From a3471469bcba61f8f18ca4c267b0cdd90a61e035 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 26 Jan 2013 11:45:35 +0000 Subject: [PATCH 1/5] regmap: regmap: avoid spurious warning in regmap_read_debugfs Gcc warns about the case where regmap_read_debugfs tries to walk an empty map->debugfs_off_cache list, which would results in uninitialized variable getting returned, if we hadn't checked the same condition just before that. After an originally suggested inferior patch from Arnd Bergmann, this is the solution that Russell King came up with, sidestepping the problem by merging the error case for an empty list with the normal path. Without this patch, building mxs_defconfig results in: drivers/base/regmap/regmap-debugfs.c: In function 'regmap_read_debugfs': drivers/base/regmap/regmap-debugfs.c:147:9: : warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] Reported-by: Vincent Stehle Cc: Mark Brown Cc: Greg Kroah-Hartman Signed-off-by: Arnd Bergmann Signed-off-by: Mark Brown --- drivers/base/regmap/regmap-debugfs.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index d9a6c94ce423..faa93cc6802e 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -128,10 +128,8 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map, * allocate and we should never be in this code if there are * no registers at all. */ - if (list_empty(&map->debugfs_off_cache)) { - WARN_ON(list_empty(&map->debugfs_off_cache)); - return base; - } + WARN_ON(list_empty(&map->debugfs_off_cache)); + ret = base; /* Find the relevant block */ list_for_each_entry(c, &map->debugfs_off_cache, list) { From f3eb83994cb4c172ce5028b5ae7ea08462cc3f1d Mon Sep 17 00:00:00 2001 From: Dimitris Papastamos Date: Thu, 7 Feb 2013 10:51:56 +0000 Subject: [PATCH 2/5] regmap: debugfs: Fix reading in register field units At the moment, if the length of the register field format is N bytes, we can only get anything meaningful back to userspace by providing a buffer that is N + 2 bytes large. Fix this so we that we only need to provide a buffer of N bytes. Signed-off-by: Dimitris Papastamos Signed-off-by: Mark Brown --- drivers/base/regmap/regmap-debugfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index faa93cc6802e..0e94fd3c95a3 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -185,7 +185,7 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from, /* If we're in the region the user is trying to read */ if (p >= *ppos) { /* ...but not beyond it */ - if (buf_pos + 1 + map->debugfs_tot_len >= count) + if (buf_pos + map->debugfs_tot_len > count) break; /* Format the register */ From c2c1ee66016a45477f58f0fd30907b1e959ca76b Mon Sep 17 00:00:00 2001 From: Dimitris Papastamos Date: Fri, 8 Feb 2013 12:47:14 +0000 Subject: [PATCH 3/5] regmap: debugfs: Add a `max_reg' member in struct regmap_debugfs_off_cache We are keeping track of the maximum register as well, this will make things easier for us in sharing this code with the code implementing the register ranges functionality. It also simplifies a bit the calculations when looking for the relevant block:offset from within the cache. Signed-off-by: Dimitris Papastamos Signed-off-by: Mark Brown --- drivers/base/regmap/internal.h | 1 + drivers/base/regmap/regmap-debugfs.c | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h index 401d1919635a..26b8ffde1458 100644 --- a/drivers/base/regmap/internal.h +++ b/drivers/base/regmap/internal.h @@ -25,6 +25,7 @@ struct regmap_debugfs_off_cache { off_t min; off_t max; unsigned int base_reg; + unsigned int max_reg; }; struct regmap_format { diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index 0e94fd3c95a3..3fade1ceaf15 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -81,6 +81,8 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map, struct regmap_debugfs_off_cache *c = NULL; loff_t p = 0; unsigned int i, ret; + unsigned int fpos_offset; + unsigned int reg_offset; /* * If we don't have a cache build one so we don't have to do a @@ -93,6 +95,9 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map, regmap_precious(map, i)) { if (c) { c->max = p - 1; + fpos_offset = c->max - c->min; + reg_offset = fpos_offset / map->debugfs_tot_len; + c->max_reg = c->base_reg + reg_offset; list_add_tail(&c->list, &map->debugfs_off_cache); c = NULL; @@ -119,6 +124,9 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map, /* Close the last entry off if we didn't scan beyond it */ if (c) { c->max = p - 1; + fpos_offset = c->max - c->min; + reg_offset = fpos_offset / map->debugfs_tot_len; + c->max_reg = c->base_reg + reg_offset; list_add_tail(&c->list, &map->debugfs_off_cache); } From cf57d6071f0610c99856c006ac06eb98a151f485 Mon Sep 17 00:00:00 2001 From: Dimitris Papastamos Date: Fri, 8 Feb 2013 12:47:20 +0000 Subject: [PATCH 4/5] regmap: debugfs: Optimize seeking within blocks of registers Optimize this so that we can better guess where to start scanning from. We know the length of the register field format, therefore given the file pointer position align to the nearest register field and scan from there onwards. We round down in this calculation and we let the rest of the code figure out where to start scanning from. Signed-off-by: Dimitris Papastamos Signed-off-by: Mark Brown --- drivers/base/regmap/regmap-debugfs.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index 3fade1ceaf15..246f459e9170 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -139,15 +139,17 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map, WARN_ON(list_empty(&map->debugfs_off_cache)); ret = base; - /* Find the relevant block */ + /* Find the relevant block:offset */ list_for_each_entry(c, &map->debugfs_off_cache, list) { if (from >= c->min && from <= c->max) { - *pos = c->min; - return c->base_reg; + fpos_offset = from - c->min; + reg_offset = fpos_offset / map->debugfs_tot_len; + *pos = c->min + (reg_offset * map->debugfs_tot_len); + return c->base_reg + reg_offset; } - *pos = c->min; - ret = c->base_reg; + *pos = c->max; + ret = c->max_reg; } return ret; From 4dd7c5531d3b046574da39096b1a66c738aca102 Mon Sep 17 00:00:00 2001 From: Dimitris Papastamos Date: Mon, 11 Feb 2013 10:50:59 +0000 Subject: [PATCH 5/5] regmap: debugfs: Factor out debugfs_tot_len calc into a function In preparation to support the regmap debugfs ranges functionality factor this code out to a separate function. We'll need to ensure that the value has been correctly calculated from two separate places in the code. Signed-off-by: Dimitris Papastamos Signed-off-by: Mark Brown --- drivers/base/regmap/regmap-debugfs.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index 246f459e9170..78d5f20c5f5b 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -155,6 +155,19 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map, 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, + buf, count); + map->debugfs_val_len = 2 * map->format.val_bytes; + map->debugfs_tot_len = map->debugfs_reg_len + + map->debugfs_val_len + 3; /* : \n */ + } +} + 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) @@ -173,14 +186,7 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from, if (!buf) return -ENOMEM; - /* Calculate the length of a fixed format */ - if (!map->debugfs_tot_len) { - map->debugfs_reg_len = regmap_calc_reg_len(map->max_register, - buf, count); - map->debugfs_val_len = 2 * map->format.val_bytes; - map->debugfs_tot_len = map->debugfs_reg_len + - map->debugfs_val_len + 3; /* : \n */ - } + 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);