diff options
Diffstat (limited to 'drivers/base/regmap/regmap-debugfs.c')
| -rw-r--r-- | drivers/base/regmap/regmap-debugfs.c | 703 |
1 files changed, 703 insertions, 0 deletions
diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c new file mode 100644 index 0000000000..bdd80b73c3 --- /dev/null +++ b/drivers/base/regmap/regmap-debugfs.c @@ -0,0 +1,703 @@ +// 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)) + count = PAGE_SIZE << MAX_ORDER; + + 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)) + count = PAGE_SIZE << MAX_ORDER; + + 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); + } + + /* + * This could interfere with driver operation. Therefore, don't provide + * any real compile time configuration option for this feature. One will + * have to modify the source code directly in order to use it. + */ +#undef REGMAP_ALLOW_FORCE_WRITE_FIELD_DEBUGFS +#ifdef REGMAP_ALLOW_FORCE_WRITE_FIELD_DEBUGFS + debugfs_create_bool("force_write_field", 0600, map->debugfs, + &map->force_write_field); +#endif + + 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); +} |