Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 24 Dec 2002 01:00:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 24 Dec 2002 01:00:03 -0500 Received: from samael.donpac.ru ([195.161.172.239]:1542 "EHLO samael.donpac.ru") by vger.kernel.org with ESMTP id ; Tue, 24 Dec 2002 00:59:58 -0500 From: "Andrey Panin" Date: Tue, 24 Dec 2002 09:03:31 +0300 To: linux-kernel@vger.kernel.org Subject: [RFC] irq handling code consolidation (common part) Message-ID: <20021224060331.GA1090@pazke> Mail-Followup-To: linux-kernel@vger.kernel.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="aM3YZ0Iwxop3KEKx" Content-Disposition: inline User-Agent: Mutt/1.3.28i X-Uname: Linux 2.4.20aa1 i686 unknown Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11020 Lines: 411 --aM3YZ0Iwxop3KEKx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi all, this patch moves some common parts of irq handling code to one place. Arch specific patches will follow. Patch for i386 is tested and performed= =20 well, but other arch specific patched are not. Please take a look. Please CC me answering this letter, I'm not subscribed to lkml currently. Best regards. --=20 Andrey Panin | Embedded systems software developer pazke@orbita1.ru | PGP key: wwwkeys.pgp.net --aM3YZ0Iwxop3KEKx Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename=patch-irq-common diff --minimal -urN -X /usr/share/dontdiff linux-2.5.52.vanilla/kernel/Makefile linux-2.5.52/kernel/Makefile --- linux-2.5.52.vanilla/kernel/Makefile Thu Dec 19 20:03:23 2002 +++ linux-2.5.52/kernel/Makefile Tue Dec 24 19:36:44 2002 @@ -22,6 +22,7 @@ obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o obj-$(CONFIG_SOFTWARE_SUSPEND) += suspend.o obj-$(CONFIG_COMPAT) += compat.o +obj-$(CONFIG_GENERIC_IRQ) += irq.o ifneq ($(CONFIG_IA64),y) # According to Alan Modra , the -fno-omit-frame-pointer is diff --minimal -urN -X /usr/share/dontdiff linux-2.5.52.vanilla/kernel/irq.c linux-2.5.52/kernel/irq.c --- linux-2.5.52.vanilla/kernel/irq.c Thu Jan 1 03:00:00 1970 +++ linux-2.5.52/kernel/irq.c Tue Dec 24 20:32:56 2002 @@ -0,0 +1,364 @@ +/* + * linux/kernel/irq.c + * + * Mostly architecture independent parts of IRQ handling. + * + * Copyright (C) 1992, 2002 Linus Torvalds, Ingo Molnar. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include + +/* + * Controller mappings for all interrupt sources: + */ +irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = { + [0 ... NR_IRQS - 1] = { + .handler = &no_irq_type, + .lock = SPIN_LOCK_UNLOCKED, + } +}; + +/* + * Special irq handlers. + */ + +void no_action(int cpl, void *dev_id, struct pt_regs *regs) { } + +/* + * Generic no controller code + */ +atomic_t irq_err_count; + +static void no_irq_enable_disable(unsigned int irq) { } +static unsigned int no_irq_startup(unsigned int irq) { return 0; } + +static void no_irq_ack(unsigned int irq) +{ + atomic_inc(&irq_err_count); + printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq); + ack_bad_irq(irq); +} + +struct hw_interrupt_type no_irq_type = { + .typename = "none", + .startup = no_irq_startup, + .shutdown = no_irq_enable_disable, + .enable = no_irq_enable_disable, + .disable = no_irq_enable_disable, + .ack = no_irq_ack, + .end = no_irq_enable_disable, +}; + +/* + * This should really return information about whether + * we should do bottom half handling etc. Right now we + * end up _always_ checking the bottom half, which is a + * waste of time and is not what some drivers would + * prefer. + */ +int handle_IRQ_event(unsigned int irq, struct pt_regs *regs, + struct irqaction *action) +{ + int status = 1; /* Force the "do bottom halves" bit */ + + if (!(action->flags & SA_INTERRUPT)) + local_irq_enable(); + + do { + status |= action->flags; + action->handler(irq, action->dev_id, regs); + action = action->next; + } while (action); + if (status & SA_SAMPLE_RANDOM) + add_interrupt_randomness(irq); + local_irq_disable(); + + return status; +} + +#if defined(CONFIG_SMP) && !defined(HAVE_ARCH_SYNCRONIZE_IRQ) + +inline void synchronize_irq(unsigned int irq) +{ + /* is there anything to synchronize with? */ + if (!irq_desc[irq].action) + return; + + while (irq_desc[irq].status & IRQ_INPROGRESS) + cpu_relax(); +} + +#endif + +/* + * Generic enable/disable code: this just calls + * down into the PIC-specific version for the actual + * hardware disable after having gotten the irq + * controller lock. + */ + +/** + * disable_irq_nosync - disable an irq without waiting + * @irq: Interrupt to disable + * + * Disable the selected interrupt line. Disables and Enables are + * nested. + * Unlike disable_irq(), this function does not ensure existing + * instances of the IRQ handler have completed before returning. + * + * This function may be called from IRQ context. + */ +inline void disable_irq_nosync(unsigned int irq) +{ + irq_desc_t *desc = irq_desc(irq); + unsigned long flags; + + spin_lock_irqsave(&desc->lock, flags); + if (!desc->depth++) { + desc->status |= IRQ_DISABLED; + desc->handler->disable(irq); + } + spin_unlock_irqrestore(&desc->lock, flags); +} + +/** + * disable_irq - disable an irq and wait for completion + * @irq: Interrupt to disable + * + * Disable the selected interrupt line. Enables and Disables are + * nested. That is for two disables you need two enables. + * This function waits for any pending IRQ handlers for this interrupt + * to complete before returning. If you use this function while + * holding a resource the IRQ handler may need you will deadlock. + * + * This function may be called - with care - from IRQ context. + */ +void disable_irq(unsigned int irq) +{ + disable_irq_nosync(irq); + synchronize_irq(irq); +} + +/** + * enable_irq - enable handling of an irq + * @irq: Interrupt to enable + * + * Undoes the effect of one call to disable_irq(). If this + * matches the last disable, processing of interrupts on this + * IRQ line is re-enabled. + * + * This function may be called from IRQ context. + */ +void enable_irq(unsigned int irq) +{ + irq_desc_t *desc = irq_desc(irq); + unsigned long flags; + + spin_lock_irqsave(&desc->lock, flags); + switch (desc->depth) { + case 1: { + unsigned int status = desc->status & ~IRQ_DISABLED; + desc->status = status; + if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) { + desc->status = status | IRQ_REPLAY; + hw_resend_irq(desc->handler,irq); + } + desc->handler->enable(irq); + /* fall-through */ + } + default: + desc->depth--; + break; + case 0: + printk(KERN_ERR "enable_irq(%u) unbalanced from %p\n", + irq, __builtin_return_address(0)); + } + spin_unlock_irqrestore(&desc->lock, flags); +} + +/* + * IRQ autodetection code.. + * + * This depends on the fact that any interrupt that + * comes in on to an unassigned handler will get stuck + * with "IRQ_WAITING" cleared and the interrupt + * disabled. + */ + +static DECLARE_MUTEX(probe_sem); + +/** + * probe_irq_on - begin an interrupt autodetect + * + * Commence probing for an interrupt. The interrupts are scanned + * and a mask of potential interrupt lines is returned. + * + */ +unsigned long probe_irq_on(void) +{ + unsigned int i; + irq_desc_t *desc; + unsigned long val; + unsigned long delay; + + down(&probe_sem); + /* + * something may have generated an irq long ago and we want to + * flush such a longstanding irq before considering it as spurious. + */ + for (i = NR_IRQS - 1; i > 0; i--) { + desc = irq_desc + i; + + spin_lock_irq(&desc->lock); + if (!irq_desc[i].action) + irq_desc[i].handler->startup(i); + spin_unlock_irq(&desc->lock); + } + + /* Wait for longstanding interrupts to trigger. */ + for (delay = jiffies + HZ/50; time_after(delay, jiffies); ) + /* about 20ms delay */ barrier(); + + /* + * enable any unassigned irqs + * (we must startup again here because if a longstanding irq + * happened in the previous stage, it may have masked itself) + */ + for (i = NR_IRQS-1; i > 0; i--) { + desc = irq_desc + i; + + spin_lock_irq(&desc->lock); + if (!desc->action) { + desc->status |= IRQ_AUTODETECT | IRQ_WAITING; + if (desc->handler->startup(i)) + desc->status |= IRQ_PENDING; + } + spin_unlock_irq(&desc->lock); + } + + /* + * Wait for spurious interrupts to trigger + */ + for (delay = jiffies + HZ/10; time_after(delay, jiffies); ) + /* about 100ms delay */ barrier(); + + /* + * Now filter out any obviously spurious interrupts + */ + val = 0; + for (i = 0; i < NR_IRQS; i++) { + irq_desc_t *desc = irq_desc + i; + unsigned int status; + + spin_lock_irq(&desc->lock); + status = desc->status; + + if (status & IRQ_AUTODETECT) { + /* It triggered already - consider it spurious. */ + if (!(status & IRQ_WAITING)) { + desc->status = status & ~IRQ_AUTODETECT; + desc->handler->shutdown(i); + } else + if (i < 32) + val |= 1 << i; + } + spin_unlock_irq(&desc->lock); + } + + return val; +} + +/** + * probe_irq_mask - scan a bitmap of interrupt lines + * @val: mask of interrupts to consider + * + * Scan the ISA bus interrupt lines and return a bitmap of + * active interrupts. The interrupt probe logic state is then + * returned to its previous value. This function can handle only + * legacy ISA interrupts + * + * Note: we need to scan all the irq's even though we will + * only return ISA irq numbers - just so that we reset them + * all to a known state. + */ +unsigned int probe_irq_mask(unsigned long val) +{ + int i; + unsigned int mask; + + mask = 0; + for (i = 0; i < NR_IRQS; i++) { + irq_desc_t *desc = irq_desc + i; + unsigned int status; + + spin_lock_irq(&desc->lock); + status = desc->status; + + if (status & IRQ_AUTODETECT) { + if (i < 16 && !(status & IRQ_WAITING)) + mask |= 1 << i; + + desc->status = status & ~IRQ_AUTODETECT; + desc->handler->shutdown(i); + } + spin_unlock_irq(&desc->lock); + } + up(&probe_sem); + + return mask & val; +} + +/** + * probe_irq_off - end an interrupt autodetect + * @val: mask of potential interrupts (unused) + * + * Scans the unused interrupt lines and returns the line which + * appears to have triggered the interrupt. If no interrupt was + * found then zero is returned. If more than one interrupt is + * found then minus the first candidate is returned to indicate + * their is doubt. This function can handle any interrupt source. + * + * The interrupt probe logic state is returned to its previous + * value. + * + * BUGS: When used in a module (which arguably shouldnt happen) + * nothing prevents two IRQ probe callers from overlapping. The + * results of this are non-optimal. + */ +int probe_irq_off(unsigned long val) +{ + int i, irq_found, nr_irqs; + + nr_irqs = 0; + irq_found = 0; + for (i = 0; i < NR_IRQS; i++) { + irq_desc_t *desc = irq_desc + i; + unsigned int status; + + spin_lock_irq(&desc->lock); + status = desc->status; + + if (status & IRQ_AUTODETECT) { + if (!(status & IRQ_WAITING)) { + if (!nr_irqs) + irq_found = i; + nr_irqs++; + } + desc->status = status & ~IRQ_AUTODETECT; + desc->handler->shutdown(i); + } + spin_unlock_irq(&desc->lock); + } + up(&probe_sem); + + if (nr_irqs > 1) + irq_found = -irq_found; + return irq_found; +} --aM3YZ0Iwxop3KEKx-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/