| // SPDX-License-Identifier: GPL-2.0 |
| // |
| // Register map access API - debugfs |
| // |
| // Copyright 2011 Wolfson Microelectronics plc |
| // |
| // Author: Mark Brown <broonie@opensource.wolfsonmicro.com> |
| |
| #include <linux/slab.h> |
| #include <linux/mutex.h> |
| #include <linux/debugfs.h> |
| #include <linux/uaccess.h> |
| #include <linux/device.h> |
| #include <linux/list.h> |
| |
| #include "internal.h" |
| |
| struct regmap_debugfs_node { |
| struct regmap *map; |
| struct list_head link; |
| }; |
| |
| static unsigned int dummy_index; |
| static struct dentry *regmap_debugfs_root; |
| static LIST_HEAD(regmap_debugfs_early_list); |
| static DEFINE_MUTEX(regmap_debugfs_early_lock); |
| |
| /* Calculate the length of a fixed format */ |
| static size_t regmap_calc_reg_len(int max_val) |
| { |
| return snprintf(NULL, 0, "%x", max_val); |
| } |
| |
| static ssize_t regmap_name_read_file(struct file *file, |
| char __user *user_buf, size_t count, |
| loff_t *ppos) |
| { |
| struct regmap *map = file->private_data; |
| const char *name = "nodev"; |
| int ret; |
| char *buf; |
| |
| buf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| if (!buf) |
| return -ENOMEM; |
| |
| if (map->dev && map->dev->driver) |
| name = map->dev->driver->name; |
| |
| ret = snprintf(buf, PAGE_SIZE, "%s\n", name); |
| if (ret >= PAGE_SIZE) { |
| kfree(buf); |
| return ret; |
| } |
| |
| ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret); |
| kfree(buf); |
| return ret; |
| } |
| |
| static const struct file_operations regmap_name_fops = { |
| .open = simple_open, |
| .read = regmap_name_read_file, |
| .llseek = default_llseek, |
| }; |
| |
| static void regmap_debugfs_free_dump_cache(struct regmap *map) |
| { |
| struct regmap_debugfs_off_cache *c; |
| |
| while (!list_empty(&map->debugfs_off_cache)) { |
| c = list_first_entry(&map->debugfs_off_cache, |
| struct regmap_debugfs_off_cache, |
| list); |
| list_del(&c->list); |
| kfree(c); |
| } |
| } |
| |
| static bool regmap_printable(struct regmap *map, unsigned int reg) |
| { |
| if (regmap_precious(map, reg)) |
| return false; |
| |
| if (!regmap_readable(map, reg) && !regmap_cached(map, reg)) |
| return false; |
| |
| return true; |
| } |
| |
| /* |
| * Work out where the start offset maps into register numbers, bearing |
| * in mind that we suppress hidden registers. |
| */ |
| static unsigned int regmap_debugfs_get_dump_start(struct regmap *map, |
| unsigned int base, |
| loff_t from, |
| loff_t *pos) |
| { |
| struct regmap_debugfs_off_cache *c = NULL; |
| loff_t p = 0; |
| unsigned int i, ret; |
| unsigned int fpos_offset; |
| unsigned int reg_offset; |
| |
| /* Suppress the cache if we're using a subrange */ |
| if (base) |
| return base; |
| |
| /* |
| * If we don't have a cache build one so we don't have to do a |
| * linear scan each time. |
| */ |
| mutex_lock(&map->cache_lock); |
| i = base; |
| if (list_empty(&map->debugfs_off_cache)) { |
| for (; i <= map->max_register; i += map->reg_stride) { |
| /* Skip unprinted registers, closing off cache entry */ |
| if (!regmap_printable(map, i)) { |
| if (c) { |
| c->max = p - 1; |
| c->max_reg = i - map->reg_stride; |
| list_add_tail(&c->list, |
| &map->debugfs_off_cache); |
| c = NULL; |
| } |
| |
| continue; |
| } |
| |
| /* No cache entry? Start a new one */ |
| if (!c) { |
| c = kzalloc(sizeof(*c), GFP_KERNEL); |
| if (!c) { |
| regmap_debugfs_free_dump_cache(map); |
| mutex_unlock(&map->cache_lock); |
| return base; |
| } |
| c->min = p; |
| c->base_reg = i; |
| } |
| |
| p += map->debugfs_tot_len; |
| } |
| } |
| |
| /* Close the last entry off if we didn't scan beyond it */ |
| if (c) { |
| c->max = p - 1; |
| c->max_reg = i - map->reg_stride; |
| list_add_tail(&c->list, |
| &map->debugfs_off_cache); |
| } |
| |
| /* |
| * This should never happen; we return above if we fail to |
| * allocate and we should never be in this code if there are |
| * no registers at all. |
| */ |
| WARN_ON(list_empty(&map->debugfs_off_cache)); |
| ret = base; |
| |
| /* Find the relevant block:offset */ |
| list_for_each_entry(c, &map->debugfs_off_cache, list) { |
| if (from >= c->min && from <= c->max) { |
| fpos_offset = from - c->min; |
| reg_offset = fpos_offset / map->debugfs_tot_len; |
| *pos = c->min + (reg_offset * map->debugfs_tot_len); |
| mutex_unlock(&map->cache_lock); |
| return c->base_reg + (reg_offset * map->reg_stride); |
| } |
| |
| *pos = c->max; |
| ret = c->max_reg; |
| } |
| mutex_unlock(&map->cache_lock); |
| |
| return ret; |
| } |
| |
| static inline void regmap_calc_tot_len(struct regmap *map, |
| void *buf, size_t count) |
| { |
| /* Calculate the length of a fixed format */ |
| if (!map->debugfs_tot_len) { |
| map->debugfs_reg_len = regmap_calc_reg_len(map->max_register); |
| map->debugfs_val_len = 2 * map->format.val_bytes; |
| map->debugfs_tot_len = map->debugfs_reg_len + |
| map->debugfs_val_len + 3; /* : \n */ |
| } |
| } |
| |
| static int regmap_next_readable_reg(struct regmap *map, int reg) |
| { |
| struct regmap_debugfs_off_cache *c; |
| int ret = -EINVAL; |
| |
| if (regmap_printable(map, reg + map->reg_stride)) { |
| ret = reg + map->reg_stride; |
| } else { |
| mutex_lock(&map->cache_lock); |
| list_for_each_entry(c, &map->debugfs_off_cache, list) { |
| if (reg > c->max_reg) |
| continue; |
| if (reg < c->base_reg) { |
| ret = c->base_reg; |
| break; |
| } |
| } |
| mutex_unlock(&map->cache_lock); |
| } |
| return ret; |
| } |
| |
| static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from, |
| unsigned int to, char __user *user_buf, |
| size_t count, loff_t *ppos) |
| { |
| size_t buf_pos = 0; |
| loff_t p = *ppos; |
| ssize_t ret; |
| int i; |
| char *buf; |
| unsigned int val, start_reg; |
| |
| if (*ppos < 0 || !count) |
| return -EINVAL; |
| |
| if (count > (PAGE_SIZE << (MAX_ORDER - 1))) |
| count = PAGE_SIZE << (MAX_ORDER - 1); |
| |
| buf = kmalloc(count, GFP_KERNEL); |
| if (!buf) |
| return -ENOMEM; |
| |
| regmap_calc_tot_len(map, buf, count); |
| |
| /* Work out which register we're starting at */ |
| start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p); |
| |
| for (i = start_reg; i >= 0 && i <= to; |
| i = regmap_next_readable_reg(map, i)) { |
| |
| /* If we're in the region the user is trying to read */ |
| if (p >= *ppos) { |
| /* ...but not beyond it */ |
| if (buf_pos + map->debugfs_tot_len > count) |
| break; |
| |
| /* Format the register */ |
| snprintf(buf + buf_pos, count - buf_pos, "%.*x: ", |
| map->debugfs_reg_len, i - from); |
| buf_pos += map->debugfs_reg_len + 2; |
| |
| /* Format the value, write all X if we can't read */ |
| ret = regmap_read(map, i, &val); |
| if (ret == 0) |
| snprintf(buf + buf_pos, count - buf_pos, |
| "%.*x", map->debugfs_val_len, val); |
| else |
| memset(buf + buf_pos, 'X', |
| map->debugfs_val_len); |
| buf_pos += 2 * map->format.val_bytes; |
| |
| buf[buf_pos++] = '\n'; |
| } |
| p += map->debugfs_tot_len; |
| } |
| |
| ret = buf_pos; |
| |
| if (copy_to_user(user_buf, buf, buf_pos)) { |
| ret = -EFAULT; |
| goto out; |
| } |
| |
| *ppos += buf_pos; |
| |
| out: |
| kfree(buf); |
| return ret; |
| } |
| |
| static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf, |
| size_t count, loff_t *ppos) |
| { |
| struct regmap *map = file->private_data; |
| |
| return regmap_read_debugfs(map, 0, map->max_register, user_buf, |
| count, ppos); |
| } |
| |
| #undef REGMAP_ALLOW_WRITE_DEBUGFS |
| #ifdef REGMAP_ALLOW_WRITE_DEBUGFS |
| /* |
| * This can be dangerous especially when we have clients such as |
| * PMICs, therefore don't provide any real compile time configuration option |
| * for this feature, people who want to use this will need to modify |
| * the source code directly. |
| */ |
| static ssize_t regmap_map_write_file(struct file *file, |
| const char __user *user_buf, |
| size_t count, loff_t *ppos) |
| { |
| char buf[32]; |
| size_t buf_size; |
| char *start = buf; |
| unsigned long reg, value; |
| struct regmap *map = file->private_data; |
| int ret; |
| |
| buf_size = min(count, (sizeof(buf)-1)); |
| if (copy_from_user(buf, user_buf, buf_size)) |
| return -EFAULT; |
| buf[buf_size] = 0; |
| |
| while (*start == ' ') |
| start++; |
| reg = simple_strtoul(start, &start, 16); |
| while (*start == ' ') |
| start++; |
| if (kstrtoul(start, 16, &value)) |
| return -EINVAL; |
| |
| /* Userspace has been fiddling around behind the kernel's back */ |
| add_taint(TAINT_USER, LOCKDEP_STILL_OK); |
| |
| ret = regmap_write(map, reg, value); |
| if (ret < 0) |
| return ret; |
| return buf_size; |
| } |
| #else |
| #define regmap_map_write_file NULL |
| #endif |
| |
| static const struct file_operations regmap_map_fops = { |
| .open = simple_open, |
| .read = regmap_map_read_file, |
| .write = regmap_map_write_file, |
| .llseek = default_llseek, |
| }; |
| |
| static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf, |
| size_t count, loff_t *ppos) |
| { |
| struct regmap_range_node *range = file->private_data; |
| struct regmap *map = range->map; |
| |
| return regmap_read_debugfs(map, range->range_min, range->range_max, |
| user_buf, count, ppos); |
| } |
| |
| static const struct file_operations regmap_range_fops = { |
| .open = simple_open, |
| .read = regmap_range_read_file, |
| .llseek = default_llseek, |
| }; |
| |
| static ssize_t regmap_reg_ranges_read_file(struct file *file, |
| char __user *user_buf, size_t count, |
| loff_t *ppos) |
| { |
| struct regmap *map = file->private_data; |
| struct regmap_debugfs_off_cache *c; |
| loff_t p = 0; |
| size_t buf_pos = 0; |
| char *buf; |
| char *entry; |
| int ret; |
| unsigned int entry_len; |
| |
| if (*ppos < 0 || !count) |
| return -EINVAL; |
| |
| if (count > (PAGE_SIZE << (MAX_ORDER - 1))) |
| count = PAGE_SIZE << (MAX_ORDER - 1); |
| |
| buf = kmalloc(count, GFP_KERNEL); |
| if (!buf) |
| return -ENOMEM; |
| |
| entry = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| if (!entry) { |
| kfree(buf); |
| return -ENOMEM; |
| } |
| |
| /* While we are at it, build the register dump cache |
| * now so the read() operation on the `registers' file |
| * can benefit from using the cache. We do not care |
| * about the file position information that is contained |
| * in the cache, just about the actual register blocks */ |
| regmap_calc_tot_len(map, buf, count); |
| regmap_debugfs_get_dump_start(map, 0, *ppos, &p); |
| |
| /* Reset file pointer as the fixed-format of the `registers' |
| * file is not compatible with the `range' file */ |
| p = 0; |
| mutex_lock(&map->cache_lock); |
| list_for_each_entry(c, &map->debugfs_off_cache, list) { |
| entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n", |
| c->base_reg, c->max_reg); |
| if (p >= *ppos) { |
| if (buf_pos + entry_len > count) |
| break; |
| memcpy(buf + buf_pos, entry, entry_len); |
| buf_pos += entry_len; |
| } |
| p += entry_len; |
| } |
| mutex_unlock(&map->cache_lock); |
| |
| kfree(entry); |
| ret = buf_pos; |
| |
| if (copy_to_user(user_buf, buf, buf_pos)) { |
| ret = -EFAULT; |
| goto out_buf; |
| } |
| |
| *ppos += buf_pos; |
| out_buf: |
| kfree(buf); |
| return ret; |
| } |
| |
| static const struct file_operations regmap_reg_ranges_fops = { |
| .open = simple_open, |
| .read = regmap_reg_ranges_read_file, |
| .llseek = default_llseek, |
| }; |
| |
| static int regmap_access_show(struct seq_file *s, void *ignored) |
| { |
| struct regmap *map = s->private; |
| int i, reg_len; |
| |
| reg_len = regmap_calc_reg_len(map->max_register); |
| |
| for (i = 0; i <= map->max_register; i += map->reg_stride) { |
| /* Ignore registers which are neither readable nor writable */ |
| if (!regmap_readable(map, i) && !regmap_writeable(map, i)) |
| continue; |
| |
| /* Format the register */ |
| seq_printf(s, "%.*x: %c %c %c %c\n", reg_len, i, |
| regmap_readable(map, i) ? 'y' : 'n', |
| regmap_writeable(map, i) ? 'y' : 'n', |
| regmap_volatile(map, i) ? 'y' : 'n', |
| regmap_precious(map, i) ? 'y' : 'n'); |
| } |
| |
| return 0; |
| } |
| |
| DEFINE_SHOW_ATTRIBUTE(regmap_access); |
| |
| static ssize_t regmap_cache_only_write_file(struct file *file, |
| const char __user *user_buf, |
| size_t count, loff_t *ppos) |
| { |
| struct regmap *map = container_of(file->private_data, |
| struct regmap, cache_only); |
| bool new_val, require_sync = false; |
| int err; |
| |
| err = kstrtobool_from_user(user_buf, count, &new_val); |
| /* Ignore malforned data like debugfs_write_file_bool() */ |
| if (err) |
| return count; |
| |
| err = debugfs_file_get(file->f_path.dentry); |
| if (err) |
| return err; |
| |
| map->lock(map->lock_arg); |
| |
| if (new_val && !map->cache_only) { |
| dev_warn(map->dev, "debugfs cache_only=Y forced\n"); |
| add_taint(TAINT_USER, LOCKDEP_STILL_OK); |
| } else if (!new_val && map->cache_only) { |
| dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n"); |
| require_sync = true; |
| } |
| map->cache_only = new_val; |
| |
| map->unlock(map->lock_arg); |
| debugfs_file_put(file->f_path.dentry); |
| |
| if (require_sync) { |
| err = regcache_sync(map); |
| if (err) |
| dev_err(map->dev, "Failed to sync cache %d\n", err); |
| } |
| |
| return count; |
| } |
| |
| static const struct file_operations regmap_cache_only_fops = { |
| .open = simple_open, |
| .read = debugfs_read_file_bool, |
| .write = regmap_cache_only_write_file, |
| }; |
| |
| static ssize_t regmap_cache_bypass_write_file(struct file *file, |
| const char __user *user_buf, |
| size_t count, loff_t *ppos) |
| { |
| struct regmap *map = container_of(file->private_data, |
| struct regmap, cache_bypass); |
| bool new_val; |
| int err; |
| |
| err = kstrtobool_from_user(user_buf, count, &new_val); |
| /* Ignore malforned data like debugfs_write_file_bool() */ |
| if (err) |
| return count; |
| |
| err = debugfs_file_get(file->f_path.dentry); |
| if (err) |
| return err; |
| |
| map->lock(map->lock_arg); |
| |
| if (new_val && !map->cache_bypass) { |
| dev_warn(map->dev, "debugfs cache_bypass=Y forced\n"); |
| add_taint(TAINT_USER, LOCKDEP_STILL_OK); |
| } else if (!new_val && map->cache_bypass) { |
| dev_warn(map->dev, "debugfs cache_bypass=N forced\n"); |
| } |
| map->cache_bypass = new_val; |
| |
| map->unlock(map->lock_arg); |
| debugfs_file_put(file->f_path.dentry); |
| |
| return count; |
| } |
| |
| static const struct file_operations regmap_cache_bypass_fops = { |
| .open = simple_open, |
| .read = debugfs_read_file_bool, |
| .write = regmap_cache_bypass_write_file, |
| }; |
| |
| void regmap_debugfs_init(struct regmap *map) |
| { |
| struct rb_node *next; |
| struct regmap_range_node *range_node; |
| const char *devname = "dummy"; |
| const char *name = map->name; |
| |
| /* |
| * Userspace can initiate reads from the hardware over debugfs. |
| * Normally internal regmap structures and buffers are protected with |
| * a mutex or a spinlock, but if the regmap owner decided to disable |
| * all locking mechanisms, this is no longer the case. For safety: |
| * don't create the debugfs entries if locking is disabled. |
| */ |
| if (map->debugfs_disable) { |
| dev_dbg(map->dev, "regmap locking disabled - not creating debugfs entries\n"); |
| return; |
| } |
| |
| /* If we don't have the debugfs root yet, postpone init */ |
| if (!regmap_debugfs_root) { |
| struct regmap_debugfs_node *node; |
| node = kzalloc(sizeof(*node), GFP_KERNEL); |
| if (!node) |
| return; |
| node->map = map; |
| mutex_lock(®map_debugfs_early_lock); |
| list_add(&node->link, ®map_debugfs_early_list); |
| mutex_unlock(®map_debugfs_early_lock); |
| return; |
| } |
| |
| INIT_LIST_HEAD(&map->debugfs_off_cache); |
| mutex_init(&map->cache_lock); |
| |
| if (map->dev) |
| devname = dev_name(map->dev); |
| |
| if (name) { |
| if (!map->debugfs_name) { |
| map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s", |
| devname, name); |
| if (!map->debugfs_name) |
| return; |
| } |
| name = map->debugfs_name; |
| } else { |
| name = devname; |
| } |
| |
| if (!strcmp(name, "dummy")) { |
| kfree(map->debugfs_name); |
| map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d", |
| dummy_index); |
| if (!map->debugfs_name) |
| return; |
| name = map->debugfs_name; |
| dummy_index++; |
| } |
| |
| map->debugfs = debugfs_create_dir(name, regmap_debugfs_root); |
| |
| debugfs_create_file("name", 0400, map->debugfs, |
| map, ®map_name_fops); |
| |
| debugfs_create_file("range", 0400, map->debugfs, |
| map, ®map_reg_ranges_fops); |
| |
| if (map->max_register || regmap_readable(map, 0)) { |
| umode_t registers_mode; |
| |
| #if defined(REGMAP_ALLOW_WRITE_DEBUGFS) |
| registers_mode = 0600; |
| #else |
| registers_mode = 0400; |
| #endif |
| |
| debugfs_create_file("registers", registers_mode, map->debugfs, |
| map, ®map_map_fops); |
| debugfs_create_file("access", 0400, map->debugfs, |
| map, ®map_access_fops); |
| } |
| |
| if (map->cache_type) { |
| debugfs_create_file("cache_only", 0600, map->debugfs, |
| &map->cache_only, ®map_cache_only_fops); |
| debugfs_create_bool("cache_dirty", 0400, map->debugfs, |
| &map->cache_dirty); |
| debugfs_create_file("cache_bypass", 0600, map->debugfs, |
| &map->cache_bypass, |
| ®map_cache_bypass_fops); |
| } |
| |
| next = rb_first(&map->range_tree); |
| while (next) { |
| range_node = rb_entry(next, struct regmap_range_node, node); |
| |
| if (range_node->name) |
| debugfs_create_file(range_node->name, 0400, |
| map->debugfs, range_node, |
| ®map_range_fops); |
| |
| next = rb_next(&range_node->node); |
| } |
| |
| if (map->cache_ops && map->cache_ops->debugfs_init) |
| map->cache_ops->debugfs_init(map); |
| } |
| |
| void regmap_debugfs_exit(struct regmap *map) |
| { |
| if (map->debugfs) { |
| debugfs_remove_recursive(map->debugfs); |
| mutex_lock(&map->cache_lock); |
| regmap_debugfs_free_dump_cache(map); |
| mutex_unlock(&map->cache_lock); |
| kfree(map->debugfs_name); |
| map->debugfs_name = NULL; |
| } else { |
| struct regmap_debugfs_node *node, *tmp; |
| |
| mutex_lock(®map_debugfs_early_lock); |
| list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list, |
| link) { |
| if (node->map == map) { |
| list_del(&node->link); |
| kfree(node); |
| } |
| } |
| mutex_unlock(®map_debugfs_early_lock); |
| } |
| } |
| |
| void regmap_debugfs_initcall(void) |
| { |
| struct regmap_debugfs_node *node, *tmp; |
| |
| regmap_debugfs_root = debugfs_create_dir("regmap", NULL); |
| |
| mutex_lock(®map_debugfs_early_lock); |
| list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list, link) { |
| regmap_debugfs_init(node->map); |
| list_del(&node->link); |
| kfree(node); |
| } |
| mutex_unlock(®map_debugfs_early_lock); |
| } |