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
24static 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 */
33static 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	spin_lock_irqsave(&nw_gpio_lock, flags);
42	nw_cpld_modify(CPLD_FLASH_WR_ENABLE, CPLD_FLASH_WR_ENABLE);
43	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
54static 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
61static 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
68static 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
75static 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
80static 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
89static 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
98static 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
105static 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
117static 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
129static 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
139static 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
147/* Partition stuff */
148static const char *probes[] = { "RedBoot", "cmdlinepart", NULL };
149
150static int __init init_dc21285(void)
151{
152	/* Determine bankwidth */
153	switch (*CSR_SA110_CNTL & (3<<14)) {
154		case SA110_CNTL_ROMWIDTH_8:
155			dc21285_map.bankwidth = 1;
156			dc21285_map.read = dc21285_read8;
157			dc21285_map.write = dc21285_write8;
158			dc21285_map.copy_to = dc21285_copy_to_8;
159			break;
160		case SA110_CNTL_ROMWIDTH_16:
161			dc21285_map.bankwidth = 2;
162			dc21285_map.read = dc21285_read16;
163			dc21285_map.write = dc21285_write16;
164			dc21285_map.copy_to = dc21285_copy_to_16;
165			break;
166		case SA110_CNTL_ROMWIDTH_32:
167			dc21285_map.bankwidth = 4;
168			dc21285_map.read = dc21285_read32;
169			dc21285_map.write = dc21285_write32;
170			dc21285_map.copy_to = dc21285_copy_to_32;
171			break;
172		default:
173			printk (KERN_ERR "DC21285 flash: undefined bankwidth\n");
174			return -ENXIO;
175	}
176	printk (KERN_NOTICE "DC21285 flash support (%d-bit bankwidth)\n",
177		dc21285_map.bankwidth*8);
178
179	/* Let's map the flash area */
180	dc21285_map.virt = ioremap(DC21285_FLASH, 16*1024*1024);
181	if (!dc21285_map.virt) {
182		printk("Failed to ioremap\n");
183		return -EIO;
184	}
185
186	if (machine_is_ebsa285()) {
187		dc21285_mtd = do_map_probe("cfi_probe", &dc21285_map);
188	} else {
189		dc21285_mtd = do_map_probe("jedec_probe", &dc21285_map);
190	}
191
192	if (!dc21285_mtd) {
193		iounmap(dc21285_map.virt);
194		return -ENXIO;
195	}
196
197	dc21285_mtd->owner = THIS_MODULE;
198
199	mtd_device_parse_register(dc21285_mtd, probes, NULL, NULL, 0);
200
201	if(machine_is_ebsa285()) {
202		/*
203		 * Flash timing is determined with bits 19-16 of the
204		 * CSR_SA110_CNTL.  The value is the number of wait cycles, or
205		 * 0 for 16 cycles (the default).  Cycles are 20 ns.
206		 * Here we use 7 for 140 ns flash chips.
207		 */
208		/* access time */
209		*CSR_SA110_CNTL = ((*CSR_SA110_CNTL & ~0x000f0000) | (7 << 16));
210		/* burst time */
211		*CSR_SA110_CNTL = ((*CSR_SA110_CNTL & ~0x00f00000) | (7 << 20));
212		/* tristate time */
213		*CSR_SA110_CNTL = ((*CSR_SA110_CNTL & ~0x0f000000) | (7 << 24));
214	}
215
216	return 0;
217}
218
219static void __exit cleanup_dc21285(void)
220{
221	mtd_device_unregister(dc21285_mtd);
222	map_destroy(dc21285_mtd);
223	iounmap(dc21285_map.virt);
224}
225
226module_init(init_dc21285);
227module_exit(cleanup_dc21285);
228
229
230MODULE_LICENSE("GPL");
231MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net>");
232MODULE_DESCRIPTION("MTD map driver for DC21285 boards");
233