u-boot/arch/arm/mach-omap2/omap3/spl_id_nand.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* (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>
*/
#include <common.h>
#include <jffs2/load_kernel.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/omap_gpmc.h>
#include <asm/io.h>
#include <asm/arch/sys_proto.h>
#include <asm/arch/mem.h>
/*
* 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.
*/
int identify_nand_chip(int *mfr, int *id)
{
int loops = 1000;
/* Make sure that we have setup GPMC for NAND correctly. */
set_gpmc_cs0(MTD_DEV_TYPE_NAND);
sdelay(2000);
/* Issue a RESET and then READID */
writeb(NAND_CMD_RESET, &gpmc_cfg->cs[0].nand_cmd);
writeb(NAND_CMD_STATUS, &gpmc_cfg->cs[0].nand_cmd);
while ((readl(&gpmc_cfg->cs[0].nand_dat) & NAND_STATUS_READY)
!= NAND_STATUS_READY) {
sdelay(100);
if (--loops == 0)
return 1;
}
writeb(NAND_CMD_READID, &gpmc_cfg->cs[0].nand_cmd);
/* Set the address to read to 0x0 */
writeb(0x0, &gpmc_cfg->cs[0].nand_adr);
/* Read off the manufacturer and device id. */
*mfr = readb(&gpmc_cfg->cs[0].nand_dat);
*id = readb(&gpmc_cfg->cs[0].nand_dat);
return 0;
}