware, Linux often uses platform_data to point @@ -648,7 +644,6 @@ struct device { struct bus_type *bus; /* type of bus device is on */ struct device_driver *driver; /* which driver has allocated this device */ - struct list_head deferred_probe; void *platform_data; /* Platform specific data, device core doesn't touch it */ struct dev_pm_info power; -- cgit v1.2.3-70-g09d2 From 8b0372a258e6bd0e9e5ea3f3d5f05a6bf3972fee Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 8 Mar 2012 12:20:37 -0800 Subject: driver core: minor comment formatting cleanups Came in in the deferred probe patch, quick, clean them up before a kernel janitor finds them and sends me 4 individual patches to fix them up... Cc: Grant Likely Signed-off-by: Greg Kroah-Hartman --- drivers/base/dd.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 9fa888e0805..1b1cbb571d3 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -80,8 +80,10 @@ static void deferred_probe_work_func(struct work_struct *work) get_device(dev); - /* Drop the mutex while probing each device; the probe path - * may manipulate the deferred list */ + /* + * Drop the mutex while probing each device; the probe path may + * manipulate the deferred list + */ mutex_unlock(&deferred_probe_mutex); dev_dbg(dev, "Retrying from deferred list\n"); bus_probe_device(dev); @@ -126,16 +128,20 @@ static void driver_deferred_probe_trigger(void) if (!driver_deferred_probe_enable) return; - /* A successful probe means that all the devices in the pending list + /* + * A successful probe means that all the devices in the pending list * should be triggered to be reprobed. Move all the deferred devices - * into the active list so they can be retried by the workqueue */ + * into the active list so they can be retried by the workqueue + */ mutex_lock(&deferred_probe_mutex); list_splice_tail_init(&deferred_probe_pending_list, &deferred_probe_active_list); mutex_unlock(&deferred_probe_mutex); - /* Kick the re-probe thread. It may already be scheduled, but - * it is safe to kick it again. */ + /* + * Kick the re-probe thread. It may already be scheduled, but it is + * safe to kick it again. + */ queue_work(deferred_wq, &deferred_probe_work); } @@ -171,8 +177,10 @@ static void driver_bound(struct device *dev) klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices); - /* Make sure the device is no longer in one of the deferred lists - * and kick off retrying all pending devices */ + /* + * Make sure the device is no longer in one of the deferred lists and + * kick off retrying all pending devices + */ driver_deferred_probe_del(dev); driver_deferred_probe_trigger(); -- cgit v1.2.3-70-g09d2