diff options
| author | Rafał Miłecki <rafal@milecki.pl> | 2023-04-04 18:21:42 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-04-05 19:41:13 +0200 |
| commit | 55d4980ce55b6bb4be66877de4dbec513911b988 (patch) | |
| tree | 64714987053babb33adfecc7946b632389daee90 /drivers/nvmem | |
| parent | 7e2805c203a6c8dc85c1cfda205161ed39ae82d5 (diff) | |
nvmem: core: support specifying both: cell raw data & post read lengths
Callback .read_post_process() is designed to modify raw cell content
before providing it to the consumer. So far we were dealing with
modifications that didn't affect cell size (length). In some cases
however cell content needs to be reformatted and resized.
It's required e.g. to provide properly formatted MAC address in case
it's stored in a non-binary format (e.g. using ASCII).
There were few discussions how to optimally handle that. Following
possible solutions were considered:
1. Allow .read_post_process() to realloc (resize) content buffer
2. Allow .read_post_process() to adjust (decrease) just buffer length
3. Register NVMEM cells using post-read sizes
The preferred solution was the last one. The problem is that simply
adjusting "bytes" in NVMEM providers would result in core code NOT
passing whole raw data to .read_post_process() callbacks. It means
callback functions couldn't do their job without somehow manually
reading original cell content on their own.
This patch deals with that by registering NVMEM cells with both lengths:
raw content one and post read one. It allows:
1. Core code to read whole raw cell content
2. Callbacks to return content they want
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-35-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/nvmem')
| -rw-r--r-- | drivers/nvmem/core.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 212c5ba5789f..a62973d010ff 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -50,6 +50,7 @@ struct nvmem_device { struct nvmem_cell_entry { const char *name; int offset; + size_t raw_len; int bytes; int bit_offset; int nbits; @@ -469,6 +470,7 @@ static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem, { cell->nvmem = nvmem; cell->offset = info->offset; + cell->raw_len = info->raw_len ?: info->bytes; cell->bytes = info->bytes; cell->name = info->name; cell->read_post_process = info->read_post_process; @@ -1560,7 +1562,7 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem, { int rc; - rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes); + rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->raw_len); if (rc) return rc; @@ -1571,7 +1573,7 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem, if (cell->read_post_process) { rc = cell->read_post_process(cell->priv, id, index, - cell->offset, buf, cell->bytes); + cell->offset, buf, cell->raw_len); if (rc) return rc; } @@ -1594,14 +1596,15 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem, */ void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len) { - struct nvmem_device *nvmem = cell->entry->nvmem; + struct nvmem_cell_entry *entry = cell->entry; + struct nvmem_device *nvmem = entry->nvmem; u8 *buf; int rc; if (!nvmem) return ERR_PTR(-EINVAL); - buf = kzalloc(cell->entry->bytes, GFP_KERNEL); + buf = kzalloc(max_t(size_t, entry->raw_len, entry->bytes), GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); |