ARM Linux中断分析以s3c2410为例Word文档下载推荐.docx

1、* set sigreturn to be a pointer to these.memcpy（void *）KERN_SIGRETURN_CODE, sigreturn_codes,sizeof（sigreturn_codes）;flush_icache_range（vectors, vectors + PAGE_SIZE）;modify_domain（DOMAIN_USER, DOMAIN_CLIENT）;init_IRQ对irq进行初始化时，又调用了init_arch_irq对于具体平台体系的中断进行初始化。而init_arch_irq是在start_kernel里调用setup_arc

2、h函数设定的/* arch/arm/kernel/irq.c n */void _init init_IRQ（void）int irq;for （irq = 0; irq init_irq;machine_desc是用于描述平台体系（处理器芯片）的结构体，其定义如下： /* include/asm/mach/arch.h */struct machine_desc * Note! The first four elements are used* by assembler code in head-armv.Sunsigned int nr; /* architecture number */

3、unsigned int phys_io; /* start of physical io */unsigned int io_pg_offst; /* byte offset for io * page tabe entry */const char *name; /* architecture name */unsigned long boot_params; /* tagged list */unsigned int video_start; /* start of video RAM */unsigned int video_end; /* end of video RAM */uns

4、igned int reserve_lp0 :1; /* never has lp0 */unsigned int reserve_lp1 : /* never has lp1 */unsigned int reserve_lp2 : /* never has lp2 */unsigned int soft_reboot : /* soft reboot */void （*fixup）（struct machine_desc *,struct tag *, char *,struct meminfo *）;void （*map_io）（void）; /* IO mapping function

5、 */void （*init_irq）（void）;struct sys_timer *timer; /* system tick timer */void （*init_machine）（void）;* Set of macros to define architecture features. This is built into* a table by the linker.#define MACHINE_START（_type,_name） static const struct machine_desc _mach_desc_#_type _used _attribute_（_sec

6、tion_（.arch.info.init） = .nr = MACH_TYPE_#_type, .name = _name,#define MACHINE_END 对于s3c2410处理器芯片,其machine_desc变量的定义如下：/* arch/arm/mach-s3c2410/mach-smdk2410.c */MACHINE_START（SMDK2410, SMDK2410） /* TODO: request a new identifier and switch* to SMDK2410 */* Maintainer: Jonas Dietsche */.phys_io = S3

7、C2410_PA_UART,.io_pg_offst = （u32）S3C24XX_VA_UART） 18） & 0xfffc,.boot_params = S3C2410_SDRAM_PA + 0x100,.map_io = smdk2410_map_io,.init_irq = s3c24xx_init_irq,.init_machine = smdk2410_init,.timer = &s3c24xx_timer,MACHINE_END接下来，我们看看s3c2410处理器芯片的irq初始化函数/* arch/arm/plat-s3c24xx/irq.c */* s3c24xx_init

8、_irq* Initialise S3C2410 IRQ system/* s3c24xx系列芯片中断初始化函数 */void _init s3c24xx_init_irq（void）unsigned long pend;unsigned long last;int irqno;int i;irqdbf（s3c2410_init_irq: clearing interrupt status flagsn）;/* first, clear all interrupts pending. */* 清空各个中断请求信号 */last = 0;for （i = 0; i 4; i+） pend = _

9、raw_readl（S3C24XX_EINTPEND）;if （pend = 0 | pend = last）break;_raw_writel（pend, S3C24XX_EINTPEND）;printk（irq: clearing pending ext status %08xn, （int）pend）;last = pend;pend = _raw_readl（S3C2410_INTPND）;_raw_writel（pend, S3C2410_SRCPND）;_raw_writel（pend, S3C2410_INTPND）; clearing pending status %08xnp

10、end = _raw_readl（S3C2410_SUBSRCPND）; clearing subpending status %08xn_raw_writel（pend, S3C2410_SUBSRCPND）;/* register the main interrupts */* 注册主要中断 */ registering s3c2410 interrupt handlersnfor （irqno = IRQ_EINT4t7; irqno = NR_IRQS）desc = &bad_irq_desc;irq_enter（）;desc_handle_irq（irq, desc）; /* 调用已

11、安装的中断高层流处理函数 */* AT91 specific workaround */irq_finish（irq）;irq_exit（）;set_irq_regs（old_regs）;接下来，我们以IRQ_UART2（s3c2410串口2中断）为例，看看中断是如何分流到我们通过request_irq注册的中断处理函数在s3c24xx_init_irq里IRQ_S3CUART_TX2中断的中断高层流处理函数被设置为s3c_irq_demux_uart2。s3c_irq_demux_uart2主要工作是调用s3c_irq_demux_uart对串口中断进行分流处理，因为串口中断包含Rx（接收）

12、中断、Tx（发送）中断和Rx error（接收错误）中断/* arch/arm/plat-s3c2410/irq.c */static void s3c_irq_demux_uart2（unsigned int irq, struct irq_desc *desc）irq = irq;s3c_irq_demux_uart（IRQ_S3CUART_RX2）;s3c_irq_demux_uart通过副中断源引脚寄存器的值,判断中断源并执行相应的中断处理函数/* start: 标示发出该中断信号的是哪个uart,即其值应为* IRQ_S3CUART_RX0、IRQ_S3CUART_RX1或IRQ_S

13、3CUART_RX2static void s3c_irq_demux_uart（unsigned int start）unsigned int subsrc, submsk;unsigned int offset = start - IRQ_S3CUART_RX0; /* 获取该UART中断源在副中断屏蔽寄存器中的偏移量 */struct irq_desc *desc;/* read the current pending interrupts, and the mask* for what it is available */subsrc = _raw_readl（S3C2410_SUBS

14、RCPND）; /* 读取副中断源引脚寄存器 */submsk = _raw_readl（S3C2410_INTSUBMSK）; /* 读取副中断屏蔽寄存器 */irqdbf2（s3c_irq_demux_uart: start=%d （%d）, subsrc=0x%08x,0x%08xn,start, offset, subsrc, submsk）;subsrc &= submsk; /* 只留下已使能（未屏蔽）的中断源 */subsrc = offset; /* 截取发送中断的uart源到subsrc低3位 */= 7;if （subsrc != 0）desc = irq_desc + start;if （subsrc & 1） /* Rx中断 */desc_handle_irq（start, desc）;desc+; 2） /* Tx中断 */desc_handle_irq（start+1, desc）; 4） /* Rx error中断 */desc_handle_irq（start+2, desc）;desc_handle_irq实际上只是调用了de