linux 中断框架 ================= 数据结构 ----------- 中断管理主要数据结构 .. image:: res/irq_data_struct.png irq_desc中断描述符 ^^^^^^^^^^^^^^^^^^^ 每个中断都有一个中断描述符 irq_desc在include/linux/irqdesc.h中定义 :: /** * struct irq_desc - interrupt descriptor * @irq_common_data: per irq and chip data passed down to chip functions * @kstat_irqs: irq stats per cpu * @handle_irq: highlevel irq-events handler * @preflow_handler: handler called before the flow handler (currently used by sparc) * @action: the irq action chain * @status: status information * @core_internal_state__do_not_mess_with_it: core internal status information * @depth: disable-depth, for nested irq_disable() calls * @wake_depth: enable depth, for multiple irq_set_irq_wake() callers * @tot_count: stats field for non-percpu irqs * @irq_count: stats field to detect stalled irqs * @last_unhandled: aging timer for unhandled count * @irqs_unhandled: stats field for spurious unhandled interrupts * @threads_handled: stats field for deferred spurious detection of threaded handlers * @threads_handled_last: comparator field for deferred spurious detection of theraded handlers * @lock: locking for SMP * @affinity_hint: hint to user space for preferred irq affinity * @affinity_notify: context for notification of affinity changes * @pending_mask: pending rebalanced interrupts * @threads_oneshot: bitfield to handle shared oneshot threads * @threads_active: number of irqaction threads currently running * @wait_for_threads: wait queue for sync_irq to wait for threaded handlers * @nr_actions: number of installed actions on this descriptor * @no_suspend_depth: number of irqactions on a irq descriptor with * IRQF_NO_SUSPEND set * @force_resume_depth: number of irqactions on a irq descriptor with * IRQF_FORCE_RESUME set * @rcu: rcu head for delayed free * @kobj: kobject used to represent this struct in sysfs * @request_mutex: mutex to protect request/free before locking desc->lock * @dir: /proc/irq/ procfs entry * @debugfs_file: dentry for the debugfs file * @name: flow handler name for /proc/interrupts output */ struct irq_desc { struct irq_common_data irq_common_data; struct irq_data irq_data; //每个irq和芯片数据传递给芯片功能 unsigned int __percpu *kstat_irqs; irq_flow_handler_t handle_irq; //高级irq-events处理程序 #ifdef CONFIG_IRQ_PREFLOW_FASTEOI irq_preflow_handler_t preflow_handler; #endif struct irqaction *action; /* IRQ action list */ unsigned int status_use_accessors; //状态信息 unsigned int core_internal_state__do_not_mess_with_it; //核心内部状态信息 unsigned int depth; /* nested irq disables */ unsigned int wake_depth; /* nested wake enables */ unsigned int tot_count; unsigned int irq_count; /* For detecting broken IRQs */ unsigned long last_unhandled; /* Aging timer for unhandled count */ unsigned int irqs_unhandled; atomic_t threads_handled; int threads_handled_last; // raw_spinlock_t lock; //锁定SMP struct cpumask *percpu_enabled; const struct cpumask *percpu_affinity; #ifdef CONFIG_SMP const struct cpumask *affinity_hint; struct irq_affinity_notify *affinity_notify; #ifdef CONFIG_GENERIC_PENDING_IRQ cpumask_var_t pending_mask; #endif #endif unsigned long threads_oneshot; atomic_t threads_active; wait_queue_head_t wait_for_threads; #ifdef CONFIG_PM_SLEEP unsigned int nr_actions; unsigned int no_suspend_depth; unsigned int cond_suspend_depth; unsigned int force_resume_depth; #endif #ifdef CONFIG_PROC_FS struct proc_dir_entry *dir; //proc irq procfs条目 #endif #ifdef CONFIG_GENERIC_IRQ_DEBUGFS struct dentry *debugfs_file; const char *dev_name; #endif #ifdef CONFIG_SPARSE_IRQ struct rcu_head rcu; struct kobject kobj; #endif struct mutex request_mutex; int parent_irq; struct module *owner; const char *name; //proc interrupt输出的中断处理名称 } ____cacheline_internodealigned_in_smp; irq_data ^^^^^^^^^^ :: /** * struct irq_data - per irq chip data passed down to chip functions * @mask: precomputed bitmask for accessing the chip registers * @irq: interrupt number * @hwirq: hardware interrupt number, local to the interrupt domain * @common: point to data shared by all irqchips * @chip: low level interrupt hardware access * @domain: Interrupt translation domain; responsible for mapping * between hwirq number and linux irq number. * @parent_data: pointer to parent struct irq_data to support hierarchy * irq_domain * @chip_data: platform-specific per-chip private data for the chip * methods, to allow shared chip implementations */ struct irq_data { u32 mask; //预先计算的位掩码，用于访问芯片寄存器 unsigned int irq; //中断号 unsigned long hwirq; //硬件中断号，中断域本地 struct irq_common_data *common; // struct irq_chip *chip; //低级中断硬件访问 struct irq_domain *domain; //中断域 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY struct irq_data *parent_data; #endif void *chip_data; }; :: /* * Interrupt flow handler typedefs are defined here to avoid circular * include dependencies. */ struct irq_desc; struct irq_data; typedef void (*irq_flow_handler_t)(struct irq_desc *desc); //handle_irq中断处理函数 typedef void (*irq_preflow_handler_t)(struct irq_data *data); :: //函数指针，通常是我们要实现的 typedef irqreturn_t (*irq_handler_t)(int, void *); /** * struct irqaction - per interrupt action descriptor * @handler: interrupt handler function * @name: name of the device * @dev_id: cookie to identify the device * @percpu_dev_id: cookie to identify the device * @next: pointer to the next irqaction for shared interrupts * @irq: interrupt number * @flags: flags (see IRQF_* above) * @thread_fn: interrupt handler function for threaded interrupts * @thread: thread pointer for threaded interrupts * @secondary: pointer to secondary irqaction (force threading) * @thread_flags: flags related to @thread * @thread_mask: bitmask for keeping track of @thread activity * @dir: pointer to the proc/irq/NN/name entry */ struct irqaction { irq_handler_t handler; //中断处理函数 void *dev_id; //用于识别设备的cookie void __percpu *percpu_dev_id; //用于识别设备的cookie struct irqaction *next; //指向共享中断的下一个irqaction指针 irq_handler_t thread_fn; //用于线程中断的中断处理函数 struct task_struct *thread; //线程中断的线程指针 struct irqaction *secondary; unsigned int irq; //中断号码 unsigned int flags; // unsigned long thread_flags; //与thread相关的标志 unsigned long thread_mask; //用于跟踪thread活动的位掩码 const char *name; //设备名称 struct proc_dir_entry *dir; //指向proc irq NN name条目的指针 } ____cacheline_internodealigned_in_smp; - 中断标志位 :: #define IRQF_TRIGGER_NONE 0x00000000 #define IRQF_TRIGGER_RISING 0x00000001 //上升沿中断 #define IRQF_TRIGGER_FALLING 0x00000002 #define IRQF_TRIGGER_HIGH 0x00000004 //高电平中断 #define IRQF_TRIGGER_LOW 0x00000008 #define IRQF_TRIGGER_MASK (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \ IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING) #define IRQF_TRIGGER_PROBE 0x00000010 #define IRQF_SHARED 0x00000080 //允许多个设备之间共享irq #define IRQF_PROBE_SHARED 0x00000100 //当呼叫着期望发生共享不匹配时由呼叫者设置 #define __IRQF_TIMER 0x00000200 //定时器中断标志 #define IRQF_PERCPU 0x00000400 //中断是每个CPU #define IRQF_NOBALANCING 0x00000800 //用于从irq平衡中排除此中断的标志 #define IRQF_IRQPOLL 0x00001000 //用于轮询 #define IRQF_ONESHOT 0x00002000 #define IRQF_NO_SUSPEND 0x00004000 #define IRQF_FORCE_RESUME 0x00008000 #define IRQF_NO_THREAD 0x00010000 #define IRQF_EARLY_RESUME 0x00020000 #define IRQF_COND_SUSPEND 0x00040000 #define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD) - irq_chip irq_chip用于描述中断控制器底层操作相关的函数操作集合 :: struct irq_chip { //硬件中断描述符 struct device *parent_device; const char *name; //proc/interrupt的名称 unsigned int (*irq_startup)(struct irq_data *data); //启动中断 void (*irq_shutdown)(struct irq_data *data); //关闭中断 void (*irq_enable)(struct irq_data *data); void (*irq_disable)(struct irq_data *data); void (*irq_ack)(struct irq_data *data); //开始新的中断 void (*irq_mask)(struct irq_data *data); //屏蔽中断源 void (*irq_mask_ack)(struct irq_data *data); void (*irq_unmask)(struct irq_data *data); void (*irq_eoi)(struct irq_data *data); //中断结束 int (*irq_set_affinity)(struct irq_data *data, const struct cpumask *dest, bool force); //在SMP机器上设置亲和力 int (*irq_retrigger)(struct irq_data *data); //向CPU重启发送IRQ int (*irq_set_type)(struct irq_data *data, unsigned int flow_type); //设置IEQ的流类型(IRQ_TYPE_LEVEL) int (*irq_set_wake)(struct irq_data *data, unsigned int on); //启用/禁用IRQ的电源管理 void (*irq_bus_lock)(struct irq_data *data); //用于锁定对慢速总线(I2c)芯片的访问功能 void (*irq_bus_sync_unlock)(struct irq_data *data); //用于同步和解锁慢速总线芯片的功能 void (*irq_cpu_online)(struct irq_data *data); //为辅助CPU设置中断源 void (*irq_cpu_offline)(struct irq_data *data); void (*irq_suspend)(struct irq_data *data); void (*irq_resume)(struct irq_data *data); //恢复时从核心代码调用的函数 void (*irq_pm_shutdown)(struct irq_data *data); void (*irq_calc_mask)(struct irq_data *data); void (*irq_print_chip)(struct irq_data *data, struct seq_file *p); int (*irq_request_resources)(struct irq_data *data); void (*irq_release_resources)(struct irq_data *data); void (*irq_compose_msi_msg)(struct irq_data *data, struct msi_msg *msg); void (*irq_write_msi_msg)(struct irq_data *data, struct msi_msg *msg); int (*irq_get_irqchip_state)(struct irq_data *data, enum irqchip_irq_state which, bool *state); int (*irq_set_irqchip_state)(struct irq_data *data, enum irqchip_irq_state which, bool state); int (*irq_set_vcpu_affinity)(struct irq_data *data, void *vcpu_info); void (*ipi_send_single)(struct irq_data *data, unsigned int cpu); void (*ipi_send_mask)(struct irq_data *data, const struct cpumask *dest); int (*irq_nmi_setup)(struct irq_data *data); void (*irq_nmi_teardown)(struct irq_data *data); unsigned long flags; }; 通常我们所说的中断可以分为两种，一种是内部中断(定时器，串口，i2c等)，另一种是外部中断(GPIO+触发类型),内部中断是由固定的独立的中断号的。而外部中断，因为数量较多， 每个单独占用一个的话特别浪费中断资源，所以有些外部中断是有单独的中断号的，而另外一些则是多个端口共享一个中断号 .. image:: res/ext_share_irq.png 中断控制器 -------------- linux内核中断管理分层架构: 1. 硬件层: CPU和中断控制器的连接 2. 处理器架构管理层: 如CPU中断异常处理 3. 中断控制器管理层: 如IRQ号的映射 4. linux内核通用中断处理器层: 如中断注册与中断处理 中断控制器 ^^^^^^^^^^^ .. image:: res/gic_controller.png GIC中断控制器由两部分组成，distributor和cpu interface - distributor 集中管理所有中断源 1. 配置中断的优先级 2. 设置每个中断可路由的CPU列表 3. 向每个CPU interface配送最高优先级的中断 4. 中断屏蔽、中断抢占 5. 配置中断时边缘触发还是水平触发 - cpu interface是GIC连接到CPU的接口，每个cpu interface提供了一个编程接口，主要功能包括 1. 使能中断请求信号到CPU 2. acknowledging 中断，表示CPU接收到中断请求 3. 指示中断的处理完成 4. 设置处理器中断优先级，高于此优先级方可发送给处理器 5. 设置处理器的抢占策略 6. 确定处理器的最高优先级待处理中断 **支持的中断类型** ===================== ================= ============== =================================================================== 中断类型 硬件中断号范围 含义 应用场景 --------------------- ----------------- -------------- ------------------------------------------------------------------- SGI私有软件触发中断 0~15 用于核间通信 通常用于多核通信 PPI私有外设中断 16~31 处理器私有中断 如CPU本地时钟Local timer SPI公用外设中断 32~1019 用用外设中断 用用外设中断，如SPI,I2C，IO等 ===================== ================= ============== =================================================================== - 中断状态 1. inactive(不活跃)状态：中断处于无效状态； 2. pending(等待)状态：中断处于有效状态，但是等待CPU响应该中断； 3. active(活跃)状态：CPU已经响应中断； 4. active and pending(活跃并等待)状态：CPU正在响应中断，但是该中断源又发送中断过来 转换图如下 .. image:: res/irq_sta.png .. note:: GIC总是会选择优先级最高的pending的中断发送给CPU，通过cat /proc/interrupts可以查看当前平台的中断源 虚拟中断号和硬中断号 --------------------- - 虚拟中断号 :: /* * NR_IRQS is the upper bound of how many interrupts can be handled * in the platform. It is used to size the static irq_map array, * so don't make it too big. */ #ifndef NR_IRQS #define NR_IRQS 64 #endif #ifdef CONFIG_SPARSE_IRQ # define IRQ_BITMAP_BITS (NR_IRQS + 8196) #else # define IRQ_BITMAP_BITS NR_IRQS #endif static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS); linux定义了位图来管理这些虚拟中断号，allocated_irqs变量分配了IRQ_BITMAP_BOTS个bit位，每个bit位代表一个中断 - 硬件中断号 1. 0~31中断号给了SGI和PPI 2. 其他外设中断号会从32开始 3. dts中会用interrupts = <硬中断号n>来指定硬件中断号，真正的硬中断号为32+n .. image:: res/irq_number.png cat /proc/interrupts看到的是实际的硬件中断号，即转换完成的 .. note:: dts中interrupts域主要包含三个属性: 1.中断类型:GIC_SPI(共享外设型，用0表示) GIC_PPI(私有外设中断，用1表示) 2.中断ID 3.触发类型:IRQ_TYPE_EDGE_RISING等