1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2022 Jonathan Neuschäfer
3
4 #include <linux/clk.h>
5 #include <linux/mfd/syscon.h>
6 #include <linux/mod_devicetable.h>
7 #include <linux/module.h>
8 #include <linux/platform_device.h>
9 #include <linux/regmap.h>
10 #include <linux/spi/spi-mem.h>
11
12 #define FIU_CFG 0x00
13 #define FIU_BURST_BFG 0x01
14 #define FIU_RESP_CFG 0x02
15 #define FIU_CFBB_PROT 0x03
16 #define FIU_FWIN1_LOW 0x04
17 #define FIU_FWIN1_HIGH 0x06
18 #define FIU_FWIN2_LOW 0x08
19 #define FIU_FWIN2_HIGH 0x0a
20 #define FIU_FWIN3_LOW 0x0c
21 #define FIU_FWIN3_HIGH 0x0e
22 #define FIU_PROT_LOCK 0x10
23 #define FIU_PROT_CLEAR 0x11
24 #define FIU_SPI_FL_CFG 0x14
25 #define FIU_UMA_CODE 0x16
26 #define FIU_UMA_AB0 0x17
27 #define FIU_UMA_AB1 0x18
28 #define FIU_UMA_AB2 0x19
29 #define FIU_UMA_DB0 0x1a
30 #define FIU_UMA_DB1 0x1b
31 #define FIU_UMA_DB2 0x1c
32 #define FIU_UMA_DB3 0x1d
33 #define FIU_UMA_CTS 0x1e
34 #define FIU_UMA_ECTS 0x1f
35
36 #define FIU_BURST_CFG_R16 3
37
38 #define FIU_UMA_CTS_D_SIZE(x) (x)
39 #define FIU_UMA_CTS_A_SIZE BIT(3)
40 #define FIU_UMA_CTS_WR BIT(4)
41 #define FIU_UMA_CTS_CS(x) ((x) << 5)
42 #define FIU_UMA_CTS_EXEC_DONE BIT(7)
43
44 #define SHM_FLASH_SIZE 0x02
45 #define SHM_FLASH_SIZE_STALL_HOST BIT(6)
46
47 /*
48 * I observed a typical wait time of 16 iterations for a UMA transfer to
49 * finish, so this should be a safe limit.
50 */
51 #define UMA_WAIT_ITERATIONS 100
52
53 /* The memory-mapped view of flash is 16 MiB long */
54 #define MAX_MEMORY_SIZE_PER_CS (16 << 20)
55 #define MAX_MEMORY_SIZE_TOTAL (4 * MAX_MEMORY_SIZE_PER_CS)
56
57 struct wpcm_fiu_spi {
58 struct device *dev;
59 struct clk *clk;
60 void __iomem *regs;
61 void __iomem *memory;
62 size_t memory_size;
63 struct regmap *shm_regmap;
64 };
65
wpcm_fiu_set_opcode(struct wpcm_fiu_spi * fiu,u8 opcode)66 static void wpcm_fiu_set_opcode(struct wpcm_fiu_spi *fiu, u8 opcode)
67 {
68 writeb(opcode, fiu->regs + FIU_UMA_CODE);
69 }
70
wpcm_fiu_set_addr(struct wpcm_fiu_spi * fiu,u32 addr)71 static void wpcm_fiu_set_addr(struct wpcm_fiu_spi *fiu, u32 addr)
72 {
73 writeb((addr >> 0) & 0xff, fiu->regs + FIU_UMA_AB0);
74 writeb((addr >> 8) & 0xff, fiu->regs + FIU_UMA_AB1);
75 writeb((addr >> 16) & 0xff, fiu->regs + FIU_UMA_AB2);
76 }
77
wpcm_fiu_set_data(struct wpcm_fiu_spi * fiu,const u8 * data,unsigned int nbytes)78 static void wpcm_fiu_set_data(struct wpcm_fiu_spi *fiu, const u8 *data, unsigned int nbytes)
79 {
80 int i;
81
82 for (i = 0; i < nbytes; i++)
83 writeb(data[i], fiu->regs + FIU_UMA_DB0 + i);
84 }
85
wpcm_fiu_get_data(struct wpcm_fiu_spi * fiu,u8 * data,unsigned int nbytes)86 static void wpcm_fiu_get_data(struct wpcm_fiu_spi *fiu, u8 *data, unsigned int nbytes)
87 {
88 int i;
89
90 for (i = 0; i < nbytes; i++)
91 data[i] = readb(fiu->regs + FIU_UMA_DB0 + i);
92 }
93
94 /*
95 * Perform a UMA (User Mode Access) operation, i.e. a software-controlled SPI transfer.
96 */
wpcm_fiu_do_uma(struct wpcm_fiu_spi * fiu,unsigned int cs,bool use_addr,bool write,int data_bytes)97 static int wpcm_fiu_do_uma(struct wpcm_fiu_spi *fiu, unsigned int cs,
98 bool use_addr, bool write, int data_bytes)
99 {
100 int i = 0;
101 u8 cts = FIU_UMA_CTS_EXEC_DONE | FIU_UMA_CTS_CS(cs);
102
103 if (use_addr)
104 cts |= FIU_UMA_CTS_A_SIZE;
105 if (write)
106 cts |= FIU_UMA_CTS_WR;
107 cts |= FIU_UMA_CTS_D_SIZE(data_bytes);
108
109 writeb(cts, fiu->regs + FIU_UMA_CTS);
110
111 for (i = 0; i < UMA_WAIT_ITERATIONS; i++)
112 if (!(readb(fiu->regs + FIU_UMA_CTS) & FIU_UMA_CTS_EXEC_DONE))
113 return 0;
114
115 dev_info(fiu->dev, "UMA transfer has not finished in %d iterations\n", UMA_WAIT_ITERATIONS);
116 return -EIO;
117 }
118
wpcm_fiu_ects_assert(struct wpcm_fiu_spi * fiu,unsigned int cs)119 static void wpcm_fiu_ects_assert(struct wpcm_fiu_spi *fiu, unsigned int cs)
120 {
121 u8 ects = readb(fiu->regs + FIU_UMA_ECTS);
122
123 ects &= ~BIT(cs);
124 writeb(ects, fiu->regs + FIU_UMA_ECTS);
125 }
126
wpcm_fiu_ects_deassert(struct wpcm_fiu_spi * fiu,unsigned int cs)127 static void wpcm_fiu_ects_deassert(struct wpcm_fiu_spi *fiu, unsigned int cs)
128 {
129 u8 ects = readb(fiu->regs + FIU_UMA_ECTS);
130
131 ects |= BIT(cs);
132 writeb(ects, fiu->regs + FIU_UMA_ECTS);
133 }
134
135 struct wpcm_fiu_op_shape {
136 bool (*match)(const struct spi_mem_op *op);
137 int (*exec)(struct spi_mem *mem, const struct spi_mem_op *op);
138 };
139
wpcm_fiu_normal_match(const struct spi_mem_op * op)140 static bool wpcm_fiu_normal_match(const struct spi_mem_op *op)
141 {
142 // Opcode 0x0b (FAST READ) is treated differently in hardware
143 if (op->cmd.opcode == 0x0b)
144 return false;
145
146 return (op->addr.nbytes == 0 || op->addr.nbytes == 3) &&
147 op->dummy.nbytes == 0 && op->data.nbytes <= 4;
148 }
149
wpcm_fiu_normal_exec(struct spi_mem * mem,const struct spi_mem_op * op)150 static int wpcm_fiu_normal_exec(struct spi_mem *mem, const struct spi_mem_op *op)
151 {
152 struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
153 int ret;
154
155 wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
156 wpcm_fiu_set_addr(fiu, op->addr.val);
157 if (op->data.dir == SPI_MEM_DATA_OUT)
158 wpcm_fiu_set_data(fiu, op->data.buf.out, op->data.nbytes);
159
160 ret = wpcm_fiu_do_uma(fiu, spi_get_chipselect(mem->spi, 0), op->addr.nbytes == 3,
161 op->data.dir == SPI_MEM_DATA_OUT, op->data.nbytes);
162
163 if (op->data.dir == SPI_MEM_DATA_IN)
164 wpcm_fiu_get_data(fiu, op->data.buf.in, op->data.nbytes);
165
166 return ret;
167 }
168
wpcm_fiu_fast_read_match(const struct spi_mem_op * op)169 static bool wpcm_fiu_fast_read_match(const struct spi_mem_op *op)
170 {
171 return op->cmd.opcode == 0x0b && op->addr.nbytes == 3 &&
172 op->dummy.nbytes == 1 &&
173 op->data.nbytes >= 1 && op->data.nbytes <= 4 &&
174 op->data.dir == SPI_MEM_DATA_IN;
175 }
176
wpcm_fiu_fast_read_exec(struct spi_mem * mem,const struct spi_mem_op * op)177 static int wpcm_fiu_fast_read_exec(struct spi_mem *mem, const struct spi_mem_op *op)
178 {
179 return -EINVAL;
180 }
181
182 /*
183 * 4-byte addressing.
184 *
185 * Flash view: [ C A A A A D D D D]
186 * bytes: 13 aa bb cc dd -> 5a a5 f0 0f
187 * FIU's view: [ C A A A][ C D D D D]
188 * FIU mode: [ read/write][ read ]
189 */
wpcm_fiu_4ba_match(const struct spi_mem_op * op)190 static bool wpcm_fiu_4ba_match(const struct spi_mem_op *op)
191 {
192 return op->addr.nbytes == 4 && op->dummy.nbytes == 0 && op->data.nbytes <= 4;
193 }
194
wpcm_fiu_4ba_exec(struct spi_mem * mem,const struct spi_mem_op * op)195 static int wpcm_fiu_4ba_exec(struct spi_mem *mem, const struct spi_mem_op *op)
196 {
197 struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
198 int cs = spi_get_chipselect(mem->spi, 0);
199
200 wpcm_fiu_ects_assert(fiu, cs);
201
202 wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
203 wpcm_fiu_set_addr(fiu, op->addr.val >> 8);
204 wpcm_fiu_do_uma(fiu, cs, true, false, 0);
205
206 wpcm_fiu_set_opcode(fiu, op->addr.val & 0xff);
207 wpcm_fiu_set_addr(fiu, 0);
208 if (op->data.dir == SPI_MEM_DATA_OUT)
209 wpcm_fiu_set_data(fiu, op->data.buf.out, op->data.nbytes);
210 wpcm_fiu_do_uma(fiu, cs, false, op->data.dir == SPI_MEM_DATA_OUT, op->data.nbytes);
211
212 wpcm_fiu_ects_deassert(fiu, cs);
213
214 if (op->data.dir == SPI_MEM_DATA_IN)
215 wpcm_fiu_get_data(fiu, op->data.buf.in, op->data.nbytes);
216
217 return 0;
218 }
219
220 /*
221 * RDID (Read Identification) needs special handling because Linux expects to
222 * be able to read 6 ID bytes and FIU can only read up to 4 at once.
223 *
224 * We're lucky in this case, because executing the RDID instruction twice will
225 * result in the same result.
226 *
227 * What we do is as follows (C: write command/opcode byte, D: read data byte,
228 * A: write address byte):
229 *
230 * 1. C D D D
231 * 2. C A A A D D D
232 */
wpcm_fiu_rdid_match(const struct spi_mem_op * op)233 static bool wpcm_fiu_rdid_match(const struct spi_mem_op *op)
234 {
235 return op->cmd.opcode == 0x9f && op->addr.nbytes == 0 &&
236 op->dummy.nbytes == 0 && op->data.nbytes == 6 &&
237 op->data.dir == SPI_MEM_DATA_IN;
238 }
239
wpcm_fiu_rdid_exec(struct spi_mem * mem,const struct spi_mem_op * op)240 static int wpcm_fiu_rdid_exec(struct spi_mem *mem, const struct spi_mem_op *op)
241 {
242 struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
243 int cs = spi_get_chipselect(mem->spi, 0);
244
245 /* First transfer */
246 wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
247 wpcm_fiu_set_addr(fiu, 0);
248 wpcm_fiu_do_uma(fiu, cs, false, false, 3);
249 wpcm_fiu_get_data(fiu, op->data.buf.in, 3);
250
251 /* Second transfer */
252 wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
253 wpcm_fiu_set_addr(fiu, 0);
254 wpcm_fiu_do_uma(fiu, cs, true, false, 3);
255 wpcm_fiu_get_data(fiu, op->data.buf.in + 3, 3);
256
257 return 0;
258 }
259
260 /*
261 * With some dummy bytes.
262 *
263 * C A A A X* X D D D D
264 * [C A A A D*][C D D D D]
265 */
wpcm_fiu_dummy_match(const struct spi_mem_op * op)266 static bool wpcm_fiu_dummy_match(const struct spi_mem_op *op)
267 {
268 // Opcode 0x0b (FAST READ) is treated differently in hardware
269 if (op->cmd.opcode == 0x0b)
270 return false;
271
272 return (op->addr.nbytes == 0 || op->addr.nbytes == 3) &&
273 op->dummy.nbytes >= 1 && op->dummy.nbytes <= 5 &&
274 op->data.nbytes <= 4;
275 }
276
wpcm_fiu_dummy_exec(struct spi_mem * mem,const struct spi_mem_op * op)277 static int wpcm_fiu_dummy_exec(struct spi_mem *mem, const struct spi_mem_op *op)
278 {
279 struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
280 int cs = spi_get_chipselect(mem->spi, 0);
281
282 wpcm_fiu_ects_assert(fiu, cs);
283
284 /* First transfer */
285 wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
286 wpcm_fiu_set_addr(fiu, op->addr.val);
287 wpcm_fiu_do_uma(fiu, cs, op->addr.nbytes != 0, true, op->dummy.nbytes - 1);
288
289 /* Second transfer */
290 wpcm_fiu_set_opcode(fiu, 0);
291 wpcm_fiu_set_addr(fiu, 0);
292 wpcm_fiu_do_uma(fiu, cs, false, false, op->data.nbytes);
293 wpcm_fiu_get_data(fiu, op->data.buf.in, op->data.nbytes);
294
295 wpcm_fiu_ects_deassert(fiu, cs);
296
297 return 0;
298 }
299
300 static const struct wpcm_fiu_op_shape wpcm_fiu_op_shapes[] = {
301 { .match = wpcm_fiu_normal_match, .exec = wpcm_fiu_normal_exec },
302 { .match = wpcm_fiu_fast_read_match, .exec = wpcm_fiu_fast_read_exec },
303 { .match = wpcm_fiu_4ba_match, .exec = wpcm_fiu_4ba_exec },
304 { .match = wpcm_fiu_rdid_match, .exec = wpcm_fiu_rdid_exec },
305 { .match = wpcm_fiu_dummy_match, .exec = wpcm_fiu_dummy_exec },
306 };
307
wpcm_fiu_find_op_shape(const struct spi_mem_op * op)308 static const struct wpcm_fiu_op_shape *wpcm_fiu_find_op_shape(const struct spi_mem_op *op)
309 {
310 size_t i;
311
312 for (i = 0; i < ARRAY_SIZE(wpcm_fiu_op_shapes); i++) {
313 const struct wpcm_fiu_op_shape *shape = &wpcm_fiu_op_shapes[i];
314
315 if (shape->match(op))
316 return shape;
317 }
318
319 return NULL;
320 }
321
wpcm_fiu_supports_op(struct spi_mem * mem,const struct spi_mem_op * op)322 static bool wpcm_fiu_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
323 {
324 if (!spi_mem_default_supports_op(mem, op))
325 return false;
326
327 if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
328 return false;
329
330 if (op->cmd.buswidth > 1 || op->addr.buswidth > 1 ||
331 op->dummy.buswidth > 1 || op->data.buswidth > 1)
332 return false;
333
334 return wpcm_fiu_find_op_shape(op) != NULL;
335 }
336
337 /*
338 * In order to ensure the integrity of SPI transfers performed via UMA,
339 * temporarily disable (stall) memory accesses coming from the host CPU.
340 */
wpcm_fiu_stall_host(struct wpcm_fiu_spi * fiu,bool stall)341 static void wpcm_fiu_stall_host(struct wpcm_fiu_spi *fiu, bool stall)
342 {
343 if (fiu->shm_regmap) {
344 int res = regmap_update_bits(fiu->shm_regmap, SHM_FLASH_SIZE,
345 SHM_FLASH_SIZE_STALL_HOST,
346 stall ? SHM_FLASH_SIZE_STALL_HOST : 0);
347 if (res)
348 dev_warn(fiu->dev, "Failed to (un)stall host memory accesses: %d\n", res);
349 }
350 }
351
wpcm_fiu_exec_op(struct spi_mem * mem,const struct spi_mem_op * op)352 static int wpcm_fiu_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
353 {
354 struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
355 const struct wpcm_fiu_op_shape *shape = wpcm_fiu_find_op_shape(op);
356
357 wpcm_fiu_stall_host(fiu, true);
358
359 if (shape)
360 return shape->exec(mem, op);
361
362 wpcm_fiu_stall_host(fiu, false);
363
364 return -EOPNOTSUPP;
365 }
366
wpcm_fiu_adjust_op_size(struct spi_mem * mem,struct spi_mem_op * op)367 static int wpcm_fiu_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
368 {
369 if (op->data.nbytes > 4)
370 op->data.nbytes = 4;
371
372 return 0;
373 }
374
wpcm_fiu_dirmap_create(struct spi_mem_dirmap_desc * desc)375 static int wpcm_fiu_dirmap_create(struct spi_mem_dirmap_desc *desc)
376 {
377 struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(desc->mem->spi->controller);
378 int cs = spi_get_chipselect(desc->mem->spi, 0);
379
380 if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
381 return -EOPNOTSUPP;
382
383 /*
384 * Unfortunately, FIU only supports a 16 MiB direct mapping window (per
385 * attached flash chip), but the SPI MEM core doesn't support partial
386 * direct mappings. This means that we can't support direct mapping on
387 * flashes that are bigger than 16 MiB.
388 */
389 if (desc->info.offset + desc->info.length > MAX_MEMORY_SIZE_PER_CS)
390 return -EINVAL;
391
392 /* Don't read past the memory window */
393 if (cs * MAX_MEMORY_SIZE_PER_CS + desc->info.offset + desc->info.length > fiu->memory_size)
394 return -EINVAL;
395
396 return 0;
397 }
398
wpcm_fiu_direct_read(struct spi_mem_dirmap_desc * desc,u64 offs,size_t len,void * buf)399 static ssize_t wpcm_fiu_direct_read(struct spi_mem_dirmap_desc *desc, u64 offs, size_t len, void *buf)
400 {
401 struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(desc->mem->spi->controller);
402 int cs = spi_get_chipselect(desc->mem->spi, 0);
403
404 if (offs >= MAX_MEMORY_SIZE_PER_CS)
405 return -ENOTSUPP;
406
407 offs += cs * MAX_MEMORY_SIZE_PER_CS;
408
409 if (!fiu->memory || offs >= fiu->memory_size)
410 return -ENOTSUPP;
411
412 len = min_t(size_t, len, fiu->memory_size - offs);
413 memcpy_fromio(buf, fiu->memory + offs, len);
414
415 return len;
416 }
417
418 static const struct spi_controller_mem_ops wpcm_fiu_mem_ops = {
419 .adjust_op_size = wpcm_fiu_adjust_op_size,
420 .supports_op = wpcm_fiu_supports_op,
421 .exec_op = wpcm_fiu_exec_op,
422 .dirmap_create = wpcm_fiu_dirmap_create,
423 .dirmap_read = wpcm_fiu_direct_read,
424 };
425
wpcm_fiu_hw_init(struct wpcm_fiu_spi * fiu)426 static void wpcm_fiu_hw_init(struct wpcm_fiu_spi *fiu)
427 {
428 /* Configure memory-mapped flash access */
429 writeb(FIU_BURST_CFG_R16, fiu->regs + FIU_BURST_BFG);
430 writeb(MAX_MEMORY_SIZE_TOTAL / (512 << 10), fiu->regs + FIU_CFG);
431 writeb(MAX_MEMORY_SIZE_PER_CS / (512 << 10) | BIT(6), fiu->regs + FIU_SPI_FL_CFG);
432
433 /* Deassert all manually asserted chip selects */
434 writeb(0x0f, fiu->regs + FIU_UMA_ECTS);
435 }
436
wpcm_fiu_probe(struct platform_device * pdev)437 static int wpcm_fiu_probe(struct platform_device *pdev)
438 {
439 struct device *dev = &pdev->dev;
440 struct spi_controller *ctrl;
441 struct wpcm_fiu_spi *fiu;
442 struct resource *res;
443
444 ctrl = devm_spi_alloc_host(dev, sizeof(*fiu));
445 if (!ctrl)
446 return -ENOMEM;
447
448 fiu = spi_controller_get_devdata(ctrl);
449 fiu->dev = dev;
450
451 fiu->regs = devm_platform_ioremap_resource_byname(pdev, "control");
452 if (IS_ERR(fiu->regs))
453 return dev_err_probe(dev, PTR_ERR(fiu->regs),
454 "Failed to map registers\n");
455
456 fiu->clk = devm_clk_get_enabled(dev, NULL);
457 if (IS_ERR(fiu->clk))
458 return PTR_ERR(fiu->clk);
459
460 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "memory");
461 fiu->memory = devm_ioremap_resource(dev, res);
462 fiu->memory_size = min_t(size_t, resource_size(res), MAX_MEMORY_SIZE_TOTAL);
463 if (IS_ERR(fiu->memory))
464 return dev_err_probe(dev, PTR_ERR(fiu->memory),
465 "Failed to map flash memory window\n");
466
467 fiu->shm_regmap = syscon_regmap_lookup_by_phandle_optional(dev->of_node, "nuvoton,shm");
468
469 wpcm_fiu_hw_init(fiu);
470
471 ctrl->bus_num = -1;
472 ctrl->mem_ops = &wpcm_fiu_mem_ops;
473 ctrl->num_chipselect = 4;
474 ctrl->dev.of_node = dev->of_node;
475
476 /*
477 * The FIU doesn't include a clock divider, the clock is entirely
478 * determined by the AHB3 bus clock.
479 */
480 ctrl->min_speed_hz = clk_get_rate(fiu->clk);
481 ctrl->max_speed_hz = clk_get_rate(fiu->clk);
482
483 return devm_spi_register_controller(dev, ctrl);
484 }
485
486 static const struct of_device_id wpcm_fiu_dt_ids[] = {
487 { .compatible = "nuvoton,wpcm450-fiu", },
488 { }
489 };
490 MODULE_DEVICE_TABLE(of, wpcm_fiu_dt_ids);
491
492 static struct platform_driver wpcm_fiu_driver = {
493 .driver = {
494 .name = "wpcm450-fiu",
495 .bus = &platform_bus_type,
496 .of_match_table = wpcm_fiu_dt_ids,
497 },
498 .probe = wpcm_fiu_probe,
499 };
500 module_platform_driver(wpcm_fiu_driver);
501
502 MODULE_DESCRIPTION("Nuvoton WPCM450 FIU SPI controller driver");
503 MODULE_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>");
504 MODULE_LICENSE("GPL");
505