3 * Texas Instruments, <www.ti.com>
6 * Tom Rini <trini@ti.com>
9 * Richard Woodruff <r-woodruff2@ti.com>
10 * Jian Zhang <jzhang@ti.com>
12 * SPDX-License-Identifier: GPL-2.0+
16 #include <jffs2/load_kernel.h>
17 #include <linux/mtd/nand.h>
18 #include <linux/mtd/omap_gpmc.h>
20 #include <asm/arch/sys_proto.h>
21 #include <asm/arch/mem.h>
24 * Many boards will want to know the results of the NAND_CMD_READID command
25 * in order to decide what to do about DDR initialization. This function
26 * allows us to do that very early and to pass those results back to the
27 * board so it can make whatever decisions need to be made.
29 int identify_nand_chip(int *mfr, int *id)
33 /* Make sure that we have setup GPMC for NAND correctly. */
34 set_gpmc_cs0(MTD_DEV_TYPE_NAND);
38 /* Issue a RESET and then READID */
39 writeb(NAND_CMD_RESET, &gpmc_cfg->cs[0].nand_cmd);
40 writeb(NAND_CMD_STATUS, &gpmc_cfg->cs[0].nand_cmd);
41 while ((readl(&gpmc_cfg->cs[0].nand_dat) & NAND_STATUS_READY)
42 != NAND_STATUS_READY) {
47 writeb(NAND_CMD_READID, &gpmc_cfg->cs[0].nand_cmd);
49 /* Set the address to read to 0x0 */
50 writeb(0x0, &gpmc_cfg->cs[0].nand_adr);
52 /* Read off the manufacturer and device id. */
53 *mfr = readb(&gpmc_cfg->cs[0].nand_dat);
54 *id = readb(&gpmc_cfg->cs[0].nand_dat);