从下到上分析中断处理《转》

S3C2410中断的定义的中断向量是从16～47.然后外部中断从48~69.70~80.一共有66(80-16)个中断其中70～78 UART是用来与PC进行通信的。

01	25 #define S3C2410_CPUIRQ_OFFSET    (16)

02

26

03	27 #define S3C2410_IRQ(x) ((x) + S3C2410_CPUIRQ_OFFSET)

04

28

05	29 /* main cpu interrupts */

06	30 #define IRQ_EINT0      S3C2410_IRQ(0)       /* 16 */

07	31 #define IRQ_EINT1      S3C2410_IRQ(1)

08	32 #define IRQ_EINT2      S3C2410_IRQ(2)

09	33 #define IRQ_EINT3      S3C2410_IRQ(3)

10	34 #define IRQ_EINT4t7    S3C2410_IRQ(4)       /* 20 */

11	35 #define IRQ_EINT8t23   S3C2410_IRQ(5)

12	36 #define IRQ_RESERVED6  S3C2410_IRQ(6)       /* for s3c2410 */

13	37 #define IRQ_CAM        S3C2410_IRQ(6)       /* for s3c2440,s3c2443 */

14	38 #define IRQ_BATT_FLT   S3C2410_IRQ(7)

15	39 #define IRQ_TICK       S3C2410_IRQ(8)       /* 24 */

16	40 #define IRQ_WDT        S3C2410_IRQ(9)       /* WDT/AC97 for s3c2443 */

17	41 #define IRQ_TIMER0     S3C2410_IRQ(10)

18	42 #define IRQ_TIMER1     S3C2410_IRQ(11)

19	43 #define IRQ_TIMER2     S3C2410_IRQ(12)

20	44 #define IRQ_TIMER3     S3C2410_IRQ(13)

21	45 #define IRQ_TIMER4     S3C2410_IRQ(14)

22	46 #define IRQ_UART2      S3C2410_IRQ(15)

23	47 #define IRQ_LCD        S3C2410_IRQ(16)      /* 32 */

24	48 #define IRQ_DMA0       S3C2410_IRQ(17)      /* IRQ_DMA for s3c2443 */

25	49 #define IRQ_DMA1       S3C2410_IRQ(18)

26	50 #define IRQ_DMA2       S3C2410_IRQ(19)

27	51 #define IRQ_DMA3       S3C2410_IRQ(20)

28	52 #define IRQ_SDI        S3C2410_IRQ(21)

29	53 #define IRQ_SPI0       S3C2410_IRQ(22)

30	54 #define IRQ_UART1      S3C2410_IRQ(23)

31	55 #define IRQ_RESERVED24 S3C2410_IRQ(24)      /* 40 */

32	56 #define IRQ_NFCON      S3C2410_IRQ(24)      /* for s3c2440 */

33	57 #define IRQ_USBD       S3C2410_IRQ(25)

34	58 #define IRQ_USBH       S3C2410_IRQ(26)

35	59 #define IRQ_IIC        S3C2410_IRQ(27)

36	60 #define IRQ_UART0      S3C2410_IRQ(28)      /* 44 */

37	61 #define IRQ_SPI1       S3C2410_IRQ(29)

38	62 #define IRQ_RTC        S3C2410_IRQ(30)

39	63 #define IRQ_ADCPARENT  S3C2410_IRQ(31)

01	65 /* interrupts generated from the external interrupts sources */

02	66 #define IRQ_EINT4      S3C2410_IRQ(32)     /* 48 */

03	67 #define IRQ_EINT5      S3C2410_IRQ(33)

04	68 #define IRQ_EINT6      S3C2410_IRQ(34)

05	69 #define IRQ_EINT7      S3C2410_IRQ(35)

06	70 #define IRQ_EINT8      S3C2410_IRQ(36)

07	71 #define IRQ_EINT9      S3C2410_IRQ(37)

08	72 #define IRQ_EINT10     S3C2410_IRQ(38)

09	73 #define IRQ_EINT11     S3C2410_IRQ(39)

10	74 #define IRQ_EINT12     S3C2410_IRQ(40)

11	75 #define IRQ_EINT13     S3C2410_IRQ(41)

12	76 #define IRQ_EINT14     S3C2410_IRQ(42)

13	77 #define IRQ_EINT15     S3C2410_IRQ(43)

14	78 #define IRQ_EINT16     S3C2410_IRQ(44)

15	79 #define IRQ_EINT17     S3C2410_IRQ(45)

16	80 #define IRQ_EINT18     S3C2410_IRQ(46)

17	81 #define IRQ_EINT19     S3C2410_IRQ(47)

18	82 #define IRQ_EINT20     S3C2410_IRQ(48)     /* 64 */

19	83 #define IRQ_EINT21     S3C2410_IRQ(49)

20	84 #define IRQ_EINT22     S3C2410_IRQ(50)

21	85 #define IRQ_EINT23     S3C2410_IRQ(51)

22

86

23

87

24	88 #define IRQ_EINT(x)    S3C2410_IRQ((x >= 4) ? (IRQ_EINT4 + (x) - 4) : (S3C2410_IRQ(0) + (x)))

25

89

26	90 #define IRQ_LCD_FIFO   S3C2410_IRQ(52)

27	91 #define IRQ_LCD_FRAME  S3C2410_IRQ(53)

28	98 #define S3C2410_IRQSUB(x)   S3C2410_IRQ((x)+54)

29

99

30	100 #define IRQ_S3CUART_RX0     S3C2410_IRQSUB(0)   /* 70 */

31	101 #define IRQ_S3CUART_TX0     S3C2410_IRQSUB(1)

32	102 #define IRQ_S3CUART_ERR0    S3C2410_IRQSUB(2)

33

103

34	104 #define IRQ_S3CUART_RX1     S3C2410_IRQSUB(3)   /* 73 */

35	105 #define IRQ_S3CUART_TX1     S3C2410_IRQSUB(4)

36	106 #define IRQ_S3CUART_ERR1    S3C2410_IRQSUB(5)

37

107

38	108 #define IRQ_S3CUART_RX2     S3C2410_IRQSUB(6)   /* 76 */

39	109 #define IRQ_S3CUART_TX2     S3C2410_IRQSUB(7)

40	110 #define IRQ_S3CUART_ERR2    S3C2410_IRQSUB(8)

41

111

42	112 #define IRQ_TC          S3C2410_IRQSUB(9)

43	113 #define IRQ_ADC         S3C2410_IRQSUB(10)

44

114

45	115 /* extra irqs for s3c2440 */

46

...

那么前16就是trap了。
这些中断向量的初始化是由

001	661 void __init s3c24xx_init_irq(void)

002

662 {

003	663     unsigned long pend;

004	664     unsigned long last;

005	665     int irqno;

006	666     int i;

007

667

008	668     irqdbf("s3c2410_init_irq: clearing interrupt status flags\n");

009

669

010	670     /* first, clear all interrupts pending... */

011

671

012	672     last = 0;

013	673     for (i = 0; i < 4; i++) {

014	674         pend = __raw_readl(S3C24XX_EINTPEND);

015

675

016	676         if (pend == 0 || pend == last)

017	677             break;

018

678

019	679         __raw_writel(pend, S3C24XX_EINTPEND);

020	680         printk("irq: clearing pending ext status %08x\n", (int)pend);

021	681         last = pend;

022

682     }

023

683

024	684     last = 0;

025	685     for (i = 0; i < 4; i++) {

026	686         pend = __raw_readl(S3C2410_INTPND);

027

687

028	688         if (pend == 0 || pend == last)

029	689             break;

030

690

031	691         __raw_writel(pend, S3C2410_SRCPND);

032	692         __raw_writel(pend, S3C2410_INTPND);

033	693         printk("irq: clearing pending status %08x\n", (int)pend);

034	694         last = pend;

035

695     }

036

696

037	697     last = 0;

038	698     for (i = 0; i < 4; i++) {

039	699         pend = __raw_readl(S3C2410_SUBSRCPND);

040

700

041	701         if (pend == 0 || pend == last)

042	702             break;

043

703

044	704         printk("irq: clearing subpending status %08x\n", (int)pend);

045	705         __raw_writel(pend, S3C2410_SUBSRCPND);

046	706         last = pend;

047

707     }

048

708

049	709     /* register the main interrupts */

050

710

051	711     irqdbf("s3c2410_init_irq: registering s3c2410 interrupt handlers\n");

052

712

053	713     for (irqno = IRQ_EINT4t7; irqno <= IRQ_ADCPARENT; irqno++) {

054	714         /* set all the s3c2410 internal irqs */

055

715

056	716         switch (irqno) {

057	717             /* deal with the special IRQs (cascaded) */

058

718

059	719         case IRQ_EINT4t7:

060	720         case IRQ_EINT8t23:

061	721         case IRQ_UART0:

062	722         case IRQ_UART1:

063	723         case IRQ_UART2:

064	724         case IRQ_ADCPARENT:

065	725             set_irq_chip(irqno, &s3c_irq_level_chip);

066	726             set_irq_handler(irqno, handle_level_irq);

067	727             break;

068

728

069	729         case IRQ_RESERVED6:

070	730         case IRQ_RESERVED24:

071	731             /* no IRQ here */

072	732             break;

073

733

074	734         default:

075	735             //irqdbf("registering irq %d (s3c irq)\n", irqno);

076	736             set_irq_chip(irqno, &s3c_irq_chip);

077	737             set_irq_handler(irqno, handle_edge_irq);

078	738             set_irq_flags(irqno, IRQF_VALID);

079	739         }

080

740     }

081

741

082	742     /* setup the cascade irq handlers */

083

743

084	744     set_irq_chained_handler(IRQ_EINT4t7, s3c_irq_demux_extint4t7);

085	745     set_irq_chained_handler(IRQ_EINT8t23, s3c_irq_demux_extint8);

086

746

087	747     set_irq_chained_handler(IRQ_UART0, s3c_irq_demux_uart0);

088	748     set_irq_chained_handler(IRQ_UART1, s3c_irq_demux_uart1);

089	749     set_irq_chained_handler(IRQ_UART2, s3c_irq_demux_uart2);

090	750     set_irq_chained_handler(IRQ_ADCPARENT, s3c_irq_demux_adc);

091

751

092	752     /* external interrupts */

093

753

094	754     for (irqno = IRQ_EINT0; irqno <= IRQ_EINT3; irqno++) {

095	755         irqdbf("registering irq %d (ext int)\n", irqno);

096	756         set_irq_chip(irqno, &s3c_irq_eint0t4);

097	757         set_irq_handler(irqno, handle_edge_irq);

098	758         set_irq_flags(irqno, IRQF_VALID);

099

759     }

100

760

101	761     for (irqno = IRQ_EINT4; irqno <= IRQ_EINT23; irqno++) {

102	762         irqdbf("registering irq %d (extended s3c irq)\n", irqno);

103	763         set_irq_chip(irqno, &s3c_irqext_chip);

104	764         set_irq_handler(irqno, handle_edge_irq);

105	765         set_irq_flags(irqno, IRQF_VALID);

106

766     }

107

767

108	768     /* register the uart interrupts */

109

769

110	770     irqdbf("s3c2410: registering external interrupts\n");

111

771

112	772     for (irqno = IRQ_S3CUART_RX0; irqno <= IRQ_S3CUART_ERR0; irqno++) {

113	773         irqdbf("registering irq %d (s3c uart0 irq)\n", irqno);

114	774         set_irq_chip(irqno, &s3c_irq_uart0);

115	775         set_irq_handler(irqno, handle_level_irq);

116	776         set_irq_flags(irqno, IRQF_VALID);

117

777     }

118

778

119	779     for (irqno = IRQ_S3CUART_RX1; irqno <= IRQ_S3CUART_ERR1; irqno++) {

120	780         irqdbf("registering irq %d (s3c uart1 irq)\n", irqno);

121	781         set_irq_chip(irqno, &s3c_irq_uart1);

122	782         set_irq_handler(irqno, handle_level_irq);

123	783         set_irq_flags(irqno, IRQF_VALID);

124

784     }

125

785

126	786     for (irqno = IRQ_S3CUART_RX2; irqno <= IRQ_S3CUART_ERR2; irqno++) {

127	787         irqdbf("registering irq %d (s3c uart2 irq)\n", irqno);

128	788         set_irq_chip(irqno, &s3c_irq_uart2);

129	789         set_irq_handler(irqno, handle_level_irq);

130	790         set_irq_flags(irqno, IRQF_VALID);

131

791     }

132

792

133	793     for (irqno = IRQ_TC; irqno <= IRQ_ADC; irqno++) {

134	794         irqdbf("registering irq %d (s3c adc irq)\n", irqno);

135	795         set_irq_chip(irqno, &s3c_irq_adc);

136	796         set_irq_handler(irqno, handle_edge_irq);

137	797         set_irq_flags(irqno, IRQF_VALID);

138

798     }

139

799

140	800     irqdbf("s3c2410: registered interrupt handlers\n");

141

801 }

上面便是对中断向量进行赋值了。其中set_irq_chip是设置irq上的中断控制器。set_irq_handle便是设置该中断线上的处理函数了，比如ack mark之类的。set_irq_flags是设置该中断线的标志位，有哪些呢？

01	49 #define IRQ_INPROGRESS      0x00000100  /* IRQ handler active - do not enter! */

02	50 #define IRQ_DISABLED        0x00000200  /* IRQ disabled - do not enter! */

03	51 #define IRQ_PENDING     0x00000400  /* IRQ pending - replay on enable */

04	52 #define IRQ_REPLAY      0x00000800  /* IRQ has been replayed but not acked yet */

05	53 #define IRQ_AUTODETECT      0x00001000  /* IRQ is being autodetected */

06	54 #define IRQ_WAITING     0x00002000  /* IRQ not yet seen - for autodetection */

07	55 #define IRQ_LEVEL       0x00004000  /* IRQ level triggered */

08	56 #define IRQ_MASKED      0x00008000  /* IRQ masked - shouldn't be seen again */

09	57 #define IRQ_PER_CPU     0x00010000  /* IRQ is per CPU */

10	58 #define IRQ_NOPROBE     0x00020000  /* IRQ is not valid for probing */

11	59 #define IRQ_NOREQUEST       0x00040000  /* IRQ cannot be requested */

12	60 #define IRQ_NOAUTOEN        0x00080000  /* IRQ will not be enabled on request irq */

13	61 #define IRQ_WAKEUP      0x00100000  /* IRQ triggers system wakeup */

14	62 #define IRQ_MOVE_PENDING    0x00200000  /* need to re-target IRQ destination */

15	63 #define IRQ_NO_BALANCING    0x00400000  /* IRQ is excluded from balancing */

另外set_irq_handler我们来看一下：

01

534 void

02	535 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,

03	536           const char *name)

04

537 {

05	538     struct irq_desc *desc;

06	539     unsigned long flags;

07

540

08	541     if (irq >= NR_IRQS) {

09	542         printk(KERN_ERR

10	543                "Trying to install type control for IRQ%d\n", irq);

11	544         return;

12

545     }

13

546

14	547     desc = irq_desc + irq;

15

548

16	549     if (!handle)              //如果形参handle没有被赋值，那么先将之赋值为handle_bad_irq.在后面567行我们会看到，实际上是会执行卸载操作

17	550         handle = handle_bad_irq;

18	551     else if (desc->chip == &no_irq_chip) {

19	552         printk(KERN_WARNING "Trying to install %sinterrupt handler "

20	553                "for IRQ%d\n", is_chained ? "chained " : "", irq);

21	554         /*

22	555          * Some ARM implementations install a handler for really dumb

23	556          * interrupt hardware without setting an irq_chip. This worked

24	557          * with the ARM no_irq_chip but the check in setup_irq would

25	558          * prevent us to setup the interrupt at all. Switch it to

26	559          * dummy_irq_chip for easy transition.

27	560          */

28	561         desc->chip = &dummy_irq_chip;

29

562     }

30

563

31	564     spin_lock_irqsave(&desc->lock, flags);

32

565

33	566     /* Uninstall? */

34	567     if (handle == handle_bad_irq) {

35	568         if (desc->chip != &no_irq_chip)

36	569             mask_ack_irq(desc, irq);

37	570         desc->status |= IRQ_DISABLED;

38	571         desc->depth = 1;

39

572     }

40	573     desc->handle_irq = handle;

41	574     desc->name = name;

另外，现在已经设置好中断向量了，那么这些中断向量在哪里放着呢？因为如果要响应中断的话，必须找到入口啊。
看一下trap_init函数：

01	678 void __init trap_init(void)

02

679 {

03	680     unsigned long vectors = CONFIG_VECTORS_BASE;

04	681     extern char __stubs_start[], __stubs_end[];

05	682     extern char __vectors_start[], __vectors_end[];

06	683     extern char __kuser_helper_start[], __kuser_helper_end[];

07	684     int kuser_sz = __kuser_helper_end - __kuser_helper_start;

08

685

09	686     /*

10	687      * Copy the vectors, stubs and kuser helpers (in entry-armv.S)

11	688      * into the vector page, mapped at 0xffff0000, and ensure these

12	689      * are visible to the instruction stream.

13	690      */

14	691     memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);

15	692     memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);

16	693     memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);

17

694

18	695     /*

19	696      * Copy signal return handlers into the vector page, and

20	697      * set sigreturn to be a pointer to these.

21	698      */

22	699     memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes,

23	700            sizeof(sigreturn_codes));

24

701

25	702     flush_icache_range(vectors, vectors + PAGE_SIZE);

26	703     modify_domain(DOMAIN_USER, DOMAIN_CLIENT);

27

704 }

看到了吧，将__vectors_start~__vectors_end还有stub都移到了vector的位置，而vector的位置既是 CONFIG_VECTORS_BASE，

1	147 #define CONFIG_VECTORS_BASE 0xffff0000

那么__vector_start在哪里捏？
~/linux-2.6.21.1/arch/arm/kernel/entry-armv.S

1062 __vectors_start: 1063 swi SYS_ERROR0 1064 b vector_und + stubs_offset 1065 ldr pc, .LCvswi + stubs_offset 1066 b vector_pabt + stubs_offset 1067 b vector_dabt + stubs_offset 1068 b vector_addrexcptn + stubs_offset 1069 b vector_irq + stubs_offset 1070 b vector_fiq + stubs_offset 1071 1072 .globl __vectors_end 1073 __vectors_end:

在该文件，我们也可以找到__stub_start的变量地址。