當前位置：首頁 > 编程资源 > 编程问答 >内容正文

编程问答

ecos代码分析(2)

發布時間：2025/5/22 编程问答 9 豆豆

生活随笔收集整理的這篇文章主要介紹了 ecos代码分析(2) 小編覺得挺不錯的,現在分享給大家,幫大家做個參考.

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

《新程序員》：云原生和全面數字化實踐50位技術專家共同創作，文字、視頻、音頻交互閱讀

總結

以上是生活随笔為你收集整理的ecos代码分析(2)的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。

代码
ecos