1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/kernel.h>
3 #include <linux/module.h>
4 #include <linux/slab.h>
5 #include <linux/delay.h>
6 #include <linux/ioport.h>
7 #include <linux/mtd/mtd.h>
8 #include <linux/platform_device.h>
9 #include <linux/bcma/bcma.h>
10
11 #include "bcm47xxsflash.h"
12
13 MODULE_LICENSE("GPL");
14 MODULE_DESCRIPTION("Serial flash driver for BCMA bus");
15
16 static const char * const probes[] = { "bcm47xxpart", NULL };
17
18 /**************************************************
19 * Various helpers
20 **************************************************/
21
bcm47xxsflash_cmd(struct bcm47xxsflash * b47s,u32 opcode)22 static void bcm47xxsflash_cmd(struct bcm47xxsflash *b47s, u32 opcode)
23 {
24 int i;
25
26 b47s->cc_write(b47s, BCMA_CC_FLASHCTL, BCMA_CC_FLASHCTL_START | opcode);
27 for (i = 0; i < 1000; i++) {
28 if (!(b47s->cc_read(b47s, BCMA_CC_FLASHCTL) &
29 BCMA_CC_FLASHCTL_BUSY))
30 return;
31 cpu_relax();
32 }
33 pr_err("Control command failed (timeout)!\n");
34 }
35
bcm47xxsflash_poll(struct bcm47xxsflash * b47s,int timeout)36 static int bcm47xxsflash_poll(struct bcm47xxsflash *b47s, int timeout)
37 {
38 unsigned long deadline = jiffies + timeout;
39
40 do {
41 switch (b47s->type) {
42 case BCM47XXSFLASH_TYPE_ST:
43 bcm47xxsflash_cmd(b47s, OPCODE_ST_RDSR);
44 if (!(b47s->cc_read(b47s, BCMA_CC_FLASHDATA) &
45 SR_ST_WIP))
46 return 0;
47 break;
48 case BCM47XXSFLASH_TYPE_ATMEL:
49 bcm47xxsflash_cmd(b47s, OPCODE_AT_STATUS);
50 if (b47s->cc_read(b47s, BCMA_CC_FLASHDATA) &
51 SR_AT_READY)
52 return 0;
53 break;
54 }
55
56 cpu_relax();
57 udelay(1);
58 } while (!time_after_eq(jiffies, deadline));
59
60 pr_err("Timeout waiting for flash to be ready!\n");
61
62 return -EBUSY;
63 }
64
65 /**************************************************
66 * MTD ops
67 **************************************************/
68
bcm47xxsflash_erase(struct mtd_info * mtd,struct erase_info * erase)69 static int bcm47xxsflash_erase(struct mtd_info *mtd, struct erase_info *erase)
70 {
71 struct bcm47xxsflash *b47s = mtd->priv;
72
73 switch (b47s->type) {
74 case BCM47XXSFLASH_TYPE_ST:
75 bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
76 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, erase->addr);
77 /* Newer flashes have "sub-sectors" which can be erased
78 * independently with a new command: ST_SSE. The ST_SE command
79 * erases 64KB just as before.
80 */
81 if (b47s->blocksize < (64 * 1024))
82 bcm47xxsflash_cmd(b47s, OPCODE_ST_SSE);
83 else
84 bcm47xxsflash_cmd(b47s, OPCODE_ST_SE);
85 break;
86 case BCM47XXSFLASH_TYPE_ATMEL:
87 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, erase->addr << 1);
88 bcm47xxsflash_cmd(b47s, OPCODE_AT_PAGE_ERASE);
89 break;
90 }
91
92 return bcm47xxsflash_poll(b47s, HZ);
93 }
94
bcm47xxsflash_read(struct mtd_info * mtd,loff_t from,size_t len,size_t * retlen,u_char * buf)95 static int bcm47xxsflash_read(struct mtd_info *mtd, loff_t from, size_t len,
96 size_t *retlen, u_char *buf)
97 {
98 struct bcm47xxsflash *b47s = mtd->priv;
99 size_t orig_len = len;
100
101 /* Check address range */
102 if ((from + len) > mtd->size)
103 return -EINVAL;
104
105 /* Read as much as possible using fast MMIO window */
106 if (from < BCM47XXSFLASH_WINDOW_SZ) {
107 size_t memcpy_len;
108
109 memcpy_len = min(len, (size_t)(BCM47XXSFLASH_WINDOW_SZ - from));
110 memcpy_fromio(buf, b47s->window + from, memcpy_len);
111 from += memcpy_len;
112 len -= memcpy_len;
113 buf += memcpy_len;
114 }
115
116 /* Use indirect access for content out of the window */
117 for (; len; len--) {
118 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, from++);
119 bcm47xxsflash_cmd(b47s, OPCODE_ST_READ4B);
120 *buf++ = b47s->cc_read(b47s, BCMA_CC_FLASHDATA);
121 }
122
123 *retlen = orig_len;
124
125 return orig_len;
126 }
127
bcm47xxsflash_write_st(struct mtd_info * mtd,u32 offset,size_t len,const u_char * buf)128 static int bcm47xxsflash_write_st(struct mtd_info *mtd, u32 offset, size_t len,
129 const u_char *buf)
130 {
131 struct bcm47xxsflash *b47s = mtd->priv;
132 int written = 0;
133
134 /* Enable writes */
135 bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
136
137 /* Write first byte */
138 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, offset);
139 b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
140
141 /* Program page */
142 if (b47s->bcma_cc->core->id.rev < 20) {
143 bcm47xxsflash_cmd(b47s, OPCODE_ST_PP);
144 return 1; /* 1B written */
145 }
146
147 /* Program page and set CSA (on newer chips we can continue writing) */
148 bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | OPCODE_ST_PP);
149 offset++;
150 len--;
151 written++;
152
153 while (len > 0) {
154 /* Page boundary, another function call is needed */
155 if ((offset & 0xFF) == 0)
156 break;
157
158 bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | *buf++);
159 offset++;
160 len--;
161 written++;
162 }
163
164 /* All done, drop CSA & poll */
165 b47s->cc_write(b47s, BCMA_CC_FLASHCTL, 0);
166 udelay(1);
167 if (bcm47xxsflash_poll(b47s, HZ / 10))
168 pr_err("Flash rejected dropping CSA\n");
169
170 return written;
171 }
172
bcm47xxsflash_write_at(struct mtd_info * mtd,u32 offset,size_t len,const u_char * buf)173 static int bcm47xxsflash_write_at(struct mtd_info *mtd, u32 offset, size_t len,
174 const u_char *buf)
175 {
176 struct bcm47xxsflash *b47s = mtd->priv;
177 u32 mask = b47s->blocksize - 1;
178 u32 page = (offset & ~mask) << 1;
179 u32 byte = offset & mask;
180 int written = 0;
181
182 /* If we don't overwrite whole page, read it to the buffer first */
183 if (byte || (len < b47s->blocksize)) {
184 int err;
185
186 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
187 bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_LOAD);
188 /* 250 us for AT45DB321B */
189 err = bcm47xxsflash_poll(b47s, HZ / 1000);
190 if (err) {
191 pr_err("Timeout reading page 0x%X info buffer\n", page);
192 return err;
193 }
194 }
195
196 /* Change buffer content with our data */
197 while (len > 0) {
198 /* Page boundary, another function call is needed */
199 if (byte == b47s->blocksize)
200 break;
201
202 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, byte++);
203 b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
204 bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_WRITE);
205 len--;
206 written++;
207 }
208
209 /* Program page with the buffer content */
210 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
211 bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_PROGRAM);
212
213 return written;
214 }
215
bcm47xxsflash_write(struct mtd_info * mtd,loff_t to,size_t len,size_t * retlen,const u_char * buf)216 static int bcm47xxsflash_write(struct mtd_info *mtd, loff_t to, size_t len,
217 size_t *retlen, const u_char *buf)
218 {
219 struct bcm47xxsflash *b47s = mtd->priv;
220 int written;
221
222 /* Writing functions can return without writing all passed data, for
223 * example when the hardware is too old or when we git page boundary.
224 */
225 while (len > 0) {
226 switch (b47s->type) {
227 case BCM47XXSFLASH_TYPE_ST:
228 written = bcm47xxsflash_write_st(mtd, to, len, buf);
229 break;
230 case BCM47XXSFLASH_TYPE_ATMEL:
231 written = bcm47xxsflash_write_at(mtd, to, len, buf);
232 break;
233 default:
234 BUG_ON(1);
235 }
236 if (written < 0) {
237 pr_err("Error writing at offset 0x%llX\n", to);
238 return written;
239 }
240 to += (loff_t)written;
241 len -= written;
242 *retlen += written;
243 buf += written;
244 }
245
246 return 0;
247 }
248
bcm47xxsflash_fill_mtd(struct bcm47xxsflash * b47s,struct device * dev)249 static void bcm47xxsflash_fill_mtd(struct bcm47xxsflash *b47s,
250 struct device *dev)
251 {
252 struct mtd_info *mtd = &b47s->mtd;
253
254 mtd->priv = b47s;
255 mtd->dev.parent = dev;
256 mtd->name = "bcm47xxsflash";
257
258 mtd->type = MTD_NORFLASH;
259 mtd->flags = MTD_CAP_NORFLASH;
260 mtd->size = b47s->size;
261 mtd->erasesize = b47s->blocksize;
262 mtd->writesize = 1;
263 mtd->writebufsize = 1;
264
265 mtd->_erase = bcm47xxsflash_erase;
266 mtd->_read = bcm47xxsflash_read;
267 mtd->_write = bcm47xxsflash_write;
268 }
269
270 /**************************************************
271 * BCMA
272 **************************************************/
273
bcm47xxsflash_bcma_cc_read(struct bcm47xxsflash * b47s,u16 offset)274 static int bcm47xxsflash_bcma_cc_read(struct bcm47xxsflash *b47s, u16 offset)
275 {
276 return bcma_cc_read32(b47s->bcma_cc, offset);
277 }
278
bcm47xxsflash_bcma_cc_write(struct bcm47xxsflash * b47s,u16 offset,u32 value)279 static void bcm47xxsflash_bcma_cc_write(struct bcm47xxsflash *b47s, u16 offset,
280 u32 value)
281 {
282 bcma_cc_write32(b47s->bcma_cc, offset, value);
283 }
284
bcm47xxsflash_bcma_probe(struct platform_device * pdev)285 static int bcm47xxsflash_bcma_probe(struct platform_device *pdev)
286 {
287 struct device *dev = &pdev->dev;
288 struct bcma_sflash *sflash = dev_get_platdata(dev);
289 struct bcm47xxsflash *b47s;
290 struct resource *res;
291 int err;
292
293 b47s = devm_kzalloc(dev, sizeof(*b47s), GFP_KERNEL);
294 if (!b47s)
295 return -ENOMEM;
296
297 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
298 if (!res) {
299 dev_err(dev, "invalid resource\n");
300 return -EINVAL;
301 }
302 if (!devm_request_mem_region(dev, res->start, resource_size(res),
303 res->name)) {
304 dev_err(dev, "can't request region for resource %pR\n", res);
305 return -EBUSY;
306 }
307
308 b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);
309 b47s->cc_read = bcm47xxsflash_bcma_cc_read;
310 b47s->cc_write = bcm47xxsflash_bcma_cc_write;
311
312 /*
313 * On old MIPS devices cache was magically invalidated when needed,
314 * allowing us to use cached access and gain some performance. Trying
315 * the same on ARM based BCM53573 results in flash corruptions, we need
316 * to use uncached access for it.
317 *
318 * It may be arch specific, but right now there is only 1 ARM SoC using
319 * this driver, so let's follow Broadcom's reference code and check
320 * ChipCommon revision.
321 */
322 if (b47s->bcma_cc->core->id.rev == 54)
323 b47s->window = ioremap(res->start, resource_size(res));
324 else
325 b47s->window = ioremap_cache(res->start, resource_size(res));
326 if (!b47s->window) {
327 dev_err(dev, "ioremap failed for resource %pR\n", res);
328 return -ENOMEM;
329 }
330
331 switch (b47s->bcma_cc->capabilities & BCMA_CC_CAP_FLASHT) {
332 case BCMA_CC_FLASHT_STSER:
333 b47s->type = BCM47XXSFLASH_TYPE_ST;
334 break;
335 case BCMA_CC_FLASHT_ATSER:
336 b47s->type = BCM47XXSFLASH_TYPE_ATMEL;
337 break;
338 }
339
340 b47s->blocksize = sflash->blocksize;
341 b47s->numblocks = sflash->numblocks;
342 b47s->size = sflash->size;
343 bcm47xxsflash_fill_mtd(b47s, &pdev->dev);
344
345 platform_set_drvdata(pdev, b47s);
346
347 err = mtd_device_parse_register(&b47s->mtd, probes, NULL, NULL, 0);
348 if (err) {
349 pr_err("Failed to register MTD device: %d\n", err);
350 iounmap(b47s->window);
351 return err;
352 }
353
354 if (bcm47xxsflash_poll(b47s, HZ / 10))
355 pr_warn("Serial flash busy\n");
356
357 return 0;
358 }
359
bcm47xxsflash_bcma_remove(struct platform_device * pdev)360 static void bcm47xxsflash_bcma_remove(struct platform_device *pdev)
361 {
362 struct bcm47xxsflash *b47s = platform_get_drvdata(pdev);
363
364 mtd_device_unregister(&b47s->mtd);
365 iounmap(b47s->window);
366 }
367
368 static struct platform_driver bcma_sflash_driver = {
369 .probe = bcm47xxsflash_bcma_probe,
370 .remove_new = bcm47xxsflash_bcma_remove,
371 .driver = {
372 .name = "bcma_sflash",
373 },
374 };
375
376 /**************************************************
377 * Init
378 **************************************************/
379
380 module_platform_driver(bcma_sflash_driver);
381