diff options
Diffstat (limited to 'include/linux/spi')
| -rw-r--r-- | include/linux/spi/spi-mem.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h index 250b6f5c47c2..3fe24500c5ee 100644 --- a/include/linux/spi/spi-mem.h +++ b/include/linux/spi/spi-mem.h @@ -125,6 +125,49 @@ struct spi_mem_op { } /** + * struct spi_mem_dirmap_info - Direct mapping information + * @op_tmpl: operation template that should be used by the direct mapping when + * the memory device is accessed + * @offset: absolute offset this direct mapping is pointing to + * @length: length in byte of this direct mapping + * + * These information are used by the controller specific implementation to know + * the portion of memory that is directly mapped and the spi_mem_op that should + * be used to access the device. + * A direct mapping is only valid for one direction (read or write) and this + * direction is directly encoded in the ->op_tmpl.data.dir field. + */ +struct spi_mem_dirmap_info { + struct spi_mem_op op_tmpl; + u64 offset; + u64 length; +}; + +/** + * struct spi_mem_dirmap_desc - Direct mapping descriptor + * @mem: the SPI memory device this direct mapping is attached to + * @info: information passed at direct mapping creation time + * @nodirmap: set to 1 if the SPI controller does not implement + * ->mem_ops->dirmap_create() or when this function returned an + * error. If @nodirmap is true, all spi_mem_dirmap_{read,write}() + * calls will use spi_mem_exec_op() to access the memory. This is a + * degraded mode that allows spi_mem drivers to use the same code + * no matter whether the controller supports direct mapping or not + * @priv: field pointing to controller specific data + * + * Common part of a direct mapping descriptor. This object is created by + * spi_mem_dirmap_create() and controller implementation of ->create_dirmap() + * can create/attach direct mapping resources to the descriptor in the ->priv + * field. + */ +struct spi_mem_dirmap_desc { + struct spi_mem *mem; + struct spi_mem_dirmap_info info; + unsigned int nodirmap; + void *priv; +}; + +/** * struct spi_mem - describes a SPI memory device * @spi: the underlying SPI device * @drvpriv: spi_mem_driver private data @@ -179,10 +222,32 @@ static inline void *spi_mem_get_drvdata(struct spi_mem *mem) * Note that if the implementation of this function allocates memory * dynamically, then it should do so with devm_xxx(), as we don't * have a ->free_name() function. + * @dirmap_create: create a direct mapping descriptor that can later be used to + * access the memory device. This method is optional + * @dirmap_destroy: destroy a memory descriptor previous created by + * ->dirmap_create() + * @dirmap_read: read data from the memory device using the direct mapping + * created by ->dirmap_create(). The function can return less + * data than requested (for example when the request is crossing + * the currently mapped area), and the caller of + * spi_mem_dirmap_read() is responsible for calling it again in + * this case. + * @dirmap_write: write data to the memory device using the direct mapping + * created by ->dirmap_create(). The function can return less + * data than requested (for example when the request is crossing + * the currently mapped area), and the caller of + * spi_mem_dirmap_write() is responsible for calling it again in + * this case. * * This interface should be implemented by SPI controllers providing an * high-level interface to execute SPI memory operation, which is usually the * case for QSPI controllers. + * + * Note on ->dirmap_{read,write}(): drivers should avoid accessing the direct + * mapping from the CPU because doing that can stall the CPU waiting for the + * SPI mem transaction to finish, and this will make real-time maintainers + * unhappy and might make your system less reactive. Instead, drivers should + * use DMA to access this direct mapping. */ struct spi_controller_mem_ops { int (*adjust_op_size)(struct spi_mem *mem, struct spi_mem_op *op); @@ -191,6 +256,12 @@ struct spi_controller_mem_ops { int (*exec_op)(struct spi_mem *mem, const struct spi_mem_op *op); const char *(*get_name)(struct spi_mem *mem); + int (*dirmap_create)(struct spi_mem_dirmap_desc *desc); + void (*dirmap_destroy)(struct spi_mem_dirmap_desc *desc); + ssize_t (*dirmap_read)(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, void *buf); + ssize_t (*dirmap_write)(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, const void *buf); }; /** @@ -251,6 +322,15 @@ int spi_mem_exec_op(struct spi_mem *mem, const char *spi_mem_get_name(struct spi_mem *mem); +struct spi_mem_dirmap_desc * +spi_mem_dirmap_create(struct spi_mem *mem, + const struct spi_mem_dirmap_info *info); +void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc); +ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, void *buf); +ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, const void *buf); + int spi_mem_driver_register_with_owner(struct spi_mem_driver *drv, struct module *owner); |