diff options
Diffstat (limited to 'drivers/mtd/maps/scb2_flash.c')
| -rw-r--r-- | drivers/mtd/maps/scb2_flash.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/drivers/mtd/maps/scb2_flash.c b/drivers/mtd/maps/scb2_flash.c new file mode 100644 index 000000000..57303f904 --- /dev/null +++ b/drivers/mtd/maps/scb2_flash.c @@ -0,0 +1,239 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * MTD map driver for BIOS Flash on Intel SCB2 boards + * Copyright (C) 2002 Sun Microsystems, Inc. + * Tim Hockin <thockin@sun.com> + * + * A few notes on this MTD map: + * + * This was developed with a small number of SCB2 boards to test on. + * Hopefully, Intel has not introducted too many unaccounted variables in the + * making of this board. + * + * The BIOS marks its own memory region as 'reserved' in the e820 map. We + * try to request it here, but if it fails, we carry on anyway. + * + * This is how the chip is attached, so said the schematic: + * * a 4 MiB (32 Mib) 16 bit chip + * * a 1 MiB memory region + * * A20 and A21 pulled up + * * D8-D15 ignored + * What this means is that, while we are addressing bytes linearly, we are + * really addressing words, and discarding the other byte. This means that + * the chip MUST BE at least 2 MiB. This also means that every block is + * actually half as big as the chip reports. It also means that accesses of + * logical address 0 hit higher-address sections of the chip, not physical 0. + * One can only hope that these 4MiB x16 chips were a lot cheaper than 1MiB x8 + * chips. + * + * This driver assumes the chip is not write-protected by an external signal. + * As of the this writing, that is true, but may change, just to spite me. + * + * The actual BIOS layout has been mostly reverse engineered. Intel BIOS + * updates for this board include 10 related (*.bio - &.bi9) binary files and + * another separate (*.bbo) binary file. The 10 files are 64k of data + a + * small header. If the headers are stripped off, the 10 64k files can be + * concatenated into a 640k image. This is your BIOS image, proper. The + * separate .bbo file also has a small header. It is the 'Boot Block' + * recovery BIOS. Once the header is stripped, no further prep is needed. + * As best I can tell, the BIOS is arranged as such: + * offset 0x00000 to 0x4ffff (320k): unknown - SCSI BIOS, etc? + * offset 0x50000 to 0xeffff (640k): BIOS proper + * offset 0xf0000 ty 0xfffff (64k): Boot Block region + * + * Intel's BIOS update program flashes the BIOS and Boot Block in separate + * steps. Probably a wise thing to do. + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <asm/io.h> +#include <linux/mtd/mtd.h> +#include <linux/mtd/map.h> +#include <linux/mtd/cfi.h> +#include <linux/pci.h> +#include <linux/pci_ids.h> + +#define MODNAME "scb2_flash" +#define SCB2_ADDR 0xfff00000 +#define SCB2_WINDOW 0x00100000 + + +static void __iomem *scb2_ioaddr; +static struct mtd_info *scb2_mtd; +static struct map_info scb2_map = { + .name = "SCB2 BIOS Flash", + .size = 0, + .bankwidth = 1, +}; +static int region_fail; + +static int scb2_fixup_mtd(struct mtd_info *mtd) +{ + int i; + int done = 0; + struct map_info *map = mtd->priv; + struct cfi_private *cfi = map->fldrv_priv; + + /* barf if this doesn't look right */ + if (cfi->cfiq->InterfaceDesc != CFI_INTERFACE_X16_ASYNC) { + printk(KERN_ERR MODNAME ": unsupported InterfaceDesc: %#x\n", + cfi->cfiq->InterfaceDesc); + return -1; + } + + /* I wasn't here. I didn't see. dwmw2. */ + + /* the chip is sometimes bigger than the map - what a waste */ + mtd->size = map->size; + + /* + * We only REALLY get half the chip, due to the way it is + * wired up - D8-D15 are tossed away. We read linear bytes, + * but in reality we are getting 1/2 of each 16-bit read, + * which LOOKS linear to us. Because CFI code accounts for + * things like lock/unlock/erase by eraseregions, we need to + * fudge them to reflect this. Erases go like this: + * * send an erase to an address + * * the chip samples the address and erases the block + * * add the block erasesize to the address and repeat + * -- the problem is that addresses are 16-bit addressable + * -- we end up erasing every-other block + */ + mtd->erasesize /= 2; + for (i = 0; i < mtd->numeraseregions; i++) { + struct mtd_erase_region_info *region = &mtd->eraseregions[i]; + region->erasesize /= 2; + } + + /* + * If the chip is bigger than the map, it is wired with the high + * address lines pulled up. This makes us access the top portion of + * the chip, so all our erase-region info is wrong. Start cutting from + * the bottom. + */ + for (i = 0; !done && i < mtd->numeraseregions; i++) { + struct mtd_erase_region_info *region = &mtd->eraseregions[i]; + + if (region->numblocks * region->erasesize > mtd->size) { + region->numblocks = ((unsigned long)mtd->size / + region->erasesize); + done = 1; + } else { + region->numblocks = 0; + } + region->offset = 0; + } + + return 0; +} + +/* CSB5's 'Function Control Register' has bits for decoding @ >= 0xffc00000 */ +#define CSB5_FCR 0x41 +#define CSB5_FCR_DECODE_ALL 0x0e +static int scb2_flash_probe(struct pci_dev *dev, + const struct pci_device_id *ent) +{ + u8 reg; + + /* enable decoding of the flash region in the south bridge */ + pci_read_config_byte(dev, CSB5_FCR, ®); + pci_write_config_byte(dev, CSB5_FCR, reg | CSB5_FCR_DECODE_ALL); + + if (!request_mem_region(SCB2_ADDR, SCB2_WINDOW, scb2_map.name)) { + /* + * The BIOS seems to mark the flash region as 'reserved' + * in the e820 map. Warn and go about our business. + */ + printk(KERN_WARNING MODNAME + ": warning - can't reserve rom window, continuing\n"); + region_fail = 1; + } + + /* remap the IO window (w/o caching) */ + scb2_ioaddr = ioremap(SCB2_ADDR, SCB2_WINDOW); + if (!scb2_ioaddr) { + printk(KERN_ERR MODNAME ": Failed to ioremap window!\n"); + if (!region_fail) + release_mem_region(SCB2_ADDR, SCB2_WINDOW); + return -ENOMEM; + } + + scb2_map.phys = SCB2_ADDR; + scb2_map.virt = scb2_ioaddr; + scb2_map.size = SCB2_WINDOW; + + simple_map_init(&scb2_map); + + /* try to find a chip */ + scb2_mtd = do_map_probe("cfi_probe", &scb2_map); + + if (!scb2_mtd) { + printk(KERN_ERR MODNAME ": flash probe failed!\n"); + iounmap(scb2_ioaddr); + if (!region_fail) + release_mem_region(SCB2_ADDR, SCB2_WINDOW); + return -ENODEV; + } + + scb2_mtd->owner = THIS_MODULE; + if (scb2_fixup_mtd(scb2_mtd) < 0) { + mtd_device_unregister(scb2_mtd); + map_destroy(scb2_mtd); + iounmap(scb2_ioaddr); + if (!region_fail) + release_mem_region(SCB2_ADDR, SCB2_WINDOW); + return -ENODEV; + } + + printk(KERN_NOTICE MODNAME ": chip size 0x%llx at offset 0x%llx\n", + (unsigned long long)scb2_mtd->size, + (unsigned long long)(SCB2_WINDOW - scb2_mtd->size)); + + mtd_device_register(scb2_mtd, NULL, 0); + + return 0; +} + +static void scb2_flash_remove(struct pci_dev *dev) +{ + if (!scb2_mtd) + return; + + /* disable flash writes */ + mtd_lock(scb2_mtd, 0, scb2_mtd->size); + + mtd_device_unregister(scb2_mtd); + map_destroy(scb2_mtd); + + iounmap(scb2_ioaddr); + scb2_ioaddr = NULL; + + if (!region_fail) + release_mem_region(SCB2_ADDR, SCB2_WINDOW); +} + +static struct pci_device_id scb2_flash_pci_ids[] = { + { + .vendor = PCI_VENDOR_ID_SERVERWORKS, + .device = PCI_DEVICE_ID_SERVERWORKS_CSB5, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID + }, + { 0, } +}; + +static struct pci_driver scb2_flash_driver = { + .name = "Intel SCB2 BIOS Flash", + .id_table = scb2_flash_pci_ids, + .probe = scb2_flash_probe, + .remove = scb2_flash_remove, +}; + +module_pci_driver(scb2_flash_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Tim Hockin <thockin@sun.com>"); +MODULE_DESCRIPTION("MTD map driver for Intel SCB2 BIOS Flash"); +MODULE_DEVICE_TABLE(pci, scb2_flash_pci_ids); |