xref: /openbmc/linux/drivers/mtd/maps/ck804xrom.c (revision 0bf49ffb)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ck804xrom.c
4  *
5  * Normal mappings of chips in physical memory
6  *
7  * Dave Olsen <dolsen@lnxi.com>
8  * Ryan Jackson <rjackson@lnxi.com>
9  */
10 
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <asm/io.h>
17 #include <linux/mtd/mtd.h>
18 #include <linux/mtd/map.h>
19 #include <linux/mtd/cfi.h>
20 #include <linux/mtd/flashchip.h>
21 #include <linux/pci.h>
22 #include <linux/pci_ids.h>
23 #include <linux/list.h>
24 
25 
26 #define MOD_NAME KBUILD_BASENAME
27 
28 #define ADDRESS_NAME_LEN 18
29 
30 #define ROM_PROBE_STEP_SIZE (64*1024)
31 
32 #define DEV_CK804 1
33 #define DEV_MCP55 2
34 
35 struct ck804xrom_window {
36 	void __iomem *virt;
37 	unsigned long phys;
38 	unsigned long size;
39 	struct list_head maps;
40 	struct resource rsrc;
41 	struct pci_dev *pdev;
42 };
43 
44 struct ck804xrom_map_info {
45 	struct list_head list;
46 	struct map_info map;
47 	struct mtd_info *mtd;
48 	struct resource rsrc;
49 	char map_name[sizeof(MOD_NAME) + 2 + ADDRESS_NAME_LEN];
50 };
51 
52 /*
53  * The following applies to ck804 only:
54  * The 2 bits controlling the window size are often set to allow reading
55  * the BIOS, but too small to allow writing, since the lock registers are
56  * 4MiB lower in the address space than the data.
57  *
58  * This is intended to prevent flashing the bios, perhaps accidentally.
59  *
60  * This parameter allows the normal driver to override the BIOS settings.
61  *
62  * The bits are 6 and 7.  If both bits are set, it is a 5MiB window.
63  * If only the 7 Bit is set, it is a 4MiB window.  Otherwise, a
64  * 64KiB window.
65  *
66  * The following applies to mcp55 only:
67  * The 15 bits controlling the window size are distributed as follows:
68  * byte @0x88: bit 0..7
69  * byte @0x8c: bit 8..15
70  * word @0x90: bit 16..30
71  * If all bits are enabled, we have a 16? MiB window
72  * Please set win_size_bits to 0x7fffffff if you actually want to do something
73  */
74 static uint win_size_bits = 0;
75 module_param(win_size_bits, uint, 0);
76 MODULE_PARM_DESC(win_size_bits, "ROM window size bits override, normally set by BIOS.");
77 
78 static struct ck804xrom_window ck804xrom_window = {
79 	.maps = LIST_HEAD_INIT(ck804xrom_window.maps),
80 };
81 
82 static void ck804xrom_cleanup(struct ck804xrom_window *window)
83 {
84 	struct ck804xrom_map_info *map, *scratch;
85 	u8 byte;
86 
87 	if (window->pdev) {
88 		/* Disable writes through the rom window */
89 		pci_read_config_byte(window->pdev, 0x6d, &byte);
90 		pci_write_config_byte(window->pdev, 0x6d, byte & ~1);
91 	}
92 
93 	/* Free all of the mtd devices */
94 	list_for_each_entry_safe(map, scratch, &window->maps, list) {
95 		if (map->rsrc.parent)
96 			release_resource(&map->rsrc);
97 
98 		mtd_device_unregister(map->mtd);
99 		map_destroy(map->mtd);
100 		list_del(&map->list);
101 		kfree(map);
102 	}
103 	if (window->rsrc.parent)
104 		release_resource(&window->rsrc);
105 
106 	if (window->virt) {
107 		iounmap(window->virt);
108 		window->virt = NULL;
109 		window->phys = 0;
110 		window->size = 0;
111 	}
112 	pci_dev_put(window->pdev);
113 }
114 
115 
116 static int __init ck804xrom_init_one(struct pci_dev *pdev,
117 				     const struct pci_device_id *ent)
118 {
119 	static char *rom_probe_types[] = { "cfi_probe", "jedec_probe", NULL };
120 	u8 byte;
121 	u16 word;
122 	struct ck804xrom_window *window = &ck804xrom_window;
123 	struct ck804xrom_map_info *map = NULL;
124 	unsigned long map_top;
125 
126 	/* Remember the pci dev I find the window in */
127 	window->pdev = pci_dev_get(pdev);
128 
129 	switch (ent->driver_data) {
130 	case DEV_CK804:
131 		/* Enable the selected rom window.  This is often incorrectly
132 		 * set up by the BIOS, and the 4MiB offset for the lock registers
133 		 * requires the full 5MiB of window space.
134 		 *
135 		 * This 'write, then read' approach leaves the bits for
136 		 * other uses of the hardware info.
137 		 */
138 		pci_read_config_byte(pdev, 0x88, &byte);
139 		pci_write_config_byte(pdev, 0x88, byte | win_size_bits );
140 
141 		/* Assume the rom window is properly setup, and find it's size */
142 		pci_read_config_byte(pdev, 0x88, &byte);
143 
144 		if ((byte & ((1<<7)|(1<<6))) == ((1<<7)|(1<<6)))
145 			window->phys = 0xffb00000; /* 5MiB */
146 		else if ((byte & (1<<7)) == (1<<7))
147 			window->phys = 0xffc00000; /* 4MiB */
148 		else
149 			window->phys = 0xffff0000; /* 64KiB */
150 		break;
151 
152 	case DEV_MCP55:
153 		pci_read_config_byte(pdev, 0x88, &byte);
154 		pci_write_config_byte(pdev, 0x88, byte | (win_size_bits & 0xff));
155 
156 		pci_read_config_byte(pdev, 0x8c, &byte);
157 		pci_write_config_byte(pdev, 0x8c, byte | ((win_size_bits & 0xff00) >> 8));
158 
159 		pci_read_config_word(pdev, 0x90, &word);
160 		pci_write_config_word(pdev, 0x90, word | ((win_size_bits & 0x7fff0000) >> 16));
161 
162 		window->phys = 0xff000000; /* 16MiB, hardcoded for now */
163 		break;
164 	}
165 
166 	window->size = 0xffffffffUL - window->phys + 1UL;
167 
168 	/*
169 	 * Try to reserve the window mem region.  If this fails then
170 	 * it is likely due to a fragment of the window being
171 	 * "reserved" by the BIOS.  In the case that the
172 	 * request_mem_region() fails then once the rom size is
173 	 * discovered we will try to reserve the unreserved fragment.
174 	 */
175 	window->rsrc.name = MOD_NAME;
176 	window->rsrc.start = window->phys;
177 	window->rsrc.end   = window->phys + window->size - 1;
178 	window->rsrc.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
179 	if (request_resource(&iomem_resource, &window->rsrc)) {
180 		window->rsrc.parent = NULL;
181 		printk(KERN_ERR MOD_NAME
182 		       " %s(): Unable to register resource %pR - kernel bug?\n",
183 			__func__, &window->rsrc);
184 	}
185 
186 
187 	/* Enable writes through the rom window */
188 	pci_read_config_byte(pdev, 0x6d, &byte);
189 	pci_write_config_byte(pdev, 0x6d, byte | 1);
190 
191 	/* FIXME handle registers 0x80 - 0x8C the bios region locks */
192 
193 	/* For write accesses caches are useless */
194 	window->virt = ioremap(window->phys, window->size);
195 	if (!window->virt) {
196 		printk(KERN_ERR MOD_NAME ": ioremap(%08lx, %08lx) failed\n",
197 			window->phys, window->size);
198 		goto out;
199 	}
200 
201 	/* Get the first address to look for a rom chip at */
202 	map_top = window->phys;
203 #if 1
204 	/* The probe sequence run over the firmware hub lock
205 	 * registers sets them to 0x7 (no access).
206 	 * Probe at most the last 4MiB of the address space.
207 	 */
208 	if (map_top < 0xffc00000)
209 		map_top = 0xffc00000;
210 #endif
211 	/* Loop  through and look for rom chips.  Since we don't know the
212 	 * starting address for each chip, probe every ROM_PROBE_STEP_SIZE
213 	 * bytes from the starting address of the window.
214 	 */
215 	while((map_top - 1) < 0xffffffffUL) {
216 		struct cfi_private *cfi;
217 		unsigned long offset;
218 		int i;
219 
220 		if (!map)
221 			map = kmalloc(sizeof(*map), GFP_KERNEL);
222 
223 		if (!map) {
224 			printk(KERN_ERR MOD_NAME ": kmalloc failed");
225 			goto out;
226 		}
227 		memset(map, 0, sizeof(*map));
228 		INIT_LIST_HEAD(&map->list);
229 		map->map.name = map->map_name;
230 		map->map.phys = map_top;
231 		offset = map_top - window->phys;
232 		map->map.virt = (void __iomem *)
233 			(((unsigned long)(window->virt)) + offset);
234 		map->map.size = 0xffffffffUL - map_top + 1UL;
235 		/* Set the name of the map to the address I am trying */
236 		sprintf(map->map_name, "%s @%08Lx",
237 			MOD_NAME, (unsigned long long)map->map.phys);
238 
239 		/* There is no generic VPP support */
240 		for(map->map.bankwidth = 32; map->map.bankwidth;
241 			map->map.bankwidth >>= 1)
242 		{
243 			char **probe_type;
244 			/* Skip bankwidths that are not supported */
245 			if (!map_bankwidth_supported(map->map.bankwidth))
246 				continue;
247 
248 			/* Setup the map methods */
249 			simple_map_init(&map->map);
250 
251 			/* Try all of the probe methods */
252 			probe_type = rom_probe_types;
253 			for(; *probe_type; probe_type++) {
254 				map->mtd = do_map_probe(*probe_type, &map->map);
255 				if (map->mtd)
256 					goto found;
257 			}
258 		}
259 		map_top += ROM_PROBE_STEP_SIZE;
260 		continue;
261 	found:
262 		/* Trim the size if we are larger than the map */
263 		if (map->mtd->size > map->map.size) {
264 			printk(KERN_WARNING MOD_NAME
265 				" rom(%llu) larger than window(%lu). fixing...\n",
266 				(unsigned long long)map->mtd->size, map->map.size);
267 			map->mtd->size = map->map.size;
268 		}
269 		if (window->rsrc.parent) {
270 			/*
271 			 * Registering the MTD device in iomem may not be possible
272 			 * if there is a BIOS "reserved" and BUSY range.  If this
273 			 * fails then continue anyway.
274 			 */
275 			map->rsrc.name  = map->map_name;
276 			map->rsrc.start = map->map.phys;
277 			map->rsrc.end   = map->map.phys + map->mtd->size - 1;
278 			map->rsrc.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
279 			if (request_resource(&window->rsrc, &map->rsrc)) {
280 				printk(KERN_ERR MOD_NAME
281 					": cannot reserve MTD resource\n");
282 				map->rsrc.parent = NULL;
283 			}
284 		}
285 
286 		/* Make the whole region visible in the map */
287 		map->map.virt = window->virt;
288 		map->map.phys = window->phys;
289 		cfi = map->map.fldrv_priv;
290 		for(i = 0; i < cfi->numchips; i++)
291 			cfi->chips[i].start += offset;
292 
293 		/* Now that the mtd devices is complete claim and export it */
294 		map->mtd->owner = THIS_MODULE;
295 		if (mtd_device_register(map->mtd, NULL, 0)) {
296 			map_destroy(map->mtd);
297 			map->mtd = NULL;
298 			goto out;
299 		}
300 
301 
302 		/* Calculate the new value of map_top */
303 		map_top += map->mtd->size;
304 
305 		/* File away the map structure */
306 		list_add(&map->list, &window->maps);
307 		map = NULL;
308 	}
309 
310  out:
311 	/* Free any left over map structures */
312 	kfree(map);
313 
314 	/* See if I have any map structures */
315 	if (list_empty(&window->maps)) {
316 		ck804xrom_cleanup(window);
317 		return -ENODEV;
318 	}
319 	return 0;
320 }
321 
322 
323 static void ck804xrom_remove_one(struct pci_dev *pdev)
324 {
325 	struct ck804xrom_window *window = &ck804xrom_window;
326 
327 	ck804xrom_cleanup(window);
328 }
329 
330 static const struct pci_device_id ck804xrom_pci_tbl[] = {
331 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0051), .driver_data = DEV_CK804 },
332 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0360), .driver_data = DEV_MCP55 },
333 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0361), .driver_data = DEV_MCP55 },
334 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0362), .driver_data = DEV_MCP55 },
335 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0363), .driver_data = DEV_MCP55 },
336 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0364), .driver_data = DEV_MCP55 },
337 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0365), .driver_data = DEV_MCP55 },
338 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0366), .driver_data = DEV_MCP55 },
339 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, 0x0367), .driver_data = DEV_MCP55 },
340 	{ 0, }
341 };
342 
343 #if 0
344 MODULE_DEVICE_TABLE(pci, ck804xrom_pci_tbl);
345 
346 static struct pci_driver ck804xrom_driver = {
347 	.name =		MOD_NAME,
348 	.id_table =	ck804xrom_pci_tbl,
349 	.probe =	ck804xrom_init_one,
350 	.remove =	ck804xrom_remove_one,
351 };
352 #endif
353 
354 static int __init init_ck804xrom(void)
355 {
356 	struct pci_dev *pdev;
357 	const struct pci_device_id *id;
358 	int retVal;
359 	pdev = NULL;
360 
361 	for(id = ck804xrom_pci_tbl; id->vendor; id++) {
362 		pdev = pci_get_device(id->vendor, id->device, NULL);
363 		if (pdev)
364 			break;
365 	}
366 	if (pdev) {
367 		retVal = ck804xrom_init_one(pdev, id);
368 		pci_dev_put(pdev);
369 		return retVal;
370 	}
371 	return -ENXIO;
372 #if 0
373 	return pci_register_driver(&ck804xrom_driver);
374 #endif
375 }
376 
377 static void __exit cleanup_ck804xrom(void)
378 {
379 	ck804xrom_remove_one(ck804xrom_window.pdev);
380 }
381 
382 module_init(init_ck804xrom);
383 module_exit(cleanup_ck804xrom);
384 
385 MODULE_LICENSE("GPL");
386 MODULE_AUTHOR("Eric Biederman <ebiederman@lnxi.com>, Dave Olsen <dolsen@lnxi.com>");
387 MODULE_DESCRIPTION("MTD map driver for BIOS chips on the Nvidia ck804 southbridge");
388 
389