linux/drivers/nvmem/core.c
Srinivas Kandagatla 2f9ba5b2f8 nvmem: core: return error for non word aligned access
nvmem providers have restrictions on register strides, so return error
when users attempt to read/write buffers with sizes which are less
than word size.

Without this patch the userspace would continue to try as it does not
get any error from the nvmem core, resulting in a hang or endless loop
in userspace.

Reported-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-02-07 23:09:13 -08:00

1090 lines
24 KiB
C

/*
* nvmem framework core.
*
* Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
* Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/device.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/slab.h>
struct nvmem_device {
const char *name;
struct regmap *regmap;
struct module *owner;
struct device dev;
int stride;
int word_size;
int ncells;
int id;
int users;
size_t size;
bool read_only;
};
struct nvmem_cell {
const char *name;
int offset;
int bytes;
int bit_offset;
int nbits;
struct nvmem_device *nvmem;
struct list_head node;
};
static DEFINE_MUTEX(nvmem_mutex);
static DEFINE_IDA(nvmem_ida);
static LIST_HEAD(nvmem_cells);
static DEFINE_MUTEX(nvmem_cells_mutex);
#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)
static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t pos, size_t count)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct nvmem_device *nvmem = to_nvmem_device(dev);
int rc;
/* Stop the user from reading */
if (pos >= nvmem->size)
return 0;
if (count < nvmem->word_size)
return -EINVAL;
if (pos + count > nvmem->size)
count = nvmem->size - pos;
count = round_down(count, nvmem->word_size);
rc = regmap_raw_read(nvmem->regmap, pos, buf, count);
if (IS_ERR_VALUE(rc))
return rc;
return count;
}
static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t pos, size_t count)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct nvmem_device *nvmem = to_nvmem_device(dev);
int rc;
/* Stop the user from writing */
if (pos >= nvmem->size)
return 0;
if (count < nvmem->word_size)
return -EINVAL;
if (pos + count > nvmem->size)
count = nvmem->size - pos;
count = round_down(count, nvmem->word_size);
rc = regmap_raw_write(nvmem->regmap, pos, buf, count);
if (IS_ERR_VALUE(rc))
return rc;
return count;
}
/* default read/write permissions */
static struct bin_attribute bin_attr_rw_nvmem = {
.attr = {
.name = "nvmem",
.mode = S_IWUSR | S_IRUGO,
},
.read = bin_attr_nvmem_read,
.write = bin_attr_nvmem_write,
};
static struct bin_attribute *nvmem_bin_rw_attributes[] = {
&bin_attr_rw_nvmem,
NULL,
};
static const struct attribute_group nvmem_bin_rw_group = {
.bin_attrs = nvmem_bin_rw_attributes,
};
static const struct attribute_group *nvmem_rw_dev_groups[] = {
&nvmem_bin_rw_group,
NULL,
};
/* read only permission */
static struct bin_attribute bin_attr_ro_nvmem = {
.attr = {
.name = "nvmem",
.mode = S_IRUGO,
},
.read = bin_attr_nvmem_read,
};
static struct bin_attribute *nvmem_bin_ro_attributes[] = {
&bin_attr_ro_nvmem,
NULL,
};
static const struct attribute_group nvmem_bin_ro_group = {
.bin_attrs = nvmem_bin_ro_attributes,
};
static const struct attribute_group *nvmem_ro_dev_groups[] = {
&nvmem_bin_ro_group,
NULL,
};
static void nvmem_release(struct device *dev)
{
struct nvmem_device *nvmem = to_nvmem_device(dev);
ida_simple_remove(&nvmem_ida, nvmem->id);
kfree(nvmem);
}
static const struct device_type nvmem_provider_type = {
.release = nvmem_release,
};
static struct bus_type nvmem_bus_type = {
.name = "nvmem",
};
static int of_nvmem_match(struct device *dev, void *nvmem_np)
{
return dev->of_node == nvmem_np;
}
static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
{
struct device *d;
if (!nvmem_np)
return NULL;
d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match);
if (!d)
return NULL;
return to_nvmem_device(d);
}
static struct nvmem_cell *nvmem_find_cell(const char *cell_id)
{
struct nvmem_cell *p;
list_for_each_entry(p, &nvmem_cells, node)
if (p && !strcmp(p->name, cell_id))
return p;
return NULL;
}
static void nvmem_cell_drop(struct nvmem_cell *cell)
{
mutex_lock(&nvmem_cells_mutex);
list_del(&cell->node);
mutex_unlock(&nvmem_cells_mutex);
kfree(cell);
}
static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
{
struct nvmem_cell *cell;
struct list_head *p, *n;
list_for_each_safe(p, n, &nvmem_cells) {
cell = list_entry(p, struct nvmem_cell, node);
if (cell->nvmem == nvmem)
nvmem_cell_drop(cell);
}
}
static void nvmem_cell_add(struct nvmem_cell *cell)
{
mutex_lock(&nvmem_cells_mutex);
list_add_tail(&cell->node, &nvmem_cells);
mutex_unlock(&nvmem_cells_mutex);
}
static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
const struct nvmem_cell_info *info,
struct nvmem_cell *cell)
{
cell->nvmem = nvmem;
cell->offset = info->offset;
cell->bytes = info->bytes;
cell->name = info->name;
cell->bit_offset = info->bit_offset;
cell->nbits = info->nbits;
if (cell->nbits)
cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
BITS_PER_BYTE);
if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
dev_err(&nvmem->dev,
"cell %s unaligned to nvmem stride %d\n",
cell->name, nvmem->stride);
return -EINVAL;
}
return 0;
}
static int nvmem_add_cells(struct nvmem_device *nvmem,
const struct nvmem_config *cfg)
{
struct nvmem_cell **cells;
const struct nvmem_cell_info *info = cfg->cells;
int i, rval;
cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL);
if (!cells)
return -ENOMEM;
for (i = 0; i < cfg->ncells; i++) {
cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
if (!cells[i]) {
rval = -ENOMEM;
goto err;
}
rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
if (IS_ERR_VALUE(rval)) {
kfree(cells[i]);
goto err;
}
nvmem_cell_add(cells[i]);
}
nvmem->ncells = cfg->ncells;
/* remove tmp array */
kfree(cells);
return 0;
err:
while (--i)
nvmem_cell_drop(cells[i]);
return rval;
}
/**
* nvmem_register() - Register a nvmem device for given nvmem_config.
* Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
*
* @config: nvmem device configuration with which nvmem device is created.
*
* Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
* on success.
*/
struct nvmem_device *nvmem_register(const struct nvmem_config *config)
{
struct nvmem_device *nvmem;
struct device_node *np;
struct regmap *rm;
int rval;
if (!config->dev)
return ERR_PTR(-EINVAL);
rm = dev_get_regmap(config->dev, NULL);
if (!rm) {
dev_err(config->dev, "Regmap not found\n");
return ERR_PTR(-EINVAL);
}
nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
if (!nvmem)
return ERR_PTR(-ENOMEM);
rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
if (rval < 0) {
kfree(nvmem);
return ERR_PTR(rval);
}
nvmem->id = rval;
nvmem->regmap = rm;
nvmem->owner = config->owner;
nvmem->stride = regmap_get_reg_stride(rm);
nvmem->word_size = regmap_get_val_bytes(rm);
nvmem->size = regmap_get_max_register(rm) + nvmem->stride;
nvmem->dev.type = &nvmem_provider_type;
nvmem->dev.bus = &nvmem_bus_type;
nvmem->dev.parent = config->dev;
np = config->dev->of_node;
nvmem->dev.of_node = np;
dev_set_name(&nvmem->dev, "%s%d",
config->name ? : "nvmem", config->id);
nvmem->read_only = of_property_read_bool(np, "read-only") |
config->read_only;
nvmem->dev.groups = nvmem->read_only ? nvmem_ro_dev_groups :
nvmem_rw_dev_groups;
device_initialize(&nvmem->dev);
dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
rval = device_add(&nvmem->dev);
if (rval) {
ida_simple_remove(&nvmem_ida, nvmem->id);
kfree(nvmem);
return ERR_PTR(rval);
}
if (config->cells)
nvmem_add_cells(nvmem, config);
return nvmem;
}
EXPORT_SYMBOL_GPL(nvmem_register);
/**
* nvmem_unregister() - Unregister previously registered nvmem device
*
* @nvmem: Pointer to previously registered nvmem device.
*
* Return: Will be an negative on error or a zero on success.
*/
int nvmem_unregister(struct nvmem_device *nvmem)
{
mutex_lock(&nvmem_mutex);
if (nvmem->users) {
mutex_unlock(&nvmem_mutex);
return -EBUSY;
}
mutex_unlock(&nvmem_mutex);
nvmem_device_remove_all_cells(nvmem);
device_del(&nvmem->dev);
return 0;
}
EXPORT_SYMBOL_GPL(nvmem_unregister);
static struct nvmem_device *__nvmem_device_get(struct device_node *np,
struct nvmem_cell **cellp,
const char *cell_id)
{
struct nvmem_device *nvmem = NULL;
mutex_lock(&nvmem_mutex);
if (np) {
nvmem = of_nvmem_find(np);
if (!nvmem) {
mutex_unlock(&nvmem_mutex);
return ERR_PTR(-EPROBE_DEFER);
}
} else {
struct nvmem_cell *cell = nvmem_find_cell(cell_id);
if (cell) {
nvmem = cell->nvmem;
*cellp = cell;
}
if (!nvmem) {
mutex_unlock(&nvmem_mutex);
return ERR_PTR(-ENOENT);
}
}
nvmem->users++;
mutex_unlock(&nvmem_mutex);
if (!try_module_get(nvmem->owner)) {
dev_err(&nvmem->dev,
"could not increase module refcount for cell %s\n",
nvmem->name);
mutex_lock(&nvmem_mutex);
nvmem->users--;
mutex_unlock(&nvmem_mutex);
return ERR_PTR(-EINVAL);
}
return nvmem;
}
static void __nvmem_device_put(struct nvmem_device *nvmem)
{
module_put(nvmem->owner);
mutex_lock(&nvmem_mutex);
nvmem->users--;
mutex_unlock(&nvmem_mutex);
}
static int nvmem_match(struct device *dev, void *data)
{
return !strcmp(dev_name(dev), data);
}
static struct nvmem_device *nvmem_find(const char *name)
{
struct device *d;
d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match);
if (!d)
return NULL;
return to_nvmem_device(d);
}
#if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
/**
* of_nvmem_device_get() - Get nvmem device from a given id
*
* @dev node: Device tree node that uses the nvmem device
* @id: nvmem name from nvmem-names property.
*
* Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
* on success.
*/
struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
{
struct device_node *nvmem_np;
int index;
index = of_property_match_string(np, "nvmem-names", id);
nvmem_np = of_parse_phandle(np, "nvmem", index);
if (!nvmem_np)
return ERR_PTR(-EINVAL);
return __nvmem_device_get(nvmem_np, NULL, NULL);
}
EXPORT_SYMBOL_GPL(of_nvmem_device_get);
#endif
/**
* nvmem_device_get() - Get nvmem device from a given id
*
* @dev : Device that uses the nvmem device
* @id: nvmem name from nvmem-names property.
*
* Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
* on success.
*/
struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
{
if (dev->of_node) { /* try dt first */
struct nvmem_device *nvmem;
nvmem = of_nvmem_device_get(dev->of_node, dev_name);
if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
return nvmem;
}
return nvmem_find(dev_name);
}
EXPORT_SYMBOL_GPL(nvmem_device_get);
static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
{
struct nvmem_device **nvmem = res;
if (WARN_ON(!nvmem || !*nvmem))
return 0;
return *nvmem == data;
}
static void devm_nvmem_device_release(struct device *dev, void *res)
{
nvmem_device_put(*(struct nvmem_device **)res);
}
/**
* devm_nvmem_device_put() - put alredy got nvmem device
*
* @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
* that needs to be released.
*/
void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
{
int ret;
ret = devres_release(dev, devm_nvmem_device_release,
devm_nvmem_device_match, nvmem);
WARN_ON(ret);
}
EXPORT_SYMBOL_GPL(devm_nvmem_device_put);
/**
* nvmem_device_put() - put alredy got nvmem device
*
* @nvmem: pointer to nvmem device that needs to be released.
*/
void nvmem_device_put(struct nvmem_device *nvmem)
{
__nvmem_device_put(nvmem);
}
EXPORT_SYMBOL_GPL(nvmem_device_put);
/**
* devm_nvmem_device_get() - Get nvmem cell of device form a given id
*
* @dev node: Device tree node that uses the nvmem cell
* @id: nvmem name in nvmems property.
*
* Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
* on success. The nvmem_cell will be freed by the automatically once the
* device is freed.
*/
struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
{
struct nvmem_device **ptr, *nvmem;
ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
nvmem = nvmem_device_get(dev, id);
if (!IS_ERR(nvmem)) {
*ptr = nvmem;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return nvmem;
}
EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id)
{
struct nvmem_cell *cell = NULL;
struct nvmem_device *nvmem;
nvmem = __nvmem_device_get(NULL, &cell, cell_id);
if (IS_ERR(nvmem))
return ERR_CAST(nvmem);
return cell;
}
#if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
/**
* of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
*
* @dev node: Device tree node that uses the nvmem cell
* @id: nvmem cell name from nvmem-cell-names property.
*
* Return: Will be an ERR_PTR() on error or a valid pointer
* to a struct nvmem_cell. The nvmem_cell will be freed by the
* nvmem_cell_put().
*/
struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
const char *name)
{
struct device_node *cell_np, *nvmem_np;
struct nvmem_cell *cell;
struct nvmem_device *nvmem;
const __be32 *addr;
int rval, len, index;
index = of_property_match_string(np, "nvmem-cell-names", name);
cell_np = of_parse_phandle(np, "nvmem-cells", index);
if (!cell_np)
return ERR_PTR(-EINVAL);
nvmem_np = of_get_next_parent(cell_np);
if (!nvmem_np)
return ERR_PTR(-EINVAL);
nvmem = __nvmem_device_get(nvmem_np, NULL, NULL);
if (IS_ERR(nvmem))
return ERR_CAST(nvmem);
addr = of_get_property(cell_np, "reg", &len);
if (!addr || (len < 2 * sizeof(u32))) {
dev_err(&nvmem->dev, "nvmem: invalid reg on %s\n",
cell_np->full_name);
rval = -EINVAL;
goto err_mem;
}
cell = kzalloc(sizeof(*cell), GFP_KERNEL);
if (!cell) {
rval = -ENOMEM;
goto err_mem;
}
cell->nvmem = nvmem;
cell->offset = be32_to_cpup(addr++);
cell->bytes = be32_to_cpup(addr);
cell->name = cell_np->name;
addr = of_get_property(cell_np, "bits", &len);
if (addr && len == (2 * sizeof(u32))) {
cell->bit_offset = be32_to_cpup(addr++);
cell->nbits = be32_to_cpup(addr);
}
if (cell->nbits)
cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
BITS_PER_BYTE);
if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
dev_err(&nvmem->dev,
"cell %s unaligned to nvmem stride %d\n",
cell->name, nvmem->stride);
rval = -EINVAL;
goto err_sanity;
}
nvmem_cell_add(cell);
return cell;
err_sanity:
kfree(cell);
err_mem:
__nvmem_device_put(nvmem);
return ERR_PTR(rval);
}
EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
#endif
/**
* nvmem_cell_get() - Get nvmem cell of device form a given cell name
*
* @dev node: Device tree node that uses the nvmem cell
* @id: nvmem cell name to get.
*
* Return: Will be an ERR_PTR() on error or a valid pointer
* to a struct nvmem_cell. The nvmem_cell will be freed by the
* nvmem_cell_put().
*/
struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id)
{
struct nvmem_cell *cell;
if (dev->of_node) { /* try dt first */
cell = of_nvmem_cell_get(dev->of_node, cell_id);
if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
return cell;
}
return nvmem_cell_get_from_list(cell_id);
}
EXPORT_SYMBOL_GPL(nvmem_cell_get);
static void devm_nvmem_cell_release(struct device *dev, void *res)
{
nvmem_cell_put(*(struct nvmem_cell **)res);
}
/**
* devm_nvmem_cell_get() - Get nvmem cell of device form a given id
*
* @dev node: Device tree node that uses the nvmem cell
* @id: nvmem id in nvmem-names property.
*
* Return: Will be an ERR_PTR() on error or a valid pointer
* to a struct nvmem_cell. The nvmem_cell will be freed by the
* automatically once the device is freed.
*/
struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
{
struct nvmem_cell **ptr, *cell;
ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
cell = nvmem_cell_get(dev, id);
if (!IS_ERR(cell)) {
*ptr = cell;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return cell;
}
EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);
static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
{
struct nvmem_cell **c = res;
if (WARN_ON(!c || !*c))
return 0;
return *c == data;
}
/**
* devm_nvmem_cell_put() - Release previously allocated nvmem cell
* from devm_nvmem_cell_get.
*
* @cell: Previously allocated nvmem cell by devm_nvmem_cell_get()
*/
void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
{
int ret;
ret = devres_release(dev, devm_nvmem_cell_release,
devm_nvmem_cell_match, cell);
WARN_ON(ret);
}
EXPORT_SYMBOL(devm_nvmem_cell_put);
/**
* nvmem_cell_put() - Release previously allocated nvmem cell.
*
* @cell: Previously allocated nvmem cell by nvmem_cell_get()
*/
void nvmem_cell_put(struct nvmem_cell *cell)
{
struct nvmem_device *nvmem = cell->nvmem;
__nvmem_device_put(nvmem);
nvmem_cell_drop(cell);
}
EXPORT_SYMBOL_GPL(nvmem_cell_put);
static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell,
void *buf)
{
u8 *p, *b;
int i, bit_offset = cell->bit_offset;
p = b = buf;
if (bit_offset) {
/* First shift */
*b++ >>= bit_offset;
/* setup rest of the bytes if any */
for (i = 1; i < cell->bytes; i++) {
/* Get bits from next byte and shift them towards msb */
*p |= *b << (BITS_PER_BYTE - bit_offset);
p = b;
*b++ >>= bit_offset;
}
/* result fits in less bytes */
if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
*p-- = 0;
}
/* clear msb bits if any leftover in the last byte */
*p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
}
static int __nvmem_cell_read(struct nvmem_device *nvmem,
struct nvmem_cell *cell,
void *buf, size_t *len)
{
int rc;
rc = regmap_raw_read(nvmem->regmap, cell->offset, buf, cell->bytes);
if (IS_ERR_VALUE(rc))
return rc;
/* shift bits in-place */
if (cell->bit_offset || cell->nbits)
nvmem_shift_read_buffer_in_place(cell, buf);
*len = cell->bytes;
return 0;
}
/**
* nvmem_cell_read() - Read a given nvmem cell
*
* @cell: nvmem cell to be read.
* @len: pointer to length of cell which will be populated on successful read.
*
* Return: ERR_PTR() on error or a valid pointer to a char * buffer on success.
* The buffer should be freed by the consumer with a kfree().
*/
void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
{
struct nvmem_device *nvmem = cell->nvmem;
u8 *buf;
int rc;
if (!nvmem || !nvmem->regmap)
return ERR_PTR(-EINVAL);
buf = kzalloc(cell->bytes, GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
rc = __nvmem_cell_read(nvmem, cell, buf, len);
if (IS_ERR_VALUE(rc)) {
kfree(buf);
return ERR_PTR(rc);
}
return buf;
}
EXPORT_SYMBOL_GPL(nvmem_cell_read);
static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell,
u8 *_buf, int len)
{
struct nvmem_device *nvmem = cell->nvmem;
int i, rc, nbits, bit_offset = cell->bit_offset;
u8 v, *p, *buf, *b, pbyte, pbits;
nbits = cell->nbits;
buf = kzalloc(cell->bytes, GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
memcpy(buf, _buf, len);
p = b = buf;
if (bit_offset) {
pbyte = *b;
*b <<= bit_offset;
/* setup the first byte with lsb bits from nvmem */
rc = regmap_raw_read(nvmem->regmap, cell->offset, &v, 1);
*b++ |= GENMASK(bit_offset - 1, 0) & v;
/* setup rest of the byte if any */
for (i = 1; i < cell->bytes; i++) {
/* Get last byte bits and shift them towards lsb */
pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
pbyte = *b;
p = b;
*b <<= bit_offset;
*b++ |= pbits;
}
}
/* if it's not end on byte boundary */
if ((nbits + bit_offset) % BITS_PER_BYTE) {
/* setup the last byte with msb bits from nvmem */
rc = regmap_raw_read(nvmem->regmap,
cell->offset + cell->bytes - 1, &v, 1);
*p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
}
return buf;
}
/**
* nvmem_cell_write() - Write to a given nvmem cell
*
* @cell: nvmem cell to be written.
* @buf: Buffer to be written.
* @len: length of buffer to be written to nvmem cell.
*
* Return: length of bytes written or negative on failure.
*/
int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
{
struct nvmem_device *nvmem = cell->nvmem;
int rc;
if (!nvmem || !nvmem->regmap || nvmem->read_only ||
(cell->bit_offset == 0 && len != cell->bytes))
return -EINVAL;
if (cell->bit_offset || cell->nbits) {
buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
if (IS_ERR(buf))
return PTR_ERR(buf);
}
rc = regmap_raw_write(nvmem->regmap, cell->offset, buf, cell->bytes);
/* free the tmp buffer */
if (cell->bit_offset || cell->nbits)
kfree(buf);
if (IS_ERR_VALUE(rc))
return rc;
return len;
}
EXPORT_SYMBOL_GPL(nvmem_cell_write);
/**
* nvmem_device_cell_read() - Read a given nvmem device and cell
*
* @nvmem: nvmem device to read from.
* @info: nvmem cell info to be read.
* @buf: buffer pointer which will be populated on successful read.
*
* Return: length of successful bytes read on success and negative
* error code on error.
*/
ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
struct nvmem_cell_info *info, void *buf)
{
struct nvmem_cell cell;
int rc;
ssize_t len;
if (!nvmem || !nvmem->regmap)
return -EINVAL;
rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
if (IS_ERR_VALUE(rc))
return rc;
rc = __nvmem_cell_read(nvmem, &cell, buf, &len);
if (IS_ERR_VALUE(rc))
return rc;
return len;
}
EXPORT_SYMBOL_GPL(nvmem_device_cell_read);
/**
* nvmem_device_cell_write() - Write cell to a given nvmem device
*
* @nvmem: nvmem device to be written to.
* @info: nvmem cell info to be written
* @buf: buffer to be written to cell.
*
* Return: length of bytes written or negative error code on failure.
* */
int nvmem_device_cell_write(struct nvmem_device *nvmem,
struct nvmem_cell_info *info, void *buf)
{
struct nvmem_cell cell;
int rc;
if (!nvmem || !nvmem->regmap)
return -EINVAL;
rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
if (IS_ERR_VALUE(rc))
return rc;
return nvmem_cell_write(&cell, buf, cell.bytes);
}
EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
/**
* nvmem_device_read() - Read from a given nvmem device
*
* @nvmem: nvmem device to read from.
* @offset: offset in nvmem device.
* @bytes: number of bytes to read.
* @buf: buffer pointer which will be populated on successful read.
*
* Return: length of successful bytes read on success and negative
* error code on error.
*/
int nvmem_device_read(struct nvmem_device *nvmem,
unsigned int offset,
size_t bytes, void *buf)
{
int rc;
if (!nvmem || !nvmem->regmap)
return -EINVAL;
rc = regmap_raw_read(nvmem->regmap, offset, buf, bytes);
if (IS_ERR_VALUE(rc))
return rc;
return bytes;
}
EXPORT_SYMBOL_GPL(nvmem_device_read);
/**
* nvmem_device_write() - Write cell to a given nvmem device
*
* @nvmem: nvmem device to be written to.
* @offset: offset in nvmem device.
* @bytes: number of bytes to write.
* @buf: buffer to be written.
*
* Return: length of bytes written or negative error code on failure.
* */
int nvmem_device_write(struct nvmem_device *nvmem,
unsigned int offset,
size_t bytes, void *buf)
{
int rc;
if (!nvmem || !nvmem->regmap)
return -EINVAL;
rc = regmap_raw_write(nvmem->regmap, offset, buf, bytes);
if (IS_ERR_VALUE(rc))
return rc;
return bytes;
}
EXPORT_SYMBOL_GPL(nvmem_device_write);
static int __init nvmem_init(void)
{
return bus_register(&nvmem_bus_type);
}
static void __exit nvmem_exit(void)
{
bus_unregister(&nvmem_bus_type);
}
subsys_initcall(nvmem_init);
module_exit(nvmem_exit);
MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
MODULE_DESCRIPTION("nvmem Driver Core");
MODULE_LICENSE("GPL v2");