OMAP3 SPL: Add identify_nand_chip function

A number of boards are populated with a PoP chip for both DDR and NAND
memory.  Other boards may simply use this as an easy way to identify
board revs.  So we provide a function that can be called early to reset
the NAND chip and return the result of NAND_CMD_READID.  All of this
code is put into spl_id_nand.c and controlled via CONFIG_SPL_OMAP3_ID_NAND.

Signed-off-by: Tom Rini <trini@ti.com>

arch/arm/cpu/armv7/omap3/Makefile

@@ -31,6 +31,9 @@ COBJS	+= board.o
 COBJS	+= clock.o
 COBJS	+= mem.o
 COBJS	+= sys_info.o
+ifdef CONFIG_SPL_BUILD
+COBJS-$(CONFIG_SPL_OMAP3_ID_NAND)	+= spl_id_nand.o
+endif
 
 COBJS-$(CONFIG_DRIVER_TI_EMAC)	+= emac.o
 COBJS-$(CONFIG_EMIF4)	+= emif4.o

arch/arm/cpu/armv7/omap3/spl_id_nand.c

@@ -0,0 +1,87 @@
+/*
+ * (C) Copyright 2011
+ * Texas Instruments, <www.ti.com>
+ *
+ * Author :
+ *     Tom Rini <trini@ti.com>
+ *
+ * Initial Code from:
+ *     Richard Woodruff <r-woodruff2@ti.com>
+ *     Jian Zhang <jzhang@ti.com>
+ *
+ * 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., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <linux/mtd/nand.h>
+#include <asm/io.h>
+#include <asm/arch/sys_proto.h>
+#include <asm/arch/mem.h>
+
+static struct gpmc *gpmc_config = (struct gpmc *)GPMC_BASE;
+
+/* nand_command: Send a flash command to the flash chip */
+static void nand_command(u8 command)
+{
+	writeb(command, &gpmc_config->cs[0].nand_cmd);
+
+	if (command == NAND_CMD_RESET) {
+		unsigned char ret_val;
+		writeb(NAND_CMD_STATUS, &gpmc_config->cs[0].nand_cmd);
+		do {
+			/* Wait until ready */
+			ret_val = readl(&gpmc_config->cs[0].nand_dat);
+		} while ((ret_val & NAND_STATUS_READY) != NAND_STATUS_READY);
+	}
+}
+
+/*
+ * Many boards will want to know the results of the NAND_CMD_READID command
+ * in order to decide what to do about DDR initialization.  This function
+ * allows us to do that very early and to pass those results back to the
+ * board so it can make whatever decisions need to be made.
+ */
+void identify_nand_chip(int *mfr, int *id)
+{
+	/* Make sure that we have setup GPMC for NAND correctly. */
+	writel(M_NAND_GPMC_CONFIG1, &gpmc_config->cs[0].config1);
+	writel(M_NAND_GPMC_CONFIG2, &gpmc_config->cs[0].config2);
+	writel(M_NAND_GPMC_CONFIG3, &gpmc_config->cs[0].config3);
+	writel(M_NAND_GPMC_CONFIG4, &gpmc_config->cs[0].config4);
+	writel(M_NAND_GPMC_CONFIG5, &gpmc_config->cs[0].config5);
+	writel(M_NAND_GPMC_CONFIG6, &gpmc_config->cs[0].config6);
+
+	/*
+	 * Enable the config.  The CS size goes in bits 11:8.  We set
+	 * bit 6 to enable the CS and the base address goes into bits 5:0.
+	 */
+	writel((GPMC_SIZE_128M << 8) | (GPMC_CS_ENABLE << 6) |
+				((NAND_BASE >> 24) & GPMC_BASEADDR_MASK),
+			&gpmc_config->cs[0].config7);
+
+	sdelay(2000);
+
+	/* Issue a RESET and then READID */
+	nand_command(NAND_CMD_RESET);
+	nand_command(NAND_CMD_READID);
+
+	/* Set the address to read to 0x0 */
+	writeb(0x0, &gpmc_config->cs[0].nand_adr);
+
+	/* Read off the manufacturer and device id. */
+	*mfr = readb(&gpmc_config->cs[0].nand_dat);
+	*id = readb(&gpmc_config->cs[0].nand_dat);
+}

arch/arm/include/asm/arch-omap3/sys_proto.h

@@ -40,6 +40,7 @@ void sdrc_init(void);
 void do_sdrc_init(u32, u32);
 void get_board_mem_timings(u32 *mcfg, u32 *ctrla, u32 *ctrlb, u32 *rfr_ctrl,
 		u32 *mr);
+void identify_nand_chip(int *mfr, int *id);
 void emif4_init(void);
 void gpmc_init(void);
 void enable_gpmc_cs_config(const u32 *gpmc_config, struct gpmc_cs *cs, u32 base,