--- /dev/null
+/* Flash mapping for Bifferboard, (c) bifferos@yahoo.co.uk
+ * Works with 1, 4 and 8MB flash versions
+ */
+
+#include <linux/delay.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/partitions.h>
+
+#define DRV "bifferboard-flash: "
+
+static struct mtd_info *bb_mtd = NULL;
+
+#define SIZE_BIFFBOOT 0x10000
+#define SIZE_SECTOR 0x10000
+#define SIZE_CONFIG 0x02000
+#define SIZE_1MB 0x00100000
+#define SIZE_4MB 0x00400000
+#define SIZE_8MB 0x00800000
+
+#define BASE_1MB 0xfff00000
+#define BASE_4MB 0xffc00000
+#define BASE_8MB 0xff800000
+
+#define OFFS_KERNEL 0x6000
+#define OFFS_CONFIG 0x4000
+
+/*
+ * Flash detection code. This is needed because the cfi_probe doesn't probe
+ * for the size correctly. You actually have to know the flash size before you
+ * call it, or so it seems. It does work correctly if you map the entire flash
+ * chip, but unsure of the implications for mapping more mem than exists.
+ */
+
+static unsigned char ReadFlash(void* base, u32 addr)
+{
+ unsigned char val = *(volatile unsigned char *)(base+addr);
+ udelay(1);
+ return val;
+}
+
+static void WriteFlash(void* base, u32 addr, unsigned short data)
+{
+ *(volatile unsigned short *)(base+addr) = data;
+}
+
+static DEFINE_SPINLOCK(flash_lock);
+
+static u32 bb_detect(void)
+{
+ u32 ret = 0;
+ ulong flags;
+
+ /* for detection, map in just the 1MB device, 1st 64k is enough */
+ void* base = ioremap_nocache(BASE_1MB, 0x10000);
+
+ if (!base)
+ {
+ pr_err(DRV "Failed to map flash for probing\n");
+ return 0;
+ }
+
+ spin_lock_irqsave(&flash_lock, flags);
+
+ /* put flash in auto-detect mode */
+ WriteFlash(base, 0xaaaa, 0xaaaa);
+ WriteFlash(base, 0x5554, 0x5555);
+ WriteFlash(base, 0xaaaa, 0x9090);
+
+ /* Read the auto-config data - 4 values in total */
+ ret = ReadFlash(base, 0x0000); ret <<= 8;
+ ret |= ReadFlash(base, 0x0200); ret <<= 8;
+ ret |= ReadFlash(base, 0x0003); ret <<= 8;
+ ret |= ReadFlash(base, 0x0002);
+
+ /* exit the autodetect state */
+ WriteFlash(base, 0x0000, 0xf0f0);
+
+ spin_unlock_irqrestore(&flash_lock, flags);
+
+ /* unmap it, it'll be re-mapped based on the detection */
+ iounmap(base);
+
+ return ret;
+}
+
+
+static struct map_info bb_map;
+
+/* Update the map, using the detected flash signature. */
+static int bb_adjust_map(unsigned long sig, struct map_info* m)
+{
+ m->bankwidth = 2;
+ switch (sig)
+ {
+ case 0x7f1c225b :
+ m->name = "ENLV800B";
+ m->phys = BASE_1MB;
+ m->size = SIZE_1MB;
+ break;
+ case 0x7f1c22f9 :
+ m->name = "ENLV320B";
+ m->phys = BASE_4MB;
+ m->size = SIZE_4MB;
+ break;
+ case 0x7f1c22cb :
+ m->name = "ENLV640B";
+ m->phys = BASE_8MB;
+ m->size = SIZE_8MB;
+ break;
+ default:
+ return -ENXIO;
+ }
+ return 0;
+}
+
+
+/* adjust partition sizes, prior to adding the partition
+ * Values not specified by defines here are subject to replacement based on
+ * the real flash size. (0x00000000 being the exception, of course) */
+
+static struct mtd_partition bb_parts[] =
+{
+/* 0 */ { name: "kernel", offset: 0x00000000, size: 0x000fa000 },
+/* 1 */ { name: "rootfs", offset: MTDPART_OFS_APPEND, size: 0x002F0000 },
+/* 2 */ { name: "biffboot", offset: MTDPART_OFS_APPEND, size: MTDPART_SIZ_FULL, mask_flags: MTD_WRITEABLE },
+};
+
+
+/* returns the count of partitions to be used */
+static ulong bb_adjust_partitions(struct map_info* m)
+{
+ /* Read the kernel offset value, 1036 bytes into the config block. */
+ u16 km_units = *((u16*)(m->virt + OFFS_CONFIG + 1036));
+ u32 kernelmax = 0x200000; /* Biffboot 2.7 or earlier default */
+
+ /* special-case 1MB devices, because there are fewer partitions */
+ if (m->size == SIZE_1MB)
+ {
+ bb_parts[0].size = SIZE_1MB - SIZE_BIFFBOOT; /* kernel */
+ bb_parts[1].name = "biffboot"; /* biffboot */
+ bb_parts[1].offset = MTDPART_OFS_APPEND; /* biffboot */
+ bb_parts[1].size = MTDPART_SIZ_FULL; /* biffboot */
+ bb_parts[1].mask_flags = MTD_WRITEABLE;
+ return 2; /* because there's no rootfs now */
+ }
+
+ /* sanity check */
+ if (km_units > ((m->size-SIZE_BIFFBOOT)/SIZE_SECTOR))
+ {
+ pr_err(DRV "config block has invalid kernelmax\n");
+ return 0;
+ }
+
+ kernelmax = km_units * SIZE_SECTOR;
+
+ /* Kernel */
+ bb_parts[0].size = kernelmax;
+
+ /* rootfs */
+ bb_parts[1].size = m->size - kernelmax - SIZE_BIFFBOOT;
+
+ return 3; /* 3 partitions */
+}
+
+
+static int __init init_bb_map(void)
+{
+ int ret;
+ ulong signature = bb_detect();
+ ulong part_len;
+
+ if (!signature)
+ {
+ pr_err(DRV "Undetected flash chip");
+ return -ENXIO;
+ }
+
+ ret = bb_adjust_map(signature, &bb_map);
+
+ if (ret)
+ {
+ pr_err(DRV "Unrecognised flash chip (signature: 0x%lx)\n", signature);
+ return ret;
+ }
+
+ bb_map.virt = ioremap_nocache(bb_map.phys, bb_map.size);
+ if (!bb_map.virt)
+ {
+ pr_err(DRV "ioremap\n");
+ return -EIO;
+ }
+
+ bb_mtd = do_map_probe("cfi_probe", &bb_map);
+ if (!bb_mtd)
+ {
+ /* cfi_probe fails here for 1MB devices */
+ pr_err(DRV "cfi_probe\n");
+ ret = -ENXIO;
+ goto err;
+ }
+
+ part_len = bb_adjust_partitions(&bb_map);
+ if (!part_len)
+ {
+ pr_err(DRV "no partitions established");
+ ret = -ENXIO;
+ goto err2;
+ }
+
+ bb_mtd->owner = THIS_MODULE;
+ ret = add_mtd_partitions(bb_mtd, bb_parts, part_len);
+ if (ret)
+ {
+ pr_err(DRV "add_mtd_partitions\n");
+ ret = -ENXIO;
+ goto err2;
+ }
+
+ return 0;
+
+err2:
+ map_destroy(bb_mtd);
+err:
+ iounmap(bb_map.virt);
+
+ return ret;
+}
+
+static void __exit exit_bb_map(void)
+{
+ del_mtd_partitions(bb_mtd);
+ map_destroy(bb_mtd);
+ iounmap(bb_map.virt);
+}
+
+module_init(init_bb_map);
+module_exit(exit_bb_map);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Bifferos <bifferos@yahoo.co.uk>");
+MODULE_DESCRIPTION("MTD map driver for Bifferboard");
+
projects / openwrt.git / commitdiff