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core.c
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// SPDX-License-Identifier: GPL-2.0
/*
* nvmem framework core.
*
* Copyright (C) 2015 Srinivas Kandagatla <[email protected]>
* Copyright (C) 2013 Maxime Ripard <[email protected]>
*/
#include <linux/device.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/kref.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/slab.h>
#include "nvmem.h"
struct nvmem_cell {
const char *name;
int offset;
int bytes;
int bit_offset;
int nbits;
struct device_node *np;
struct nvmem_device *nvmem;
struct list_head node;
};
static DEFINE_MUTEX(nvmem_mutex);
static DEFINE_IDA(nvmem_ida);
static DEFINE_MUTEX(nvmem_cell_mutex);
static LIST_HEAD(nvmem_cell_tables);
static DEFINE_MUTEX(nvmem_lookup_mutex);
static LIST_HEAD(nvmem_lookup_list);
static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
void *val, size_t bytes)
{
if (nvmem->reg_read)
return nvmem->reg_read(nvmem->priv, offset, val, bytes);
return -EINVAL;
}
static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
void *val, size_t bytes)
{
if (nvmem->reg_write)
return nvmem->reg_write(nvmem->priv, offset, val, bytes);
return -EINVAL;
}
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 struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
{
struct device *d;
if (!nvmem_np)
return NULL;
d = bus_find_device_by_of_node(&nvmem_bus_type, nvmem_np);
if (!d)
return NULL;
return to_nvmem_device(d);
}
static struct nvmem_device *nvmem_find(const char *name)
{
struct device *d;
d = bus_find_device_by_name(&nvmem_bus_type, NULL, name);
if (!d)
return NULL;
return to_nvmem_device(d);
}
static void nvmem_cell_drop(struct nvmem_cell *cell)
{
blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell);
mutex_lock(&nvmem_mutex);
list_del(&cell->node);
mutex_unlock(&nvmem_mutex);
of_node_put(cell->np);
kfree(cell->name);
kfree(cell);
}
static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
{
struct nvmem_cell *cell, *p;
list_for_each_entry_safe(cell, p, &nvmem->cells, node)
nvmem_cell_drop(cell);
}
static void nvmem_cell_add(struct nvmem_cell *cell)
{
mutex_lock(&nvmem_mutex);
list_add_tail(&cell->node, &cell->nvmem->cells);
mutex_unlock(&nvmem_mutex);
blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
}
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;
}
/**
* nvmem_add_cells() - Add cell information to an nvmem device
*
* @nvmem: nvmem device to add cells to.
* @info: nvmem cell info to add to the device
* @ncells: number of cells in info
*
* Return: 0 or negative error code on failure.
*/
static int nvmem_add_cells(struct nvmem_device *nvmem,
const struct nvmem_cell_info *info,
int ncells)
{
struct nvmem_cell **cells;
int i, rval;
cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
if (!cells)
return -ENOMEM;
for (i = 0; i < 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 (rval) {
kfree(cells[i]);
goto err;
}
nvmem_cell_add(cells[i]);
}
/* remove tmp array */
kfree(cells);
return 0;
err:
while (i--)
nvmem_cell_drop(cells[i]);
kfree(cells);
return rval;
}
/**
* nvmem_register_notifier() - Register a notifier block for nvmem events.
*
* @nb: notifier block to be called on nvmem events.
*
* Return: 0 on success, negative error number on failure.
*/
int nvmem_register_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&nvmem_notifier, nb);
}
EXPORT_SYMBOL_GPL(nvmem_register_notifier);
/**
* nvmem_unregister_notifier() - Unregister a notifier block for nvmem events.
*
* @nb: notifier block to be unregistered.
*
* Return: 0 on success, negative error number on failure.
*/
int nvmem_unregister_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&nvmem_notifier, nb);
}
EXPORT_SYMBOL_GPL(nvmem_unregister_notifier);
static int nvmem_add_cells_from_table(struct nvmem_device *nvmem)
{
const struct nvmem_cell_info *info;
struct nvmem_cell_table *table;
struct nvmem_cell *cell;
int rval = 0, i;
mutex_lock(&nvmem_cell_mutex);
list_for_each_entry(table, &nvmem_cell_tables, node) {
if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) {
for (i = 0; i < table->ncells; i++) {
info = &table->cells[i];
cell = kzalloc(sizeof(*cell), GFP_KERNEL);
if (!cell) {
rval = -ENOMEM;
goto out;
}
rval = nvmem_cell_info_to_nvmem_cell(nvmem,
info,
cell);
if (rval) {
kfree(cell);
goto out;
}
nvmem_cell_add(cell);
}
}
}
out:
mutex_unlock(&nvmem_cell_mutex);
return rval;
}
static struct nvmem_cell *
nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id)
{
struct nvmem_cell *iter, *cell = NULL;
mutex_lock(&nvmem_mutex);
list_for_each_entry(iter, &nvmem->cells, node) {
if (strcmp(cell_id, iter->name) == 0) {
cell = iter;
break;
}
}
mutex_unlock(&nvmem_mutex);
return cell;
}
static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
{
struct device_node *parent, *child;
struct device *dev = &nvmem->dev;
struct nvmem_cell *cell;
const __be32 *addr;
int len;
parent = dev->of_node;
for_each_child_of_node(parent, child) {
addr = of_get_property(child, "reg", &len);
if (!addr || (len < 2 * sizeof(u32))) {
dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
return -EINVAL;
}
cell = kzalloc(sizeof(*cell), GFP_KERNEL);
if (!cell)
return -ENOMEM;
cell->nvmem = nvmem;
cell->np = of_node_get(child);
cell->offset = be32_to_cpup(addr++);
cell->bytes = be32_to_cpup(addr);
cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
addr = of_get_property(child, "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(dev, "cell %s unaligned to nvmem stride %d\n",
cell->name, nvmem->stride);
/* Cells already added will be freed later. */
kfree(cell->name);
kfree(cell);
return -EINVAL;
}
nvmem_cell_add(cell);
}
return 0;
}
/**
* 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;
int rval;
if (!config->dev)
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);
}
kref_init(&nvmem->refcnt);
INIT_LIST_HEAD(&nvmem->cells);
nvmem->id = rval;
nvmem->owner = config->owner;
if (!nvmem->owner && config->dev->driver)
nvmem->owner = config->dev->driver->owner;
nvmem->stride = config->stride ?: 1;
nvmem->word_size = config->word_size ?: 1;
nvmem->size = config->size;
nvmem->dev.type = &nvmem_provider_type;
nvmem->dev.bus = &nvmem_bus_type;
nvmem->dev.parent = config->dev;
nvmem->priv = config->priv;
nvmem->type = config->type;
nvmem->reg_read = config->reg_read;
nvmem->reg_write = config->reg_write;
if (!config->no_of_node)
nvmem->dev.of_node = config->dev->of_node;
if (config->id == -1 && config->name) {
dev_set_name(&nvmem->dev, "%s", config->name);
} else {
dev_set_name(&nvmem->dev, "%s%d",
config->name ? : "nvmem",
config->name ? config->id : nvmem->id);
}
nvmem->read_only = device_property_present(config->dev, "read-only") ||
config->read_only || !nvmem->reg_write;
nvmem->dev.groups = nvmem_sysfs_get_groups(nvmem, config);
device_initialize(&nvmem->dev);
dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
rval = device_add(&nvmem->dev);
if (rval)
goto err_put_device;
if (config->compat) {
rval = nvmem_sysfs_setup_compat(nvmem, config);
if (rval)
goto err_device_del;
}
if (config->cells) {
rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
if (rval)
goto err_teardown_compat;
}
rval = nvmem_add_cells_from_table(nvmem);
if (rval)
goto err_remove_cells;
rval = nvmem_add_cells_from_of(nvmem);
if (rval)
goto err_remove_cells;
blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
return nvmem;
err_remove_cells:
nvmem_device_remove_all_cells(nvmem);
err_teardown_compat:
if (config->compat)
nvmem_sysfs_remove_compat(nvmem, config);
err_device_del:
device_del(&nvmem->dev);
err_put_device:
put_device(&nvmem->dev);
return ERR_PTR(rval);
}
EXPORT_SYMBOL_GPL(nvmem_register);
static void nvmem_device_release(struct kref *kref)
{
struct nvmem_device *nvmem;
nvmem = container_of(kref, struct nvmem_device, refcnt);
blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);
if (nvmem->flags & FLAG_COMPAT)
device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
nvmem_device_remove_all_cells(nvmem);
device_del(&nvmem->dev);
put_device(&nvmem->dev);
}
/**
* nvmem_unregister() - Unregister previously registered nvmem device
*
* @nvmem: Pointer to previously registered nvmem device.
*/
void nvmem_unregister(struct nvmem_device *nvmem)
{
kref_put(&nvmem->refcnt, nvmem_device_release);
}
EXPORT_SYMBOL_GPL(nvmem_unregister);
static void devm_nvmem_release(struct device *dev, void *res)
{
nvmem_unregister(*(struct nvmem_device **)res);
}
/**
* devm_nvmem_register() - Register a managed nvmem device for given
* nvmem_config.
* Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
*
* @dev: Device that uses the nvmem device.
* @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 *devm_nvmem_register(struct device *dev,
const struct nvmem_config *config)
{
struct nvmem_device **ptr, *nvmem;
ptr = devres_alloc(devm_nvmem_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
nvmem = nvmem_register(config);
if (!IS_ERR(nvmem)) {
*ptr = nvmem;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return nvmem;
}
EXPORT_SYMBOL_GPL(devm_nvmem_register);
static int devm_nvmem_match(struct device *dev, void *res, void *data)
{
struct nvmem_device **r = res;
return *r == data;
}
/**
* devm_nvmem_unregister() - Unregister previously registered managed nvmem
* device.
*
* @dev: Device that uses the nvmem device.
* @nvmem: Pointer to previously registered nvmem device.
*
* Return: Will be an negative on error or a zero on success.
*/
int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
{
return devres_release(dev, devm_nvmem_release, devm_nvmem_match, nvmem);
}
EXPORT_SYMBOL(devm_nvmem_unregister);
static struct nvmem_device *__nvmem_device_get(struct device_node *np,
const char *nvmem_name)
{
struct nvmem_device *nvmem = NULL;
mutex_lock(&nvmem_mutex);
nvmem = np ? of_nvmem_find(np) : nvmem_find(nvmem_name);
mutex_unlock(&nvmem_mutex);
if (!nvmem)
return ERR_PTR(-EPROBE_DEFER);
if (!try_module_get(nvmem->owner)) {
dev_err(&nvmem->dev,
"could not increase module refcount for cell %s\n",
nvmem_dev_name(nvmem));
put_device(&nvmem->dev);
return ERR_PTR(-EINVAL);
}
kref_get(&nvmem->refcnt);
return nvmem;
}
static void __nvmem_device_put(struct nvmem_device *nvmem)
{
put_device(&nvmem->dev);
module_put(nvmem->owner);
kref_put(&nvmem->refcnt, nvmem_device_release);
}
#if IS_ENABLED(CONFIG_OF)
/**
* of_nvmem_device_get() - Get nvmem device from a given id
*
* @np: 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 = 0;
if (id)
index = of_property_match_string(np, "nvmem-names", id);
nvmem_np = of_parse_phandle(np, "nvmem", index);
if (!nvmem_np)
return ERR_PTR(-ENOENT);
return __nvmem_device_get(nvmem_np, 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.
* @dev_name: name of the requested nvmem device.
*
* 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_device_get(NULL, 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
*
* @dev: Device that uses the 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: Device that requests the nvmem device.
* @id: name id for the requested nvmem device.
*
* 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_lookup(struct device *dev, const char *con_id)
{
struct nvmem_cell *cell = ERR_PTR(-ENOENT);
struct nvmem_cell_lookup *lookup;
struct nvmem_device *nvmem;
const char *dev_id;
if (!dev)
return ERR_PTR(-EINVAL);
dev_id = dev_name(dev);
mutex_lock(&nvmem_lookup_mutex);
list_for_each_entry(lookup, &nvmem_lookup_list, node) {
if ((strcmp(lookup->dev_id, dev_id) == 0) &&
(strcmp(lookup->con_id, con_id) == 0)) {
/* This is the right entry. */
nvmem = __nvmem_device_get(NULL, lookup->nvmem_name);
if (IS_ERR(nvmem)) {
/* Provider may not be registered yet. */
cell = ERR_CAST(nvmem);
break;
}
cell = nvmem_find_cell_by_name(nvmem,
lookup->cell_name);
if (!cell) {
__nvmem_device_put(nvmem);
cell = ERR_PTR(-ENOENT);
}
break;
}
}
mutex_unlock(&nvmem_lookup_mutex);
return cell;
}
#if IS_ENABLED(CONFIG_OF)
static struct nvmem_cell *
nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np)
{
struct nvmem_cell *iter, *cell = NULL;
mutex_lock(&nvmem_mutex);
list_for_each_entry(iter, &nvmem->cells, node) {
if (np == iter->np) {
cell = iter;
break;
}
}
mutex_unlock(&nvmem_mutex);
return cell;
}
/**
* of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
*
* @np: Device tree node that uses the nvmem cell.
* @id: nvmem cell name from nvmem-cell-names property, or NULL
* for the cell at index 0 (the lone cell with no accompanying
* 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 *id)
{
struct device_node *cell_np, *nvmem_np;
struct nvmem_device *nvmem;
struct nvmem_cell *cell;
int index = 0;
/* if cell name exists, find index to the name */
if (id)
index = of_property_match_string(np, "nvmem-cell-names", id);
cell_np = of_parse_phandle(np, "nvmem-cells", index);
if (!cell_np)
return ERR_PTR(-ENOENT);
nvmem_np = of_get_next_parent(cell_np);
if (!nvmem_np)
return ERR_PTR(-EINVAL);
nvmem = __nvmem_device_get(nvmem_np, NULL);
of_node_put(nvmem_np);
if (IS_ERR(nvmem))
return ERR_CAST(nvmem);
cell = nvmem_find_cell_by_node(nvmem, cell_np);
if (!cell) {
__nvmem_device_put(nvmem);
return ERR_PTR(-ENOENT);
}
return cell;
}
EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
#endif
/**
* nvmem_cell_get() - Get nvmem cell of device form a given cell name
*
* @dev: Device that requests the nvmem cell.
* @id: nvmem cell name to get (this corresponds with the name from the
* nvmem-cell-names property for DT systems and with the con_id from
* the lookup entry for non-DT systems).
*
* 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 *id)
{
struct nvmem_cell *cell;
if (dev->of_node) { /* try dt first */
cell = of_nvmem_cell_get(dev->of_node, id);
if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
return cell;
}
/* NULL cell id only allowed for device tree; invalid otherwise */
if (!id)
return ERR_PTR(-EINVAL);
return nvmem_cell_get_from_lookup(dev, 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: Device that requests the nvmem cell.
* @id: nvmem cell name id 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
* 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.
*
* @dev: Device that requests the nvmem cell.
* @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);
}
EXPORT_SYMBOL_GPL(nvmem_cell_put);
static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
{
u8 *p, *b;
int i, extra, 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;
}
} else {
/* point to the msb */
p += cell->bytes - 1;
}
/* result fits in less bytes */
extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
while (--extra >= 0)
*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 = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes);
if (rc)
return rc;
/* shift bits in-place */
if (cell->bit_offset || cell->nbits)
nvmem_shift_read_buffer_in_place(cell, buf);
if (len)
*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;
* can be NULL.
*
* Return: ERR_PTR() on error or a valid pointer to a 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)
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 (rc) {
kfree(buf);
return ERR_PTR(rc);
}
return buf;
}
EXPORT_SYMBOL_GPL(nvmem_cell_read);
static 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)