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-rw-r--r--include/linux/spi/spi-mem.h307
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diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
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+++ b/include/linux/spi/spi-mem.h
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+/* 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 */