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board_init_r函数分析

重定向完成后，lr就会跳转到board_init_r函数处开始执行下半部分板子的初始化。

(1)将重定位后的gd还是放在r8寄存器里边，给gd->flags赋值

gd=id;

gd->flags|=GD_FLG_RELOC;

(2)enable_caches();(位于uboot/arch/arm/lib/Cache.c)

->

__enable_caches(void)

->

puts(“WARNING: Caches not

enabled\n”);

实际上并没有真正对cache进行操作，只是打印了一下："WARNING: Caches not enabled”。

(3)板级初始化 board_init();(位于\uboot\board\davinci\da8xxevm目录下)

#define DAVINCI_ABCR_STROBE_SELECT               (1 << 31)#define DAVINCI_ABCR_EXT_WAIT                        (1 << 30)#define DAVINCI_ABCR_WSETUP(n)                       (n << 26)#define DAVINCI_ABCR_WSTROBE(n)                           (n << 20)#define DAVINCI_ABCR_WHOLD(n)                       (n << 17)#define DAVINCI_ABCR_RSETUP(n)                        (n << 13)#define DAVINCI_ABCR_RSTROBE(n)                      (n << 7)#define DAVINCI_ABCR_RHOLD(n)                        (n << 4)#define DAVINCI_ABCR_TA(n)                         (n << 2)#define DAVINCI_ABCR_ASIZE_16BIT              1#define DAVINCI_ABCR_ASIZE_8BIT                       0 1)     writel((DAVINCI_ABCR_WSETUP(2)|              DAVINCI_ABCR_WSTROBE(2)|              DAVINCI_ABCR_WHOLD(1)|              DAVINCI_ABCR_RSETUP(2)|              DAVINCI_ABCR_RSTROBE(2)|              DAVINCI_ABCR_RHOLD(1)|              DAVINCI_ABCR_TA(1)|              DAVINCI_ABCR_ASIZE_8BIT),              &davinci_emif_regs->ab2cr); /*CS3 */)))

/* arch number of the board */

2 )

gd->bd->bi_arch_number =MACH_TYPE_DAVINCI_DA850_EVM;

/* address of boot parameters */

MACH_TYPE_DAVINCI_DA850_EVM=2157

3 ) gd->bd->bi_boot_params= LINUX_BOOT_PARAM_ADDR;

->

#define LINUX_BOOT_PARAM_ADDR (PHYS_SDRAM_1 + 0x100)

->

#define PHYS_SDRAM_1 DAVINCI_DDR_EMIF_DATA_BASE /* DDR Start */

->

#define DAVINCI_DDR_EMIF_DATA_BASE 0xc0000000

最后得到:LINUX_BOOT_PARAM_ADDR =0xc0000100

4 ) /*

setup the SUSPSRC for ARM to control emulation suspend */

writel(readl(&davinci_syscfg_regs->suspsrc)&              ~(DAVINCI_SYSCFG_SUSPSRC_EMAC |DAVINCI_SYSCFG_SUSPSRC_I2C |               DAVINCI_SYSCFG_SUSPSRC_SPI1 |DAVINCI_SYSCFG_SUSPSRC_TIMER0 |               DAVINCI_SYSCFG_SUSPSRC_UART2),              &davinci_syscfg_regs->suspsrc); /* Emulation suspend bits */#define DAVINCI_SYSCFG_SUSPSRC_EMAC            (1 << 5)#define DAVINCI_SYSCFG_SUSPSRC_I2C         (1 << 16)#define DAVINCI_SYSCFG_SUSPSRC_SPI0       (1 << 21)#define DAVINCI_SYSCFG_SUSPSRC_SPI1       (1 << 22)#define DAVINCI_SYSCFG_SUSPSRC_UART0           (1 << 18)#define DAVINCI_SYSCFG_SUSPSRC_UART2           (1 << 20)#define DAVINCI_SYSCFG_SUSPSRC_TIMER0         (1 << 27)

上述设置表明，EMAC，I2C,SPI0,SPI1,UART0,UART2,TIMER0的仿真暂停是由arm来控制的。

5 ) /* configure pinmux settings */

if(davinci_configure_pin_mux_items(pinmuxes, ARRAY_SIZE(pinmuxes)))              return 1;->(位于\uboot\board\davinci\da8xxevm\目录下)const struct pinmux_resource pinmuxes[] = {#ifdef CONFIG_DRIVER_TI_EMAC       PINMUX_ITEM(emac_pins_mdio),#ifdef CONFIG_DRIVER_TI_EMAC_USE_RMII       PINMUX_ITEM(emac_pins_rmii),#else       PINMUX_ITEM(emac_pins_mii),#endif#endif#ifdef CONFIG_SPI_FLASH       PINMUX_ITEM(spi1_pins_base),       PINMUX_ITEM(spi1_pins_scs0),#endif       PINMUX_ITEM(uart2_pins_txrx),/*    PINMUX_ITEM(uart2_pins_rtscts),*/       PINMUX_ITEM(i2c0_pins),#ifdef CONFIG_NAND_DAVINCI       PINMUX_ITEM(emifa_pins_cs0),       PINMUX_ITEM(emifa_pins_cs2),       PINMUX_ITEM(emifa_pins_cs3),       PINMUX_ITEM(emifa_pins_cs4),       PINMUX_ITEM(emifa_pins_cs5),       PINMUX_ITEM(emifa_pins_nand),#elif defined(CONFIG_USE_NOR)       PINMUX_ITEM(emifa_pins_cs2),       PINMUX_ITEM(emifa_pins_nor),#endif       PINMUX_ITEM(gpio_pins),       PINMUX_ITEM(clkout_pins),#ifdef CONFIG_DAVINCI_MMC       PINMUX_ITEM(mmc0_pins),#endif};

跟踪其中一个函数来获得编译的结果

PINMUX_ITEM(emac_pins_mdio),{.pins=emac_pings_mdio;.n_pins=ARRAY_SIZE(emac_pins_mdio)}->davinci_configure_pin_mux_items(conststruct pinmux_resource *item,const int n_items)->davinci_configure_pin_mux(item[i].pins,   item[i].n_pins)->davinci_configure_pin_mux(emac_pings_mdio,2)->conststruct pinmux_config emac_pins_mdio[] = {       { pinmux(4), 8, 0 }, /* MDIO_CLK */       { pinmux(4), 8, 1 }, /* MDIO_D */};->offset=0*4=0;value=8<<0=8;mask=(1<<4)-1<<0=1111;查表可知配置为MDIO_CLK->offset=1*4=1;value=8<<4=1000,0000make=(1<<4)-1<<4=1111,0000查表可知配置为MDIO_D

同理可得此处其他管脚复用的配置有：

l  /* EMAC pin muxer settings*/const struct pinmux_config emac_pins_mii[] = {       {pinmux(2), 8, 1 }, /* MII_TXEN */       {pinmux(2), 8, 2 }, /* MII_TXCLK */       {pinmux(2), 8, 3 }, /* MII_COL */       {pinmux(2), 8, 4 }, /* MII_TXD[3] */       {pinmux(2), 8, 5 }, /* MII_TXD[2] */       {pinmux(2), 8, 6 }, /* MII_TXD[1] */       {pinmux(2), 8, 7 }, /* MII_TXD[0] */       {pinmux(3), 8, 0 }, /* MII_RXCLK */       {pinmux(3), 8, 1 }, /* MII_RXDV */       {pinmux(3), 8, 2 }, /* MII_RXER */       {pinmux(3), 8, 3 }, /* MII_CRS */       {pinmux(3), 8, 4 }, /* MII_RXD[3] */       {pinmux(3), 8, 5 }, /* MII_RXD[2] */       {pinmux(3), 8, 6 }, /* MII_RXD[1] */       {pinmux(3), 8, 7 }, /* MII_RXD[0] */}; l  /* SPI pin muxer settings */const struct pinmux_config spi1_pins_base[]= {       {pinmux(5), 1, 2 }, /* SPI1_CLK */       {pinmux(5), 1, 4 }, /* SPI1_SOMI */       {pinmux(5), 1, 5 }, /* SPI1_SIMO */}; const struct pinmux_config spi1_pins_scs0[]= {       {pinmux(5), 1, 1 }, /* SPI1_SCS[0] */}; l  /* UART pin muxer settings */const struct pinmux_config uart2_pins_txrx[]= {       {pinmux(4), 2, 4 }, /* UART2_RXD */       {pinmux(4), 2, 5 }, /* UART2_TXD */};l  /* EMIFA pin muxer settings */const struct pinmux_config emifa_pins_cs0[]= {       {pinmux(6), 1, 7 }, /* EMA_CS0 */}; const struct pinmux_config emifa_pins_cs2[]= {       {pinmux(7), 1, 0 }, /* EMA_CS2 */}; const struct pinmux_config emifa_pins_cs3[]= {       {pinmux(7), 1, 1 }, /* EMA_CS[3] */}; const struct pinmux_config emifa_pins_cs4[]= {       {pinmux(7), 1, 2 }, /* EMA_CS[4] */}; const struct pinmux_config emifa_pins_cs5[]= {       {pinmux(7), 1, 3 }, /* EMA_CS[5] */}; const struct pinmux_configemifa_pins_nand[] = {       {pinmux(7), 1, 4 },  /* EMA_WE */       {pinmux(7), 1, 5 },  /* EMA_OE */       {pinmux(9), 1, 0 },  /* EMA_D[7] */       {pinmux(9), 1, 1 },  /* EMA_D[6] */       {pinmux(9), 1, 2 },  /* EMA_D[5] */       {pinmux(9), 1, 3 },  /* EMA_D[4] */       {pinmux(9), 1, 4 },  /* EMA_D[3] */       {pinmux(9), 1, 5 },  /* EMA_D[2] */       {pinmux(9), 1, 6 },  /* EMA_D[1] */       {pinmux(9), 1, 7 },  /* EMA_D[0] */       {pinmux(12), 1, 5 }, /* EMA_A[2] */       {pinmux(12), 1, 6 }, /* EMA_A[1] */}; l  #ifdef CONFIG_DAVINCI_MMC       /*GP0[11] is required for SD to work on Rev 3 EVMs */       {pinmux(0),  8, 4 },     /* GP0[11] */#endif       /*GP6[13] is indicator for SPL to work on TL BOARD */       {pinmux(13),  8, 2 },    /* GP6[13] */       /*GP6[12] is indicator for U-BOOT to work on TL BOARD */       {pinmux(13),  8, 3 },    /* GP6[12] */        /*GP0[7] is pwm blacklight for LCD to work on TL BOARD */       {pinmux(1),  8, 0 },     /* GP0[7] */};l  static const struct pinmux_config clkout_pins[] = {       /*PLL_CLKOUT is to work on TL BOARD */       {pinmux(13), 1, 1 },      /* PLL_CLKOUT*/};l  /* MMC0 pin muxer settings */const struct pinmux_config mmc0_pins[] = {       {pinmux(10), 2, 0 },      /* MMCSD0_CLK */       {pinmux(10), 2, 1 },      /* MMCSD0_CMD */       {pinmux(10), 2, 2 },      /* MMCSD0_DAT_0*/       {pinmux(10), 2, 3 },      /* MMCSD0_DAT_1*/       {pinmux(10), 2, 4 },      /* MMCSD0_DAT_2*/       {pinmux(10), 2, 5 },      /* MMCSD0_DAT_3*/       /*DA850 supports only 4-bit mode, remaining pins are not configured */};

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