include/linux/spi/spi-mem.h

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * Copyright (C) 2018 Exceet Electronics GmbH
   4  * Copyright (C) 2018 Bootlin
   5  *
   6  * Author:
   7  *      Peter Pan <peterpandong@micron.com>
   8  *      Boris Brezillon <boris.brezillon@bootlin.com>
   9  */
  10
  11 #ifndef __LINUX_SPI_MEM_H
  12 #define __LINUX_SPI_MEM_H
  13
  14 #include <linux/spi/spi.h>
  15
  16 #define SPI_MEM_OP_CMD(__opcode, __buswidth)                    \
  17         {                                                       \
  18                 .buswidth = __buswidth,                         \
  19                 .opcode = __opcode,                             \
  20         }
  21
  22 #define SPI_MEM_OP_ADDR(__nbytes, __val, __buswidth)            \
  23         {                                                       \
  24                 .nbytes = __nbytes,                             \
  25                 .val = __val,                                   \
  26                 .buswidth = __buswidth,                         \
  27         }
  28
  29 #define SPI_MEM_OP_NO_ADDR      { }
  30
  31 #define SPI_MEM_OP_DUMMY(__nbytes, __buswidth)                  \
  32         {                                                       \
  33                 .nbytes = __nbytes,                             \
  34                 .buswidth = __buswidth,                         \
  35         }
  36
  37 #define SPI_MEM_OP_NO_DUMMY     { }
  38
  39 #define SPI_MEM_OP_DATA_IN(__nbytes, __buf, __buswidth)         \
  40         {                                                       \
  41                 .dir = SPI_MEM_DATA_IN,                         \
  42                 .nbytes = __nbytes,                             \
  43                 .buf.in = __buf,                                \
  44                 .buswidth = __buswidth,                         \
  45         }
  46
  47 #define SPI_MEM_OP_DATA_OUT(__nbytes, __buf, __buswidth)        \
  48         {                                                       \
  49                 .dir = SPI_MEM_DATA_OUT,                        \
  50                 .nbytes = __nbytes,                             \
  51                 .buf.out = __buf,                               \
  52                 .buswidth = __buswidth,                         \
  53         }
  54
  55 #define SPI_MEM_OP_NO_DATA      { }
  56
  57 /**
  58  * enum spi_mem_data_dir - describes the direction of a SPI memory data
  59  *                         transfer from the controller perspective
  60  * @SPI_MEM_NO_DATA: no data transferred
  61  * @SPI_MEM_DATA_IN: data coming from the SPI memory
  62  * @SPI_MEM_DATA_OUT: data sent to the SPI memory
  63  */
  64 enum spi_mem_data_dir {
  65         SPI_MEM_NO_DATA,
  66         SPI_MEM_DATA_IN,
  67         SPI_MEM_DATA_OUT,
  68 };
  69
  70 /**
  71  * struct spi_mem_op - describes a SPI memory operation
  72  * @cmd.buswidth: number of IO lines used to transmit the command
  73  * @cmd.opcode: operation opcode
  74  * @addr.nbytes: number of address bytes to send. Can be zero if the operation
  75  *               does not need to send an address
  76  * @addr.buswidth: number of IO lines used to transmit the address cycles
  77  * @addr.val: address value. This value is always sent MSB first on the bus.
  78  *            Note that only @addr.nbytes are taken into account in this
  79  *            address value, so users should make sure the value fits in the
  80  *            assigned number of bytes.
  81  * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
  82  *                be zero if the operation does not require dummy bytes
  83  * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
  84  * @data.buswidth: number of IO lanes used to send/receive the data
  85  * @data.dir: direction of the transfer
  86  * @data.nbytes: number of data bytes to send/receive. Can be zero if the
  87  *               operation does not involve transferring data
  88  * @data.buf.in: input buffer (must be DMA-able)
  89  * @data.buf.out: output buffer (must be DMA-able)
  90  */
  91 struct spi_mem_op {
  92         struct {
  93                 u8 buswidth;
  94                 u8 opcode;
  95         } cmd;
  96
  97         struct {
  98                 u8 nbytes;
  99                 u8 buswidth;
 100                 u64 val;
 101         } addr;
 102
 103         struct {
 104                 u8 nbytes;
 105                 u8 buswidth;
 106         } dummy;
 107
 108         struct {
 109                 u8 buswidth;
 110                 enum spi_mem_data_dir dir;
 111                 unsigned int nbytes;
 112                 union {
 113                         void *in;
 114                         const void *out;
 115                 } buf;
 116         } data;
 117 };
 118
 119 #define SPI_MEM_OP(__cmd, __addr, __dummy, __data)              \
 120         {                                                       \
 121                 .cmd = __cmd,                                   \
 122                 .addr = __addr,                                 \
 123                 .dummy = __dummy,                               \
 124                 .data = __data,                                 \
 125         }
 126
 127 /**
 128  * struct spi_mem_dirmap_info - Direct mapping information
 129  * @op_tmpl: operation template that should be used by the direct mapping when
 130  *           the memory device is accessed
 131  * @offset: absolute offset this direct mapping is pointing to
 132  * @length: length in byte of this direct mapping
 133  *
 134  * These information are used by the controller specific implementation to know
 135  * the portion of memory that is directly mapped and the spi_mem_op that should
 136  * be used to access the device.
 137  * A direct mapping is only valid for one direction (read or write) and this
 138  * direction is directly encoded in the ->op_tmpl.data.dir field.
 139  */
 140 struct spi_mem_dirmap_info {
 141         struct spi_mem_op op_tmpl;
 142         u64 offset;
 143         u64 length;
 144 };
 145
 146 /**
 147  * struct spi_mem_dirmap_desc - Direct mapping descriptor
 148  * @mem: the SPI memory device this direct mapping is attached to
 149  * @info: information passed at direct mapping creation time
 150  * @nodirmap: set to 1 if the SPI controller does not implement
 151  *            ->mem_ops->dirmap_create() or when this function returned an
 152  *            error. If @nodirmap is true, all spi_mem_dirmap_{read,write}()
 153  *            calls will use spi_mem_exec_op() to access the memory. This is a
 154  *            degraded mode that allows spi_mem drivers to use the same code
 155  *            no matter whether the controller supports direct mapping or not
 156  * @priv: field pointing to controller specific data
 157  *
 158  * Common part of a direct mapping descriptor. This object is created by
 159  * spi_mem_dirmap_create() and controller implementation of ->create_dirmap()
 160  * can create/attach direct mapping resources to the descriptor in the ->priv
 161  * field.
 162  */
 163 struct spi_mem_dirmap_desc {
 164         struct spi_mem *mem;
 165         struct spi_mem_dirmap_info info;
 166         unsigned int nodirmap;
 167         void *priv;
 168 };
 169
 170 /**
 171  * struct spi_mem - describes a SPI memory device
 172  * @spi: the underlying SPI device
 173  * @drvpriv: spi_mem_driver private data
 174  * @name: name of the SPI memory device
 175  *
 176  * Extra information that describe the SPI memory device and may be needed by
 177  * the controller to properly handle this device should be placed here.
 178  *
 179  * One example would be the device size since some controller expose their SPI
 180  * mem devices through a io-mapped region.
 181  */
 182 struct spi_mem {
 183         struct spi_device *spi;
 184         void *drvpriv;
 185         const char *name;
 186 };
 187
 188 /**
 189  * struct spi_mem_set_drvdata() - attach driver private data to a SPI mem
 190  *                                device
 191  * @mem: memory device
 192  * @data: data to attach to the memory device
 193  */
 194 static inline void spi_mem_set_drvdata(struct spi_mem *mem, void *data)
 195 {
 196         mem->drvpriv = data;
 197 }
 198
 199 /**
 200  * struct spi_mem_get_drvdata() - get driver private data attached to a SPI mem
 201  *                                device
 202  * @mem: memory device
 203  *
 204  * Return: the data attached to the mem device.
 205  */
 206 static inline void *spi_mem_get_drvdata(struct spi_mem *mem)
 207 {
 208         return mem->drvpriv;
 209 }
 210
 211 /**
 212  * struct spi_controller_mem_ops - SPI memory operations
 213  * @adjust_op_size: shrink the data xfer of an operation to match controller's
 214  *                  limitations (can be alignment of max RX/TX size
 215  *                  limitations)
 216  * @supports_op: check if an operation is supported by the controller
 217  * @exec_op: execute a SPI memory operation
 218  * @get_name: get a custom name for the SPI mem device from the controller.
 219  *            This might be needed if the controller driver has been ported
 220  *            to use the SPI mem layer and a custom name is used to keep
 221  *            mtdparts compatible.
 222  *            Note that if the implementation of this function allocates memory
 223  *            dynamically, then it should do so with devm_xxx(), as we don't
 224  *            have a ->free_name() function.
 225  * @dirmap_create: create a direct mapping descriptor that can later be used to
 226  *                 access the memory device. This method is optional
 227  * @dirmap_destroy: destroy a memory descriptor previous created by
 228  *                  ->dirmap_create()
 229  * @dirmap_read: read data from the memory device using the direct mapping
 230  *               created by ->dirmap_create(). The function can return less
 231  *               data than requested (for example when the request is crossing
 232  *               the currently mapped area), and the caller of
 233  *               spi_mem_dirmap_read() is responsible for calling it again in
 234  *               this case.
 235  * @dirmap_write: write data to the memory device using the direct mapping
 236  *                created by ->dirmap_create(). The function can return less
 237  *                data than requested (for example when the request is crossing
 238  *                the currently mapped area), and the caller of
 239  *                spi_mem_dirmap_write() is responsible for calling it again in
 240  *                this case.
 241  *
 242  * This interface should be implemented by SPI controllers providing an
 243  * high-level interface to execute SPI memory operation, which is usually the
 244  * case for QSPI controllers.
 245  *
 246  * Note on ->dirmap_{read,write}(): drivers should avoid accessing the direct
 247  * mapping from the CPU because doing that can stall the CPU waiting for the
 248  * SPI mem transaction to finish, and this will make real-time maintainers
 249  * unhappy and might make your system less reactive. Instead, drivers should
 250  * use DMA to access this direct mapping.
 251  */
 252 struct spi_controller_mem_ops {
 253         int (*adjust_op_size)(struct spi_mem *mem, struct spi_mem_op *op);
 254         bool (*supports_op)(struct spi_mem *mem,
 255                             const struct spi_mem_op *op);
 256         int (*exec_op)(struct spi_mem *mem,
 257                        const struct spi_mem_op *op);
 258         const char *(*get_name)(struct spi_mem *mem);
 259         int (*dirmap_create)(struct spi_mem_dirmap_desc *desc);
 260         void (*dirmap_destroy)(struct spi_mem_dirmap_desc *desc);
 261         ssize_t (*dirmap_read)(struct spi_mem_dirmap_desc *desc,
 262                                u64 offs, size_t len, void *buf);
 263         ssize_t (*dirmap_write)(struct spi_mem_dirmap_desc *desc,
 264                                 u64 offs, size_t len, const void *buf);
 265 };
 266
 267 /**
 268  * struct spi_mem_driver - SPI memory driver
 269  * @spidrv: inherit from a SPI driver
 270  * @probe: probe a SPI memory. Usually where detection/initialization takes
 271  *         place
 272  * @remove: remove a SPI memory
 273  * @shutdown: take appropriate action when the system is shutdown
 274  *
 275  * This is just a thin wrapper around a spi_driver. The core takes care of
 276  * allocating the spi_mem object and forwarding the probe/remove/shutdown
 277  * request to the spi_mem_driver. The reason we use this wrapper is because
 278  * we might have to stuff more information into the spi_mem struct to let
 279  * SPI controllers know more about the SPI memory they interact with, and
 280  * having this intermediate layer allows us to do that without adding more
 281  * useless fields to the spi_device object.
 282  */
 283 struct spi_mem_driver {
 284         struct spi_driver spidrv;
 285         int (*probe)(struct spi_mem *mem);
 286         int (*remove)(struct spi_mem *mem);
 287         void (*shutdown)(struct spi_mem *mem);
 288 };
 289
 290 #if IS_ENABLED(CONFIG_SPI_MEM)
 291 int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
 292                                        const struct spi_mem_op *op,
 293                                        struct sg_table *sg);
 294
 295 void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
 296                                           const struct spi_mem_op *op,
 297                                           struct sg_table *sg);
 298
 299 bool spi_mem_default_supports_op(struct spi_mem *mem,
 300                                  const struct spi_mem_op *op);
 301
 302 #else
 303 static inline int
 304 spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
 305                                    const struct spi_mem_op *op,
 306                                    struct sg_table *sg)
 307 {
 308         return -ENOTSUPP;
 309 }
 310
 311 static inline void
 312 spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
 313                                      const struct spi_mem_op *op,
 314                                      struct sg_table *sg)
 315 {
 316 }
 317
 318 static inline
 319 bool spi_mem_default_supports_op(struct spi_mem *mem,
 320                                  const struct spi_mem_op *op)
 321 {
 322         return false;
 323 }
 324
 325 #endif /* CONFIG_SPI_MEM */
 326
 327 int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op);
 328
 329 bool spi_mem_supports_op(struct spi_mem *mem,
 330                          const struct spi_mem_op *op);
 331
 332 int spi_mem_exec_op(struct spi_mem *mem,
 333                     const struct spi_mem_op *op);
 334
 335 const char *spi_mem_get_name(struct spi_mem *mem);
 336
 337 struct spi_mem_dirmap_desc *
 338 spi_mem_dirmap_create(struct spi_mem *mem,
 339                       const struct spi_mem_dirmap_info *info);
 340 void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc);
 341 ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
 342                             u64 offs, size_t len, void *buf);
 343 ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
 344                              u64 offs, size_t len, const void *buf);
 345 struct spi_mem_dirmap_desc *
 346 devm_spi_mem_dirmap_create(struct device *dev, struct spi_mem *mem,
 347                            const struct spi_mem_dirmap_info *info);
 348 void devm_spi_mem_dirmap_destroy(struct device *dev,
 349                                  struct spi_mem_dirmap_desc *desc);
 350
 351 int spi_mem_driver_register_with_owner(struct spi_mem_driver *drv,
 352                                        struct module *owner);
 353
 354 void spi_mem_driver_unregister(struct spi_mem_driver *drv);
 355
 356 #define spi_mem_driver_register(__drv)                                  \
 357         spi_mem_driver_register_with_owner(__drv, THIS_MODULE)
 358
 359 #define module_spi_mem_driver(__drv)                                    \
 360         module_driver(__drv, spi_mem_driver_register,                   \
 361                       spi_mem_driver_unregister)
 362
 363 #endif /* __LINUX_SPI_MEM_H */