1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* sc520cdp.c -- MTD map driver for AMD SC520 Customer Development Platform
3 *
4 * Copyright (C) 2001 Sysgo Real-Time Solutions GmbH
5 *
6 * The SC520CDP is an evaluation board for the Elan SC520 processor available
7 * from AMD. It has two banks of 32-bit Flash ROM, each 8 Megabytes in size,
8 * and up to 512 KiB of 8-bit DIL Flash ROM.
9 * For details see https://www.amd.com/products/epd/desiging/evalboards/18.elansc520/520_cdp_brief/index.html
10 */
11
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <asm/io.h>
17 #include <linux/mtd/mtd.h>
18 #include <linux/mtd/map.h>
19 #include <linux/mtd/concat.h>
20
21 /*
22 ** The Embedded Systems BIOS decodes the first FLASH starting at
23 ** 0x8400000. This is a *terrible* place for it because accessing
24 ** the flash at this location causes the A22 address line to be high
25 ** (that's what 0x8400000 binary's ought to be). But this is the highest
26 ** order address line on the raw flash devices themselves!!
27 ** This causes the top HALF of the flash to be accessed first. Beyond
28 ** the physical limits of the flash, the flash chip aliases over (to
29 ** 0x880000 which causes the bottom half to be accessed. This splits the
30 ** flash into two and inverts it! If you then try to access this from another
31 ** program that does NOT do this insanity, then you *will* access the
32 ** first half of the flash, but not find what you expect there. That
33 ** stuff is in the *second* half! Similarly, the address used by the
34 ** BIOS for the second FLASH bank is also quite a bad choice.
35 ** If REPROGRAM_PAR is defined below (the default), then this driver will
36 ** choose more useful addresses for the FLASH banks by reprogramming the
37 ** responsible PARxx registers in the SC520's MMCR region. This will
38 ** cause the settings to be incompatible with the BIOS's settings, which
39 ** shouldn't be a problem since you are running Linux, (i.e. the BIOS is
40 ** not much use anyway). However, if you need to be compatible with
41 ** the BIOS for some reason, just undefine REPROGRAM_PAR.
42 */
43 #define REPROGRAM_PAR
44
45
46
47 #ifdef REPROGRAM_PAR
48
49 /* These are the addresses we want.. */
50 #define WINDOW_ADDR_0 0x08800000
51 #define WINDOW_ADDR_1 0x09000000
52 #define WINDOW_ADDR_2 0x09800000
53
54 /* .. and these are the addresses the BIOS gives us */
55 #define WINDOW_ADDR_0_BIOS 0x08400000
56 #define WINDOW_ADDR_1_BIOS 0x08c00000
57 #define WINDOW_ADDR_2_BIOS 0x09400000
58
59 #else
60
61 #define WINDOW_ADDR_0 0x08400000
62 #define WINDOW_ADDR_1 0x08C00000
63 #define WINDOW_ADDR_2 0x09400000
64
65 #endif
66
67 #define WINDOW_SIZE_0 0x00800000
68 #define WINDOW_SIZE_1 0x00800000
69 #define WINDOW_SIZE_2 0x00080000
70
71
72 static struct map_info sc520cdp_map[] = {
73 {
74 .name = "SC520CDP Flash Bank #0",
75 .size = WINDOW_SIZE_0,
76 .bankwidth = 4,
77 .phys = WINDOW_ADDR_0
78 },
79 {
80 .name = "SC520CDP Flash Bank #1",
81 .size = WINDOW_SIZE_1,
82 .bankwidth = 4,
83 .phys = WINDOW_ADDR_1
84 },
85 {
86 .name = "SC520CDP DIL Flash",
87 .size = WINDOW_SIZE_2,
88 .bankwidth = 1,
89 .phys = WINDOW_ADDR_2
90 },
91 };
92
93 #define NUM_FLASH_BANKS ARRAY_SIZE(sc520cdp_map)
94
95 static struct mtd_info *mymtd[NUM_FLASH_BANKS];
96 static struct mtd_info *merged_mtd;
97
98 #ifdef REPROGRAM_PAR
99
100 /*
101 ** The SC520 MMCR (memory mapped control register) region resides
102 ** at 0xFFFEF000. The 16 Programmable Address Region (PAR) registers
103 ** are at offset 0x88 in the MMCR:
104 */
105 #define SC520_MMCR_BASE 0xFFFEF000
106 #define SC520_MMCR_EXTENT 0x1000
107 #define SC520_PAR(x) ((0x88/sizeof(unsigned long)) + (x))
108 #define NUM_SC520_PAR 16 /* total number of PAR registers */
109
110 /*
111 ** The highest three bits in a PAR register determine what target
112 ** device is controlled by this PAR. Here, only ROMCS? and BOOTCS
113 ** devices are of interest.
114 */
115 #define SC520_PAR_BOOTCS (0x4<<29)
116 #define SC520_PAR_ROMCS0 (0x5<<29)
117 #define SC520_PAR_ROMCS1 (0x6<<29)
118 #define SC520_PAR_TRGDEV (0x7<<29)
119
120 /*
121 ** Bits 28 thru 26 determine some attributes for the
122 ** region controlled by the PAR. (We only use non-cacheable)
123 */
124 #define SC520_PAR_WRPROT (1<<26) /* write protected */
125 #define SC520_PAR_NOCACHE (1<<27) /* non-cacheable */
126 #define SC520_PAR_NOEXEC (1<<28) /* code execution denied */
127
128
129 /*
130 ** Bit 25 determines the granularity: 4K or 64K
131 */
132 #define SC520_PAR_PG_SIZ4 (0<<25)
133 #define SC520_PAR_PG_SIZ64 (1<<25)
134
135 /*
136 ** Build a value to be written into a PAR register.
137 ** We only need ROM entries, 64K page size:
138 */
139 #define SC520_PAR_ENTRY(trgdev, address, size) \
140 ((trgdev) | SC520_PAR_NOCACHE | SC520_PAR_PG_SIZ64 | \
141 (address) >> 16 | (((size) >> 16) - 1) << 14)
142
143 struct sc520_par_table
144 {
145 unsigned long trgdev;
146 unsigned long new_par;
147 unsigned long default_address;
148 };
149
150 static const struct sc520_par_table par_table[NUM_FLASH_BANKS] =
151 {
152 { /* Flash Bank #0: selected by ROMCS0 */
153 SC520_PAR_ROMCS0,
154 SC520_PAR_ENTRY(SC520_PAR_ROMCS0, WINDOW_ADDR_0, WINDOW_SIZE_0),
155 WINDOW_ADDR_0_BIOS
156 },
157 { /* Flash Bank #1: selected by ROMCS1 */
158 SC520_PAR_ROMCS1,
159 SC520_PAR_ENTRY(SC520_PAR_ROMCS1, WINDOW_ADDR_1, WINDOW_SIZE_1),
160 WINDOW_ADDR_1_BIOS
161 },
162 { /* DIL (BIOS) Flash: selected by BOOTCS */
163 SC520_PAR_BOOTCS,
164 SC520_PAR_ENTRY(SC520_PAR_BOOTCS, WINDOW_ADDR_2, WINDOW_SIZE_2),
165 WINDOW_ADDR_2_BIOS
166 }
167 };
168
169
sc520cdp_setup_par(void)170 static void sc520cdp_setup_par(void)
171 {
172 unsigned long __iomem *mmcr;
173 unsigned long mmcr_val;
174 int i, j;
175
176 /* map in SC520's MMCR area */
177 mmcr = ioremap(SC520_MMCR_BASE, SC520_MMCR_EXTENT);
178 if(!mmcr) { /* ioremap failed: skip the PAR reprogramming */
179 /* force physical address fields to BIOS defaults: */
180 for(i = 0; i < NUM_FLASH_BANKS; i++)
181 sc520cdp_map[i].phys = par_table[i].default_address;
182 return;
183 }
184
185 /*
186 ** Find the PARxx registers that are responsible for activating
187 ** ROMCS0, ROMCS1 and BOOTCS. Reprogram each of these with a
188 ** new value from the table.
189 */
190 for(i = 0; i < NUM_FLASH_BANKS; i++) { /* for each par_table entry */
191 for(j = 0; j < NUM_SC520_PAR; j++) { /* for each PAR register */
192 mmcr_val = readl(&mmcr[SC520_PAR(j)]);
193 /* if target device field matches, reprogram the PAR */
194 if((mmcr_val & SC520_PAR_TRGDEV) == par_table[i].trgdev)
195 {
196 writel(par_table[i].new_par, &mmcr[SC520_PAR(j)]);
197 break;
198 }
199 }
200 if(j == NUM_SC520_PAR)
201 { /* no matching PAR found: try default BIOS address */
202 printk(KERN_NOTICE "Could not find PAR responsible for %s\n",
203 sc520cdp_map[i].name);
204 printk(KERN_NOTICE "Trying default address 0x%lx\n",
205 par_table[i].default_address);
206 sc520cdp_map[i].phys = par_table[i].default_address;
207 }
208 }
209 iounmap(mmcr);
210 }
211 #endif
212
213
init_sc520cdp(void)214 static int __init init_sc520cdp(void)
215 {
216 int i, j, devices_found = 0;
217
218 #ifdef REPROGRAM_PAR
219 /* reprogram PAR registers so flash appears at the desired addresses */
220 sc520cdp_setup_par();
221 #endif
222
223 for (i = 0; i < NUM_FLASH_BANKS; i++) {
224 printk(KERN_NOTICE "SC520 CDP flash device: 0x%Lx at 0x%Lx\n",
225 (unsigned long long)sc520cdp_map[i].size,
226 (unsigned long long)sc520cdp_map[i].phys);
227
228 sc520cdp_map[i].virt = ioremap(sc520cdp_map[i].phys, sc520cdp_map[i].size);
229
230 if (!sc520cdp_map[i].virt) {
231 printk("Failed to ioremap\n");
232 for (j = 0; j < i; j++) {
233 if (mymtd[j]) {
234 map_destroy(mymtd[j]);
235 iounmap(sc520cdp_map[j].virt);
236 }
237 }
238 return -EIO;
239 }
240
241 simple_map_init(&sc520cdp_map[i]);
242
243 mymtd[i] = do_map_probe("cfi_probe", &sc520cdp_map[i]);
244 if(!mymtd[i])
245 mymtd[i] = do_map_probe("jedec_probe", &sc520cdp_map[i]);
246 if(!mymtd[i])
247 mymtd[i] = do_map_probe("map_rom", &sc520cdp_map[i]);
248
249 if (mymtd[i]) {
250 mymtd[i]->owner = THIS_MODULE;
251 ++devices_found;
252 }
253 else {
254 iounmap(sc520cdp_map[i].virt);
255 }
256 }
257 if(devices_found >= 2) {
258 /* Combine the two flash banks into a single MTD device & register it: */
259 merged_mtd = mtd_concat_create(mymtd, 2, "SC520CDP Flash Banks #0 and #1");
260 if(merged_mtd)
261 mtd_device_register(merged_mtd, NULL, 0);
262 }
263 if(devices_found == 3) /* register the third (DIL-Flash) device */
264 mtd_device_register(mymtd[2], NULL, 0);
265 return(devices_found ? 0 : -ENXIO);
266 }
267
cleanup_sc520cdp(void)268 static void __exit cleanup_sc520cdp(void)
269 {
270 int i;
271
272 if (merged_mtd) {
273 mtd_device_unregister(merged_mtd);
274 mtd_concat_destroy(merged_mtd);
275 }
276 if (mymtd[2])
277 mtd_device_unregister(mymtd[2]);
278
279 for (i = 0; i < NUM_FLASH_BANKS; i++) {
280 if (mymtd[i])
281 map_destroy(mymtd[i]);
282 if (sc520cdp_map[i].virt) {
283 iounmap(sc520cdp_map[i].virt);
284 sc520cdp_map[i].virt = NULL;
285 }
286 }
287 }
288
289 module_init(init_sc520cdp);
290 module_exit(cleanup_sc520cdp);
291
292 MODULE_LICENSE("GPL");
293 MODULE_AUTHOR("Sysgo Real-Time Solutions GmbH");
294 MODULE_DESCRIPTION("MTD map driver for AMD SC520 Customer Development Platform");
295