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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /drivers/mtd/devices/block2mtd.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'drivers/mtd/devices/block2mtd.c')
| -rw-r--r-- | drivers/mtd/devices/block2mtd.c | 532 |
1 files changed, 532 insertions, 0 deletions
diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c new file mode 100644 index 000000000..03e80b2c4 --- /dev/null +++ b/drivers/mtd/devices/block2mtd.c @@ -0,0 +1,532 @@ +/* + * block2mtd.c - create an mtd from a block device + * + * Copyright (C) 2001,2002 Simon Evans <spse@secret.org.uk> + * Copyright (C) 2004-2006 Joern Engel <joern@wh.fh-wedel.de> + * + * Licence: GPL + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +/* + * When the first attempt at device initialization fails, we may need to + * wait a little bit and retry. This timeout, by default 3 seconds, gives + * device time to start up. Required on BCM2708 and a few other chipsets. + */ +#define MTD_DEFAULT_TIMEOUT 3 + +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/fs.h> +#include <linux/blkdev.h> +#include <linux/backing-dev.h> +#include <linux/bio.h> +#include <linux/pagemap.h> +#include <linux/list.h> +#include <linux/init.h> +#include <linux/mtd/mtd.h> +#include <linux/mutex.h> +#include <linux/mount.h> +#include <linux/slab.h> +#include <linux/major.h> + +/* Maximum number of comma-separated items in the 'block2mtd=' parameter */ +#define BLOCK2MTD_PARAM_MAX_COUNT 3 + +/* Info for the block device */ +struct block2mtd_dev { + struct list_head list; + struct file *bdev_file; + struct mtd_info mtd; + struct mutex write_mutex; +}; + + +/* Static info about the MTD, used in cleanup_module */ +static LIST_HEAD(blkmtd_device_list); + + +static struct page *page_read(struct address_space *mapping, pgoff_t index) +{ + return read_mapping_page(mapping, index, NULL); +} + +/* erase a specified part of the device */ +static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len) +{ + struct address_space *mapping = dev->bdev_file->f_mapping; + struct page *page; + pgoff_t index = to >> PAGE_SHIFT; // page index + int pages = len >> PAGE_SHIFT; + u_long *p; + u_long *max; + + while (pages) { + page = page_read(mapping, index); + if (IS_ERR(page)) + return PTR_ERR(page); + + max = page_address(page) + PAGE_SIZE; + for (p=page_address(page); p<max; p++) + if (*p != -1UL) { + lock_page(page); + memset(page_address(page), 0xff, PAGE_SIZE); + set_page_dirty(page); + unlock_page(page); + balance_dirty_pages_ratelimited(mapping); + break; + } + + put_page(page); + pages--; + index++; + } + return 0; +} +static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr) +{ + struct block2mtd_dev *dev = mtd->priv; + size_t from = instr->addr; + size_t len = instr->len; + int err; + + mutex_lock(&dev->write_mutex); + err = _block2mtd_erase(dev, from, len); + mutex_unlock(&dev->write_mutex); + if (err) + pr_err("erase failed err = %d\n", err); + + return err; +} + + +static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len, + size_t *retlen, u_char *buf) +{ + struct block2mtd_dev *dev = mtd->priv; + struct address_space *mapping = dev->bdev_file->f_mapping; + struct page *page; + pgoff_t index = from >> PAGE_SHIFT; + int offset = from & (PAGE_SIZE-1); + int cpylen; + + while (len) { + if ((offset + len) > PAGE_SIZE) + cpylen = PAGE_SIZE - offset; // multiple pages + else + cpylen = len; // this page + len = len - cpylen; + + page = page_read(mapping, index); + if (IS_ERR(page)) + return PTR_ERR(page); + + memcpy(buf, page_address(page) + offset, cpylen); + put_page(page); + + if (retlen) + *retlen += cpylen; + buf += cpylen; + offset = 0; + index++; + } + return 0; +} + + +/* write data to the underlying device */ +static int _block2mtd_write(struct block2mtd_dev *dev, const u_char *buf, + loff_t to, size_t len, size_t *retlen) +{ + struct page *page; + struct address_space *mapping = dev->bdev_file->f_mapping; + pgoff_t index = to >> PAGE_SHIFT; // page index + int offset = to & ~PAGE_MASK; // page offset + int cpylen; + + while (len) { + if ((offset+len) > PAGE_SIZE) + cpylen = PAGE_SIZE - offset; // multiple pages + else + cpylen = len; // this page + len = len - cpylen; + + page = page_read(mapping, index); + if (IS_ERR(page)) + return PTR_ERR(page); + + if (memcmp(page_address(page)+offset, buf, cpylen)) { + lock_page(page); + memcpy(page_address(page) + offset, buf, cpylen); + set_page_dirty(page); + unlock_page(page); + balance_dirty_pages_ratelimited(mapping); + } + put_page(page); + + if (retlen) + *retlen += cpylen; + + buf += cpylen; + offset = 0; + index++; + } + return 0; +} + + +static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len, + size_t *retlen, const u_char *buf) +{ + struct block2mtd_dev *dev = mtd->priv; + int err; + + mutex_lock(&dev->write_mutex); + err = _block2mtd_write(dev, buf, to, len, retlen); + mutex_unlock(&dev->write_mutex); + if (err > 0) + err = 0; + return err; +} + + +/* sync the device - wait until the write queue is empty */ +static void block2mtd_sync(struct mtd_info *mtd) +{ + struct block2mtd_dev *dev = mtd->priv; + sync_blockdev(file_bdev(dev->bdev_file)); + return; +} + + +static void block2mtd_free_device(struct block2mtd_dev *dev) +{ + if (!dev) + return; + + kfree(dev->mtd.name); + + if (dev->bdev_file) { + invalidate_mapping_pages(dev->bdev_file->f_mapping, 0, -1); + bdev_fput(dev->bdev_file); + } + + kfree(dev); +} + +/* + * This function is marked __ref because it calls the __init marked + * early_lookup_bdev when called from the early boot code. + */ +static struct file __ref *mdtblock_early_get_bdev(const char *devname, + blk_mode_t mode, int timeout, struct block2mtd_dev *dev) +{ + struct file *bdev_file = ERR_PTR(-ENODEV); +#ifndef MODULE + int i; + + /* + * We can't use early_lookup_bdev from a running system. + */ + if (system_state >= SYSTEM_RUNNING) + return bdev_file; + + /* + * We might not have the root device mounted at this point. + * Try to resolve the device name by other means. + */ + for (i = 0; i <= timeout; i++) { + dev_t devt; + + if (i) + /* + * Calling wait_for_device_probe in the first loop + * was not enough, sleep for a bit in subsequent + * go-arounds. + */ + msleep(1000); + wait_for_device_probe(); + + if (!early_lookup_bdev(devname, &devt)) { + bdev_file = bdev_file_open_by_dev(devt, mode, dev, NULL); + if (!IS_ERR(bdev_file)) + break; + } + } +#endif + return bdev_file; +} + +static struct block2mtd_dev *add_device(char *devname, int erase_size, + char *label, int timeout) +{ + const blk_mode_t mode = BLK_OPEN_READ | BLK_OPEN_WRITE; + struct file *bdev_file; + struct block_device *bdev; + struct block2mtd_dev *dev; + loff_t size; + char *name; + + if (!devname) + return NULL; + + dev = kzalloc_obj(struct block2mtd_dev); + if (!dev) + return NULL; + + /* Get a handle on the device */ + bdev_file = bdev_file_open_by_path(devname, mode, dev, NULL); + if (IS_ERR(bdev_file)) + bdev_file = mdtblock_early_get_bdev(devname, mode, timeout, + dev); + if (IS_ERR(bdev_file)) { + pr_err("error: cannot open device %s\n", devname); + goto err_free_block2mtd; + } + dev->bdev_file = bdev_file; + bdev = file_bdev(bdev_file); + + if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) { + pr_err("attempting to use an MTD device as a block device\n"); + goto err_free_block2mtd; + } + + size = bdev_nr_bytes(bdev); + if ((long)size % erase_size) { + pr_err("erasesize must be a divisor of device size\n"); + goto err_free_block2mtd; + } + + mutex_init(&dev->write_mutex); + + /* Setup the MTD structure */ + /* make the name contain the block device in */ + if (!label) + name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname); + else + name = kstrdup(label, GFP_KERNEL); + if (!name) + goto err_destroy_mutex; + + dev->mtd.name = name; + + dev->mtd.size = size & PAGE_MASK; + dev->mtd.erasesize = erase_size; + dev->mtd.writesize = 1; + dev->mtd.writebufsize = PAGE_SIZE; + dev->mtd.type = MTD_RAM; + dev->mtd.flags = MTD_CAP_RAM; + dev->mtd._erase = block2mtd_erase; + dev->mtd._write = block2mtd_write; + dev->mtd._sync = block2mtd_sync; + dev->mtd._read = block2mtd_read; + dev->mtd.priv = dev; + dev->mtd.owner = THIS_MODULE; + + if (mtd_device_register(&dev->mtd, NULL, 0)) { + /* Device didn't get added, so free the entry */ + goto err_destroy_mutex; + } + + list_add(&dev->list, &blkmtd_device_list); + pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n", + dev->mtd.index, + label ? label : dev->mtd.name + strlen("block2mtd: "), + dev->mtd.erasesize >> 10, dev->mtd.erasesize); + return dev; + +err_destroy_mutex: + mutex_destroy(&dev->write_mutex); +err_free_block2mtd: + block2mtd_free_device(dev); + return NULL; +} + + +/* This function works similar to reguler strtoul. In addition, it + * allows some suffixes for a more human-readable number format: + * ki, Ki, kiB, KiB - multiply result with 1024 + * Mi, MiB - multiply result with 1024^2 + * Gi, GiB - multiply result with 1024^3 + */ +static int ustrtoul(const char *cp, char **endp, unsigned int base) +{ + unsigned long result = simple_strtoul(cp, endp, base); + switch (**endp) { + case 'G' : + result *= 1024; + fallthrough; + case 'M': + result *= 1024; + fallthrough; + case 'K': + case 'k': + result *= 1024; + /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ + if ((*endp)[1] == 'i') { + if ((*endp)[2] == 'B') + (*endp) += 3; + else + (*endp) += 2; + } + } + return result; +} + + +static int parse_num(size_t *num, const char *token) +{ + char *endp; + size_t n; + + n = (size_t) ustrtoul(token, &endp, 0); + if (*endp) + return -EINVAL; + + *num = n; + return 0; +} + + +static inline void kill_final_newline(char *str) +{ + char *newline = strrchr(str, '\n'); + if (newline && !newline[1]) + *newline = 0; +} + + +#ifndef MODULE +static int block2mtd_init_called = 0; +/* 80 for device, 12 for erase size */ +static char block2mtd_paramline[80 + 12]; +#endif + +static int block2mtd_setup2(const char *val) +{ + /* 80 for device, 12 for erase size, 80 for name, 8 for timeout */ + char buf[80 + 12 + 80 + 8]; + char *str = buf; + char *token[BLOCK2MTD_PARAM_MAX_COUNT]; + char *name; + char *label = NULL; + size_t erase_size = PAGE_SIZE; + unsigned long timeout = MTD_DEFAULT_TIMEOUT; + int i, ret; + + if (strnlen(val, sizeof(buf)) >= sizeof(buf)) { + pr_err("parameter too long\n"); + return 0; + } + + strcpy(str, val); + kill_final_newline(str); + + for (i = 0; i < BLOCK2MTD_PARAM_MAX_COUNT; i++) + token[i] = strsep(&str, ","); + + if (str) { + pr_err("too many arguments\n"); + return 0; + } + + if (!token[0]) { + pr_err("no argument\n"); + return 0; + } + + name = token[0]; + if (strlen(name) + 1 > 80) { + pr_err("device name too long\n"); + return 0; + } + + /* Optional argument when custom label is used */ + if (token[1] && strlen(token[1])) { + ret = parse_num(&erase_size, token[1]); + if (ret) { + pr_err("illegal erase size\n"); + return 0; + } + } + + if (token[2]) { + label = token[2]; + pr_info("Using custom MTD label '%s' for dev %s\n", label, name); + } + + add_device(name, erase_size, label, timeout); + + return 0; +} + + +static int block2mtd_setup(const char *val, const struct kernel_param *kp) +{ +#ifdef MODULE + return block2mtd_setup2(val); +#else + /* If more parameters are later passed in via + /sys/module/block2mtd/parameters/block2mtd + and block2mtd_init() has already been called, + we can parse the argument now. */ + + if (block2mtd_init_called) + return block2mtd_setup2(val); + + /* During early boot stage, we only save the parameters + here. We must parse them later: if the param passed + from kernel boot command line, block2mtd_setup() is + called so early that it is not possible to resolve + the device (even kmalloc() fails). Deter that work to + block2mtd_setup2(). */ + + strscpy(block2mtd_paramline, val, sizeof(block2mtd_paramline)); + + return 0; +#endif +} + + +module_param_call(block2mtd, block2mtd_setup, NULL, NULL, 0200); +MODULE_PARM_DESC(block2mtd, "Device to use. \"block2mtd=<dev>[,[<erasesize>][,<label>]]\""); + +static int __init block2mtd_init(void) +{ + int ret = 0; + +#ifndef MODULE + if (strlen(block2mtd_paramline)) + ret = block2mtd_setup2(block2mtd_paramline); + block2mtd_init_called = 1; +#endif + + return ret; +} + + +static void block2mtd_exit(void) +{ + struct list_head *pos, *next; + + /* Remove the MTD devices */ + list_for_each_safe(pos, next, &blkmtd_device_list) { + struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list); + block2mtd_sync(&dev->mtd); + mtd_device_unregister(&dev->mtd); + mutex_destroy(&dev->write_mutex); + pr_info("mtd%d: [%s] removed\n", + dev->mtd.index, + dev->mtd.name + strlen("block2mtd: ")); + list_del(&dev->list); + block2mtd_free_device(dev); + } +} + +late_initcall(block2mtd_init); +module_exit(block2mtd_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joern Engel <joern@lazybastard.org>"); +MODULE_DESCRIPTION("Emulate an MTD using a block device"); |
