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 */