xref: /openbmc/linux/drivers/mtd/maps/dc21285.c (revision e5babdf9)
1 /*
2  * MTD map driver for flash on the DC21285 (the StrongARM-110 companion chip)
3  *
4  * (C) 2000  Nicolas Pitre <nico@fluxnic.net>
5  *
6  * This code is GPL
7  */
8 #include <linux/module.h>
9 #include <linux/types.h>
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/delay.h>
13 #include <linux/slab.h>
14 
15 #include <linux/mtd/mtd.h>
16 #include <linux/mtd/map.h>
17 #include <linux/mtd/partitions.h>
18 
19 #include <asm/io.h>
20 #include <asm/hardware/dec21285.h>
21 #include <asm/mach-types.h>
22 
23 
24 static struct mtd_info *dc21285_mtd;
25 
26 #ifdef CONFIG_ARCH_NETWINDER
27 /*
28  * This is really ugly, but it seams to be the only
29  * realiable way to do it, as the cpld state machine
30  * is unpredictible. So we have a 25us penalty per
31  * write access.
32  */
nw_en_write(void)33 static void nw_en_write(void)
34 {
35 	unsigned long flags;
36 
37 	/*
38 	 * we want to write a bit pattern XXX1 to Xilinx to enable
39 	 * the write gate, which will be open for about the next 2ms.
40 	 */
41 	raw_spin_lock_irqsave(&nw_gpio_lock, flags);
42 	nw_cpld_modify(CPLD_FLASH_WR_ENABLE, CPLD_FLASH_WR_ENABLE);
43 	raw_spin_unlock_irqrestore(&nw_gpio_lock, flags);
44 
45 	/*
46 	 * let the ISA bus to catch on...
47 	 */
48 	udelay(25);
49 }
50 #else
51 #define nw_en_write() do { } while (0)
52 #endif
53 
dc21285_read8(struct map_info * map,unsigned long ofs)54 static map_word dc21285_read8(struct map_info *map, unsigned long ofs)
55 {
56 	map_word val;
57 	val.x[0] = *(uint8_t*)(map->virt + ofs);
58 	return val;
59 }
60 
dc21285_read16(struct map_info * map,unsigned long ofs)61 static map_word dc21285_read16(struct map_info *map, unsigned long ofs)
62 {
63 	map_word val;
64 	val.x[0] = *(uint16_t*)(map->virt + ofs);
65 	return val;
66 }
67 
dc21285_read32(struct map_info * map,unsigned long ofs)68 static map_word dc21285_read32(struct map_info *map, unsigned long ofs)
69 {
70 	map_word val;
71 	val.x[0] = *(uint32_t*)(map->virt + ofs);
72 	return val;
73 }
74 
dc21285_copy_from(struct map_info * map,void * to,unsigned long from,ssize_t len)75 static void dc21285_copy_from(struct map_info *map, void *to, unsigned long from, ssize_t len)
76 {
77 	memcpy(to, (void*)(map->virt + from), len);
78 }
79 
dc21285_write8(struct map_info * map,const map_word d,unsigned long adr)80 static void dc21285_write8(struct map_info *map, const map_word d, unsigned long adr)
81 {
82 	if (machine_is_netwinder())
83 		nw_en_write();
84 	*CSR_ROMWRITEREG = adr & 3;
85 	adr &= ~3;
86 	*(uint8_t*)(map->virt + adr) = d.x[0];
87 }
88 
dc21285_write16(struct map_info * map,const map_word d,unsigned long adr)89 static void dc21285_write16(struct map_info *map, const map_word d, unsigned long adr)
90 {
91 	if (machine_is_netwinder())
92 		nw_en_write();
93 	*CSR_ROMWRITEREG = adr & 3;
94 	adr &= ~3;
95 	*(uint16_t*)(map->virt + adr) = d.x[0];
96 }
97 
dc21285_write32(struct map_info * map,const map_word d,unsigned long adr)98 static void dc21285_write32(struct map_info *map, const map_word d, unsigned long adr)
99 {
100 	if (machine_is_netwinder())
101 		nw_en_write();
102 	*(uint32_t*)(map->virt + adr) = d.x[0];
103 }
104 
dc21285_copy_to_32(struct map_info * map,unsigned long to,const void * from,ssize_t len)105 static void dc21285_copy_to_32(struct map_info *map, unsigned long to, const void *from, ssize_t len)
106 {
107 	while (len > 0) {
108 		map_word d;
109 		d.x[0] = *((uint32_t*)from);
110 		dc21285_write32(map, d, to);
111 		from += 4;
112 		to += 4;
113 		len -= 4;
114 	}
115 }
116 
dc21285_copy_to_16(struct map_info * map,unsigned long to,const void * from,ssize_t len)117 static void dc21285_copy_to_16(struct map_info *map, unsigned long to, const void *from, ssize_t len)
118 {
119 	while (len > 0) {
120 		map_word d;
121 		d.x[0] = *((uint16_t*)from);
122 		dc21285_write16(map, d, to);
123 		from += 2;
124 		to += 2;
125 		len -= 2;
126 	}
127 }
128 
dc21285_copy_to_8(struct map_info * map,unsigned long to,const void * from,ssize_t len)129 static void dc21285_copy_to_8(struct map_info *map, unsigned long to, const void *from, ssize_t len)
130 {
131 	map_word d;
132 	d.x[0] = *((uint8_t*)from);
133 	dc21285_write8(map, d, to);
134 	from++;
135 	to++;
136 	len--;
137 }
138 
139 static struct map_info dc21285_map = {
140 	.name = "DC21285 flash",
141 	.phys = NO_XIP,
142 	.size = 16*1024*1024,
143 	.copy_from = dc21285_copy_from,
144 };
145 
146 /* Partition stuff */
147 static const char * const probes[] = { "RedBoot", "cmdlinepart", NULL };
148 
init_dc21285(void)149 static int __init init_dc21285(void)
150 {
151 	/* Determine bankwidth */
152 	switch (*CSR_SA110_CNTL & (3<<14)) {
153 		case SA110_CNTL_ROMWIDTH_8:
154 			dc21285_map.bankwidth = 1;
155 			dc21285_map.read = dc21285_read8;
156 			dc21285_map.write = dc21285_write8;
157 			dc21285_map.copy_to = dc21285_copy_to_8;
158 			break;
159 		case SA110_CNTL_ROMWIDTH_16:
160 			dc21285_map.bankwidth = 2;
161 			dc21285_map.read = dc21285_read16;
162 			dc21285_map.write = dc21285_write16;
163 			dc21285_map.copy_to = dc21285_copy_to_16;
164 			break;
165 		case SA110_CNTL_ROMWIDTH_32:
166 			dc21285_map.bankwidth = 4;
167 			dc21285_map.read = dc21285_read32;
168 			dc21285_map.write = dc21285_write32;
169 			dc21285_map.copy_to = dc21285_copy_to_32;
170 			break;
171 		default:
172 			printk (KERN_ERR "DC21285 flash: undefined bankwidth\n");
173 			return -ENXIO;
174 	}
175 	printk (KERN_NOTICE "DC21285 flash support (%d-bit bankwidth)\n",
176 		dc21285_map.bankwidth*8);
177 
178 	/* Let's map the flash area */
179 	dc21285_map.virt = ioremap(DC21285_FLASH, 16*1024*1024);
180 	if (!dc21285_map.virt) {
181 		printk("Failed to ioremap\n");
182 		return -EIO;
183 	}
184 
185 	if (machine_is_ebsa285()) {
186 		dc21285_mtd = do_map_probe("cfi_probe", &dc21285_map);
187 	} else {
188 		dc21285_mtd = do_map_probe("jedec_probe", &dc21285_map);
189 	}
190 
191 	if (!dc21285_mtd) {
192 		iounmap(dc21285_map.virt);
193 		return -ENXIO;
194 	}
195 
196 	dc21285_mtd->owner = THIS_MODULE;
197 
198 	mtd_device_parse_register(dc21285_mtd, probes, NULL, NULL, 0);
199 
200 	if(machine_is_ebsa285()) {
201 		/*
202 		 * Flash timing is determined with bits 19-16 of the
203 		 * CSR_SA110_CNTL.  The value is the number of wait cycles, or
204 		 * 0 for 16 cycles (the default).  Cycles are 20 ns.
205 		 * Here we use 7 for 140 ns flash chips.
206 		 */
207 		/* access time */
208 		*CSR_SA110_CNTL = ((*CSR_SA110_CNTL & ~0x000f0000) | (7 << 16));
209 		/* burst time */
210 		*CSR_SA110_CNTL = ((*CSR_SA110_CNTL & ~0x00f00000) | (7 << 20));
211 		/* tristate time */
212 		*CSR_SA110_CNTL = ((*CSR_SA110_CNTL & ~0x0f000000) | (7 << 24));
213 	}
214 
215 	return 0;
216 }
217 
cleanup_dc21285(void)218 static void __exit cleanup_dc21285(void)
219 {
220 	mtd_device_unregister(dc21285_mtd);
221 	map_destroy(dc21285_mtd);
222 	iounmap(dc21285_map.virt);
223 }
224 
225 module_init(init_dc21285);
226 module_exit(cleanup_dc21285);
227 
228 
229 MODULE_LICENSE("GPL");
230 MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net>");
231 MODULE_DESCRIPTION("MTD map driver for DC21285 boards");
232