From: David Brownell Date: Thu, 26 Mar 2009 07:42:41 +0000 (-0700) Subject: [MTD] driver model updates X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1f24b5a8ecbb2a3c7080f418974d40e3ffedb221;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git [MTD] driver model updates Update driver model support in the MTD framework, so it fits better into the current udev-based hotplug framework: - Each mtd_info now has a device node. MTD drivers should set the dev.parent field to point to the physical device, before setting up partitions or otherwise declaring MTDs. - Those device nodes always map to /sys/class/mtdX device nodes, which no longer depend on MTD_CHARDEV. - Those mtdX sysfs nodes have a "starter set" of attributes; it's not yet sufficient to replace /proc/mtd. - Enabling MTD_CHARDEV provides /sys/class/mtdXro/ nodes and the /sys/class/mtd*/dev attributes (for udev, mdev, etc). - Include a MODULE_ALIAS_CHARDEV_MAJOR macro. It'll work with udev creating the /dev/mtd* nodes, not just a static rootfs. So the sysfs structure is pretty much what you'd expect, except that readonly chardev nodes are a bit quirky. Signed-off-by: David Brownell Signed-off-by: David Woodhouse --- diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index 4109e0bb94f5..a49a9c8f2cb1 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -286,6 +286,7 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) gd->private_data = new; new->blkcore_priv = gd; gd->queue = tr->blkcore_priv->rq; + gd->driverfs_dev = new->mtd->dev.parent; if (new->readonly) set_disk_ro(gd, 1); diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c index f478f1fc3949..763d3f0a1f42 100644 --- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -20,33 +20,6 @@ #include -static struct class *mtd_class; - -static void mtd_notify_add(struct mtd_info* mtd) -{ - if (!mtd) - return; - - device_create(mtd_class, NULL, MKDEV(MTD_CHAR_MAJOR, mtd->index*2), - NULL, "mtd%d", mtd->index); - - device_create(mtd_class, NULL, MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1), - NULL, "mtd%dro", mtd->index); -} - -static void mtd_notify_remove(struct mtd_info* mtd) -{ - if (!mtd) - return; - - device_destroy(mtd_class, MKDEV(MTD_CHAR_MAJOR, mtd->index*2)); - device_destroy(mtd_class, MKDEV(MTD_CHAR_MAJOR, mtd->index*2+1)); -} - -static struct mtd_notifier notifier = { - .add = mtd_notify_add, - .remove = mtd_notify_remove, -}; /* * Data structure to hold the pointer to the mtd device as well @@ -854,34 +827,26 @@ static const struct file_operations mtd_fops = { static int __init init_mtdchar(void) { - if (register_chrdev(MTD_CHAR_MAJOR, "mtd", &mtd_fops)) { + int status; + + status = register_chrdev(MTD_CHAR_MAJOR, "mtd", &mtd_fops); + if (status < 0) { printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n", MTD_CHAR_MAJOR); - return -EAGAIN; - } - - mtd_class = class_create(THIS_MODULE, "mtd"); - - if (IS_ERR(mtd_class)) { - printk(KERN_ERR "Error creating mtd class.\n"); - unregister_chrdev(MTD_CHAR_MAJOR, "mtd"); - return PTR_ERR(mtd_class); } - register_mtd_user(¬ifier); - return 0; + return status; } static void __exit cleanup_mtdchar(void) { - unregister_mtd_user(¬ifier); - class_destroy(mtd_class); unregister_chrdev(MTD_CHAR_MAJOR, "mtd"); } module_init(init_mtdchar); module_exit(cleanup_mtdchar); +MODULE_ALIAS_CHARDEV_MAJOR(MTD_CHAR_MAJOR); MODULE_LICENSE("GPL"); MODULE_AUTHOR("David Woodhouse "); diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 65a7f3703881..a88f8bc9a534 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -23,6 +23,9 @@ #include "mtdcore.h" + +static struct class *mtd_class; + /* These are exported solely for the purpose of mtd_blkdevs.c. You should not use them for _anything_ else */ DEFINE_MUTEX(mtd_table_mutex); @@ -33,6 +36,82 @@ EXPORT_SYMBOL_GPL(mtd_table); static LIST_HEAD(mtd_notifiers); + +#if defined(CONFIG_MTD_CHAR) || defined(CONFIG_MTD_CHAR_MODULE) +#define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2) +#else +#define MTD_DEVT(index) 0 +#endif + +/* REVISIT once MTD uses the driver model better, whoever allocates + * the mtd_info will probably want to use the release() hook... + */ +static void mtd_release(struct device *dev) +{ + struct mtd_info *mtd = dev_to_mtd(dev); + + /* remove /dev/mtdXro node if needed */ + if (MTD_DEVT(mtd->index)) + device_destroy(mtd_class, MTD_DEVT(mtd->index) + 1); +} + +static ssize_t mtd_type_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct mtd_info *mtd = dev_to_mtd(dev); + char *type; + + switch (mtd->type) { + case MTD_ABSENT: + type = "absent"; + break; + case MTD_RAM: + type = "ram"; + break; + case MTD_ROM: + type = "rom"; + break; + case MTD_NORFLASH: + type = "nor"; + break; + case MTD_NANDFLASH: + type = "nand"; + break; + case MTD_DATAFLASH: + type = "dataflash"; + break; + case MTD_UBIVOLUME: + type = "ubi"; + break; + default: + type = "unknown"; + } + + return snprintf(buf, PAGE_SIZE, "%s\n", type); +} +static DEVICE_ATTR(mtd_type, S_IRUGO, mtd_type_show, NULL); + +static struct attribute *mtd_attrs[] = { + &dev_attr_mtd_type.attr, + /* FIXME provide a /proc/mtd superset */ + NULL, +}; + +struct attribute_group mtd_group = { + .attrs = mtd_attrs, +}; + +struct attribute_group *mtd_groups[] = { + &mtd_group, + NULL, +}; + +static struct device_type mtd_devtype = { + .name = "mtd", + .groups = mtd_groups, + .release = mtd_release, +}; + /** * add_mtd_device - register an MTD device * @mtd: pointer to new MTD device info structure @@ -41,6 +120,7 @@ static LIST_HEAD(mtd_notifiers); * notify each currently active MTD 'user' of its arrival. Returns * zero on success or 1 on failure, which currently will only happen * if the number of present devices exceeds MAX_MTD_DEVICES (i.e. 16) + * or there's a sysfs error. */ int add_mtd_device(struct mtd_info *mtd) @@ -95,6 +175,23 @@ int add_mtd_device(struct mtd_info *mtd) mtd->name); } + /* Caller should have set dev.parent to match the + * physical device. + */ + mtd->dev.type = &mtd_devtype; + mtd->dev.class = mtd_class; + mtd->dev.devt = MTD_DEVT(i); + dev_set_name(&mtd->dev, "mtd%d", i); + if (device_register(&mtd->dev) != 0) { + mtd_table[i] = NULL; + break; + } + + if (MTD_DEVT(i)) + device_create(mtd_class, mtd->dev.parent, + MTD_DEVT(i) + 1, + NULL, "mtd%dro", i); + DEBUG(0, "mtd: Giving out device %d to %s\n",i, mtd->name); /* No need to get a refcount on the module containing the notifier, since we hold the mtd_table_mutex */ @@ -358,6 +455,24 @@ EXPORT_SYMBOL_GPL(register_mtd_user); EXPORT_SYMBOL_GPL(unregister_mtd_user); EXPORT_SYMBOL_GPL(default_mtd_writev); +static int __init mtd_setup(void) +{ + mtd_class = class_create(THIS_MODULE, "mtd"); + + if (IS_ERR(mtd_class)) { + pr_err("Error creating mtd class.\n"); + return PTR_ERR(mtd_class); + } + return 0; +} +core_initcall(mtd_setup); + +static void __exit mtd_teardown(void) +{ + class_destroy(mtd_class); +} +__exitcall(mtd_teardown); + #ifdef CONFIG_PROC_FS /*====================================================================*/ diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index 06d5b9d8853a..02ce38fb1fc3 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -356,6 +356,11 @@ static struct mtd_part *add_one_partition(struct mtd_info *master, slave->mtd.owner = master->owner; slave->mtd.backing_dev_info = master->backing_dev_info; + /* NOTE: we don't arrange MTDs as a tree; it'd be error-prone + * to have the same data be in two different partitions. + */ + slave->mtd.dev.parent = master->dev.parent; + slave->mtd.read = part_read; slave->mtd.write = part_write; @@ -508,7 +513,9 @@ out_register: * This function, given a master MTD object and a partition table, creates * and registers slave MTD objects which are bound to the master according to * the partition definitions. - * (Q: should we register the master MTD object as well?) + * + * We don't register the master, or expect the caller to have done so, + * for reasons of data integrity. */ int add_mtd_partitions(struct mtd_info *master, diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index 0c079fd307a5..5675b63a0631 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -11,6 +11,7 @@ #include #include #include +#include #include #include @@ -237,6 +238,7 @@ struct mtd_info { void *priv; struct module *owner; + struct device dev; int usecount; /* If the driver is something smart, like UBI, it may need to maintain @@ -247,6 +249,11 @@ struct mtd_info { void (*put_device) (struct mtd_info *mtd); }; +static inline struct mtd_info *dev_to_mtd(struct device *dev) +{ + return dev ? container_of(dev, struct mtd_info, dev) : NULL; +} + static inline uint32_t mtd_div_by_eb(uint64_t sz, struct mtd_info *mtd) { if (mtd->erasesize_shift)