diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-mem.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index 7916e655afc8..b12a7974b665 100644 --- a/drivers/spi/spi-mem.c +++ b/drivers/spi/spi-mem.c @@ -432,6 +432,210 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op) } EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size); +static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, void *buf) +{ + struct spi_mem_op op = desc->info.op_tmpl; + int ret; + + op.addr.val = desc->info.offset + offs; + op.data.buf.in = buf; + op.data.nbytes = len; + ret = spi_mem_adjust_op_size(desc->mem, &op); + if (ret) + return ret; + + ret = spi_mem_exec_op(desc->mem, &op); + if (ret) + return ret; + + return op.data.nbytes; +} + +static ssize_t spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, const void *buf) +{ + struct spi_mem_op op = desc->info.op_tmpl; + int ret; + + op.addr.val = desc->info.offset + offs; + op.data.buf.out = buf; + op.data.nbytes = len; + ret = spi_mem_adjust_op_size(desc->mem, &op); + if (ret) + return ret; + + ret = spi_mem_exec_op(desc->mem, &op); + if (ret) + return ret; + + return op.data.nbytes; +} + +/** + * spi_mem_dirmap_create() - Create a direct mapping descriptor + * @mem: SPI mem device this direct mapping should be created for + * @info: direct mapping information + * + * This function is creating a direct mapping descriptor which can then be used + * to access the memory using spi_mem_dirmap_read() or spi_mem_dirmap_write(). + * If the SPI controller driver does not support direct mapping, this function + * fallback to an implementation using spi_mem_exec_op(), so that the caller + * doesn't have to bother implementing a fallback on his own. + * + * Return: a valid pointer in case of success, and ERR_PTR() otherwise. + */ +struct spi_mem_dirmap_desc * +spi_mem_dirmap_create(struct spi_mem *mem, + const struct spi_mem_dirmap_info *info) +{ + struct spi_controller *ctlr = mem->spi->controller; + struct spi_mem_dirmap_desc *desc; + int ret = -ENOTSUPP; + + /* Make sure the number of address cycles is between 1 and 8 bytes. */ + if (!info->op_tmpl.addr.nbytes || info->op_tmpl.addr.nbytes > 8) + return ERR_PTR(-EINVAL); + + /* data.dir should either be SPI_MEM_DATA_IN or SPI_MEM_DATA_OUT. */ + if (info->op_tmpl.data.dir == SPI_MEM_NO_DATA) + return ERR_PTR(-EINVAL); + + desc = kzalloc(sizeof(*desc), GFP_KERNEL); + if (!desc) + return ERR_PTR(-ENOMEM); + + desc->mem = mem; + desc->info = *info; + if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create) + ret = ctlr->mem_ops->dirmap_create(desc); + + if (ret) { + desc->nodirmap = true; + if (!spi_mem_supports_op(desc->mem, &desc->info.op_tmpl)) + ret = -ENOTSUPP; + else + ret = 0; + } + + if (ret) { + kfree(desc); + return ERR_PTR(ret); + } + + return desc; +} +EXPORT_SYMBOL_GPL(spi_mem_dirmap_create); + +/** + * spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor + * @desc: the direct mapping descriptor to destroy + * @info: direct mapping information + * + * This function destroys a direct mapping descriptor previously created by + * spi_mem_dirmap_create(). + */ +void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc) +{ + struct spi_controller *ctlr = desc->mem->spi->controller; + + if (!desc->nodirmap && ctlr->mem_ops && ctlr->mem_ops->dirmap_destroy) + ctlr->mem_ops->dirmap_destroy(desc); +} +EXPORT_SYMBOL_GPL(spi_mem_dirmap_destroy); + +/** + * spi_mem_dirmap_dirmap_read() - Read data through a direct mapping + * @desc: direct mapping descriptor + * @offs: offset to start reading from. Note that this is not an absolute + * offset, but the offset within the direct mapping which already has + * its own offset + * @len: length in bytes + * @buf: destination buffer. This buffer must be DMA-able + * + * This function reads data from a memory device using a direct mapping + * previously instantiated with spi_mem_dirmap_create(). + * + * Return: the amount of data read from the memory device or a negative error + * code. Note that the returned size might be smaller than @len, and the caller + * is responsible for calling spi_mem_dirmap_read() again when that happens. + */ +ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, void *buf) +{ + struct spi_controller *ctlr = desc->mem->spi->controller; + ssize_t ret; + + if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN) + return -EINVAL; + + if (!len) + return 0; + + if (desc->nodirmap) { + ret = spi_mem_no_dirmap_read(desc, offs, len, buf); + } else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_read) { + ret = spi_mem_access_start(desc->mem); + if (ret) + return ret; + + ret = ctlr->mem_ops->dirmap_read(desc, offs, len, buf); + + spi_mem_access_end(desc->mem); + } else { + ret = -ENOTSUPP; + } + + return ret; +} +EXPORT_SYMBOL_GPL(spi_mem_dirmap_read); + +/** + * spi_mem_dirmap_dirmap_write() - Write data through a direct mapping + * @desc: direct mapping descriptor + * @offs: offset to start writing from. Note that this is not an absolute + * offset, but the offset within the direct mapping which already has + * its own offset + * @len: length in bytes + * @buf: source buffer. This buffer must be DMA-able + * + * This function writes data to a memory device using a direct mapping + * previously instantiated with spi_mem_dirmap_create(). + * + * Return: the amount of data written to the memory device or a negative error + * code. Note that the returned size might be smaller than @len, and the caller + * is responsible for calling spi_mem_dirmap_write() again when that happens. + */ +ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, const void *buf) +{ + struct spi_controller *ctlr = desc->mem->spi->controller; + ssize_t ret; + + if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_OUT) + return -EINVAL; + + if (!len) + return 0; + + if (desc->nodirmap) { + ret = spi_mem_no_dirmap_write(desc, offs, len, buf); + } else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_write) { + ret = spi_mem_access_start(desc->mem); + if (ret) + return ret; + + ret = ctlr->mem_ops->dirmap_write(desc, offs, len, buf); + + spi_mem_access_end(desc->mem); + } else { + ret = -ENOTSUPP; + } + + return ret; +} +EXPORT_SYMBOL_GPL(spi_mem_dirmap_write); + static inline struct spi_mem_driver *to_spi_mem_drv(struct device_driver *drv) { return container_of(drv, struct spi_mem_driver, spidrv.driver); |