Add support for the Eon EN29LV640B chip

This chip needs special command sequences in 8 bit mode. Also, 8 bit
programming needs actually 16bit double byte program.

The chip is found on the Bifferos Bifferboard, for example.

Corresponding to flashrom svn r1521.

Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>
diff --git a/en29lv640b.c b/en29lv640b.c
new file mode 100644
index 0000000..0dff2d1
--- /dev/null
+++ b/en29lv640b.c
@@ -0,0 +1,138 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2000 Silicon Integrated System Corporation
+ * Copyright (C) 2012 Rudolf Marek <r.marek@assembler.cz>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include "flash.h"
+#include "chipdrivers.h"
+
+/*
+ * WARNING!
+ * This chip uses the standard JEDEC addresses in 16-bit mode as word
+ * addresses. In byte mode, 0xAAA has to be used instead of 0x555 and
+ * 0x555 instead of 0x2AA. Do *not* blindly replace with standard JEDEC
+ * functions.
+ */
+
+/* chunksize is 1 */
+int write_en29lv640b(struct flashctx *flash, uint8_t *src, unsigned int start,
+		     unsigned int len)
+{
+	int i;
+	chipaddr bios = flash->virtual_memory;
+	chipaddr dst = flash->virtual_memory + start;
+
+	for (i = 0; i < len; i += 2) {
+		chip_writeb(flash, 0xAA, bios + 0xAAA);
+		chip_writeb(flash, 0x55, bios + 0x555);
+		chip_writeb(flash, 0xA0, bios + 0xAAA);
+
+		/* Transfer data from source to destination. */
+		chip_writew(flash, (*src) | ((*(src + 1)) << 8 ), dst);
+		toggle_ready_jedec(flash, dst);
+#if 0
+		/* We only want to print something in the error case. */
+		msg_cerr("Value in the flash at address 0x%lx = %#x, want %#x\n",
+			 (dst - bios), chip_readb(flash, dst), *src);
+#endif
+		dst += 2;
+		src += 2;
+	}
+
+	/* FIXME: Ignore errors for now. */
+	return 0;
+}
+
+int probe_en29lv640b(struct flashctx *flash)
+{
+	chipaddr bios = flash->virtual_memory;
+	uint16_t id1, id2;
+
+	chip_writeb(flash, 0xAA, bios + 0xAAA);
+	chip_writeb(flash, 0x55, bios + 0x555);
+	chip_writeb(flash, 0x90, bios + 0xAAA);
+
+	programmer_delay(10);
+
+	id1 = chip_readb(flash, bios + 0x200);
+	id1 |= (chip_readb(flash, bios) << 8);
+
+	id2 = chip_readb(flash, bios + 0x02);
+
+	chip_writeb(flash, 0xF0, bios + 0xAAA);
+
+	programmer_delay(10);
+
+	msg_cdbg("%s: id1 0x%04x, id2 0x%04x\n", __func__, id1, id2);
+
+	if (id1 == flash->manufacture_id && id2 == flash->model_id)
+		return 1;
+
+	return 0;
+}
+
+int erase_en29lv640b(struct flashctx *flash)
+{
+	chipaddr bios = flash->virtual_memory;
+
+	chip_writeb(flash, 0xAA, bios + 0xAAA);
+	chip_writeb(flash, 0x55, bios + 0x555);
+	chip_writeb(flash, 0x80, bios + 0xAAA);
+
+	chip_writeb(flash, 0xAA, bios + 0xAAA);
+	chip_writeb(flash, 0x55, bios + 0x555);
+	chip_writeb(flash, 0x10, bios + 0xAAA);
+
+	programmer_delay(10);
+	toggle_ready_jedec(flash, bios);
+
+	/* FIXME: Check the status register for errors. */
+	return 0;
+}
+
+int block_erase_en29lv640b(struct flashctx *flash, unsigned int start,
+			   unsigned int len)
+{
+	chipaddr bios = flash->virtual_memory;
+	chipaddr dst = bios + start;
+
+	chip_writeb(flash, 0xAA, bios + 0xAAA);
+	chip_writeb(flash, 0x55, bios + 0x555);
+	chip_writeb(flash, 0x80, bios + 0xAAA);
+
+	chip_writeb(flash, 0xAA, bios + 0xAAA);
+	chip_writeb(flash, 0x55, bios + 0x555);
+	chip_writeb(flash, 0x30, dst);
+
+	programmer_delay(10);
+	toggle_ready_jedec(flash, bios);
+
+	/* FIXME: Check the status register for errors. */
+	return 0;
+}
+
+int block_erase_chip_en29lv640b(struct flashctx *flash, unsigned int address,
+			        unsigned int blocklen)
+{
+	if ((address != 0) || (blocklen != flash->total_size * 1024)) {
+		msg_cerr("%s called with incorrect arguments\n", __func__);
+		return -1;
+	}
+	return erase_en29lv640b(flash);
+}