boardc.docx

1、boardc/* * (C) Copyright 2002 * Wolfgang Denk, DENX Software Engineering, wddenx.de. * * (C) Copyright 2002 * Sysgo Real-Time Solutions, GmbH * Marius Groeger * * See file CREDITS for list of people who contributed to this * project. * * This program is free software; you can redistribute it and/or

2、* 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 imp

3、lied 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, Suit

4、e 330, Boston, * MA 02111-1307 USA */#include #include #include #include #include #include #ifdef CONFIG_DRIVER_SMC91111 /添加 驱动支持#include ./drivers/smc91111.h#endif#ifdef CONFIG_DRIVER_LAN91C96#include ./drivers/lan91c96.h#endif#if (CONFIG_COMMANDS & CFG_CMD_NAND) /命令选项 & NAND 设置void nand_init (void

5、);#endifulong monitor_flash_len;#ifdef CONFIG_HAS_DATAFLASHextern int AT91F_DataflashInit(void);extern void dataflash_print_info(void);#endif#ifndef CONFIG_IDENT_STRING#define CONFIG_IDENT_STRING #endifconst char version_string = U_BOOT_VERSION ( _DATE_ - _TIME_ )CONFIG_IDENT_STRING;#ifdef CONFIG_DR

6、IVER_CS8900 /添加驱动extern void cs8900_get_enetaddr (uchar * addr);#endif#ifdef CONFIG_DRIVER_RTL8019extern void rtl8019_get_enetaddr (uchar * addr);#endif/* * Begin and End of memory area for malloc(), and current brk */static ulong mem_malloc_start = 0; /MEM 显示内存状态static ulong mem_malloc_end = 0; /存储

7、器分配 malloc.static ulong mem_malloc_brk = 0;staticvoid mem_malloc_init (ulong dest_addr) mem_malloc_start = dest_addr; mem_malloc_end = dest_addr + CFG_MALLOC_LEN; mem_malloc_brk = mem_malloc_start; memset (void *) mem_malloc_start, 0, mem_malloc_end - mem_malloc_start);void *sbrk (ptrdiff_t incremen

8、t) /*本函数用于扩展堆空间，用incriment来指定扩展的大小*/ ulong old = mem_malloc_brk; ulong new = old + increment; if (new mem_malloc_end) return (NULL); mem_malloc_brk = new; return (void *) old);/* * Init Utilities * * * Some of this code should be moved into the core functions, * or dropped completely, * but lets get

9、 it working (again) first. */*获取环境变量，把波特率值赋给全局gd，若获取为空值，则赋给默认115200*/static int init_baudrate (void) DECLARE_GLOBAL_DATA_PTR; uchar tmp64; /* long enough for environment variables */*把环境变量获取到tmp中，i为得到的环境变量的长度*/ int i = getenv_r (baudrate, tmp, sizeof (tmp);/*如果获得了env，则把它赋给gd，否则把115200赋给gd*/ gd-bd-bi

10、_baudrate = gd-baudrate = (i 0)/*此函数把字符串转换为ulong型*/ ? (int) simple_strtoul (tmp, NULL, 10) : CONFIG_BAUDRATE; return (0);static int display_banner (void) printf (nn%snn, version_string); printf (U-Boot code: %08lX - %08lX BSS: - %08lXn, _armboot_start, _bss_start, _bss_end);#ifdef CONFIG_MODEM_SUPPO

11、RT puts (Modem Support enabledn);#endif#ifdef CONFIG_USE_IRQ printf (IRQ Stack: %08lxn, IRQ_STACK_START); printf (FIQ Stack: %08lxn, FIQ_STACK_START);#endif return (0);/* * WARNING: this code looks cleaner than the PowerPC version, but * has the disadvantage that you either get nothing, or everythin

12、g. * On PowerPC, you might see DRAM: before the system hangs - which * gives a simple yet clear indication which part of the * initialization if failing. */static int display_dram_config (void) DECLARE_GLOBAL_DATA_PTR; int i; puts (RAM Configuration:n); for(i=0; ibd-bi_drami.start); print_size (gd-b

13、d-bi_drami.size, n); return (0);static void display_flash_config (ulong size) puts (Flash: ); print_size (size, n);/* * Breathe some life into the board. * * Initialize a serial port as console, and carry out some hardware * tests. * * The first part of initialization is running from Flash memory; *

14、 its main purpose is to initialize the RAM so that we * can relocate the monitor code to RAM. */* * All attempts to come up with a common initialization sequence * that works for all boards and architectures failed: some of the * requirements are just _too_ different. To get rid of the resulting * m

15、ess of board dependent #ifdefed code we now make the whole * initialization sequence configurable to the user. * * The requirements for any new initalization function is simple: it * receives a pointer to the global data structure as its only * argument, and returns an integer return code, where 0 m

16、eans * continue and != 0 means fatal error, hang the system. */typedef int (init_fnc_t) (void);init_fnc_t *init_sequence = cpu_init, /* basic cpu dependent setup 基本处理器相关配置*/ board_init, /* basic board dependent setup 基本的开发板相关配置*/ interrupt_init, /* set up exceptions 初始化例外处理*/ env_init, /* initialize

17、 environment 初始化环境变量*/ init_baudrate, /* initialze baudrate settings 初始化波特率设置*/ serial_init, /* serial communications setup 串口通讯设置*/ console_init_f, /* stage 1 init of console 控制台初始化阶段1*/ display_banner, /* say that we are here 打印 u-boot信息*/ dram_init, /* configure available RAM banks 配置可用的RAM*/ dis

18、play_dram_config, /显示 RAM的配置大小#if defined(CONFIG_VCMA9) checkboard,#endif NULL,;/*start_armboot是U-Boot执行的第一个C语言函数，完成系统初始化工作，进入主循环，处理用户输入的命令。*/void start_armboot (void) DECLARE_GLOBAL_DATA_PTR; ulong size; init_fnc_t *init_fnc_ptr; char *s;#if defined(CONFIG_VFD) | defined(CONFIG_LCD) unsigned long a

19、ddr;#endif /* Pointer is writable since we allocated a register for it */*全局数据结构的初始化*/*gd_t结构的初始化:*/ gd = (gd_t*)(_armboot_start - CFG_MALLOC_LEN - sizeof(gd_t); /* compiler optimization barrier needed for GCC = 3.4 */ _asm_ _volatile_(: : :memory); memset (void*)gd, 0, sizeof (gd_t); /用0填充全局数据表gd g

20、d-bd = (bd_t*)(char*)gd - sizeof(bd_t); /bd_t结构的初始化: memset (gd-bd, 0, sizeof (bd_t); /用0填充（初始化）*gd-bd monitor_flash_len = _bss_start - _armboot_start; /取u-boot的 长度/*调用通用初始化函数*/* 顺序执行init_sequence数组中的初始化函数 */ for (init_fnc_ptr = init_sequence; *init_fnc_ptr; +init_fnc_ptr) if (*init_fnc_ptr)() != 0)

21、 hang (); /打印错误信息并死锁 /*init_sequence是init_fnc_t函数指针数组，这个数组包含了众多初始化函数，比如cpu_init，board_init等。*/ /* configure available FLASH banks */ /*配置可用的Flash */ size = flash_init (); /初始化 flash display_flash_config (size); /显示 flash 大小#ifdef CONFIG_VFD# ifndef PAGE_SIZE# define PAGE_SIZE 4096# endif /* * reserv

22、e memory for VFD display (always full pages)为VFD显示预留内存（整个页面） */ /* bss_end is defined in the board-specific linker script */* _armboot_start 在u-boot.lds链接脚本中定义 */ addr = (_bss_end + (PAGE_SIZE - 1) & (PAGE_SIZE - 1); size = vfd_setmem (addr); gd-fb_base = addr; #endif /* CONFIG_VFD */ /进入下一个界面#ifdef

23、 CONFIG_LCD# ifndef PAGE_SIZE# define PAGE_SIZE 4096# endif /* * reserve memory for LCD display (always full pages) */ /* bss_end is defined in the board-specific linker script */ addr = (_bss_end + (PAGE_SIZE - 1) & (PAGE_SIZE - 1); size = lcd_setmem (addr); gd-fb_base = addr;#endif /* CONFIG_LCD *

24、/*内存分配的初始化(全局数据结构的初始化)*/ /* armboot_start is defined in the board-specific linker script */ mem_malloc_init (_armboot_start - CFG_MALLOC_LEN);/*将CFG_MALLOC_LEN 区域用memset清0（直接往目的地址写0）*/*初始化具体设备*/#if (CONFIG_COMMANDS & CFG_CMD_NAND) puts (NAND:); nand_init(); /* go init the NAND nand初始化*/#endif#ifdef

25、CONFIG_HAS_DATAFLASH AT91F_DataflashInit(); dataflash_print_info();#endif /* initialize environment 初始化环境*/ env_relocate ();/函数作用将环境变量从flash到RAM的拷贝#ifdef CONFIG_VFD /* must do this after the framebuffer is allocated 配置环境变量，重新定位*/ drv_vfd_init();#endif /* CONFIG_VFD */ /* IP Address */ /* 从环境变量中获取IP地

26、址 */ gd-bd-bi_ip_addr = getenv_IPaddr (ipaddr); /* MAC Address */* 以太网接口MAC 地址 */ int i; ulong reg; char *s, *e; uchar tmp64; i = getenv_r (ethaddr, tmp, sizeof (tmp); s = (i 0) ? tmp : NULL; for (reg = 0; reg bd-bi_enetaddrreg = s ? simple_strtoul (s, &e, 16) : 0; if (s) s = (*e) ? e + 1 : e; devic

27、es_init (); /* get the devices list going. */* 获取列表中的设备（外围设备初始化） */ jumptable_init (); /跳转表初始化 console_init_r (); /* fully init console as a device */* 完整地初始化控制台设备 */#if defined(CONFIG_MISC_INIT_R) /* miscellaneous platform dependent initialisations 其他平台由初始化决定*/ misc_init_r ();#endif /* enable excep

28、tions */*启用异常处理 */ enable_interrupts (); /* Perform network card initialisation if necessary */#ifdef CONFIG_DRIVER_CS8900 cs8900_get_enetaddr (gd-bd-bi_enetaddr);#endif#if defined(CONFIG_DRIVER_SMC91111) | defined (CONFIG_DRIVER_LAN91C96) if (getenv (ethaddr) smc_set_mac_addr(gd-bd-bi_enetaddr); #endif /* CONFIG_DRIVER_SMC91111 | CONFIG_DRIVER_LAN91C96 */ /* Initialize from environment */* 通过环境变量初始化 */ if (s = getenv (loadaddr) != NULL) load_addr = simple_strtoul (s, NULL, 16); #if (CONFIG_COMMANDS & CFG_CMD_NET) if (s = getenv (bootfile) != NULL) copy_filename (BootFile, s,