[RFC PATCH] add support for N25Q256

[Cédric Le Goater]

I needed to reflash a N25Q256 on a host system and hacked flashrom
to make this work. For this, I used the 4-Bytes address support
developed by Boris Baykov. This is why the patch is an RFC. The
whole patchset is available under github here:

https://github.com/legoater/flashrom

I can help in getting this patchset merged but do the comments
in :

http://patchwork.coreboot.org/patch/4272/

need to be all addressed or can we rework a bit the patchset to
merge the main changes separately :

- 4-bytes addressing
       - W25Q256.V support
       - SFDP
       - Progress visualization
       - ...

Tested under Linux with spidev.

Signed-off-by: Cédric Le Goater 
---
 flashchips.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

Index: flashrom.git/flashchips.c
===================================================================
--- flashrom.git.orig/flashchips.c
+++ flashrom.git/flashchips.c
@@ -9330,6 +9330,48 @@ const struct flashchip flashchips[] = {
    },

{
+		.vendor		= "Micron/Numonyx/ST",
+		.name		= "N25Q256..3E", /* ..3E = 3V, uniform 64KB/4KB blocks/sectors */
+		.bustype	= BUS_SPI,
+		.manufacture_id = ST_ID,
+		.model_id	= ST_N25Q256__3E,
+		.total_size	= 32768,
+		.page_size	= 256,
+		/* supports SFDP */
+		/* OTP: 64B total; read 0x4B, write 0x42 */
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_QPI
+		| FEATURE_4BA_SUPPORT,
+		 .four_bytes_addr_funcs =
+		 {
+			  .enter_4ba = spi_enter_4ba_b7_we, /* enter 4-bytes addressing mode by CMD B7 + WREN */
+			  .read_nbyte = spi_nbyte_read_4ba_direct, /* read directly from any mode, no need to enter 4ba */
+			  .program_byte = spi_byte_program_4ba, /* write from 4-bytes addressing mode */
+			  .program_nbyte = spi_nbyte_program_4ba /* write from 4-bytes addressing mode */
+		 },
+		.tested		= TEST_OK_PREW,
+		.probe		= probe_spi_rdid,
+		.probe_timing	= TIMING_ZERO,
+		.block_erasers	=
+		{
+			{
+				.eraseblocks = { {4 * 1024, 8192 } },
+				.block_erase = spi_block_erase_20_4ba,
+			}, {
+				.eraseblocks = { {64 * 1024, 512} },
+				.block_erase = spi_block_erase_d8_4ba,
+			}, {
+				.eraseblocks = { {32 * 1024 * 1024, 1} },
+				.block_erase = spi_block_erase_c7,
+			}
+		},
+		.printlock	= spi_prettyprint_status_register_n25q, /* TODO: config, lock, flag regs */
+		.unlock		= spi_disable_blockprotect_n25q, /* TODO: per 64kB sector lock registers */
+		.write		= spi_chip_write_256, /* Multi I/O supported */
+		.read		= spi_chip_read, /* Fast read (0x0B) and multi I/O supported */
+		.voltage	= {2700, 3600},
+	},
+
+	{
    	.vendor		= "MoselVitelic",
    	.name		= "V29C51000B",
    	.bustype	= BUS_PARALLEL,