ecos代码分析(2)
ecos代碼分析(2)
228?????????bl??????hal_mmu_init
此前內存初始化好了，sp也設置好了，可以運行C程序
????170 void
????171 hal_mmu_init(void)
????172 {
????173?????unsigned long ttb_base = SMDK2410_SDRAM_PHYS_BASE + 0x4000;
????174?????unsigned long i;
????175
????176?????// Set the TTB register
????177?????asm volatile ("mcr??p15,0,%0,c2,c0,0" : : "r"(ttb_base) );
????178
????179?????// Set the Domain Access Control Register
????180?????i = ARM_ACCESS_TYPE_MANAGER(0)????|
????181?????????ARM_ACCESS_TYPE_NO_ACCESS(1)??|
????182?????????ARM_ACCESS_TYPE_NO_ACCESS(2)??|
????183?????????ARM_ACCESS_TYPE_NO_ACCESS(3)??|
????184?????????ARM_ACCESS_TYPE_NO_ACCESS(4)??|
????185?????????ARM_ACCESS_TYPE_NO_ACCESS(5)??|
????186?????????ARM_ACCESS_TYPE_NO_ACCESS(6)??|
????187?????????ARM_ACCESS_TYPE_NO_ACCESS(7)??|
????188?????????ARM_ACCESS_TYPE_NO_ACCESS(8)??|
????189?????????ARM_ACCESS_TYPE_NO_ACCESS(9)??|
????190?????????ARM_ACCESS_TYPE_NO_ACCESS(10) |
????191?????????ARM_ACCESS_TYPE_NO_ACCESS(11) |
????192?????????ARM_ACCESS_TYPE_NO_ACCESS(12) |
????193?????????ARM_ACCESS_TYPE_NO_ACCESS(13) |
????194?????????ARM_ACCESS_TYPE_NO_ACCESS(14) |
????195?????????ARM_ACCESS_TYPE_NO_ACCESS(15);
????196?????asm volatile ("mcr??p15,0,%0,c3,c0,0" : : "r"(i) );
????197
????198?????// First clear all TT entries - ie Set them to Faulting
????199?????memset((void *)ttb_base, 0, ARM_FIRST_LEVEL_PAGE_TABLE_SIZE);
????200
????201?????// Memory layout after MMU is turned on
????202?????//
????203?????//???SDRAM_BASE_ADDRESS:?????0x00000000,??64M
????204?????//???SRAM_BASE_ADDRESS:??????0x40000000,???4K
????205?????//???SFR_BASE_ADDRESS:???????0x48000000, 512M
????206?????//???FLASH_BASE_ADDRESS:?????0x80000000,???2M
????207
????208??//Actual Virtual Size Attributes???????????????????????????????????????Function
????209 //Base Base??MB cached? buffered? access permissions
????210?????//?????????????xxx00000??xxx00000
????211?????X_ARM_MMU_SECTION(0x000,??0x800,????2,??ARM_UNCACHEABLE, ARM_UNBUFFERABLE, ARM_ACCESS_PERM_RW_RW); // Flash
????212?????X_ARM_MMU_SECTION(0x300,??0x000,???64,??ARM_CACHEABLE,???ARM_BUFFERABLE,??ARM_ACCESS_PERM_RW_RW); // SDRAM
????213?????X_ARM_MMU_SECTION(0x400,??0x400,????1,??ARM_CACHEABLE,???ARM_BUFFERABLE,??ARM_ACCESS_PERM_RW_RW); // SRAM
????214?????X_ARM_MMU_SECTION(0x480,??0x480,??512,??ARM_UNCACHEABLE, ARM_UNBUFFERABLE, ARM_ACCESS_PERM_RW_RW); // SFRs
????215?????X_ARM_MMU_SECTION(0x300,??0x300,???64,??ARM_UNCACHEABLE, ARM_UNBUFFERABLE, ARM_ACCESS_PERM_RW_RW); // Raw SDRAM
????216 }
還有
#define SMDK2410_SDRAM_PHYS_BASE?????????0x30000000
#define SMDK2410_SDRAM_VIRT_BASE?????????0x00000000
?
#define SMDK2410_FLASH_PHYS_BASE?????????0x00000000
#define SMDK2410_FLASH_VIRT_BASE?????????0x80000000
內存從0x30000000開始的
ttb_base=0x30004000是translation table base，虛擬地址到實地址內存映射表的基地址
第177行，ttb_base要存放在cp15的reg2中
第196行，對section的進入權限控制，存放在cp15的reg3中
????142 #define X_ARM_MMU_SECTION(abase,vbase,size,cache,buff,access)??????\
????143?????{ int i; int j = abase; int k = vbase;?????????????????????????\
????144???????for (i = size; i > 0 ; i--,j++,k++)??????????????????????????\
????145???????{????????????????????????????????????????????????????????????\
????146?????????ARM_MMU_SECTION(ttb_base, j, k, cache, buff, access);??????\
????147???????}????????????????????????????????????????????????????????????\
148?????}
????125 #define ARM_MMU_SECTION(ttb_base, actual_base, virtual_base,??????????????\
????126?????????????????????????cacheable, bufferable, perm)??????????????????????\
????127?????CYG_MACRO_START???????????????????????????????????????????????????????\
????128?????????register union ARM_MMU_FIRST_LEVEL_DESCRIPTOR desc;???????????????\
????129???????????????????????????????????????????????????????????????????????????\
????130?????????desc.word = 0;????????????????????????????????????????????????????\
????131?????????desc.section.id = ARM_MMU_FIRST_LEVEL_SECTION_ID;?????????????????\
????132?????????desc.section.imp = 1;?????????????????????????????????????????????\
????133?????????desc.section.domain = 0;??????????????????????????????????????????\
????134?????????desc.section.c = (cacheable);?????????????????????????????????????\
????135?????????desc.section.b = (bufferable);????????????????????????????????????\
????136?????????desc.section.ap = (perm);?????????????????????????????????????????\
????137?????????desc.section.base_address = (actual_base);????????????????????????\
????138?????????*ARM_MMU_FIRST_LEVEL_DESCRIPTOR_ADDRESS(ttb_base, (virtual_base)) \
????139?????????????????????????????= desc.word;??????????????????????????????????\
????140?????CYG_MACRO_END
將空間劃分為以section為單位，即1M每個。
開始填充每個descriptor，按照手冊上的位圖填好就完事。
????120 #define ARM_MMU_FIRST_LEVEL_DESCRIPTOR_ADDRESS(ttb_base, table_index) \
121????(unsigned long *)((unsigned long)(ttb_base) + ((table_index) << 2))
struct ARM_MMU_FIRST_LEVEL_SECTION {
????int id : 2;
????int b : 1;
????int c : 1;
????int imp : 1;
????int domain : 4;
????int sbz0 : 1;
????int ap : 2;
????int sbz1 : 8;
????int base_address : 12;
};
為了有個直觀的影響，現在把填好的ttb這個表列出來
?
| address | b_addr:12 | sbz1:1 | ap:2 | sbz0:1 | domain:4 | imp:1 | c:1 | b:1 | id:2 |
| 0x30004000 | 0x300 | 0 | 3 | 0 | 0 | 1 | 1 | 1 | 2 |
| … | … | 0 | 3 | 0 | 0 | 1 | 1 | 1 | 2 |
| 0x300040fc | 0x33f | 0 | 3 | 0 | 0 | 1 | 1 | 1 | 2 |
| ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
| 0x30004c00 | 0x300 | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 2 |
| … | … | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 2 |
| 0x30004cfc | 0x33f | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 2 |
| ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
| 0x30005000 | 0x400 | 0 | 3 | 0 | 0 | 1 | 1 | 1 | 2 |
| ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
| 0x30005200 | 0x480 | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 2 |
| … | … | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 2 |
| 0x300059fc | 0x67f | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 2 |
| ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
| 0x30006000 | 0x000 | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 2 |
| 0x30006004 | 0x001 | 0 | 3 | 0 | 0 | 1 | 0 | 0 | 2 |
| ? | ? | ? | ? | ? | ? | ? | ? | ? | ? |
?
< hal/arm/arch/v3_0/src/vectors.S >
????464?????????// Call platform specific hardware initialization
????465?????????bl??????hal_hardware_init
????494?????????// Run through static constructors
????495?????????bl??????cyg_hal_invoke_constructors
????499?????????// This starts up the eCos kernel
500 #ifdef CYGIMP_HAL_COMMON_INTERRUPTS_USE_INTERRUPT_STACK
????501?????????ldr?????r1,=__startup_stack
????502?????????mov?????sp,r1
????503 #endif
????504?????????bl??????cyg_start
第465行
?????????<hal/arm/arm9/var/v3_0/src/arm9_misc.c>
?????67 void hal_hardware_init(void)
?????68 {
?????69?????// Perform any platform specific initializations
?????70?????plf_hardware_init();
?????72?????// Set up eCos/ROM interfaces
?????73?????hal_if_init();
?????75 #ifndef CYG_HAL_STARTUP_RAM
?????76?????// Invalidate caches
?????77?????HAL_DCACHE_INVALIDATE_ALL();
?????78?????HAL_ICACHE_INVALIDATE_ALL();
?????79 #endif
?????80?????// Enable caches
?????81 #ifdef CYGSEM_HAL_ENABLE_DCACHE_ON_STARTUP
?????82?????HAL_DCACHE_ENABLE();
?????83 #endif
?????84 #ifdef CYGSEM_HAL_ENABLE_ICACHE_ON_STARTUP
?????85?????HAL_ICACHE_ENABLE();
?????86 #endif
?????87 }
第70行
????306 void
????307 plf_hardware_init(void)
????308 {
????309?????HAL_WRITE_UINT32(INTMOD, 0x0);?????????????????????//All=IRQ mode
????310?????HAL_WRITE_UINT32(INTMSK, BIT_ALLMSK);??????????????//All interrupt is masked.
????311?????HAL_WRITE_UINT32(INTSUBMSK, BIT_SUB_ALLMSK);???????//All sub-interrupt is masked.
????313?????port_init();
????315?????// Initialize real-time clock (for delays, etc, even if kernel doesn't use it)
????316?????hal_clock_initialize(CYGNUM_HAL_RTC_PERIOD);
????317 }
???????????????????第313行，設置gpio
???????????????????第316行，設置時鐘
第73行
??????????hal_if_init()
???????????????????:: hal_virtual_vector_table[]初始化為空操作
hal_virtual_vector_table[]是個全局的系統調用列表，每個的具體功能如下
??????????// Main calling interface table. Will be assigned a location by the
// linker script. Both ROM and RAM startup applications will know about
// the location.
#define CYGNUM_CALL_IF_VERSION????????????????????0
#define CYGNUM_CALL_IF_available_1????????????????1
#define CYGNUM_CALL_IF_available_2????????????????2
#define CYGNUM_CALL_IF_available_3????????????????3
#define CYGNUM_CALL_IF_KILL_VECTOR????????????????4
#define CYGNUM_CALL_IF_CONSOLE_PROCS??????????????5
#define CYGNUM_CALL_IF_DEBUG_PROCS????????????????6
#define CYGNUM_CALL_IF_available_7????????????????7
#define CYGNUM_CALL_IF_available_8????????????????8
#define CYGNUM_CALL_IF_available_9????????????????9
#define CYGNUM_CALL_IF_available_10???????????????10
#define CYGNUM_CALL_IF_available_11???????????????11
#define CYGNUM_CALL_IF_SET_DEBUG_COMM?????????????12
#define CYGNUM_CALL_IF_SET_CONSOLE_COMM???????????13
#define CYGNUM_CALL_IF_MONITOR_VERSION????????????14
#define CYGNUM_CALL_IF_DBG_SYSCALL????????????????15
#define CYGNUM_CALL_IF_RESET??????????????????????16
#define CYGNUM_CALL_IF_CONSOLE_INTERRUPT_FLAG?????17
#define CYGNUM_CALL_IF_DELAY_US???????????????????18
#define CYGNUM_CALL_IF_DBG_DATA???????????????????19
#define CYGNUM_CALL_IF_FLASH_CFG_OP???????????????20
#define CYGNUM_CALL_IF_MONITOR_RETURN?????????????21
#define CYGNUM_CALL_IF_FLASH_FIS_OP???????????????22
#define CYGNUM_CALL_IF_FLASH_FIS_OP2??????????????23
#define CYGNUM_CALL_IF_LAST_ENTRY?????????????????CYGNUM_CALL_IF_FLASH_FIS_OP2
#define CYGNUM_CALL_IF_INSTALL_BPT_FN?????????????35
#define CYGNUM_CALL_IF_TABLE_SIZE?????????????????64
???????????????????::?初始化該數組的每個成員
???????????????????è?cyg_hal_plf_comms_init()
????????????????????????????è?cyg_hal_plf_serial_init()
??????????????????????????????????????:: initiate serial and call CYGNUM_CALL_IF_SET_CONSOLE_COMM set console
??????????????????????????????????????è?cyg_hal_plf_serial_init_channel()
???????????????????????????????????????????????:: initiate the serial channel
???????????????????::?此后串口應該設置好了，可以進行輸出
?
hal_hardware_init()
???????????????????è?plf_hardware_init()
???????????????????è?hal_if_init()
???????????????????è?HAL_DCACHE_INVALIDATE_ALL()
????????????????????????????:: dcache invalidate
è?HAL_ICACHE_INVALIDATE_ALL()
?????????:: icache invalidate
è?HAL_DCACHE_ENABLE()
?????????:: dcache enable
è?HAL_ICACHE_ENABLE()
?????????:: icache enable
cyg_hal_invoke_constructors()
???????????????????::?運行指令segment內的函數，但是沒有找到相應的宏定義
然后，sp指向__startup_stack
跳轉到cyg_start()運行
http://blog.sina.com.cn/s/blog_559f6ffc0100mjlq.html
轉載于:https://www.cnblogs.com/kuainiao/archive/2013/01/15/2861369.html
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