ARM中的中断

其中，中断分为?
Supports three interrupt types:
Private Peripheral Interrupt (PPI）一个中断源对应一个CPU
Software Generated Interrupt (SGI) CPU对应CPU
Shared Peripheral Interrupt (SPI) 一个中断源对应多个CPU

今天的例子是用SGI中断来实现的，在处理中断的时候，主要分三步：

//step 1: cpu cpsr

CPU允许中断
20 __asm__ __volatile__(
21 "mrs r0, cpsr\n"
22 "bic r0, r0, #0x80\n"//设置CPSR的I位，将IRQ位打开
23 "msr cpsr, r0\n"
24 ::: "r0"
25 );
26
27//step 2: GIC

GIC
28 ICCICR_CPU0 = 1;//CPU接口控制寄存器
29 ICCPMR_CPU0 = 0xff;//中断优先标志寄存器
30 ICDDCR = 1;//设置本中断的开关
31 ICDIPR0_CPU0 = (0x00 < 0);//本中断的优先级
32 ICDIPTR0_CPU0 = 1;//选择指定的CPU
33 ICDISER0_CPU0 = (1 < 0);//设置本中断开启
34 　　各个寄存器描述如下：详细见4412 782页

35//step 3: interrupt source

中断源
36 ICDSGIR = 0 (1 < 16) (0 < 24);//SGI控制寄存器CPUTargetList.TargetListFi lte
37 printf("welcome back! \n");

下面是代码：

1 #include"regs.h"2 3 int (*printf)(char *, ...) = 0xc3e114d8;4 5 void init_ttb(unsigned long *addr);6 void enable_mmu(void);7 unsigned long data_abort_init();8 void memcopy(unsigned long* dest,unsigned long* source,int len);9 void do_irq();10 11 int main()12 {13      *(unsigned long *)0x66 = do_irq;14     unsigned long source_addr=data_abort_init();15     printf("swi_souce addr is %x\n",source_addr);16     memcopy(0x60,source_addr,0x1);17     enable_mmu();18 19      //step 1: cpu cpsr20       __asm__ __volatile__(21           "mrs r0, cpsr\n"22           "bic r0, r0, #0x80\n"//设置CPSR的I位，将IRQ位打开23           "msr cpsr, r0\n"24           ::: "r0"25       );26 27       //step 2: GIC 28       ICCICR_CPU0 = 1;//CPU接口控制寄存器29       ICCPMR_CPU0 = 0xff;//中断优先标志寄存器30       ICDDCR = 1;//设置本中断的开关31       ICDIPR0_CPU0 = (0x00 < 0);//本中断的优先级32       ICDIPTR0_CPU0 = 1;//选择指定的CPU33       ICDISER0_CPU0 = (1 < 0);//设置本中断开启34 35       //step 3: interrupt source36       ICDSGIR = 0  (1 < 16)  (0 < 24);//SGI控制寄存器CPUTargetList.TargetListFi    lte37       printf("welcome back! \n");38 }39 40 void do_irq()41     {42         unsigned long data = ICCIAR_CPU0;43         unsigned long irq_id = data & 0x3ff;44         unsigned long cpu_id = (data >> 10) & 0x7;45         ICCEOIR_CPU0 = irq_id  (cpu_id < 10);46         printf("irq is %d, cpu is %d\n", irq_id, cpu_id);47     }48 49 void memcopy(unsigned long* dest, unsigned long* source,int len)50 {51     int i=0;;52     for(i=0;i> 20] = pa  2;154         //2的目的是将0-2位置为10此时将是小页模式4K155     }156 157     //00-10   ====  6070158     for(va=0x00; va<=0x10; va+=0x100){159         pa = va+0x60;160         addr[va >> 20] = pa  2;161     }162 163     //10-14   ====  1014164     for(va=0x10; va<=0x14; va+=0x100){165         pa = va;166         addr[va >> 20] = pa  2;167     }168 169     //30-40   ====  5060170     for(va=0x30; va<0x40; va+=0x100){171         pa = va + 0x20;172         addr[va >> 20] = pa  2;173     }174 }175 176 void enable_mmu(void)177 178 {179     unsigned long addr = 0x70;180     init_ttb(addr);181     //step:初始化页表182 183     unsigned long mmu = 1  (1 < 1)  (1 < 8);184     //将MMU的第0,1,8位置1185     __asm__ __volatile__(186         "mov r0, #3\n"187         "MCR p15, 0, r0, c3, c0, 0\n"//manager188         "MCR p15, 0, %0, c2, c0, 0\n"//addr  189         "MCR p15, 0, %1, c1, c0, 0\n"// enable mmu190         :191         : "r" (addr), "r" (mmu)192         : "r0"193     );194     printf("MMU is enable!\n");195 }196 

在代码中，主函数其他的部分在前面都已经说了，已不再说。主要是在VICTOR函数中，将处理中断的部分，做成了一个函数，以后更容易修改处理的部分。

void do_irq()
41 {
42 unsigned long data = ICCIAR_CPU0;//取出IRQ ID 和CPU ID
43 unsigned long irq_id = data & 0x3ff;
44 unsigned long cpu_id = (data >> 10) & 0x7;
45 ICCEOIR_CPU0 = irq_id (cpu_id < 10);//清除CPU
46 printf("irq is %d, cpu is %d\n", irq_id, cpu_id);
47 }
//总的来说，在以前的基础上面，今天主要认识了GIC的配置，更重要的是，中断分为四步：