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Diffstat (limited to 'include/linux/spi/spi-mem.h')
| -rw-r--r-- | include/linux/spi/spi-mem.h | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h new file mode 100644 index 0000000000..f65104d2d1 --- /dev/null +++ b/include/linux/spi/spi-mem.h @@ -0,0 +1,307 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Copyright (C) 2018 Exceet Electronics GmbH + * Copyright (C) 2018 Bootlin + * + * Author: + * Peter Pan <peterpandong@micron.com> + * Boris Brezillon <boris.brezillon@bootlin.com> + */ + +#ifndef __LINUX_SPI_MEM_H +#define __LINUX_SPI_MEM_H + +#include <spi/spi.h> + +#define SPI_MEM_OP_CMD(__opcode, __buswidth) \ + { \ + .buswidth = __buswidth, \ + .opcode = __opcode, \ + } + +#define SPI_MEM_OP_ADDR(__nbytes, __val, __buswidth) \ + { \ + .nbytes = __nbytes, \ + .val = __val, \ + .buswidth = __buswidth, \ + } + +#define SPI_MEM_OP_NO_ADDR { } + +#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth) \ + { \ + .nbytes = __nbytes, \ + .buswidth = __buswidth, \ + } + +#define SPI_MEM_OP_NO_DUMMY { } + +#define SPI_MEM_OP_DATA_IN(__nbytes, __buf, __buswidth) \ + { \ + .dir = SPI_MEM_DATA_IN, \ + .nbytes = __nbytes, \ + .buf.in = __buf, \ + .buswidth = __buswidth, \ + } + +#define SPI_MEM_OP_DATA_OUT(__nbytes, __buf, __buswidth) \ + { \ + .dir = SPI_MEM_DATA_OUT, \ + .nbytes = __nbytes, \ + .buf.out = __buf, \ + .buswidth = __buswidth, \ + } + +#define SPI_MEM_OP_NO_DATA { } + +/** + * enum spi_mem_data_dir - describes the direction of a SPI memory data + * transfer from the controller perspective + * @SPI_MEM_NO_DATA: no data transferred + * @SPI_MEM_DATA_IN: data coming from the SPI memory + * @SPI_MEM_DATA_OUT: data sent to the SPI memory + */ +enum spi_mem_data_dir { + SPI_MEM_NO_DATA, + SPI_MEM_DATA_IN, + SPI_MEM_DATA_OUT, +}; + +/** + * struct spi_mem_op - describes a SPI memory operation + * @cmd.buswidth: number of IO lines used to transmit the command + * @cmd.opcode: operation opcode + * @addr.nbytes: number of address bytes to send. Can be zero if the operation + * does not need to send an address + * @addr.buswidth: number of IO lines used to transmit the address cycles + * @addr.val: address value. This value is always sent MSB first on the bus. + * Note that only @addr.nbytes are taken into account in this + * address value, so users should make sure the value fits in the + * assigned number of bytes. + * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can + * be zero if the operation does not require dummy bytes + * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes + * @data.buswidth: number of IO lanes used to send/receive the data + * @data.dir: direction of the transfer + * @data.nbytes: number of data bytes to send/receive. Can be zero if the + * operation does not involve transferring data + * @data.buf.in: input buffer (must be DMA-able) + * @data.buf.out: output buffer (must be DMA-able) + */ +struct spi_mem_op { + struct { + u8 buswidth; + u8 opcode; + } cmd; + + struct { + u8 nbytes; + u8 buswidth; + u64 val; + } addr; + + struct { + u8 nbytes; + u8 buswidth; + } dummy; + + struct { + u8 buswidth; + enum spi_mem_data_dir dir; + unsigned int nbytes; + union { + void *in; + const void *out; + } buf; + } data; +}; + +#define SPI_MEM_OP(__cmd, __addr, __dummy, __data) \ + { \ + .cmd = __cmd, \ + .addr = __addr, \ + .dummy = __dummy, \ + .data = __data, \ + } + +/** + * 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 + * @name: name of the SPI memory device + * + * Extra information that describe the SPI memory device and may be needed by + * the controller to properly handle this device should be placed here. + * + * One example would be the device size since some controller expose their SPI + * mem devices through a io-mapped region. + */ +struct spi_mem { + struct spi_device *spi; + void *drvpriv; + const char *name; +}; + +/** + * struct spi_mem_set_drvdata() - attach driver private data to a SPI mem + * device + * @mem: memory device + * @data: data to attach to the memory device + */ +static inline void spi_mem_set_drvdata(struct spi_mem *mem, void *data) +{ + mem->drvpriv = data; +} + +/** + * struct spi_mem_get_drvdata() - get driver private data attached to a SPI mem + * device + * @mem: memory device + * + * Return: the data attached to the mem device. + */ +static inline void *spi_mem_get_drvdata(struct spi_mem *mem) +{ + return mem->drvpriv; +} + +/** + * struct spi_controller_mem_ops - SPI memory operations + * @adjust_op_size: shrink the data xfer of an operation to match controller's + * limitations (can be alignment of max RX/TX size + * limitations) + * @supports_op: check if an operation is supported by the controller + * @exec_op: execute a SPI memory operation + * @get_name: get a custom name for the SPI mem device from the controller. + * This might be needed if the controller driver has been ported + * to use the SPI mem layer and a custom name is used to keep + * mtdparts compatible. + * 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); + bool (*supports_op)(struct spi_mem *mem, + const struct spi_mem_op *op); + 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); +}; + +/** + * struct spi_mem_driver - SPI memory driver + * @spidrv: inherit from a SPI driver + * @probe: probe a SPI memory. Usually where detection/initialization takes + * place + * @remove: remove a SPI memory + * + * This is just a thin wrapper around a spi_driver. The core takes care of + * allocating the spi_mem object and forwarding the probe/remove + * request to the spi_mem_driver. The reason we use this wrapper is because + * we might have to stuff more information into the spi_mem struct to let + * SPI controllers know more about the SPI memory they interact with, and + * having this intermediate layer allows us to do that without adding more + * useless fields to the spi_device object. + */ +struct spi_mem_driver { + struct driver_d spidrv; + int (*probe)(struct spi_mem *mem); + int (*remove)(struct spi_mem *mem); +}; + +int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op); + +bool spi_mem_supports_op(struct spi_mem *mem, + const struct spi_mem_op *op); + +int spi_mem_exec_op(struct spi_mem *mem, + const struct spi_mem_op *op); + +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); + +#endif /* __LINUX_SPI_MEM_H */ |