1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 //
3 // AMD SPI controller driver
4 //
5 // Copyright (c) 2020, Advanced Micro Devices, Inc.
6 //
7 // Author: Sanjay R Mehta <sanju.mehta@amd.com>
8
9 #include <linux/acpi.h>
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/delay.h>
14 #include <linux/spi/spi.h>
15 #include <linux/iopoll.h>
16
17 #define AMD_SPI_CTRL0_REG 0x00
18 #define AMD_SPI_EXEC_CMD BIT(16)
19 #define AMD_SPI_FIFO_CLEAR BIT(20)
20 #define AMD_SPI_BUSY BIT(31)
21
22 #define AMD_SPI_OPCODE_REG 0x45
23 #define AMD_SPI_CMD_TRIGGER_REG 0x47
24 #define AMD_SPI_TRIGGER_CMD BIT(7)
25
26 #define AMD_SPI_OPCODE_MASK 0xFF
27
28 #define AMD_SPI_ALT_CS_REG 0x1D
29 #define AMD_SPI_ALT_CS_MASK 0x3
30
31 #define AMD_SPI_FIFO_BASE 0x80
32 #define AMD_SPI_TX_COUNT_REG 0x48
33 #define AMD_SPI_RX_COUNT_REG 0x4B
34 #define AMD_SPI_STATUS_REG 0x4C
35
36 #define AMD_SPI_FIFO_SIZE 70
37 #define AMD_SPI_MEM_SIZE 200
38
39 #define AMD_SPI_ENA_REG 0x20
40 #define AMD_SPI_ALT_SPD_SHIFT 20
41 #define AMD_SPI_ALT_SPD_MASK GENMASK(23, AMD_SPI_ALT_SPD_SHIFT)
42 #define AMD_SPI_SPI100_SHIFT 0
43 #define AMD_SPI_SPI100_MASK GENMASK(AMD_SPI_SPI100_SHIFT, AMD_SPI_SPI100_SHIFT)
44 #define AMD_SPI_SPEED_REG 0x6C
45 #define AMD_SPI_SPD7_SHIFT 8
46 #define AMD_SPI_SPD7_MASK GENMASK(13, AMD_SPI_SPD7_SHIFT)
47
48 #define AMD_SPI_MAX_HZ 100000000
49 #define AMD_SPI_MIN_HZ 800000
50
51 /**
52 * enum amd_spi_versions - SPI controller versions
53 * @AMD_SPI_V1: AMDI0061 hardware version
54 * @AMD_SPI_V2: AMDI0062 hardware version
55 */
56 enum amd_spi_versions {
57 AMD_SPI_V1 = 1,
58 AMD_SPI_V2,
59 };
60
61 enum amd_spi_speed {
62 F_66_66MHz,
63 F_33_33MHz,
64 F_22_22MHz,
65 F_16_66MHz,
66 F_100MHz,
67 F_800KHz,
68 SPI_SPD7 = 0x7,
69 F_50MHz = 0x4,
70 F_4MHz = 0x32,
71 F_3_17MHz = 0x3F
72 };
73
74 /**
75 * struct amd_spi_freq - Matches device speed with values to write in regs
76 * @speed_hz: Device frequency
77 * @enable_val: Value to be written to "enable register"
78 * @spd7_val: Some frequencies requires to have a value written at SPISPEED register
79 */
80 struct amd_spi_freq {
81 u32 speed_hz;
82 u32 enable_val;
83 u32 spd7_val;
84 };
85
86 /**
87 * struct amd_spi - SPI driver instance
88 * @io_remap_addr: Start address of the SPI controller registers
89 * @version: SPI controller hardware version
90 * @speed_hz: Device frequency
91 */
92 struct amd_spi {
93 void __iomem *io_remap_addr;
94 enum amd_spi_versions version;
95 unsigned int speed_hz;
96 };
97
amd_spi_readreg8(struct amd_spi * amd_spi,int idx)98 static inline u8 amd_spi_readreg8(struct amd_spi *amd_spi, int idx)
99 {
100 return ioread8((u8 __iomem *)amd_spi->io_remap_addr + idx);
101 }
102
amd_spi_writereg8(struct amd_spi * amd_spi,int idx,u8 val)103 static inline void amd_spi_writereg8(struct amd_spi *amd_spi, int idx, u8 val)
104 {
105 iowrite8(val, ((u8 __iomem *)amd_spi->io_remap_addr + idx));
106 }
107
amd_spi_setclear_reg8(struct amd_spi * amd_spi,int idx,u8 set,u8 clear)108 static void amd_spi_setclear_reg8(struct amd_spi *amd_spi, int idx, u8 set, u8 clear)
109 {
110 u8 tmp = amd_spi_readreg8(amd_spi, idx);
111
112 tmp = (tmp & ~clear) | set;
113 amd_spi_writereg8(amd_spi, idx, tmp);
114 }
115
amd_spi_readreg32(struct amd_spi * amd_spi,int idx)116 static inline u32 amd_spi_readreg32(struct amd_spi *amd_spi, int idx)
117 {
118 return ioread32((u8 __iomem *)amd_spi->io_remap_addr + idx);
119 }
120
amd_spi_writereg32(struct amd_spi * amd_spi,int idx,u32 val)121 static inline void amd_spi_writereg32(struct amd_spi *amd_spi, int idx, u32 val)
122 {
123 iowrite32(val, ((u8 __iomem *)amd_spi->io_remap_addr + idx));
124 }
125
amd_spi_setclear_reg32(struct amd_spi * amd_spi,int idx,u32 set,u32 clear)126 static inline void amd_spi_setclear_reg32(struct amd_spi *amd_spi, int idx, u32 set, u32 clear)
127 {
128 u32 tmp = amd_spi_readreg32(amd_spi, idx);
129
130 tmp = (tmp & ~clear) | set;
131 amd_spi_writereg32(amd_spi, idx, tmp);
132 }
133
amd_spi_select_chip(struct amd_spi * amd_spi,u8 cs)134 static void amd_spi_select_chip(struct amd_spi *amd_spi, u8 cs)
135 {
136 amd_spi_setclear_reg8(amd_spi, AMD_SPI_ALT_CS_REG, cs, AMD_SPI_ALT_CS_MASK);
137 }
138
amd_spi_clear_chip(struct amd_spi * amd_spi,u8 chip_select)139 static inline void amd_spi_clear_chip(struct amd_spi *amd_spi, u8 chip_select)
140 {
141 amd_spi_writereg8(amd_spi, AMD_SPI_ALT_CS_REG, chip_select & ~AMD_SPI_ALT_CS_MASK);
142 }
143
amd_spi_clear_fifo_ptr(struct amd_spi * amd_spi)144 static void amd_spi_clear_fifo_ptr(struct amd_spi *amd_spi)
145 {
146 amd_spi_setclear_reg32(amd_spi, AMD_SPI_CTRL0_REG, AMD_SPI_FIFO_CLEAR, AMD_SPI_FIFO_CLEAR);
147 }
148
amd_spi_set_opcode(struct amd_spi * amd_spi,u8 cmd_opcode)149 static int amd_spi_set_opcode(struct amd_spi *amd_spi, u8 cmd_opcode)
150 {
151 switch (amd_spi->version) {
152 case AMD_SPI_V1:
153 amd_spi_setclear_reg32(amd_spi, AMD_SPI_CTRL0_REG, cmd_opcode,
154 AMD_SPI_OPCODE_MASK);
155 return 0;
156 case AMD_SPI_V2:
157 amd_spi_writereg8(amd_spi, AMD_SPI_OPCODE_REG, cmd_opcode);
158 return 0;
159 default:
160 return -ENODEV;
161 }
162 }
163
amd_spi_set_rx_count(struct amd_spi * amd_spi,u8 rx_count)164 static inline void amd_spi_set_rx_count(struct amd_spi *amd_spi, u8 rx_count)
165 {
166 amd_spi_setclear_reg8(amd_spi, AMD_SPI_RX_COUNT_REG, rx_count, 0xff);
167 }
168
amd_spi_set_tx_count(struct amd_spi * amd_spi,u8 tx_count)169 static inline void amd_spi_set_tx_count(struct amd_spi *amd_spi, u8 tx_count)
170 {
171 amd_spi_setclear_reg8(amd_spi, AMD_SPI_TX_COUNT_REG, tx_count, 0xff);
172 }
173
amd_spi_busy_wait(struct amd_spi * amd_spi)174 static int amd_spi_busy_wait(struct amd_spi *amd_spi)
175 {
176 u32 val;
177 int reg;
178
179 switch (amd_spi->version) {
180 case AMD_SPI_V1:
181 reg = AMD_SPI_CTRL0_REG;
182 break;
183 case AMD_SPI_V2:
184 reg = AMD_SPI_STATUS_REG;
185 break;
186 default:
187 return -ENODEV;
188 }
189
190 return readl_poll_timeout(amd_spi->io_remap_addr + reg, val,
191 !(val & AMD_SPI_BUSY), 20, 2000000);
192 }
193
amd_spi_execute_opcode(struct amd_spi * amd_spi)194 static int amd_spi_execute_opcode(struct amd_spi *amd_spi)
195 {
196 int ret;
197
198 ret = amd_spi_busy_wait(amd_spi);
199 if (ret)
200 return ret;
201
202 switch (amd_spi->version) {
203 case AMD_SPI_V1:
204 /* Set ExecuteOpCode bit in the CTRL0 register */
205 amd_spi_setclear_reg32(amd_spi, AMD_SPI_CTRL0_REG, AMD_SPI_EXEC_CMD,
206 AMD_SPI_EXEC_CMD);
207 return 0;
208 case AMD_SPI_V2:
209 /* Trigger the command execution */
210 amd_spi_setclear_reg8(amd_spi, AMD_SPI_CMD_TRIGGER_REG,
211 AMD_SPI_TRIGGER_CMD, AMD_SPI_TRIGGER_CMD);
212 return 0;
213 default:
214 return -ENODEV;
215 }
216 }
217
amd_spi_host_setup(struct spi_device * spi)218 static int amd_spi_host_setup(struct spi_device *spi)
219 {
220 struct amd_spi *amd_spi = spi_controller_get_devdata(spi->controller);
221
222 amd_spi_clear_fifo_ptr(amd_spi);
223
224 return 0;
225 }
226
227 static const struct amd_spi_freq amd_spi_freq[] = {
228 { AMD_SPI_MAX_HZ, F_100MHz, 0},
229 { 66660000, F_66_66MHz, 0},
230 { 50000000, SPI_SPD7, F_50MHz},
231 { 33330000, F_33_33MHz, 0},
232 { 22220000, F_22_22MHz, 0},
233 { 16660000, F_16_66MHz, 0},
234 { 4000000, SPI_SPD7, F_4MHz},
235 { 3170000, SPI_SPD7, F_3_17MHz},
236 { AMD_SPI_MIN_HZ, F_800KHz, 0},
237 };
238
amd_set_spi_freq(struct amd_spi * amd_spi,u32 speed_hz)239 static int amd_set_spi_freq(struct amd_spi *amd_spi, u32 speed_hz)
240 {
241 unsigned int i, spd7_val, alt_spd;
242
243 if (speed_hz < AMD_SPI_MIN_HZ)
244 return -EINVAL;
245
246 for (i = 0; i < ARRAY_SIZE(amd_spi_freq); i++)
247 if (speed_hz >= amd_spi_freq[i].speed_hz)
248 break;
249
250 if (amd_spi->speed_hz == amd_spi_freq[i].speed_hz)
251 return 0;
252
253 amd_spi->speed_hz = amd_spi_freq[i].speed_hz;
254
255 alt_spd = (amd_spi_freq[i].enable_val << AMD_SPI_ALT_SPD_SHIFT)
256 & AMD_SPI_ALT_SPD_MASK;
257 amd_spi_setclear_reg32(amd_spi, AMD_SPI_ENA_REG, alt_spd,
258 AMD_SPI_ALT_SPD_MASK);
259
260 if (amd_spi->speed_hz == AMD_SPI_MAX_HZ)
261 amd_spi_setclear_reg32(amd_spi, AMD_SPI_ENA_REG, 1,
262 AMD_SPI_SPI100_MASK);
263
264 if (amd_spi_freq[i].spd7_val) {
265 spd7_val = (amd_spi_freq[i].spd7_val << AMD_SPI_SPD7_SHIFT)
266 & AMD_SPI_SPD7_MASK;
267 amd_spi_setclear_reg32(amd_spi, AMD_SPI_SPEED_REG, spd7_val,
268 AMD_SPI_SPD7_MASK);
269 }
270
271 return 0;
272 }
273
amd_spi_fifo_xfer(struct amd_spi * amd_spi,struct spi_controller * host,struct spi_message * message)274 static inline int amd_spi_fifo_xfer(struct amd_spi *amd_spi,
275 struct spi_controller *host,
276 struct spi_message *message)
277 {
278 struct spi_transfer *xfer = NULL;
279 struct spi_device *spi = message->spi;
280 u8 cmd_opcode = 0, fifo_pos = AMD_SPI_FIFO_BASE;
281 u8 *buf = NULL;
282 u32 i = 0;
283 u32 tx_len = 0, rx_len = 0;
284
285 list_for_each_entry(xfer, &message->transfers,
286 transfer_list) {
287 if (xfer->speed_hz)
288 amd_set_spi_freq(amd_spi, xfer->speed_hz);
289 else
290 amd_set_spi_freq(amd_spi, spi->max_speed_hz);
291
292 if (xfer->tx_buf) {
293 buf = (u8 *)xfer->tx_buf;
294 if (!tx_len) {
295 cmd_opcode = *(u8 *)xfer->tx_buf;
296 buf++;
297 xfer->len--;
298 }
299 tx_len += xfer->len;
300
301 /* Write data into the FIFO. */
302 for (i = 0; i < xfer->len; i++)
303 amd_spi_writereg8(amd_spi, fifo_pos + i, buf[i]);
304
305 fifo_pos += xfer->len;
306 }
307
308 /* Store no. of bytes to be received from FIFO */
309 if (xfer->rx_buf)
310 rx_len += xfer->len;
311 }
312
313 if (!buf) {
314 message->status = -EINVAL;
315 goto fin_msg;
316 }
317
318 amd_spi_set_opcode(amd_spi, cmd_opcode);
319 amd_spi_set_tx_count(amd_spi, tx_len);
320 amd_spi_set_rx_count(amd_spi, rx_len);
321
322 /* Execute command */
323 message->status = amd_spi_execute_opcode(amd_spi);
324 if (message->status)
325 goto fin_msg;
326
327 if (rx_len) {
328 message->status = amd_spi_busy_wait(amd_spi);
329 if (message->status)
330 goto fin_msg;
331
332 list_for_each_entry(xfer, &message->transfers, transfer_list)
333 if (xfer->rx_buf) {
334 buf = (u8 *)xfer->rx_buf;
335 /* Read data from FIFO to receive buffer */
336 for (i = 0; i < xfer->len; i++)
337 buf[i] = amd_spi_readreg8(amd_spi, fifo_pos + i);
338 fifo_pos += xfer->len;
339 }
340 }
341
342 /* Update statistics */
343 message->actual_length = tx_len + rx_len + 1;
344
345 fin_msg:
346 switch (amd_spi->version) {
347 case AMD_SPI_V1:
348 break;
349 case AMD_SPI_V2:
350 amd_spi_clear_chip(amd_spi, spi_get_chipselect(message->spi, 0));
351 break;
352 default:
353 return -ENODEV;
354 }
355
356 spi_finalize_current_message(host);
357
358 return message->status;
359 }
360
amd_spi_host_transfer(struct spi_controller * host,struct spi_message * msg)361 static int amd_spi_host_transfer(struct spi_controller *host,
362 struct spi_message *msg)
363 {
364 struct amd_spi *amd_spi = spi_controller_get_devdata(host);
365 struct spi_device *spi = msg->spi;
366
367 amd_spi_select_chip(amd_spi, spi_get_chipselect(spi, 0));
368
369 /*
370 * Extract spi_transfers from the spi message and
371 * program the controller.
372 */
373 return amd_spi_fifo_xfer(amd_spi, host, msg);
374 }
375
amd_spi_max_transfer_size(struct spi_device * spi)376 static size_t amd_spi_max_transfer_size(struct spi_device *spi)
377 {
378 return AMD_SPI_FIFO_SIZE;
379 }
380
amd_spi_probe(struct platform_device * pdev)381 static int amd_spi_probe(struct platform_device *pdev)
382 {
383 struct device *dev = &pdev->dev;
384 struct spi_controller *host;
385 struct amd_spi *amd_spi;
386 int err;
387
388 /* Allocate storage for host and driver private data */
389 host = devm_spi_alloc_host(dev, sizeof(struct amd_spi));
390 if (!host)
391 return dev_err_probe(dev, -ENOMEM, "Error allocating SPI host\n");
392
393 amd_spi = spi_controller_get_devdata(host);
394 amd_spi->io_remap_addr = devm_platform_ioremap_resource(pdev, 0);
395 if (IS_ERR(amd_spi->io_remap_addr))
396 return dev_err_probe(dev, PTR_ERR(amd_spi->io_remap_addr),
397 "ioremap of SPI registers failed\n");
398
399 dev_dbg(dev, "io_remap_address: %p\n", amd_spi->io_remap_addr);
400
401 amd_spi->version = (uintptr_t) device_get_match_data(dev);
402
403 /* Initialize the spi_controller fields */
404 host->bus_num = 0;
405 host->num_chipselect = 4;
406 host->mode_bits = 0;
407 host->flags = SPI_CONTROLLER_HALF_DUPLEX;
408 host->max_speed_hz = AMD_SPI_MAX_HZ;
409 host->min_speed_hz = AMD_SPI_MIN_HZ;
410 host->setup = amd_spi_host_setup;
411 host->transfer_one_message = amd_spi_host_transfer;
412 host->max_transfer_size = amd_spi_max_transfer_size;
413 host->max_message_size = amd_spi_max_transfer_size;
414
415 /* Register the controller with SPI framework */
416 err = devm_spi_register_controller(dev, host);
417 if (err)
418 return dev_err_probe(dev, err, "error registering SPI controller\n");
419
420 return 0;
421 }
422
423 #ifdef CONFIG_ACPI
424 static const struct acpi_device_id spi_acpi_match[] = {
425 { "AMDI0061", AMD_SPI_V1 },
426 { "AMDI0062", AMD_SPI_V2 },
427 {},
428 };
429 MODULE_DEVICE_TABLE(acpi, spi_acpi_match);
430 #endif
431
432 static struct platform_driver amd_spi_driver = {
433 .driver = {
434 .name = "amd_spi",
435 .acpi_match_table = ACPI_PTR(spi_acpi_match),
436 },
437 .probe = amd_spi_probe,
438 };
439
440 module_platform_driver(amd_spi_driver);
441
442 MODULE_LICENSE("Dual BSD/GPL");
443 MODULE_AUTHOR("Sanjay Mehta <sanju.mehta@amd.com>");
444 MODULE_DESCRIPTION("AMD SPI Master Controller Driver");
445
