irq

问题 I am looking for how a RISC-V processor processes interrupt requests. I looked at the Instruction Set Manuals and information on the internet. The focus is on explaining exactly what the title sets: the instruction set. In my view, how interrupts are handled is a question of what is called the "programmer's model" of the processor. It does not clearly fit into a document about an instruction set, because parts of interrupt processing are not expressed in instructions. Clearly, jumping into an

问题 I posted this is the thread which discussed about request_threaded_irq but I did not get any reply. So I am posting it freshly. I am working on a touchscreen driver for capacitive touchscree. It used request_threaded_irq() call instead of request_irq(). I could not understand the basic difference betweeen two. It says :- Name request_threaded_irq — allocate an interrupt line Synopsis int request_threaded_irq (unsigned int irq, irq_handler_t handler,irq_handler_t thread_fn, unsigned long

问题 When we use irq_set_chained_handler the irq line will not be disabled or not, when we are servicing the associated handler, as in case of request_irq. 回答1: It doesn't matter how the interrupt was setup. When any interrupt occurred, all interrupts (for this CPU) will be disabled during the interrupt handler. For example, on ARM architecture first place in C code where interrupt handling is found is asm_do_IRQ() function (defined in arch/arm/kernel/irq.c ). It's being called from assembler code

问题 I am programming a kernel module in C which is struggling to access IRQ description array elements and to display all action names of these elements. At the beginning, I thought that this irq_desc array is sonething like a macro but after compiling i understood it is not. Then I used for_each_irq_desc(irq, desc) function. but this time it returned a warning: WARNING: "irq_to_desc" [/home/samet/Masaüstü/Assignment3/Ass-1.ko] undefined! and after this warning, i tried to insmod the module into

问题 I am trying to retrieve the return address of an IRQ handler in my code. My aim is to save the value of the PC just before the watchdog timer expires and before the reset for debug purposes, using WDT_IRQHandler(). I am also testing this approach with other IRQs to check if I grasped the idea. But it seems I haven't. I have read the documentation available. I understood that when an exception happens, 8 registers are pushed to the stack: R0, R1, R2, R3, R12, LR, PC and XPSR. I have also read

问题 I'm following several tutorials and references trying to get my kernel set up. I've come across some unfamiliar code in a tutorial that isn't explaining it at all. It's code that I'm told maps the 16 IRQs (0-15) to ISR locations 32-47 : void irq_remap(void) { outportb(0x20, 0x11); outportb(0xA0, 0x11); outportb(0x21, 0x20); outportb(0xA1, 0x28); outportb(0x21, 0x04); outportb(0xA1, 0x02); outportb(0x21, 0x01); outportb(0xA1, 0x01); outportb(0x21, 0x0); outportb(0xA1, 0x0); } The code for

问题 I am using Linux kernel 3.0.35 on Freescale i.MX6 (ARM Cortex-A9). After running into a kernel OOPS I tried to understand the exception stack initialization. Here is what I have uncovered so far. In cpu_init() in arch/arm/kernel/setup.c , I see the exception stack getting initialized: struct stack { u32 irq[3]; u32 abt[3]; u32 und[3]; } ____cacheline_aligned; static struct stack stacks[NR_CPUS]; void cpu_init(void) { struct stack *stk = &stacks[cpu]; ...<snip> /* * setup stacks for re-entrant

问题 Whilst researching the input event system in the kernel, I came across the need to access the input handlers that have already been registered with an IRQ lane given only the irq lane (just the integer). Is there a method to access ALL event handlers associated with an IRQ? I am looking to map each list of handlers from a given input device (say mouse) to each possible event that the device could make. Not sure if it matters, but I am working with the AOSP for ARM devices. 回答1: There is an

问题 For some reason, IRQ 6 never hits in my Qemu, Bochs, VMWare, or VirtualBox emulators. Do I need some type of virtual Floppy Drive or something? Here is my IRq6 handler: void i86_flpy_irq (struct regs *r) { //! irq fired _FloppyDiskIRQ = 1; printf("IRQ 6 HIT"); } It never says "IRQ 6 HIT", and not only that, in my install function for my irq6 where I call in kernel: void flpydsk_install (int irq) { //! install irq handler install_handler_irq (irq, i86_flpy_irq); //! initialize the DMA for FDC

问题 I'm newbie on Linux Kernel. Currently, I looked into idle codes and had a quesition. When processor doesn't have any taks in their own runqueue then it may go into idle mode, specific WFI(wating for interrupt). (All I mentioned is about ARM architecture not X86. So something is wrong for X86.) After staying in WFI state, maybe other processor(not idle) want to spread their task to this, idle processor(by load balance). At that time a busy processor makes task imigrated. In my point of view,