[MTD] [MAPS] Support for BIOS flash chips on the nvidia ck804 southbridge

Add support for accessing BIOS flash chips connected to the NVIDIA ck804 southbridge.
Signed-off-by: Ryan Jackson <rjackson@lnxi.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/maps/Kconfig

@@ -193,6 +193,15 @@ config MTD_ESB2ROM
 
           BE VERY CAREFUL.
 
+config MTD_CK804XROM
+	tristate "BIOS flash chip on Nvidia CK804"
+	depends on X86 && MTD_JEDECPROBE
+	help
+	  Support for treating the BIOS flash chip on nvidia motherboards
+	  as an MTD device - with this you can reprogram your BIOS.
+
+	  BE VERY CAREFUL.
+
 config MTD_SCB2_FLASH
 	tristate "BIOS flash chip on Intel SCB2 boards"
 	depends on X86 && MTD_JEDECPROBE

drivers/mtd/maps/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_MTD_L440GX)	+= l440gx.o
 obj-$(CONFIG_MTD_AMD76XROM)	+= amd76xrom.o
 obj-$(CONFIG_MTD_ESB2ROM)	+= esb2rom.o
 obj-$(CONFIG_MTD_ICHXROM)	+= ichxrom.o
+obj-$(CONFIG_MTD_CK804XROM)	+= ck804xrom.o
 obj-$(CONFIG_MTD_TSUNAMI)	+= tsunami_flash.o
 obj-$(CONFIG_MTD_LUBBOCK)	+= lubbock-flash.o
 obj-$(CONFIG_MTD_MAINSTONE)	+= mainstone-flash.o

drivers/mtd/maps/ck804xrom.c

+/*
+ * ck804xrom.c
+ *
+ * Normal mappings of chips in physical memory
+ *
+ * Dave Olsen <dolsen@lnxi.com>
+ * Ryan Jackson <rjackson@lnxi.com>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <asm/io.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/cfi.h>
+#include <linux/mtd/flashchip.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
+#include <linux/list.h>
+
+
+#define MOD_NAME KBUILD_BASENAME
+
+#define ADDRESS_NAME_LEN 18
+
+#define ROM_PROBE_STEP_SIZE (64*1024) 
+
+struct ck804xrom_window {
+	void __iomem *virt;
+	unsigned long phys;
+	unsigned long size;
+	struct list_head maps;
+	struct resource rsrc;
+	struct pci_dev *pdev;
+};
+
+struct ck804xrom_map_info {
+	struct list_head list;
+	struct map_info map;
+	struct mtd_info *mtd;
+	struct resource rsrc;
+	char map_name[sizeof(MOD_NAME) + 2 + ADDRESS_NAME_LEN];
+};
+
+
+/* The 2 bits controlling the window size are often set to allow reading
+ * the BIOS, but too small to allow writing, since the lock registers are
+ * 4MiB lower in the address space than the data.
+ *
+ * This is intended to prevent flashing the bios, perhaps accidentally.
+ *
+ * This parameter allows the normal driver to override the BIOS settings.
+ *
+ * The bits are 6 and 7.  If both bits are set, it is a 5MiB window.
+ * If only the 7 Bit is set, it is a 4MiB window.  Otherwise, a
+ * 64KiB window.
+ *
+ */
+static uint win_size_bits = 0;
+module_param(win_size_bits, uint, 0);
+MODULE_PARM_DESC(win_size_bits, "ROM window size bits override for 0x88 byte, normally set by BIOS.");
+
+static struct ck804xrom_window ck804xrom_window = {
+	.maps = LIST_HEAD_INIT(ck804xrom_window.maps),
+};
+
+static void ck804xrom_cleanup(struct ck804xrom_window *window)
+{
+	struct ck804xrom_map_info *map, *scratch;
+	u8 byte;
+
+	if (window->pdev) {
+		/* Disable writes through the rom window */
+		pci_read_config_byte(window->pdev, 0x6d, &byte);
+		pci_write_config_byte(window->pdev, 0x6d, byte & ~1);
+	}
+
+	/* Free all of the mtd devices */
+	list_for_each_entry_safe(map, scratch, &window->maps, list) {
+		if (map->rsrc.parent)
+			release_resource(&map->rsrc);
+
+		del_mtd_device(map->mtd);
+		map_destroy(map->mtd);
+		list_del(&map->list);
+		kfree(map);
+	}
+	if (window->rsrc.parent)
+		release_resource(&window->rsrc);
+
+	if (window->virt) {
+		iounmap(window->virt);
+		window->virt = NULL;
+		window->phys = 0;
+		window->size = 0;
+	}
+	pci_dev_put(window->pdev);
+}
+
+
+static int __devinit ck804xrom_init_one (struct pci_dev *pdev,
+	const struct pci_device_id *ent)
+{
+	static char *rom_probe_types[] = { "cfi_probe", "jedec_probe", NULL };
+	u8 byte;
+	struct ck804xrom_window *window = &ck804xrom_window;
+	struct ck804xrom_map_info *map = NULL;
+	unsigned long map_top;
+
+	/* Remember the pci dev I find the window in */
+	window->pdev = pci_dev_get(pdev);
+
+	/* Enable the selected rom window.  This is often incorrectly
+	 * set up by the BIOS, and the 4MiB offset for the lock registers
+	 * requires the full 5MiB of window space.
+	 *
+	 * This 'write, then read' approach leaves the bits for
+	 * other uses of the hardware info.
+	 */
+        pci_read_config_byte(pdev, 0x88, &byte);
+        pci_write_config_byte(pdev, 0x88, byte | win_size_bits );
+
+
+	/* Assume the rom window is properly setup, and find it's size */
+	pci_read_config_byte(pdev, 0x88, &byte);
+
+	if ((byte & ((1<<7)|(1<<6))) == ((1<<7)|(1<<6)))
+		window->phys = 0xffb00000; /* 5MiB */
+	else if ((byte & (1<<7)) == (1<<7))
+		window->phys = 0xffc00000; /* 4MiB */
+	else
+		window->phys = 0xffff0000; /* 64KiB */
+
+	window->size = 0xffffffffUL - window->phys + 1UL;
+
+	/*
+	 * Try to reserve the window mem region.  If this fails then
+	 * it is likely due to a fragment of the window being
+	 * "reserved" by the BIOS.  In the case that the
+	 * request_mem_region() fails then once the rom size is
+	 * discovered we will try to reserve the unreserved fragment.
+	 */
+	window->rsrc.name = MOD_NAME;
+	window->rsrc.start = window->phys;
+	window->rsrc.end   = window->phys + window->size - 1;
+	window->rsrc.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+	if (request_resource(&iomem_resource, &window->rsrc)) {
+		window->rsrc.parent = NULL;
+		printk(KERN_ERR MOD_NAME
+			" %s(): Unable to register resource"
+			" 0x%.016llx-0x%.016llx - kernel bug?\n",
+			__func__,
+			(unsigned long long)window->rsrc.start,
+			(unsigned long long)window->rsrc.end);
+	}
+
+
+	/* Enable writes through the rom window */
+	pci_read_config_byte(pdev, 0x6d, &byte);
+	pci_write_config_byte(pdev, 0x6d, byte | 1);
+
+	/* FIXME handle registers 0x80 - 0x8C the bios region locks */
+
+	/* For write accesses caches are useless */
+	window->virt = ioremap_nocache(window->phys, window->size);
+	if (!window->virt) {
+		printk(KERN_ERR MOD_NAME ": ioremap(%08lx, %08lx) failed\n",
+			window->phys, window->size);
+		goto out;
+	}
+
+	/* Get the first address to look for a rom chip at */
+	map_top = window->phys;
+#if 1
+	/* The probe sequence run over the firmware hub lock
+	 * registers sets them to 0x7 (no access).
+	 * Probe at most the last 4MiB of the address space.
+	 */
+	if (map_top < 0xffc00000)
+		map_top = 0xffc00000;
+#endif
+	/* Loop  through and look for rom chips.  Since we don't know the
+	 * starting address for each chip, probe every ROM_PROBE_STEP_SIZE
+	 * bytes from the starting address of the window.
+	 */
+	while((map_top - 1) < 0xffffffffUL) {
+		struct cfi_private *cfi;
+		unsigned long offset;
+		int i;
+
+		if (!map)
+			map = kmalloc(sizeof(*map), GFP_KERNEL);
+
+		if (!map) {
+			printk(KERN_ERR MOD_NAME ": kmalloc failed");
+			goto out;
+		}
+		memset(map, 0, sizeof(*map));
+		INIT_LIST_HEAD(&map->list);
+		map->map.name = map->map_name;
+		map->map.phys = map_top;
+		offset = map_top - window->phys;
+		map->map.virt = (void __iomem *)
+			(((unsigned long)(window->virt)) + offset);
+		map->map.size = 0xffffffffUL - map_top + 1UL;
+		/* Set the name of the map to the address I am trying */
+		sprintf(map->map_name, "%s @%08lx",
+			MOD_NAME, map->map.phys);
+
+		/* There is no generic VPP support */
+		for(map->map.bankwidth = 32; map->map.bankwidth;
+			map->map.bankwidth >>= 1)
+		{
+			char **probe_type;
+			/* Skip bankwidths that are not supported */
+			if (!map_bankwidth_supported(map->map.bankwidth))
+				continue;
+
+			/* Setup the map methods */
+			simple_map_init(&map->map);
+
+			/* Try all of the probe methods */
+			probe_type = rom_probe_types;
+			for(; *probe_type; probe_type++) {
+				map->mtd = do_map_probe(*probe_type, &map->map);
+				if (map->mtd)
+					goto found;
+			}
+		}
+		map_top += ROM_PROBE_STEP_SIZE;
+		continue;
+	found:
+		/* Trim the size if we are larger than the map */
+		if (map->mtd->size > map->map.size) {
+			printk(KERN_WARNING MOD_NAME
+				" rom(%u) larger than window(%lu). fixing...\n",
+				map->mtd->size, map->map.size);
+			map->mtd->size = map->map.size;
+		}
+		if (window->rsrc.parent) {
+			/*
+			 * Registering the MTD device in iomem may not be possible
+			 * if there is a BIOS "reserved" and BUSY range.  If this
+			 * fails then continue anyway.
+			 */
+			map->rsrc.name  = map->map_name;
+			map->rsrc.start = map->map.phys;
+			map->rsrc.end   = map->map.phys + map->mtd->size - 1;
+			map->rsrc.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+			if (request_resource(&window->rsrc, &map->rsrc)) {
+				printk(KERN_ERR MOD_NAME
+					": cannot reserve MTD resource\n");
+				map->rsrc.parent = NULL;
+			}
+		}
+
+		/* Make the whole region visible in the map */
+		map->map.virt = window->virt;
+		map->map.phys = window->phys;
+		cfi = map->map.fldrv_priv;
+		for(i = 0; i < cfi->numchips; i++)
+			cfi->chips[i].start += offset;
+
+		/* Now that the mtd devices is complete claim and export it */
+		map->mtd->owner = THIS_MODULE;
+		if (add_mtd_device(map->mtd)) {
+			map_destroy(map->mtd);
+			map->mtd = NULL;
+			goto out;
+		}
+
+
+		/* Calculate the new value of map_top */
+		map_top += map->mtd->size;
+
+		/* File away the map structure */
+		list_add(&map->list, &window->maps);
+		map = NULL;
+	}
+
+ out:
+	/* Free any left over map structures */
+	if (map)
+		kfree(map);
+
+	/* See if I have any map structures */
+	if (list_empty(&window->maps)) {
+		ck804xrom_cleanup(window);
+		return -ENODEV;
+	}
+	return 0;
+}
+
+
+static void __devexit ck804xrom_remove_one (struct pci_dev *pdev)
+{
+	struct ck804xrom_window *window = &ck804xrom_window;
+
+	ck804xrom_cleanup(window);
+}
+
+static struct pci_device_id ck804xrom_pci_tbl[] = {
+	{ PCI_VENDOR_ID_NVIDIA, 0x0051,
+        PCI_ANY_ID, PCI_ANY_ID, }, /* nvidia ck804 */
+	{ 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, ck804xrom_pci_tbl);
+
+#if 0
+static struct pci_driver ck804xrom_driver = {
+	.name =		MOD_NAME,
+	.id_table =	ck804xrom_pci_tbl,
+	.probe =	ck804xrom_init_one,
+	.remove =	ck804xrom_remove_one,
+};
+#endif
+
+static int __init init_ck804xrom(void)
+{
+	struct pci_dev *pdev;
+	struct pci_device_id *id;
+	int retVal;
+	pdev = NULL;
+
+	for(id = ck804xrom_pci_tbl; id->vendor; id++) {
+		pdev = pci_find_device(id->vendor, id->device, NULL);
+		if (pdev)
+			break;
+	}
+	if (pdev) {
+		retVal = ck804xrom_init_one(pdev, &ck804xrom_pci_tbl[0]);
+		pci_dev_put(pdev);
+		return retVal;
+	}
+	return -ENXIO;
+#if 0
+	return pci_module_init(&ck804xrom_driver);
+#endif
+}
+
+static void __exit cleanup_ck804xrom(void)
+{
+	ck804xrom_remove_one(ck804xrom_window.pdev);
+}
+
+module_init(init_ck804xrom);
+module_exit(cleanup_ck804xrom);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Eric Biederman <ebiederman@lnxi.com>, Dave Olsen <dolsen@lnxi.com>");
+MODULE_DESCRIPTION("MTD map driver for BIOS chips on the Nvidia ck804 southbridge");
+