xref: /linux/include/linux/spi/spi-mem.h (revision 06d07429858317ded2db7986113a9e0129cd599b)
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 		.nbytes = 1,					\
21 	}
22 
23 #define SPI_MEM_OP_ADDR(__nbytes, __val, __buswidth)		\
24 	{							\
25 		.nbytes = __nbytes,				\
26 		.val = __val,					\
27 		.buswidth = __buswidth,				\
28 	}
29 
30 #define SPI_MEM_OP_NO_ADDR	{ }
31 
32 #define SPI_MEM_OP_DUMMY(__nbytes, __buswidth)			\
33 	{							\
34 		.nbytes = __nbytes,				\
35 		.buswidth = __buswidth,				\
36 	}
37 
38 #define SPI_MEM_OP_NO_DUMMY	{ }
39 
40 #define SPI_MEM_OP_DATA_IN(__nbytes, __buf, __buswidth)		\
41 	{							\
42 		.dir = SPI_MEM_DATA_IN,				\
43 		.nbytes = __nbytes,				\
44 		.buf.in = __buf,				\
45 		.buswidth = __buswidth,				\
46 	}
47 
48 #define SPI_MEM_OP_DATA_OUT(__nbytes, __buf, __buswidth)	\
49 	{							\
50 		.dir = SPI_MEM_DATA_OUT,			\
51 		.nbytes = __nbytes,				\
52 		.buf.out = __buf,				\
53 		.buswidth = __buswidth,				\
54 	}
55 
56 #define SPI_MEM_OP_NO_DATA	{ }
57 
58 /**
59  * enum spi_mem_data_dir - describes the direction of a SPI memory data
60  *			   transfer from the controller perspective
61  * @SPI_MEM_NO_DATA: no data transferred
62  * @SPI_MEM_DATA_IN: data coming from the SPI memory
63  * @SPI_MEM_DATA_OUT: data sent to the SPI memory
64  */
65 enum spi_mem_data_dir {
66 	SPI_MEM_NO_DATA,
67 	SPI_MEM_DATA_IN,
68 	SPI_MEM_DATA_OUT,
69 };
70 
71 /**
72  * struct spi_mem_op - describes a SPI memory operation
73  * @cmd.nbytes: number of opcode bytes (only 1 or 2 are valid). The opcode is
74  *		sent MSB-first.
75  * @cmd.buswidth: number of IO lines used to transmit the command
76  * @cmd.opcode: operation opcode
77  * @cmd.dtr: whether the command opcode should be sent in DTR mode or not
78  * @addr.nbytes: number of address bytes to send. Can be zero if the operation
79  *		 does not need to send an address
80  * @addr.buswidth: number of IO lines used to transmit the address cycles
81  * @addr.dtr: whether the address should be sent in DTR mode or not
82  * @addr.val: address value. This value is always sent MSB first on the bus.
83  *	      Note that only @addr.nbytes are taken into account in this
84  *	      address value, so users should make sure the value fits in the
85  *	      assigned number of bytes.
86  * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
87  *		  be zero if the operation does not require dummy bytes
88  * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
89  * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
90  * @data.buswidth: number of IO lanes used to send/receive the data
91  * @data.dtr: whether the data should be sent in DTR mode or not
92  * @data.ecc: whether error correction is required or not
93  * @data.dir: direction of the transfer
94  * @data.nbytes: number of data bytes to send/receive. Can be zero if the
95  *		 operation does not involve transferring data
96  * @data.buf.in: input buffer (must be DMA-able)
97  * @data.buf.out: output buffer (must be DMA-able)
98  */
99 struct spi_mem_op {
100 	struct {
101 		u8 nbytes;
102 		u8 buswidth;
103 		u8 dtr : 1;
104 		u8 __pad : 7;
105 		u16 opcode;
106 	} cmd;
107 
108 	struct {
109 		u8 nbytes;
110 		u8 buswidth;
111 		u8 dtr : 1;
112 		u8 __pad : 7;
113 		u64 val;
114 	} addr;
115 
116 	struct {
117 		u8 nbytes;
118 		u8 buswidth;
119 		u8 dtr : 1;
120 		u8 __pad : 7;
121 	} dummy;
122 
123 	struct {
124 		u8 buswidth;
125 		u8 dtr : 1;
126 		u8 ecc : 1;
127 		u8 __pad : 6;
128 		enum spi_mem_data_dir dir;
129 		unsigned int nbytes;
130 		union {
131 			void *in;
132 			const void *out;
133 		} buf;
134 	} data;
135 };
136 
137 #define SPI_MEM_OP(__cmd, __addr, __dummy, __data)		\
138 	{							\
139 		.cmd = __cmd,					\
140 		.addr = __addr,					\
141 		.dummy = __dummy,				\
142 		.data = __data,					\
143 	}
144 
145 /**
146  * struct spi_mem_dirmap_info - Direct mapping information
147  * @op_tmpl: operation template that should be used by the direct mapping when
148  *	     the memory device is accessed
149  * @offset: absolute offset this direct mapping is pointing to
150  * @length: length in byte of this direct mapping
151  *
152  * These information are used by the controller specific implementation to know
153  * the portion of memory that is directly mapped and the spi_mem_op that should
154  * be used to access the device.
155  * A direct mapping is only valid for one direction (read or write) and this
156  * direction is directly encoded in the ->op_tmpl.data.dir field.
157  */
158 struct spi_mem_dirmap_info {
159 	struct spi_mem_op op_tmpl;
160 	u64 offset;
161 	u64 length;
162 };
163 
164 /**
165  * struct spi_mem_dirmap_desc - Direct mapping descriptor
166  * @mem: the SPI memory device this direct mapping is attached to
167  * @info: information passed at direct mapping creation time
168  * @nodirmap: set to 1 if the SPI controller does not implement
169  *	      ->mem_ops->dirmap_create() or when this function returned an
170  *	      error. If @nodirmap is true, all spi_mem_dirmap_{read,write}()
171  *	      calls will use spi_mem_exec_op() to access the memory. This is a
172  *	      degraded mode that allows spi_mem drivers to use the same code
173  *	      no matter whether the controller supports direct mapping or not
174  * @priv: field pointing to controller specific data
175  *
176  * Common part of a direct mapping descriptor. This object is created by
177  * spi_mem_dirmap_create() and controller implementation of ->create_dirmap()
178  * can create/attach direct mapping resources to the descriptor in the ->priv
179  * field.
180  */
181 struct spi_mem_dirmap_desc {
182 	struct spi_mem *mem;
183 	struct spi_mem_dirmap_info info;
184 	unsigned int nodirmap;
185 	void *priv;
186 };
187 
188 /**
189  * struct spi_mem - describes a SPI memory device
190  * @spi: the underlying SPI device
191  * @drvpriv: spi_mem_driver private data
192  * @name: name of the SPI memory device
193  *
194  * Extra information that describe the SPI memory device and may be needed by
195  * the controller to properly handle this device should be placed here.
196  *
197  * One example would be the device size since some controller expose their SPI
198  * mem devices through a io-mapped region.
199  */
200 struct spi_mem {
201 	struct spi_device *spi;
202 	void *drvpriv;
203 	const char *name;
204 };
205 
206 /**
207  * struct spi_mem_set_drvdata() - attach driver private data to a SPI mem
208  *				  device
209  * @mem: memory device
210  * @data: data to attach to the memory device
211  */
spi_mem_set_drvdata(struct spi_mem * mem,void * data)212 static inline void spi_mem_set_drvdata(struct spi_mem *mem, void *data)
213 {
214 	mem->drvpriv = data;
215 }
216 
217 /**
218  * struct spi_mem_get_drvdata() - get driver private data attached to a SPI mem
219  *				  device
220  * @mem: memory device
221  *
222  * Return: the data attached to the mem device.
223  */
spi_mem_get_drvdata(struct spi_mem * mem)224 static inline void *spi_mem_get_drvdata(struct spi_mem *mem)
225 {
226 	return mem->drvpriv;
227 }
228 
229 /**
230  * struct spi_controller_mem_ops - SPI memory operations
231  * @adjust_op_size: shrink the data xfer of an operation to match controller's
232  *		    limitations (can be alignment or max RX/TX size
233  *		    limitations)
234  * @supports_op: check if an operation is supported by the controller
235  * @exec_op: execute a SPI memory operation
236  *           not all driver provides supports_op(), so it can return -EOPNOTSUPP
237  *           if the op is not supported by the driver/controller
238  * @get_name: get a custom name for the SPI mem device from the controller.
239  *	      This might be needed if the controller driver has been ported
240  *	      to use the SPI mem layer and a custom name is used to keep
241  *	      mtdparts compatible.
242  *	      Note that if the implementation of this function allocates memory
243  *	      dynamically, then it should do so with devm_xxx(), as we don't
244  *	      have a ->free_name() function.
245  * @dirmap_create: create a direct mapping descriptor that can later be used to
246  *		   access the memory device. This method is optional
247  * @dirmap_destroy: destroy a memory descriptor previous created by
248  *		    ->dirmap_create()
249  * @dirmap_read: read data from the memory device using the direct mapping
250  *		 created by ->dirmap_create(). The function can return less
251  *		 data than requested (for example when the request is crossing
252  *		 the currently mapped area), and the caller of
253  *		 spi_mem_dirmap_read() is responsible for calling it again in
254  *		 this case.
255  * @dirmap_write: write data to the memory device using the direct mapping
256  *		  created by ->dirmap_create(). The function can return less
257  *		  data than requested (for example when the request is crossing
258  *		  the currently mapped area), and the caller of
259  *		  spi_mem_dirmap_write() is responsible for calling it again in
260  *		  this case.
261  * @poll_status: poll memory device status until (status & mask) == match or
262  *               when the timeout has expired. It fills the data buffer with
263  *               the last status value.
264  *
265  * This interface should be implemented by SPI controllers providing an
266  * high-level interface to execute SPI memory operation, which is usually the
267  * case for QSPI controllers.
268  *
269  * Note on ->dirmap_{read,write}(): drivers should avoid accessing the direct
270  * mapping from the CPU because doing that can stall the CPU waiting for the
271  * SPI mem transaction to finish, and this will make real-time maintainers
272  * unhappy and might make your system less reactive. Instead, drivers should
273  * use DMA to access this direct mapping.
274  */
275 struct spi_controller_mem_ops {
276 	int (*adjust_op_size)(struct spi_mem *mem, struct spi_mem_op *op);
277 	bool (*supports_op)(struct spi_mem *mem,
278 			    const struct spi_mem_op *op);
279 	int (*exec_op)(struct spi_mem *mem,
280 		       const struct spi_mem_op *op);
281 	const char *(*get_name)(struct spi_mem *mem);
282 	int (*dirmap_create)(struct spi_mem_dirmap_desc *desc);
283 	void (*dirmap_destroy)(struct spi_mem_dirmap_desc *desc);
284 	ssize_t (*dirmap_read)(struct spi_mem_dirmap_desc *desc,
285 			       u64 offs, size_t len, void *buf);
286 	ssize_t (*dirmap_write)(struct spi_mem_dirmap_desc *desc,
287 				u64 offs, size_t len, const void *buf);
288 	int (*poll_status)(struct spi_mem *mem,
289 			   const struct spi_mem_op *op,
290 			   u16 mask, u16 match,
291 			   unsigned long initial_delay_us,
292 			   unsigned long polling_rate_us,
293 			   unsigned long timeout_ms);
294 };
295 
296 /**
297  * struct spi_controller_mem_caps - SPI memory controller capabilities
298  * @dtr: Supports DTR operations
299  * @ecc: Supports operations with error correction
300  */
301 struct spi_controller_mem_caps {
302 	bool dtr;
303 	bool ecc;
304 };
305 
306 #define spi_mem_controller_is_capable(ctlr, cap)	\
307 	((ctlr)->mem_caps && (ctlr)->mem_caps->cap)
308 
309 /**
310  * struct spi_mem_driver - SPI memory driver
311  * @spidrv: inherit from a SPI driver
312  * @probe: probe a SPI memory. Usually where detection/initialization takes
313  *	   place
314  * @remove: remove a SPI memory
315  * @shutdown: take appropriate action when the system is shutdown
316  *
317  * This is just a thin wrapper around a spi_driver. The core takes care of
318  * allocating the spi_mem object and forwarding the probe/remove/shutdown
319  * request to the spi_mem_driver. The reason we use this wrapper is because
320  * we might have to stuff more information into the spi_mem struct to let
321  * SPI controllers know more about the SPI memory they interact with, and
322  * having this intermediate layer allows us to do that without adding more
323  * useless fields to the spi_device object.
324  */
325 struct spi_mem_driver {
326 	struct spi_driver spidrv;
327 	int (*probe)(struct spi_mem *mem);
328 	int (*remove)(struct spi_mem *mem);
329 	void (*shutdown)(struct spi_mem *mem);
330 };
331 
332 #if IS_ENABLED(CONFIG_SPI_MEM)
333 int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
334 				       const struct spi_mem_op *op,
335 				       struct sg_table *sg);
336 
337 void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
338 					  const struct spi_mem_op *op,
339 					  struct sg_table *sg);
340 
341 bool spi_mem_default_supports_op(struct spi_mem *mem,
342 				 const struct spi_mem_op *op);
343 #else
344 static inline int
spi_controller_dma_map_mem_op_data(struct spi_controller * ctlr,const struct spi_mem_op * op,struct sg_table * sg)345 spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
346 				   const struct spi_mem_op *op,
347 				   struct sg_table *sg)
348 {
349 	return -ENOTSUPP;
350 }
351 
352 static inline void
spi_controller_dma_unmap_mem_op_data(struct spi_controller * ctlr,const struct spi_mem_op * op,struct sg_table * sg)353 spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
354 				     const struct spi_mem_op *op,
355 				     struct sg_table *sg)
356 {
357 }
358 
359 static inline
spi_mem_default_supports_op(struct spi_mem * mem,const struct spi_mem_op * op)360 bool spi_mem_default_supports_op(struct spi_mem *mem,
361 				 const struct spi_mem_op *op)
362 {
363 	return false;
364 }
365 #endif /* CONFIG_SPI_MEM */
366 
367 int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op);
368 
369 bool spi_mem_supports_op(struct spi_mem *mem,
370 			 const struct spi_mem_op *op);
371 
372 int spi_mem_exec_op(struct spi_mem *mem,
373 		    const struct spi_mem_op *op);
374 
375 const char *spi_mem_get_name(struct spi_mem *mem);
376 
377 struct spi_mem_dirmap_desc *
378 spi_mem_dirmap_create(struct spi_mem *mem,
379 		      const struct spi_mem_dirmap_info *info);
380 void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc);
381 ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
382 			    u64 offs, size_t len, void *buf);
383 ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
384 			     u64 offs, size_t len, const void *buf);
385 struct spi_mem_dirmap_desc *
386 devm_spi_mem_dirmap_create(struct device *dev, struct spi_mem *mem,
387 			   const struct spi_mem_dirmap_info *info);
388 void devm_spi_mem_dirmap_destroy(struct device *dev,
389 				 struct spi_mem_dirmap_desc *desc);
390 
391 int spi_mem_poll_status(struct spi_mem *mem,
392 			const struct spi_mem_op *op,
393 			u16 mask, u16 match,
394 			unsigned long initial_delay_us,
395 			unsigned long polling_delay_us,
396 			u16 timeout_ms);
397 
398 int spi_mem_driver_register_with_owner(struct spi_mem_driver *drv,
399 				       struct module *owner);
400 
401 void spi_mem_driver_unregister(struct spi_mem_driver *drv);
402 
403 #define spi_mem_driver_register(__drv)                                  \
404 	spi_mem_driver_register_with_owner(__drv, THIS_MODULE)
405 
406 #define module_spi_mem_driver(__drv)                                    \
407 	module_driver(__drv, spi_mem_driver_register,                   \
408 		      spi_mem_driver_unregister)
409 
410 #endif /* __LINUX_SPI_MEM_H */
411