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@@ -0,0 +1,243 @@
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+/* Flash mapping for Bifferboard, (c) [email protected]
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+ * Works with 1, 4 and 8MB flash versions
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+ */
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+
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+#include <linux/delay.h>
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+#include <linux/mtd/mtd.h>
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+#include <linux/mtd/map.h>
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+#include <linux/mtd/partitions.h>
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+
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+#define DRV "bifferboard-flash: "
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+
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+static struct mtd_info *bb_mtd = NULL;
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+
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+#define SIZE_BIFFBOOT 0x10000
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+#define SIZE_SECTOR 0x10000
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+#define SIZE_CONFIG 0x02000
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+#define SIZE_1MB 0x00100000
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+#define SIZE_4MB 0x00400000
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+#define SIZE_8MB 0x00800000
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+
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+#define BASE_1MB 0xfff00000
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+#define BASE_4MB 0xffc00000
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+#define BASE_8MB 0xff800000
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+
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+#define OFFS_KERNEL 0x6000
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+#define OFFS_CONFIG 0x4000
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+
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+/*
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+ * Flash detection code. This is needed because the cfi_probe doesn't probe
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+ * for the size correctly. You actually have to know the flash size before you
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+ * call it, or so it seems. It does work correctly if you map the entire flash
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+ * chip, but unsure of the implications for mapping more mem than exists.
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+ */
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+
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+static unsigned char ReadFlash(void* base, u32 addr)
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+{
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+ unsigned char val = *(volatile unsigned char *)(base+addr);
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+ udelay(1);
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+ return val;
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+}
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+
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+static void WriteFlash(void* base, u32 addr, unsigned short data)
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+{
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+ *(volatile unsigned short *)(base+addr) = data;
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+}
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+
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+static DEFINE_SPINLOCK(flash_lock);
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+
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+static u32 bb_detect(void)
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+{
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+ u32 ret = 0;
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+ ulong flags;
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+
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+ /* for detection, map in just the 1MB device, 1st 64k is enough */
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+ void* base = ioremap_nocache(BASE_1MB, 0x10000);
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+
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+ if (!base)
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+ {
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+ pr_err(DRV "Failed to map flash for probing\n");
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+ return 0;
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+ }
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+
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+ spin_lock_irqsave(&flash_lock, flags);
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+
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+ /* put flash in auto-detect mode */
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+ WriteFlash(base, 0xaaaa, 0xaaaa);
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+ WriteFlash(base, 0x5554, 0x5555);
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+ WriteFlash(base, 0xaaaa, 0x9090);
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+
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+ /* Read the auto-config data - 4 values in total */
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+ ret = ReadFlash(base, 0x0000); ret <<= 8;
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+ ret |= ReadFlash(base, 0x0200); ret <<= 8;
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+ ret |= ReadFlash(base, 0x0003); ret <<= 8;
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+ ret |= ReadFlash(base, 0x0002);
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+
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+ /* exit the autodetect state */
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+ WriteFlash(base, 0x0000, 0xf0f0);
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+
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+ spin_unlock_irqrestore(&flash_lock, flags);
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+
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+ /* unmap it, it'll be re-mapped based on the detection */
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+ iounmap(base);
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+
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+ return ret;
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+}
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+
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+
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+static struct map_info bb_map;
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+
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+/* Update the map, using the detected flash signature. */
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+static int bb_adjust_map(unsigned long sig, struct map_info* m)
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+{
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+ m->bankwidth = 2;
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+ switch (sig)
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+ {
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+ case 0x7f1c225b :
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+ m->name = "ENLV800B";
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+ m->phys = BASE_1MB;
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+ m->size = SIZE_1MB;
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+ break;
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+ case 0x7f1c22f9 :
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+ m->name = "ENLV320B";
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+ m->phys = BASE_4MB;
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+ m->size = SIZE_4MB;
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+ break;
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+ case 0x7f1c22cb :
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+ m->name = "ENLV640B";
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+ m->phys = BASE_8MB;
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+ m->size = SIZE_8MB;
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+ break;
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+ default:
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+ return -ENXIO;
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+ }
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+ return 0;
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+}
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+
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+
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+/* adjust partition sizes, prior to adding the partition
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+ * Values not specified by defines here are subject to replacement based on
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+ * the real flash size. (0x00000000 being the exception, of course) */
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+
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+static struct mtd_partition bb_parts[] =
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+{
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+/* 0 */ { name: "kernel", offset: 0x00000000, size: 0x000fa000 },
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+/* 1 */ { name: "rootfs", offset: MTDPART_OFS_APPEND, size: 0x002F0000 },
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+/* 2 */ { name: "biffboot", offset: MTDPART_OFS_APPEND, size: MTDPART_SIZ_FULL, mask_flags: MTD_WRITEABLE },
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+};
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+
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+
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+/* returns the count of partitions to be used */
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+static ulong bb_adjust_partitions(struct map_info* m)
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+{
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+ /* Read the kernel offset value, 1036 bytes into the config block. */
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+ u16 km_units = *((u16*)(m->virt + OFFS_CONFIG + 1036));
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+ u32 kernelmax = 0x200000; /* Biffboot 2.7 or earlier default */
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+
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+ /* special-case 1MB devices, because there are fewer partitions */
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+ if (m->size == SIZE_1MB)
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+ {
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+ bb_parts[0].size = SIZE_1MB - SIZE_BIFFBOOT; /* kernel */
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+ bb_parts[1].name = "biffboot"; /* biffboot */
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+ bb_parts[1].offset = MTDPART_OFS_APPEND; /* biffboot */
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+ bb_parts[1].size = MTDPART_SIZ_FULL; /* biffboot */
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+ bb_parts[1].mask_flags = MTD_WRITEABLE;
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+ return 2; /* because there's no rootfs now */
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+ }
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+
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+ /* sanity check */
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+ if (km_units > ((m->size-SIZE_BIFFBOOT)/SIZE_SECTOR))
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+ {
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+ pr_err(DRV "config block has invalid kernelmax\n");
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+ return 0;
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+ }
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+
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+ kernelmax = km_units * SIZE_SECTOR;
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+
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+ /* Kernel */
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+ bb_parts[0].size = kernelmax;
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+
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+ /* rootfs */
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+ bb_parts[1].size = m->size - kernelmax - SIZE_BIFFBOOT;
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+
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+ return 3; /* 3 partitions */
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+}
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+
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+
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+static int __init init_bb_map(void)
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+{
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+ int ret;
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+ ulong signature = bb_detect();
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+ ulong part_len;
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+
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+ if (!signature)
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+ {
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+ pr_err(DRV "Undetected flash chip");
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+ return -ENXIO;
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+ }
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+
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+ ret = bb_adjust_map(signature, &bb_map);
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+
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+ if (ret)
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+ {
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+ pr_err(DRV "Unrecognised flash chip (signature: 0x%lx)\n", signature);
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+ return ret;
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+ }
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+
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+ bb_map.virt = ioremap_nocache(bb_map.phys, bb_map.size);
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+ if (!bb_map.virt)
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+ {
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+ pr_err(DRV "ioremap\n");
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+ return -EIO;
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+ }
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+
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+ bb_mtd = do_map_probe("cfi_probe", &bb_map);
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+ if (!bb_mtd)
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+ {
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+ /* cfi_probe fails here for 1MB devices */
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+ pr_err(DRV "cfi_probe\n");
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+ ret = -ENXIO;
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+ goto err;
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+ }
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+
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+ part_len = bb_adjust_partitions(&bb_map);
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+ if (!part_len)
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+ {
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+ pr_err(DRV "no partitions established");
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+ ret = -ENXIO;
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+ goto err2;
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+ }
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+
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+ bb_mtd->owner = THIS_MODULE;
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+ ret = add_mtd_partitions(bb_mtd, bb_parts, part_len);
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+ if (ret)
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+ {
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+ pr_err(DRV "add_mtd_partitions\n");
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+ ret = -ENXIO;
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+ goto err2;
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+ }
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+
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+ return 0;
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+
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+err2:
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+ map_destroy(bb_mtd);
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+err:
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+ iounmap(bb_map.virt);
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+
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+ return ret;
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+}
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+
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+static void __exit exit_bb_map(void)
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+{
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+ del_mtd_partitions(bb_mtd);
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+ map_destroy(bb_mtd);
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+ iounmap(bb_map.virt);
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+}
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+
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+module_init(init_bb_map);
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+module_exit(exit_bb_map);
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+
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+MODULE_LICENSE("GPL");
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+MODULE_AUTHOR("Bifferos <[email protected]>");
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+MODULE_DESCRIPTION("MTD map driver for Bifferboard");
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+
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