xref: /openbmc/linux/drivers/infiniband/hw/hfi1/eprom.c (revision f05643a0)
1 // SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
2 /*
3  * Copyright(c) 2015, 2016 Intel Corporation.
4  */
5 
6 #include <linux/delay.h>
7 #include "hfi.h"
8 #include "common.h"
9 #include "eprom.h"
10 
11 /*
12  * The EPROM is logically divided into three partitions:
13  *	partition 0: the first 128K, visible from PCI ROM BAR
14  *	partition 1: 4K config file (sector size)
15  *	partition 2: the rest
16  */
17 #define P0_SIZE (128 * 1024)
18 #define P1_SIZE   (4 * 1024)
19 #define P1_START P0_SIZE
20 #define P2_START (P0_SIZE + P1_SIZE)
21 
22 /* controller page size, in bytes */
23 #define EP_PAGE_SIZE 256
24 #define EP_PAGE_MASK (EP_PAGE_SIZE - 1)
25 #define EP_PAGE_DWORDS (EP_PAGE_SIZE / sizeof(u32))
26 
27 /* controller commands */
28 #define CMD_SHIFT 24
29 #define CMD_NOP			    (0)
30 #define CMD_READ_DATA(addr)	    ((0x03 << CMD_SHIFT) | addr)
31 #define CMD_RELEASE_POWERDOWN_NOID  ((0xab << CMD_SHIFT))
32 
33 /* controller interface speeds */
34 #define EP_SPEED_FULL 0x2	/* full speed */
35 
36 /*
37  * How long to wait for the EPROM to become available, in ms.
38  * The spec 32 Mb EPROM takes around 40s to erase then write.
39  * Double it for safety.
40  */
41 #define EPROM_TIMEOUT 80000 /* ms */
42 
43 /*
44  * Read a 256 byte (64 dword) EPROM page.
45  * All callers have verified the offset is at a page boundary.
46  */
47 static void read_page(struct hfi1_devdata *dd, u32 offset, u32 *result)
48 {
49 	int i;
50 
51 	write_csr(dd, ASIC_EEP_ADDR_CMD, CMD_READ_DATA(offset));
52 	for (i = 0; i < EP_PAGE_DWORDS; i++)
53 		result[i] = (u32)read_csr(dd, ASIC_EEP_DATA);
54 	write_csr(dd, ASIC_EEP_ADDR_CMD, CMD_NOP); /* close open page */
55 }
56 
57 /*
58  * Read length bytes starting at offset from the start of the EPROM.
59  */
60 static int read_length(struct hfi1_devdata *dd, u32 start, u32 len, void *dest)
61 {
62 	u32 buffer[EP_PAGE_DWORDS];
63 	u32 end;
64 	u32 start_offset;
65 	u32 read_start;
66 	u32 bytes;
67 
68 	if (len == 0)
69 		return 0;
70 
71 	end = start + len;
72 
73 	/*
74 	 * Make sure the read range is not outside of the controller read
75 	 * command address range.  Note that '>' is correct below - the end
76 	 * of the range is OK if it stops at the limit, but no higher.
77 	 */
78 	if (end > (1 << CMD_SHIFT))
79 		return -EINVAL;
80 
81 	/* read the first partial page */
82 	start_offset = start & EP_PAGE_MASK;
83 	if (start_offset) {
84 		/* partial starting page */
85 
86 		/* align and read the page that contains the start */
87 		read_start = start & ~EP_PAGE_MASK;
88 		read_page(dd, read_start, buffer);
89 
90 		/* the rest of the page is available data */
91 		bytes = EP_PAGE_SIZE - start_offset;
92 
93 		if (len <= bytes) {
94 			/* end is within this page */
95 			memcpy(dest, (u8 *)buffer + start_offset, len);
96 			return 0;
97 		}
98 
99 		memcpy(dest, (u8 *)buffer + start_offset, bytes);
100 
101 		start += bytes;
102 		len -= bytes;
103 		dest += bytes;
104 	}
105 	/* start is now page aligned */
106 
107 	/* read whole pages */
108 	while (len >= EP_PAGE_SIZE) {
109 		read_page(dd, start, buffer);
110 		memcpy(dest, buffer, EP_PAGE_SIZE);
111 
112 		start += EP_PAGE_SIZE;
113 		len -= EP_PAGE_SIZE;
114 		dest += EP_PAGE_SIZE;
115 	}
116 
117 	/* read the last partial page */
118 	if (len) {
119 		read_page(dd, start, buffer);
120 		memcpy(dest, buffer, len);
121 	}
122 
123 	return 0;
124 }
125 
126 /*
127  * Initialize the EPROM handler.
128  */
129 int eprom_init(struct hfi1_devdata *dd)
130 {
131 	int ret = 0;
132 
133 	/* only the discrete chip has an EPROM */
134 	if (dd->pcidev->device != PCI_DEVICE_ID_INTEL0)
135 		return 0;
136 
137 	/*
138 	 * It is OK if both HFIs reset the EPROM as long as they don't
139 	 * do it at the same time.
140 	 */
141 	ret = acquire_chip_resource(dd, CR_EPROM, EPROM_TIMEOUT);
142 	if (ret) {
143 		dd_dev_err(dd,
144 			   "%s: unable to acquire EPROM resource, no EPROM support\n",
145 			   __func__);
146 		goto done_asic;
147 	}
148 
149 	/* reset EPROM to be sure it is in a good state */
150 
151 	/* set reset */
152 	write_csr(dd, ASIC_EEP_CTL_STAT, ASIC_EEP_CTL_STAT_EP_RESET_SMASK);
153 	/* clear reset, set speed */
154 	write_csr(dd, ASIC_EEP_CTL_STAT,
155 		  EP_SPEED_FULL << ASIC_EEP_CTL_STAT_RATE_SPI_SHIFT);
156 
157 	/* wake the device with command "release powerdown NoID" */
158 	write_csr(dd, ASIC_EEP_ADDR_CMD, CMD_RELEASE_POWERDOWN_NOID);
159 
160 	dd->eprom_available = true;
161 	release_chip_resource(dd, CR_EPROM);
162 done_asic:
163 	return ret;
164 }
165 
166 /* magic character sequence that begins an image */
167 #define IMAGE_START_MAGIC "APO="
168 
169 /* magic character sequence that might trail an image */
170 #define IMAGE_TRAIL_MAGIC "egamiAPO"
171 
172 /* EPROM file types */
173 #define HFI1_EFT_PLATFORM_CONFIG 2
174 
175 /* segment size - 128 KiB */
176 #define SEG_SIZE (128 * 1024)
177 
178 struct hfi1_eprom_footer {
179 	u32 oprom_size;		/* size of the oprom, in bytes */
180 	u16 num_table_entries;
181 	u16 version;		/* version of this footer */
182 	u32 magic;		/* must be last */
183 };
184 
185 struct hfi1_eprom_table_entry {
186 	u32 type;		/* file type */
187 	u32 offset;		/* file offset from start of EPROM */
188 	u32 size;		/* file size, in bytes */
189 };
190 
191 /*
192  * Calculate the max number of table entries that will fit within a directory
193  * buffer of size 'dir_size'.
194  */
195 #define MAX_TABLE_ENTRIES(dir_size) \
196 	(((dir_size) - sizeof(struct hfi1_eprom_footer)) / \
197 		sizeof(struct hfi1_eprom_table_entry))
198 
199 #define DIRECTORY_SIZE(n) (sizeof(struct hfi1_eprom_footer) + \
200 	(sizeof(struct hfi1_eprom_table_entry) * (n)))
201 
202 #define MAGIC4(a, b, c, d) ((d) << 24 | (c) << 16 | (b) << 8 | (a))
203 #define FOOTER_MAGIC MAGIC4('e', 'p', 'r', 'm')
204 #define FOOTER_VERSION 1
205 
206 /*
207  * Read all of partition 1.  The actual file is at the front.  Adjust
208  * the returned size if a trailing image magic is found.
209  */
210 static int read_partition_platform_config(struct hfi1_devdata *dd, void **data,
211 					  u32 *size)
212 {
213 	void *buffer;
214 	void *p;
215 	u32 length;
216 	int ret;
217 
218 	buffer = kmalloc(P1_SIZE, GFP_KERNEL);
219 	if (!buffer)
220 		return -ENOMEM;
221 
222 	ret = read_length(dd, P1_START, P1_SIZE, buffer);
223 	if (ret) {
224 		kfree(buffer);
225 		return ret;
226 	}
227 
228 	/* config partition is valid only if it starts with IMAGE_START_MAGIC */
229 	if (memcmp(buffer, IMAGE_START_MAGIC, strlen(IMAGE_START_MAGIC))) {
230 		kfree(buffer);
231 		return -ENOENT;
232 	}
233 
234 	/* scan for image magic that may trail the actual data */
235 	p = strnstr(buffer, IMAGE_TRAIL_MAGIC, P1_SIZE);
236 	if (p)
237 		length = p - buffer;
238 	else
239 		length = P1_SIZE;
240 
241 	*data = buffer;
242 	*size = length;
243 	return 0;
244 }
245 
246 /*
247  * The segment magic has been checked.  There is a footer and table of
248  * contents present.
249  *
250  * directory is a u32 aligned buffer of size EP_PAGE_SIZE.
251  */
252 static int read_segment_platform_config(struct hfi1_devdata *dd,
253 					void *directory, void **data, u32 *size)
254 {
255 	struct hfi1_eprom_footer *footer;
256 	struct hfi1_eprom_table_entry *table;
257 	struct hfi1_eprom_table_entry *entry;
258 	void *buffer = NULL;
259 	void *table_buffer = NULL;
260 	int ret, i;
261 	u32 directory_size;
262 	u32 seg_base, seg_offset;
263 	u32 bytes_available, ncopied, to_copy;
264 
265 	/* the footer is at the end of the directory */
266 	footer = (struct hfi1_eprom_footer *)
267 			(directory + EP_PAGE_SIZE - sizeof(*footer));
268 
269 	/* make sure the structure version is supported */
270 	if (footer->version != FOOTER_VERSION)
271 		return -EINVAL;
272 
273 	/* oprom size cannot be larger than a segment */
274 	if (footer->oprom_size >= SEG_SIZE)
275 		return -EINVAL;
276 
277 	/* the file table must fit in a segment with the oprom */
278 	if (footer->num_table_entries >
279 			MAX_TABLE_ENTRIES(SEG_SIZE - footer->oprom_size))
280 		return -EINVAL;
281 
282 	/* find the file table start, which precedes the footer */
283 	directory_size = DIRECTORY_SIZE(footer->num_table_entries);
284 	if (directory_size <= EP_PAGE_SIZE) {
285 		/* the file table fits into the directory buffer handed in */
286 		table = (struct hfi1_eprom_table_entry *)
287 				(directory + EP_PAGE_SIZE - directory_size);
288 	} else {
289 		/* need to allocate and read more */
290 		table_buffer = kmalloc(directory_size, GFP_KERNEL);
291 		if (!table_buffer)
292 			return -ENOMEM;
293 		ret = read_length(dd, SEG_SIZE - directory_size,
294 				  directory_size, table_buffer);
295 		if (ret)
296 			goto done;
297 		table = table_buffer;
298 	}
299 
300 	/* look for the platform configuration file in the table */
301 	for (entry = NULL, i = 0; i < footer->num_table_entries; i++) {
302 		if (table[i].type == HFI1_EFT_PLATFORM_CONFIG) {
303 			entry = &table[i];
304 			break;
305 		}
306 	}
307 	if (!entry) {
308 		ret = -ENOENT;
309 		goto done;
310 	}
311 
312 	/*
313 	 * Sanity check on the configuration file size - it should never
314 	 * be larger than 4 KiB.
315 	 */
316 	if (entry->size > (4 * 1024)) {
317 		dd_dev_err(dd, "Bad configuration file size 0x%x\n",
318 			   entry->size);
319 		ret = -EINVAL;
320 		goto done;
321 	}
322 
323 	/* check for bogus offset and size that wrap when added together */
324 	if (entry->offset + entry->size < entry->offset) {
325 		dd_dev_err(dd,
326 			   "Bad configuration file start + size 0x%x+0x%x\n",
327 			   entry->offset, entry->size);
328 		ret = -EINVAL;
329 		goto done;
330 	}
331 
332 	/* allocate the buffer to return */
333 	buffer = kmalloc(entry->size, GFP_KERNEL);
334 	if (!buffer) {
335 		ret = -ENOMEM;
336 		goto done;
337 	}
338 
339 	/*
340 	 * Extract the file by looping over segments until it is fully read.
341 	 */
342 	seg_offset = entry->offset % SEG_SIZE;
343 	seg_base = entry->offset - seg_offset;
344 	ncopied = 0;
345 	while (ncopied < entry->size) {
346 		/* calculate data bytes available in this segment */
347 
348 		/* start with the bytes from the current offset to the end */
349 		bytes_available = SEG_SIZE - seg_offset;
350 		/* subtract off footer and table from segment 0 */
351 		if (seg_base == 0) {
352 			/*
353 			 * Sanity check: should not have a starting point
354 			 * at or within the directory.
355 			 */
356 			if (bytes_available <= directory_size) {
357 				dd_dev_err(dd,
358 					   "Bad configuration file - offset 0x%x within footer+table\n",
359 					   entry->offset);
360 				ret = -EINVAL;
361 				goto done;
362 			}
363 			bytes_available -= directory_size;
364 		}
365 
366 		/* calculate bytes wanted */
367 		to_copy = entry->size - ncopied;
368 
369 		/* max out at the available bytes in this segment */
370 		if (to_copy > bytes_available)
371 			to_copy = bytes_available;
372 
373 		/*
374 		 * Read from the EPROM.
375 		 *
376 		 * The sanity check for entry->offset is done in read_length().
377 		 * The EPROM offset is validated against what the hardware
378 		 * addressing supports.  In addition, if the offset is larger
379 		 * than the actual EPROM, it silently wraps.  It will work
380 		 * fine, though the reader may not get what they expected
381 		 * from the EPROM.
382 		 */
383 		ret = read_length(dd, seg_base + seg_offset, to_copy,
384 				  buffer + ncopied);
385 		if (ret)
386 			goto done;
387 
388 		ncopied += to_copy;
389 
390 		/* set up for next segment */
391 		seg_offset = footer->oprom_size;
392 		seg_base += SEG_SIZE;
393 	}
394 
395 	/* success */
396 	ret = 0;
397 	*data = buffer;
398 	*size = entry->size;
399 
400 done:
401 	kfree(table_buffer);
402 	if (ret)
403 		kfree(buffer);
404 	return ret;
405 }
406 
407 /*
408  * Read the platform configuration file from the EPROM.
409  *
410  * On success, an allocated buffer containing the data and its size are
411  * returned.  It is up to the caller to free this buffer.
412  *
413  * Return value:
414  *   0	      - success
415  *   -ENXIO   - no EPROM is available
416  *   -EBUSY   - not able to acquire access to the EPROM
417  *   -ENOENT  - no recognizable file written
418  *   -ENOMEM  - buffer could not be allocated
419  *   -EINVAL  - invalid EPROM contentents found
420  */
421 int eprom_read_platform_config(struct hfi1_devdata *dd, void **data, u32 *size)
422 {
423 	u32 directory[EP_PAGE_DWORDS]; /* aligned buffer */
424 	int ret;
425 
426 	if (!dd->eprom_available)
427 		return -ENXIO;
428 
429 	ret = acquire_chip_resource(dd, CR_EPROM, EPROM_TIMEOUT);
430 	if (ret)
431 		return -EBUSY;
432 
433 	/* read the last page of the segment for the EPROM format magic */
434 	ret = read_length(dd, SEG_SIZE - EP_PAGE_SIZE, EP_PAGE_SIZE, directory);
435 	if (ret)
436 		goto done;
437 
438 	/* last dword of the segment contains a magic value */
439 	if (directory[EP_PAGE_DWORDS - 1] == FOOTER_MAGIC) {
440 		/* segment format */
441 		ret = read_segment_platform_config(dd, directory, data, size);
442 	} else {
443 		/* partition format */
444 		ret = read_partition_platform_config(dd, data, size);
445 	}
446 
447 done:
448 	release_chip_resource(dd, CR_EPROM);
449 	return ret;
450 }
451