移植U-Boot-2008.10到友善之臂mini2440（三）
1.2.2 添加Nand Flash 读取函数
在board/ mini2440加入NAND Flash读取函数（start.S中需要的nand_read_ll函数）文件nand_read.c ，内容如下：
#include <config.h>#define __REGb(x) (*(volatile unsigned char *)(x))
#define __REGi(x) (*(volatile unsigned int *)(x))
#define NF_BASE 0x4e000000
#if defined(CONFIG_S3C2440)
#define NFCONF __REGi(NF_BASE + 0x0)
#define NFCONT __REGi(NF_BASE + 0x4)
#define NFCMD __REGb(NF_BASE + 0x8)
#define NFADDR __REGb(NF_BASE + 0xC)
#define NFDATA __REGb(NF_BASE + 0x10)
#define NFSTAT __REGb(NF_BASE + 0x20)
//#define GPDAT __REGi(GPIO_CTL_BASE+oGPIO_F+oGPIO_DAT)
#define NAND_CHIP_ENABLE (NFCONT &= ~(1<<1))
#define NAND_CHIP_DISABLE (NFCONT |= (1<<1))
#define NAND_CLEAR_RB (NFSTAT |= (1<<2))
#define NAND_DETECT_RB { while(! (NFSTAT&(1<<2)));}
#define BUSY 4
inline void wait_idle(void) {
while(!(NFSTAT & BUSY));
NFSTAT |= BUSY;
}
#define NAND_SECTOR_SIZE 512
#define NAND_BLOCK_MASK (NAND_SECTOR_SIZE - 1)
/* low level nand read function */
int
nand_read_ll(unsigned char *buf, unsigned long start_addr, int size)
{
int i, j;
if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
return -1; /* invalid alignment */
}
NAND_CHIP_ENABLE;
for(i=start_addr; i < (start_addr + size);) {
/* READ0 */
NAND_CLEAR_RB;
NFCMD = 0;
/* Write Address */
NFADDR = i & 0xff;
NFADDR = (i >> 9) & 0xff;
NFADDR = (i >> 17) & 0xff;
NFADDR = (i >> 25) & 0xff;
NAND_DETECT_RB;
for(j=0; j < NAND_SECTOR_SIZE; j++, i++) {
*buf = (NFDATA & 0xff);
buf++;
}
}
NAND_CHIP_DISABLE;
return 0;
}
#endif
#if defined(CONFIG_S3C2410)
#define NFCONF __REGi(NF_BASE + 0x0)
#define NFCMD __REGb(NF_BASE + 0x4)
#define NFADDR __REGb(NF_BASE + 0x8)
#define NFDATA __REGb(NF_BASE + 0xc)
#define NFSTAT __REGb(NF_BASE + 0x10)
#define BUSY 1
#define NAND_SECTOR_SIZE 512
#define NAND_BLOCK_MASK (NAND_SECTOR_SIZE - 1)
inline void wait_idle(void) {
int i;
while(!(NFSTAT & BUSY))
for(i=0; i<10; i++);
}
/* low level nand read function */
int
nand_read_ll(unsigned char *buf, unsigned long start_addr, int size)
{
int i, j;
if ((start_addr & NAND_BLOCK_MASK) || (size & NAND_BLOCK_MASK)) {
return -1; /* invalid alignment */
}
/* chip Enable */
NFCONF &= ~0x800;
for(i=0; i<10; i++);
for(i=start_addr; i < (start_addr + size);) {
/* READ0 */
NFCMD = 0;
/* Write Address */
NFADDR = i & 0xff;
NFADDR = (i >> 9) & 0xff;
NFADDR = (i >> 17) & 0xff;
NFADDR = (i >> 25) & 0xff;
wait_idle();
for(j=0; j < NAND_SECTOR_SIZE; j++, i++) {
*buf = (NFDATA & 0xff);
buf++;
}
}
/* chip Disable */
NFCONF |= 0x800; /* chip disable */
return 0;
}
#endif
另外还要修改board/ /mini2440/Makefile文件,将nand_read.c编译进u-boot：
OBJS := mini2440.o nand_read.o flash.o
1.2.3 修改board/mini2440/lowlevel_init.S文件
(1)修改BWSCON，mini2440 BANK0接NOR Flash，BANK4接DM9000，BANK6接RAM，对于mini2440，只要修改B4_BWSCON即可：
#define B3_BWSCON (DW16 + WAIT + UBLB)
//#define B4_BWSCON (DW16)
#define B4_BWSCON (DW16 + WAIT + UBLB)
#define B5_BWSCON (DW16)
……
#define B4_Tacs 0x0 /* 0clk */
#define B4_Tcos 0x3 /* 4clk */
#define B4_Tacc 0x7 /* 14clk */
#define B4_Tcoh 0x1 /* 1clk */
#define B4_Tah 0x3 /* 4clk */
#define B4_Tacp 0x6 /* 6clk */
#define B4_PMC 0x0 /* normal */
#define B5_Tacs 0x0 /* 0clk */
(2)然后修改 REFRESH 的刷新周期：
#define B7_SCAN 0x1 /* 9bit */
/* REFRESH parameter */
#define REFEN 0x1 /* Refresh enable */
#define TREFMD 0x0 /* CBR(CAS before RAS)/Auto refresh */
#define Trc 0x3 /* 7clk */
#define Tchr 0x2 /* 3clk */
//#define REFCNT 1113 /* period=15.6us, HCLK=60Mhz, (2048+1-15.6*60) */
# if defined(CONFIG_S3C2440)
#define Trp 0x2 /* 4clk */
#define REFCNT 1012
#else
#define Trp 0x0 /* 2clk */
#define REFCNT 0x4f4 /* period=7.8125us, HCLK=100Mhz, (2048+1-7.8125*100) */
#endif
_TEXT_BASE:
.word TEXT_BASE
1.2.4 修改GPIO和PLL的配置
在/board/ mini2440/mini2440.c 中对GPIO和PLL的配置进行修改(参阅开发板的硬件说明和芯片手册)：
#elif FCLK_SPEED==1 /* Fout = 202.8MHz */
/*#define M_MDIV 0xA1
#define M_PDIV 0x3
#define M_SDIV 0x1*/
#if defined(CONFIG_S3C2410)
/* Fout = 202.8MHz */
#define M_MDIV 0xA1
#define M_PDIV 0x3
#define M_SDIV 0x1
#endif
#if defined(CONFIG_S3C2440)
/* Fout = 405MHz */
#define M_MDIV 0x7f
#define M_PDIV 0x2
#define M_SDIV 0x1
#endif
/*------------------------*/
#endif
……
#elif USB_CLOCK==1
/*#define U_M_MDIV 0x48
#define U_M_PDIV 0x3*/
#if defined(CONFIG_S3C2410)
#define U_M_MDIV 0x48
#define U_M_PDIV 0x3
#endif
#if defined(CONFIG_S3C2440)
#define U_M_MDIV 0x38
#define U_M_PDIV 0x2
#endif
#define U_M_SDIV 0x2
#endif
为连接LED和蜂鸣器的GPIO修改配置寄存器：
/* set up the I/O ports */
gpio->GPACON = 0x007FFFFF;
/*gpio->GPBCON = 0x00044555;*/
#if defined(CONFIG_mini2440_LED)
gpio->GPBCON = 0x00055555;
#else
gpio->GPBCON = 0x00044555;
#endif
gpio->GPBUP = 0x000007FF;
为引导linux 内核，修改开发板的类型代码：
gpio->GPHUP = 0x000007FF;
/* arch number of SMDK2410-Board */
//gd->bd->bi_arch_number = MACH_TYPE_SMDK2410;
#if defined(CONFIG_S3C2410)
/* arch number of SMDK2410-Board */
gd->bd->bi_arch_number = MACH_TYPE_SMDK2410;
#endif
#if defined(CONFIG_S3C2440)
/* arch number of S3C2440 -Board */
gd->bd->bi_arch_number = MACH_TYPE_mini2440 ;
#endif
/* adress of boot parameters */
为使int board_init (void)设置完成后，LED1和LED2同时亮起，在int board_init (void)的最后添加：
icache_enable();
dcache_enable();
# if defined(CONFIG_mini2440_LED)
gpio->GPBDAT = 0x180;
//int board_init (void)设置完成后，LED1和LED2会亮起！
#endif
return 0;