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-rw-r--r--drivers/mtd/maps/scb2_flash.c239
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, &reg);
+ 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);