drivers/mtd/maps/scb2_flash.c

   1 /*
   2  * MTD map driver for BIOS Flash on Intel SCB2 boards
   3  * Copyright (C) 2002 Sun Microsystems, Inc.
   4  * Tim Hockin <thockin@sun.com>
   5  *
   6  * A few notes on this MTD map:
   7  *
   8  * This was developed with a small number of SCB2 boards to test on.
   9  * Hopefully, Intel has not introducted too many unaccounted variables in the
  10  * making of this board.
  11  *
  12  * The BIOS marks its own memory region as 'reserved' in the e820 map.  We
  13  * try to request it here, but if it fails, we carry on anyway.
  14  *
  15  * This is how the chip is attached, so said the schematic:
  16  * * a 4 MiB (32 Mib) 16 bit chip
  17  * * a 1 MiB memory region
  18  * * A20 and A21 pulled up
  19  * * D8-D15 ignored
  20  * What this means is that, while we are addressing bytes linearly, we are
  21  * really addressing words, and discarding the other byte.  This means that
  22  * the chip MUST BE at least 2 MiB.  This also means that every block is
  23  * actually half as big as the chip reports.  It also means that accesses of
  24  * logical address 0 hit higher-address sections of the chip, not physical 0.
  25  * One can only hope that these 4MiB x16 chips were a lot cheaper than 1MiB x8
  26  * chips.
  27  *
  28  * This driver assumes the chip is not write-protected by an external signal.
  29  * As of the this writing, that is true, but may change, just to spite me.
  30  *
  31  * The actual BIOS layout has been mostly reverse engineered.  Intel BIOS
  32  * updates for this board include 10 related (*.bio - &.bi9) binary files and
  33  * another separate (*.bbo) binary file.  The 10 files are 64k of data + a
  34  * small header.  If the headers are stripped off, the 10 64k files can be
  35  * concatenated into a 640k image.  This is your BIOS image, proper.  The
  36  * separate .bbo file also has a small header.  It is the 'Boot Block'
  37  * recovery BIOS.  Once the header is stripped, no further prep is needed.
  38  * As best I can tell, the BIOS is arranged as such:
  39  * offset 0x00000 to 0x4ffff (320k):  unknown - SCSI BIOS, etc?
  40  * offset 0x50000 to 0xeffff (640k):  BIOS proper
  41  * offset 0xf0000 ty 0xfffff (64k):   Boot Block region
  42  *
  43  * Intel's BIOS update program flashes the BIOS and Boot Block in separate
  44  * steps.  Probably a wise thing to do.
  45  */
  46
  47 #include <linux/module.h>
  48 #include <linux/types.h>
  49 #include <linux/kernel.h>
  50 #include <linux/init.h>
  51 #include <asm/io.h>
  52 #include <linux/mtd/mtd.h>
  53 #include <linux/mtd/map.h>
  54 #include <linux/mtd/cfi.h>
  55 #include <linux/pci.h>
  56 #include <linux/pci_ids.h>
  57
  58 #define MODNAME         "scb2_flash"
  59 #define SCB2_ADDR       0xfff00000
  60 #define SCB2_WINDOW     0x00100000
  61
  62
  63 static void __iomem *scb2_ioaddr;
  64 static struct mtd_info *scb2_mtd;
  65 static struct map_info scb2_map = {
  66         .name =      "SCB2 BIOS Flash",
  67         .size =      0,
  68         .bankwidth =  1,
  69 };
  70 static int region_fail;
  71
  72 static int
  73 scb2_fixup_mtd(struct mtd_info *mtd)
  74 {
  75         int i;
  76         int done = 0;
  77         struct map_info *map = mtd->priv;
  78         struct cfi_private *cfi = map->fldrv_priv;
  79
  80         /* barf if this doesn't look right */
  81         if (cfi->cfiq->InterfaceDesc != CFI_INTERFACE_X16_ASYNC) {
  82                 printk(KERN_ERR MODNAME ": unsupported InterfaceDesc: %#x\n",
  83                     cfi->cfiq->InterfaceDesc);
  84                 return -1;
  85         }
  86
  87         /* I wasn't here. I didn't see. dwmw2. */
  88
  89         /* the chip is sometimes bigger than the map - what a waste */
  90         mtd->size = map->size;
  91
  92         /*
  93          * We only REALLY get half the chip, due to the way it is
  94          * wired up - D8-D15 are tossed away.  We read linear bytes,
  95          * but in reality we are getting 1/2 of each 16-bit read,
  96          * which LOOKS linear to us.  Because CFI code accounts for
  97          * things like lock/unlock/erase by eraseregions, we need to
  98          * fudge them to reflect this.  Erases go like this:
  99          *   * send an erase to an address
 100          *   * the chip samples the address and erases the block
 101          *   * add the block erasesize to the address and repeat
 102          *   -- the problem is that addresses are 16-bit addressable
 103          *   -- we end up erasing every-other block
 104          */
 105         mtd->erasesize /= 2;
 106         for (i = 0; i < mtd->numeraseregions; i++) {
 107                 struct mtd_erase_region_info *region = &mtd->eraseregions[i];
 108                 region->erasesize /= 2;
 109         }
 110
 111         /*
 112          * If the chip is bigger than the map, it is wired with the high
 113          * address lines pulled up.  This makes us access the top portion of
 114          * the chip, so all our erase-region info is wrong.  Start cutting from
 115          * the bottom.
 116          */
 117         for (i = 0; !done && i < mtd->numeraseregions; i++) {
 118                 struct mtd_erase_region_info *region = &mtd->eraseregions[i];
 119
 120                 if (region->numblocks * region->erasesize > mtd->size) {
 121                         region->numblocks = ((unsigned long)mtd->size /
 122                                                 region->erasesize);
 123                         done = 1;
 124                 } else {
 125                         region->numblocks = 0;
 126                 }
 127                 region->offset = 0;
 128         }
 129
 130         return 0;
 131 }
 132
 133 /* CSB5's 'Function Control Register' has bits for decoding @ >= 0xffc00000 */
 134 #define CSB5_FCR        0x41
 135 #define CSB5_FCR_DECODE_ALL 0x0e
 136 static int
 137 scb2_flash_probe(struct pci_dev *dev, const struct pci_device_id *ent)
 138 {
 139         u8 reg;
 140
 141         /* enable decoding of the flash region in the south bridge */
 142         pci_read_config_byte(dev, CSB5_FCR, &reg);
 143         pci_write_config_byte(dev, CSB5_FCR, reg | CSB5_FCR_DECODE_ALL);
 144
 145         if (!request_mem_region(SCB2_ADDR, SCB2_WINDOW, scb2_map.name)) {
 146                 /*
 147                  * The BIOS seems to mark the flash region as 'reserved'
 148                  * in the e820 map.  Warn and go about our business.
 149                  */
 150                 printk(KERN_WARNING MODNAME
 151                     ": warning - can't reserve rom window, continuing\n");
 152                 region_fail = 1;
 153         }
 154
 155         /* remap the IO window (w/o caching) */
 156         scb2_ioaddr = ioremap_nocache(SCB2_ADDR, SCB2_WINDOW);
 157         if (!scb2_ioaddr) {
 158                 printk(KERN_ERR MODNAME ": Failed to ioremap window!\n");
 159                 if (!region_fail)
 160                         release_mem_region(SCB2_ADDR, SCB2_WINDOW);
 161                 return -ENOMEM;
 162         }
 163
 164         scb2_map.phys = SCB2_ADDR;
 165         scb2_map.virt = scb2_ioaddr;
 166         scb2_map.size = SCB2_WINDOW;
 167
 168         simple_map_init(&scb2_map);
 169
 170         /* try to find a chip */
 171         scb2_mtd = do_map_probe("cfi_probe", &scb2_map);
 172
 173         if (!scb2_mtd) {
 174                 printk(KERN_ERR MODNAME ": flash probe failed!\n");
 175                 iounmap(scb2_ioaddr);
 176                 if (!region_fail)
 177                         release_mem_region(SCB2_ADDR, SCB2_WINDOW);
 178                 return -ENODEV;
 179         }
 180
 181         scb2_mtd->owner = THIS_MODULE;
 182         if (scb2_fixup_mtd(scb2_mtd) < 0) {
 183                 mtd_device_unregister(scb2_mtd);
 184                 map_destroy(scb2_mtd);
 185                 iounmap(scb2_ioaddr);
 186                 if (!region_fail)
 187                         release_mem_region(SCB2_ADDR, SCB2_WINDOW);
 188                 return -ENODEV;
 189         }
 190
 191         printk(KERN_NOTICE MODNAME ": chip size 0x%llx at offset 0x%llx\n",
 192                (unsigned long long)scb2_mtd->size,
 193                (unsigned long long)(SCB2_WINDOW - scb2_mtd->size));
 194
 195         mtd_device_register(scb2_mtd, NULL, 0);
 196
 197         return 0;
 198 }
 199
 200 static void
 201 scb2_flash_remove(struct pci_dev *dev)
 202 {
 203         if (!scb2_mtd)
 204                 return;
 205
 206         /* disable flash writes */
 207         mtd_lock(scb2_mtd, 0, scb2_mtd->size);
 208
 209         mtd_device_unregister(scb2_mtd);
 210         map_destroy(scb2_mtd);
 211
 212         iounmap(scb2_ioaddr);
 213         scb2_ioaddr = NULL;
 214
 215         if (!region_fail)
 216                 release_mem_region(SCB2_ADDR, SCB2_WINDOW);
 217         pci_set_drvdata(dev, NULL);
 218 }
 219
 220 static struct pci_device_id scb2_flash_pci_ids[] = {
 221         {
 222           .vendor = PCI_VENDOR_ID_SERVERWORKS,
 223           .device = PCI_DEVICE_ID_SERVERWORKS_CSB5,
 224           .subvendor = PCI_ANY_ID,
 225           .subdevice = PCI_ANY_ID
 226         },
 227         { 0, }
 228 };
 229
 230 static struct pci_driver scb2_flash_driver = {
 231         .name =     "Intel SCB2 BIOS Flash",
 232         .id_table = scb2_flash_pci_ids,
 233         .probe =    scb2_flash_probe,
 234         .remove =   scb2_flash_remove,
 235 };
 236
 237 module_pci_driver(scb2_flash_driver);
 238
 239 MODULE_LICENSE("GPL");
 240 MODULE_AUTHOR("Tim Hockin <thockin@sun.com>");
 241 MODULE_DESCRIPTION("MTD map driver for Intel SCB2 BIOS Flash");
 242 MODULE_DEVICE_TABLE(pci, scb2_flash_pci_ids);