diff options
Diffstat (limited to 'drivers/nvmem')
-rw-r--r-- | drivers/nvmem/core.c | 421 |
1 files changed, 420 insertions, 1 deletions
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 2b02491..8c16ae2 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -377,8 +377,12 @@ EXPORT_SYMBOL_GPL(nvmem_register); */ int nvmem_unregister(struct nvmem_device *nvmem) { - if (nvmem->users) + 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); @@ -387,6 +391,421 @@ int nvmem_unregister(struct nvmem_device *nvmem) } 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 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->bit_offset) + 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) + kfree(buf); + + if (IS_ERR_VALUE(rc)) + return rc; + + return len; +} +EXPORT_SYMBOL_GPL(nvmem_cell_write); + static int __init nvmem_init(void) { return bus_register(&nvmem_bus_type); |