tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
2
3#include <linux/kernel.h>
4#include <linux/module.h>
5#include <linux/slab.h>
6#include <linux/delay.h>
7#include <linux/bcma/bcma.h>
8#include <linux/spi/spi.h>
9
10#include "spi-bcm53xx.h"
11
12#define BCM53XXSPI_MAX_SPI_BAUD 13500000 /* 216 MHz? */
13#define BCM53XXSPI_FLASH_WINDOW SZ_32M
14
15/* The longest observed required wait was 19 ms */
16#define BCM53XXSPI_SPE_TIMEOUT_MS 80
17
18struct bcm53xxspi {
19 struct bcma_device *core;
20 struct spi_master *master;
21 void __iomem *mmio_base;
22
23 size_t read_offset;
24 bool bspi; /* Boot SPI mode with memory mapping */
25};
26
27static inline u32 bcm53xxspi_read(struct bcm53xxspi *b53spi, u16 offset)
28{
29 return bcma_read32(b53spi->core, offset);
30}
31
32static inline void bcm53xxspi_write(struct bcm53xxspi *b53spi, u16 offset,
33 u32 value)
34{
35 bcma_write32(b53spi->core, offset, value);
36}
37
38static void bcm53xxspi_disable_bspi(struct bcm53xxspi *b53spi)
39{
40 struct device *dev = &b53spi->core->dev;
41 unsigned long deadline;
42 u32 tmp;
43
44 if (!b53spi->bspi)
45 return;
46
47 tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL);
48 if (tmp & 0x1)
49 return;
50
51 deadline = jiffies + usecs_to_jiffies(200);
52 do {
53 tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_BUSY_STATUS);
54 if (!(tmp & 0x1)) {
55 bcm53xxspi_write(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL,
56 0x1);
57 ndelay(200);
58 b53spi->bspi = false;
59 return;
60 }
61 udelay(1);
62 } while (!time_after_eq(jiffies, deadline));
63
64 dev_warn(dev, "Timeout disabling BSPI\n");
65}
66
67static void bcm53xxspi_enable_bspi(struct bcm53xxspi *b53spi)
68{
69 u32 tmp;
70
71 if (b53spi->bspi)
72 return;
73
74 tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL);
75 if (!(tmp & 0x1))
76 return;
77
78 bcm53xxspi_write(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL, 0x0);
79 b53spi->bspi = true;
80}
81
82static inline unsigned int bcm53xxspi_calc_timeout(size_t len)
83{
84 /* Do some magic calculation based on length and buad. Add 10% and 1. */
85 return (len * 9000 / BCM53XXSPI_MAX_SPI_BAUD * 110 / 100) + 1;
86}
87
88static int bcm53xxspi_wait(struct bcm53xxspi *b53spi, unsigned int timeout_ms)
89{
90 unsigned long deadline;
91 u32 tmp;
92
93 /* SPE bit has to be 0 before we read MSPI STATUS */
94 deadline = jiffies + msecs_to_jiffies(BCM53XXSPI_SPE_TIMEOUT_MS);
95 do {
96 tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
97 if (!(tmp & B53SPI_MSPI_SPCR2_SPE))
98 break;
99 udelay(5);
100 } while (!time_after_eq(jiffies, deadline));
101
102 if (tmp & B53SPI_MSPI_SPCR2_SPE)
103 goto spi_timeout;
104
105 /* Check status */
106 deadline = jiffies + msecs_to_jiffies(timeout_ms);
107 do {
108 tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_MSPI_STATUS);
109 if (tmp & B53SPI_MSPI_MSPI_STATUS_SPIF) {
110 bcm53xxspi_write(b53spi, B53SPI_MSPI_MSPI_STATUS, 0);
111 return 0;
112 }
113
114 cpu_relax();
115 udelay(100);
116 } while (!time_after_eq(jiffies, deadline));
117
118spi_timeout:
119 bcm53xxspi_write(b53spi, B53SPI_MSPI_MSPI_STATUS, 0);
120
121 pr_err("Timeout waiting for SPI to be ready!\n");
122
123 return -EBUSY;
124}
125
126static void bcm53xxspi_buf_write(struct bcm53xxspi *b53spi, u8 *w_buf,
127 size_t len, bool cont)
128{
129 u32 tmp;
130 int i;
131
132 for (i = 0; i < len; i++) {
133 /* Transmit Register File MSB */
134 bcm53xxspi_write(b53spi, B53SPI_MSPI_TXRAM + 4 * (i * 2),
135 (unsigned int)w_buf[i]);
136 }
137
138 for (i = 0; i < len; i++) {
139 tmp = B53SPI_CDRAM_CONT | B53SPI_CDRAM_PCS_DISABLE_ALL |
140 B53SPI_CDRAM_PCS_DSCK;
141 if (!cont && i == len - 1)
142 tmp &= ~B53SPI_CDRAM_CONT;
143 tmp &= ~0x1;
144 /* Command Register File */
145 bcm53xxspi_write(b53spi, B53SPI_MSPI_CDRAM + 4 * i, tmp);
146 }
147
148 /* Set queue pointers */
149 bcm53xxspi_write(b53spi, B53SPI_MSPI_NEWQP, 0);
150 bcm53xxspi_write(b53spi, B53SPI_MSPI_ENDQP, len - 1);
151
152 if (cont)
153 bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 1);
154
155 /* Start SPI transfer */
156 tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
157 tmp |= B53SPI_MSPI_SPCR2_SPE;
158 if (cont)
159 tmp |= B53SPI_MSPI_SPCR2_CONT_AFTER_CMD;
160 bcm53xxspi_write(b53spi, B53SPI_MSPI_SPCR2, tmp);
161
162 /* Wait for SPI to finish */
163 bcm53xxspi_wait(b53spi, bcm53xxspi_calc_timeout(len));
164
165 if (!cont)
166 bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 0);
167
168 b53spi->read_offset = len;
169}
170
171static void bcm53xxspi_buf_read(struct bcm53xxspi *b53spi, u8 *r_buf,
172 size_t len, bool cont)
173{
174 u32 tmp;
175 int i;
176
177 for (i = 0; i < b53spi->read_offset + len; i++) {
178 tmp = B53SPI_CDRAM_CONT | B53SPI_CDRAM_PCS_DISABLE_ALL |
179 B53SPI_CDRAM_PCS_DSCK;
180 if (!cont && i == b53spi->read_offset + len - 1)
181 tmp &= ~B53SPI_CDRAM_CONT;
182 tmp &= ~0x1;
183 /* Command Register File */
184 bcm53xxspi_write(b53spi, B53SPI_MSPI_CDRAM + 4 * i, tmp);
185 }
186
187 /* Set queue pointers */
188 bcm53xxspi_write(b53spi, B53SPI_MSPI_NEWQP, 0);
189 bcm53xxspi_write(b53spi, B53SPI_MSPI_ENDQP,
190 b53spi->read_offset + len - 1);
191
192 if (cont)
193 bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 1);
194
195 /* Start SPI transfer */
196 tmp = bcm53xxspi_read(b53spi, B53SPI_MSPI_SPCR2);
197 tmp |= B53SPI_MSPI_SPCR2_SPE;
198 if (cont)
199 tmp |= B53SPI_MSPI_SPCR2_CONT_AFTER_CMD;
200 bcm53xxspi_write(b53spi, B53SPI_MSPI_SPCR2, tmp);
201
202 /* Wait for SPI to finish */
203 bcm53xxspi_wait(b53spi, bcm53xxspi_calc_timeout(len));
204
205 if (!cont)
206 bcm53xxspi_write(b53spi, B53SPI_MSPI_WRITE_LOCK, 0);
207
208 for (i = 0; i < len; ++i) {
209 int offset = b53spi->read_offset + i;
210
211 /* Data stored in the transmit register file LSB */
212 r_buf[i] = (u8)bcm53xxspi_read(b53spi, B53SPI_MSPI_RXRAM + 4 * (1 + offset * 2));
213 }
214
215 b53spi->read_offset = 0;
216}
217
218static int bcm53xxspi_transfer_one(struct spi_master *master,
219 struct spi_device *spi,
220 struct spi_transfer *t)
221{
222 struct bcm53xxspi *b53spi = spi_master_get_devdata(master);
223 u8 *buf;
224 size_t left;
225
226 bcm53xxspi_disable_bspi(b53spi);
227
228 if (t->tx_buf) {
229 buf = (u8 *)t->tx_buf;
230 left = t->len;
231 while (left) {
232 size_t to_write = min_t(size_t, 16, left);
233 bool cont = left - to_write > 0;
234
235 bcm53xxspi_buf_write(b53spi, buf, to_write, cont);
236 left -= to_write;
237 buf += to_write;
238 }
239 }
240
241 if (t->rx_buf) {
242 buf = (u8 *)t->rx_buf;
243 left = t->len;
244 while (left) {
245 size_t to_read = min_t(size_t, 16 - b53spi->read_offset,
246 left);
247 bool cont = left - to_read > 0;
248
249 bcm53xxspi_buf_read(b53spi, buf, to_read, cont);
250 left -= to_read;
251 buf += to_read;
252 }
253 }
254
255 return 0;
256}
257
258static int bcm53xxspi_flash_read(struct spi_device *spi,
259 struct spi_flash_read_message *msg)
260{
261 struct bcm53xxspi *b53spi = spi_master_get_devdata(spi->master);
262 int ret = 0;
263
264 if (msg->from + msg->len > BCM53XXSPI_FLASH_WINDOW)
265 return -EINVAL;
266
267 bcm53xxspi_enable_bspi(b53spi);
268 memcpy_fromio(msg->buf, b53spi->mmio_base + msg->from, msg->len);
269 msg->retlen = msg->len;
270
271 return ret;
272}
273
274/**************************************************
275 * BCMA
276 **************************************************/
277
278static struct spi_board_info bcm53xx_info = {
279 .modalias = "bcm53xxspiflash",
280};
281
282static const struct bcma_device_id bcm53xxspi_bcma_tbl[] = {
283 BCMA_CORE(BCMA_MANUF_BCM, BCMA_CORE_NS_QSPI, BCMA_ANY_REV, BCMA_ANY_CLASS),
284 {},
285};
286MODULE_DEVICE_TABLE(bcma, bcm53xxspi_bcma_tbl);
287
288static int bcm53xxspi_bcma_probe(struct bcma_device *core)
289{
290 struct device *dev = &core->dev;
291 struct bcm53xxspi *b53spi;
292 struct spi_master *master;
293 int err;
294
295 if (core->bus->drv_cc.core->id.rev != 42) {
296 pr_err("SPI on SoC with unsupported ChipCommon rev\n");
297 return -ENOTSUPP;
298 }
299
300 master = spi_alloc_master(dev, sizeof(*b53spi));
301 if (!master)
302 return -ENOMEM;
303
304 b53spi = spi_master_get_devdata(master);
305 b53spi->master = master;
306 b53spi->core = core;
307
308 if (core->addr_s[0])
309 b53spi->mmio_base = devm_ioremap(dev, core->addr_s[0],
310 BCM53XXSPI_FLASH_WINDOW);
311 b53spi->bspi = true;
312 bcm53xxspi_disable_bspi(b53spi);
313
314 master->transfer_one = bcm53xxspi_transfer_one;
315 if (b53spi->mmio_base)
316 master->spi_flash_read = bcm53xxspi_flash_read;
317
318 bcma_set_drvdata(core, b53spi);
319
320 err = devm_spi_register_master(dev, master);
321 if (err) {
322 spi_master_put(master);
323 bcma_set_drvdata(core, NULL);
324 return err;
325 }
326
327 /* Broadcom SoCs (at least with the CC rev 42) use SPI for flash only */
328 spi_new_device(master, &bcm53xx_info);
329
330 return 0;
331}
332
333static struct bcma_driver bcm53xxspi_bcma_driver = {
334 .name = KBUILD_MODNAME,
335 .id_table = bcm53xxspi_bcma_tbl,
336 .probe = bcm53xxspi_bcma_probe,
337};
338
339/**************************************************
340 * Init & exit
341 **************************************************/
342
343static int __init bcm53xxspi_module_init(void)
344{
345 int err = 0;
346
347 err = bcma_driver_register(&bcm53xxspi_bcma_driver);
348 if (err)
349 pr_err("Failed to register bcma driver: %d\n", err);
350
351 return err;
352}
353
354static void __exit bcm53xxspi_module_exit(void)
355{
356 bcma_driver_unregister(&bcm53xxspi_bcma_driver);
357}
358
359module_init(bcm53xxspi_module_init);
360module_exit(bcm53xxspi_module_exit);
361
362MODULE_DESCRIPTION("Broadcom BCM53xx SPI Controller driver");
363MODULE_AUTHOR("Rafał Miłecki <zajec5@gmail.com>");
364MODULE_LICENSE("GPL");