xref: /openbmc/linux/drivers/mtd/maps/amd76xrom.c (revision 588b48ca)
1 /*
2  * amd76xrom.c
3  *
4  * Normal mappings of chips in physical memory
5  */
6 
7 #include <linux/module.h>
8 #include <linux/types.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/slab.h>
12 #include <asm/io.h>
13 #include <linux/mtd/mtd.h>
14 #include <linux/mtd/map.h>
15 #include <linux/mtd/cfi.h>
16 #include <linux/mtd/flashchip.h>
17 #include <linux/pci.h>
18 #include <linux/pci_ids.h>
19 #include <linux/list.h>
20 
21 
22 #define xstr(s) str(s)
23 #define str(s) #s
24 #define MOD_NAME xstr(KBUILD_BASENAME)
25 
26 #define ADDRESS_NAME_LEN 18
27 
28 #define ROM_PROBE_STEP_SIZE (64*1024) /* 64KiB */
29 
30 struct amd76xrom_window {
31 	void __iomem *virt;
32 	unsigned long phys;
33 	unsigned long size;
34 	struct list_head maps;
35 	struct resource rsrc;
36 	struct pci_dev *pdev;
37 };
38 
39 struct amd76xrom_map_info {
40 	struct list_head list;
41 	struct map_info map;
42 	struct mtd_info *mtd;
43 	struct resource rsrc;
44 	char map_name[sizeof(MOD_NAME) + 2 + ADDRESS_NAME_LEN];
45 };
46 
47 /* The 2 bits controlling the window size are often set to allow reading
48  * the BIOS, but too small to allow writing, since the lock registers are
49  * 4MiB lower in the address space than the data.
50  *
51  * This is intended to prevent flashing the bios, perhaps accidentally.
52  *
53  * This parameter allows the normal driver to over-ride the BIOS settings.
54  *
55  * The bits are 6 and 7.  If both bits are set, it is a 5MiB window.
56  * If only the 7 Bit is set, it is a 4MiB window.  Otherwise, a
57  * 64KiB window.
58  *
59  */
60 static uint win_size_bits;
61 module_param(win_size_bits, uint, 0);
62 MODULE_PARM_DESC(win_size_bits, "ROM window size bits override for 0x43 byte, normally set by BIOS.");
63 
64 static struct amd76xrom_window amd76xrom_window = {
65 	.maps = LIST_HEAD_INIT(amd76xrom_window.maps),
66 };
67 
68 static void amd76xrom_cleanup(struct amd76xrom_window *window)
69 {
70 	struct amd76xrom_map_info *map, *scratch;
71 	u8 byte;
72 
73 	if (window->pdev) {
74 		/* Disable writes through the rom window */
75 		pci_read_config_byte(window->pdev, 0x40, &byte);
76 		pci_write_config_byte(window->pdev, 0x40, byte & ~1);
77 		pci_dev_put(window->pdev);
78 	}
79 
80 	/* Free all of the mtd devices */
81 	list_for_each_entry_safe(map, scratch, &window->maps, list) {
82 		if (map->rsrc.parent) {
83 			release_resource(&map->rsrc);
84 		}
85 		mtd_device_unregister(map->mtd);
86 		map_destroy(map->mtd);
87 		list_del(&map->list);
88 		kfree(map);
89 	}
90 	if (window->rsrc.parent)
91 		release_resource(&window->rsrc);
92 
93 	if (window->virt) {
94 		iounmap(window->virt);
95 		window->virt = NULL;
96 		window->phys = 0;
97 		window->size = 0;
98 		window->pdev = NULL;
99 	}
100 }
101 
102 
103 static int amd76xrom_init_one(struct pci_dev *pdev,
104 			      const struct pci_device_id *ent)
105 {
106 	static char *rom_probe_types[] = { "cfi_probe", "jedec_probe", NULL };
107 	u8 byte;
108 	struct amd76xrom_window *window = &amd76xrom_window;
109 	struct amd76xrom_map_info *map = NULL;
110 	unsigned long map_top;
111 
112 	/* Remember the pci dev I find the window in - already have a ref */
113 	window->pdev = pdev;
114 
115 	/* Enable the selected rom window.  This is often incorrectly
116 	 * set up by the BIOS, and the 4MiB offset for the lock registers
117 	 * requires the full 5MiB of window space.
118 	 *
119 	 * This 'write, then read' approach leaves the bits for
120 	 * other uses of the hardware info.
121 	 */
122 	pci_read_config_byte(pdev, 0x43, &byte);
123 	pci_write_config_byte(pdev, 0x43, byte | win_size_bits );
124 
125 	/* Assume the rom window is properly setup, and find it's size */
126 	pci_read_config_byte(pdev, 0x43, &byte);
127 	if ((byte & ((1<<7)|(1<<6))) == ((1<<7)|(1<<6))) {
128 		window->phys = 0xffb00000; /* 5MiB */
129 	}
130 	else if ((byte & (1<<7)) == (1<<7)) {
131 		window->phys = 0xffc00000; /* 4MiB */
132 	}
133 	else {
134 		window->phys = 0xffff0000; /* 64KiB */
135 	}
136 	window->size = 0xffffffffUL - window->phys + 1UL;
137 
138 	/*
139 	 * Try to reserve the window mem region.  If this fails then
140 	 * it is likely due to a fragment of the window being
141 	 * "reseved" by the BIOS.  In the case that the
142 	 * request_mem_region() fails then once the rom size is
143 	 * discovered we will try to reserve the unreserved fragment.
144 	 */
145 	window->rsrc.name = MOD_NAME;
146 	window->rsrc.start = window->phys;
147 	window->rsrc.end   = window->phys + window->size - 1;
148 	window->rsrc.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
149 	if (request_resource(&iomem_resource, &window->rsrc)) {
150 		window->rsrc.parent = NULL;
151 		printk(KERN_ERR MOD_NAME
152 		       " %s(): Unable to register resource %pR - kernel bug?\n",
153 		       __func__, &window->rsrc);
154 		return -EBUSY;
155 	}
156 
157 
158 	/* Enable writes through the rom window */
159 	pci_read_config_byte(pdev, 0x40, &byte);
160 	pci_write_config_byte(pdev, 0x40, byte | 1);
161 
162 	/* FIXME handle registers 0x80 - 0x8C the bios region locks */
163 
164 	/* For write accesses caches are useless */
165 	window->virt = ioremap_nocache(window->phys, window->size);
166 	if (!window->virt) {
167 		printk(KERN_ERR MOD_NAME ": ioremap(%08lx, %08lx) failed\n",
168 			window->phys, window->size);
169 		goto out;
170 	}
171 
172 	/* Get the first address to look for an rom chip at */
173 	map_top = window->phys;
174 #if 1
175 	/* The probe sequence run over the firmware hub lock
176 	 * registers sets them to 0x7 (no access).
177 	 * Probe at most the last 4M of the address space.
178 	 */
179 	if (map_top < 0xffc00000) {
180 		map_top = 0xffc00000;
181 	}
182 #endif
183 	/* Loop  through and look for rom chips */
184 	while((map_top - 1) < 0xffffffffUL) {
185 		struct cfi_private *cfi;
186 		unsigned long offset;
187 		int i;
188 
189 		if (!map) {
190 			map = kmalloc(sizeof(*map), GFP_KERNEL);
191 		}
192 		if (!map) {
193 			printk(KERN_ERR MOD_NAME ": kmalloc failed");
194 			goto out;
195 		}
196 		memset(map, 0, sizeof(*map));
197 		INIT_LIST_HEAD(&map->list);
198 		map->map.name = map->map_name;
199 		map->map.phys = map_top;
200 		offset = map_top - window->phys;
201 		map->map.virt = (void __iomem *)
202 			(((unsigned long)(window->virt)) + offset);
203 		map->map.size = 0xffffffffUL - map_top + 1UL;
204 		/* Set the name of the map to the address I am trying */
205 		sprintf(map->map_name, "%s @%08Lx",
206 			MOD_NAME, (unsigned long long)map->map.phys);
207 
208 		/* There is no generic VPP support */
209 		for(map->map.bankwidth = 32; map->map.bankwidth;
210 			map->map.bankwidth >>= 1)
211 		{
212 			char **probe_type;
213 			/* Skip bankwidths that are not supported */
214 			if (!map_bankwidth_supported(map->map.bankwidth))
215 				continue;
216 
217 			/* Setup the map methods */
218 			simple_map_init(&map->map);
219 
220 			/* Try all of the probe methods */
221 			probe_type = rom_probe_types;
222 			for(; *probe_type; probe_type++) {
223 				map->mtd = do_map_probe(*probe_type, &map->map);
224 				if (map->mtd)
225 					goto found;
226 			}
227 		}
228 		map_top += ROM_PROBE_STEP_SIZE;
229 		continue;
230 	found:
231 		/* Trim the size if we are larger than the map */
232 		if (map->mtd->size > map->map.size) {
233 			printk(KERN_WARNING MOD_NAME
234 				" rom(%llu) larger than window(%lu). fixing...\n",
235 				(unsigned long long)map->mtd->size, map->map.size);
236 			map->mtd->size = map->map.size;
237 		}
238 		if (window->rsrc.parent) {
239 			/*
240 			 * Registering the MTD device in iomem may not be possible
241 			 * if there is a BIOS "reserved" and BUSY range.  If this
242 			 * fails then continue anyway.
243 			 */
244 			map->rsrc.name  = map->map_name;
245 			map->rsrc.start = map->map.phys;
246 			map->rsrc.end   = map->map.phys + map->mtd->size - 1;
247 			map->rsrc.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
248 			if (request_resource(&window->rsrc, &map->rsrc)) {
249 				printk(KERN_ERR MOD_NAME
250 					": cannot reserve MTD resource\n");
251 				map->rsrc.parent = NULL;
252 			}
253 		}
254 
255 		/* Make the whole region visible in the map */
256 		map->map.virt = window->virt;
257 		map->map.phys = window->phys;
258 		cfi = map->map.fldrv_priv;
259 		for(i = 0; i < cfi->numchips; i++) {
260 			cfi->chips[i].start += offset;
261 		}
262 
263 		/* Now that the mtd devices is complete claim and export it */
264 		map->mtd->owner = THIS_MODULE;
265 		if (mtd_device_register(map->mtd, NULL, 0)) {
266 			map_destroy(map->mtd);
267 			map->mtd = NULL;
268 			goto out;
269 		}
270 
271 
272 		/* Calculate the new value of map_top */
273 		map_top += map->mtd->size;
274 
275 		/* File away the map structure */
276 		list_add(&map->list, &window->maps);
277 		map = NULL;
278 	}
279 
280  out:
281 	/* Free any left over map structures */
282 	kfree(map);
283 	/* See if I have any map structures */
284 	if (list_empty(&window->maps)) {
285 		amd76xrom_cleanup(window);
286 		return -ENODEV;
287 	}
288 	return 0;
289 }
290 
291 
292 static void amd76xrom_remove_one(struct pci_dev *pdev)
293 {
294 	struct amd76xrom_window *window = &amd76xrom_window;
295 
296 	amd76xrom_cleanup(window);
297 }
298 
299 static struct pci_device_id amd76xrom_pci_tbl[] = {
300 	{ PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_7410,
301 		PCI_ANY_ID, PCI_ANY_ID, },
302 	{ PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_7440,
303 		PCI_ANY_ID, PCI_ANY_ID, },
304 	{ PCI_VENDOR_ID_AMD, 0x7468 }, /* amd8111 support */
305 	{ 0, }
306 };
307 
308 MODULE_DEVICE_TABLE(pci, amd76xrom_pci_tbl);
309 
310 #if 0
311 static struct pci_driver amd76xrom_driver = {
312 	.name =		MOD_NAME,
313 	.id_table =	amd76xrom_pci_tbl,
314 	.probe =	amd76xrom_init_one,
315 	.remove =	amd76xrom_remove_one,
316 };
317 #endif
318 
319 static int __init init_amd76xrom(void)
320 {
321 	struct pci_dev *pdev;
322 	struct pci_device_id *id;
323 	pdev = NULL;
324 	for(id = amd76xrom_pci_tbl; id->vendor; id++) {
325 		pdev = pci_get_device(id->vendor, id->device, NULL);
326 		if (pdev) {
327 			break;
328 		}
329 	}
330 	if (pdev) {
331 		return amd76xrom_init_one(pdev, &amd76xrom_pci_tbl[0]);
332 	}
333 	return -ENXIO;
334 #if 0
335 	return pci_register_driver(&amd76xrom_driver);
336 #endif
337 }
338 
339 static void __exit cleanup_amd76xrom(void)
340 {
341 	amd76xrom_remove_one(amd76xrom_window.pdev);
342 }
343 
344 module_init(init_amd76xrom);
345 module_exit(cleanup_amd76xrom);
346 
347 MODULE_LICENSE("GPL");
348 MODULE_AUTHOR("Eric Biederman <ebiederman@lnxi.com>");
349 MODULE_DESCRIPTION("MTD map driver for BIOS chips on the AMD76X southbridge");
350