drivers/mtd/maps/dc21285.c

   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  */
  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         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
  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
  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
  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
  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
  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
  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
  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
 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
 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
 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
 147 /* Partition stuff */
 148 static const char *probes[] = { "RedBoot", "cmdlinepart", NULL };
 149
 150 static 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, 0, 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
 219 static void __exit cleanup_dc21285(void)
 220 {
 221         mtd_device_unregister(dc21285_mtd);
 222         map_destroy(dc21285_mtd);
 223         iounmap(dc21285_map.virt);
 224 }
 225
 226 module_init(init_dc21285);
 227 module_exit(cleanup_dc21285);
 228
 229
 230 MODULE_LICENSE("GPL");
 231 MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net>");
 232 MODULE_DESCRIPTION("MTD map driver for DC21285 boards");