429 lines
11 KiB
C
429 lines
11 KiB
C
/* -*- linux-c -*-
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* linux/arch/blackfin/kernel/ipipe.c
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*
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* Copyright (C) 2005-2007 Philippe Gerum.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
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* USA; either version 2 of the License, or (at your option) any later
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* version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Architecture-dependent I-pipe support for the Blackfin.
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/percpu.h>
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#include <linux/bitops.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/kthread.h>
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#include <asm/unistd.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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#include <asm/io.h>
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static int create_irq_threads;
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DEFINE_PER_CPU(struct pt_regs, __ipipe_tick_regs);
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static DEFINE_PER_CPU(unsigned long, pending_irqthread_mask);
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static DEFINE_PER_CPU(int [IVG13 + 1], pending_irq_count);
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asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs);
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static void __ipipe_no_irqtail(void);
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unsigned long __ipipe_irq_tail_hook = (unsigned long)&__ipipe_no_irqtail;
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EXPORT_SYMBOL(__ipipe_irq_tail_hook);
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unsigned long __ipipe_core_clock;
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EXPORT_SYMBOL(__ipipe_core_clock);
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unsigned long __ipipe_freq_scale;
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EXPORT_SYMBOL(__ipipe_freq_scale);
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atomic_t __ipipe_irq_lvdepth[IVG15 + 1];
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unsigned long __ipipe_irq_lvmask = __all_masked_irq_flags;
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EXPORT_SYMBOL(__ipipe_irq_lvmask);
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static void __ipipe_ack_irq(unsigned irq, struct irq_desc *desc)
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{
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desc->ipipe_ack(irq, desc);
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}
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/*
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* __ipipe_enable_pipeline() -- We are running on the boot CPU, hw
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* interrupts are off, and secondary CPUs are still lost in space.
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*/
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void __ipipe_enable_pipeline(void)
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{
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unsigned irq;
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__ipipe_core_clock = get_cclk(); /* Fetch this once. */
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__ipipe_freq_scale = 1000000000UL / __ipipe_core_clock;
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for (irq = 0; irq < NR_IRQS; ++irq)
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ipipe_virtualize_irq(ipipe_root_domain,
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irq,
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(ipipe_irq_handler_t)&asm_do_IRQ,
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NULL,
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&__ipipe_ack_irq,
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IPIPE_HANDLE_MASK | IPIPE_PASS_MASK);
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}
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/*
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* __ipipe_handle_irq() -- IPIPE's generic IRQ handler. An optimistic
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* interrupt protection log is maintained here for each domain. Hw
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* interrupts are masked on entry.
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*/
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void __ipipe_handle_irq(unsigned irq, struct pt_regs *regs)
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{
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struct ipipe_domain *this_domain, *next_domain;
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struct list_head *head, *pos;
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int m_ack, s = -1;
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/*
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* Software-triggered IRQs do not need any ack. The contents
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* of the register frame should only be used when processing
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* the timer interrupt, but not for handling any other
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* interrupt.
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*/
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m_ack = (regs == NULL || irq == IRQ_SYSTMR || irq == IRQ_CORETMR);
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this_domain = ipipe_current_domain;
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if (unlikely(test_bit(IPIPE_STICKY_FLAG, &this_domain->irqs[irq].control)))
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head = &this_domain->p_link;
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else {
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head = __ipipe_pipeline.next;
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next_domain = list_entry(head, struct ipipe_domain, p_link);
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if (likely(test_bit(IPIPE_WIRED_FLAG, &next_domain->irqs[irq].control))) {
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if (!m_ack && next_domain->irqs[irq].acknowledge != NULL)
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next_domain->irqs[irq].acknowledge(irq, irq_desc + irq);
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if (test_bit(IPIPE_ROOTLOCK_FLAG, &ipipe_root_domain->flags))
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s = __test_and_set_bit(IPIPE_STALL_FLAG,
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&ipipe_root_cpudom_var(status));
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__ipipe_dispatch_wired(next_domain, irq);
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goto finalize;
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return;
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}
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}
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/* Ack the interrupt. */
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pos = head;
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while (pos != &__ipipe_pipeline) {
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next_domain = list_entry(pos, struct ipipe_domain, p_link);
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/*
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* For each domain handling the incoming IRQ, mark it
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* as pending in its log.
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*/
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if (test_bit(IPIPE_HANDLE_FLAG, &next_domain->irqs[irq].control)) {
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/*
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* Domains that handle this IRQ are polled for
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* acknowledging it by decreasing priority
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* order. The interrupt must be made pending
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* _first_ in the domain's status flags before
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* the PIC is unlocked.
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*/
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__ipipe_set_irq_pending(next_domain, irq);
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if (!m_ack && next_domain->irqs[irq].acknowledge != NULL) {
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next_domain->irqs[irq].acknowledge(irq, irq_desc + irq);
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m_ack = 1;
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}
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}
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/*
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* If the domain does not want the IRQ to be passed
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* down the interrupt pipe, exit the loop now.
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*/
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if (!test_bit(IPIPE_PASS_FLAG, &next_domain->irqs[irq].control))
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break;
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pos = next_domain->p_link.next;
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}
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/*
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* Now walk the pipeline, yielding control to the highest
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* priority domain that has pending interrupt(s) or
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* immediately to the current domain if the interrupt has been
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* marked as 'sticky'. This search does not go beyond the
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* current domain in the pipeline. We also enforce the
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* additional root stage lock (blackfin-specific). */
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if (test_bit(IPIPE_ROOTLOCK_FLAG, &ipipe_root_domain->flags))
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s = __test_and_set_bit(IPIPE_STALL_FLAG,
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&ipipe_root_cpudom_var(status));
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finalize:
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__ipipe_walk_pipeline(head);
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if (!s)
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__clear_bit(IPIPE_STALL_FLAG,
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&ipipe_root_cpudom_var(status));
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}
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int __ipipe_check_root(void)
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{
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return ipipe_root_domain_p;
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}
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void __ipipe_enable_irqdesc(struct ipipe_domain *ipd, unsigned irq)
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{
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struct irq_desc *desc = irq_desc + irq;
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int prio = desc->ic_prio;
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desc->depth = 0;
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if (ipd != &ipipe_root &&
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atomic_inc_return(&__ipipe_irq_lvdepth[prio]) == 1)
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__set_bit(prio, &__ipipe_irq_lvmask);
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}
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EXPORT_SYMBOL(__ipipe_enable_irqdesc);
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void __ipipe_disable_irqdesc(struct ipipe_domain *ipd, unsigned irq)
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{
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struct irq_desc *desc = irq_desc + irq;
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int prio = desc->ic_prio;
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if (ipd != &ipipe_root &&
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atomic_dec_and_test(&__ipipe_irq_lvdepth[prio]))
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__clear_bit(prio, &__ipipe_irq_lvmask);
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}
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EXPORT_SYMBOL(__ipipe_disable_irqdesc);
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void __ipipe_stall_root_raw(void)
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{
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/*
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* This code is called by the ins{bwl} routines (see
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* arch/blackfin/lib/ins.S), which are heavily used by the
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* network stack. It masks all interrupts but those handled by
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* non-root domains, so that we keep decent network transfer
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* rates for Linux without inducing pathological jitter for
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* the real-time domain.
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*/
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__asm__ __volatile__ ("sti %0;" : : "d"(__ipipe_irq_lvmask));
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__set_bit(IPIPE_STALL_FLAG,
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&ipipe_root_cpudom_var(status));
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}
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void __ipipe_unstall_root_raw(void)
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{
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__clear_bit(IPIPE_STALL_FLAG,
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&ipipe_root_cpudom_var(status));
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__asm__ __volatile__ ("sti %0;" : : "d"(bfin_irq_flags));
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}
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int __ipipe_syscall_root(struct pt_regs *regs)
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{
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unsigned long flags;
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/* We need to run the IRQ tail hook whenever we don't
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* propagate a syscall to higher domains, because we know that
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* important operations might be pending there (e.g. Xenomai
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* deferred rescheduling). */
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if (!__ipipe_syscall_watched_p(current, regs->orig_p0)) {
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void (*hook)(void) = (void (*)(void))__ipipe_irq_tail_hook;
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hook();
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return 0;
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}
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/*
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* This routine either returns:
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* 0 -- if the syscall is to be passed to Linux;
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* 1 -- if the syscall should not be passed to Linux, and no
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* tail work should be performed;
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* -1 -- if the syscall should not be passed to Linux but the
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* tail work has to be performed (for handling signals etc).
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*/
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if (__ipipe_event_monitored_p(IPIPE_EVENT_SYSCALL) &&
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__ipipe_dispatch_event(IPIPE_EVENT_SYSCALL, regs) > 0) {
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if (ipipe_root_domain_p && !in_atomic()) {
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/*
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* Sync pending VIRQs before _TIF_NEED_RESCHED
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* is tested.
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*/
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local_irq_save_hw(flags);
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if ((ipipe_root_cpudom_var(irqpend_himask) & IPIPE_IRQMASK_VIRT) != 0)
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__ipipe_sync_pipeline(IPIPE_IRQMASK_VIRT);
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local_irq_restore_hw(flags);
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return -1;
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}
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return 1;
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}
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return 0;
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}
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unsigned long ipipe_critical_enter(void (*syncfn) (void))
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{
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unsigned long flags;
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local_irq_save_hw(flags);
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return flags;
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}
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void ipipe_critical_exit(unsigned long flags)
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{
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local_irq_restore_hw(flags);
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}
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static void __ipipe_no_irqtail(void)
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{
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}
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int ipipe_get_sysinfo(struct ipipe_sysinfo *info)
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{
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info->ncpus = num_online_cpus();
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info->cpufreq = ipipe_cpu_freq();
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info->archdep.tmirq = IPIPE_TIMER_IRQ;
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info->archdep.tmfreq = info->cpufreq;
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return 0;
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}
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/*
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* ipipe_trigger_irq() -- Push the interrupt at front of the pipeline
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* just like if it has been actually received from a hw source. Also
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* works for virtual interrupts.
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*/
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int ipipe_trigger_irq(unsigned irq)
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{
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unsigned long flags;
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if (irq >= IPIPE_NR_IRQS ||
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(ipipe_virtual_irq_p(irq)
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&& !test_bit(irq - IPIPE_VIRQ_BASE, &__ipipe_virtual_irq_map)))
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return -EINVAL;
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local_irq_save_hw(flags);
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__ipipe_handle_irq(irq, NULL);
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local_irq_restore_hw(flags);
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return 1;
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}
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/* Move Linux IRQ to threads. */
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static int do_irqd(void *__desc)
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{
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struct irq_desc *desc = __desc;
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unsigned irq = desc - irq_desc;
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int thrprio = desc->thr_prio;
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int thrmask = 1 << thrprio;
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int cpu = smp_processor_id();
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cpumask_t cpumask;
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sigfillset(¤t->blocked);
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current->flags |= PF_NOFREEZE;
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cpumask = cpumask_of_cpu(cpu);
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set_cpus_allowed(current, cpumask);
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ipipe_setscheduler_root(current, SCHED_FIFO, 50 + thrprio);
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while (!kthread_should_stop()) {
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local_irq_disable();
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if (!(desc->status & IRQ_SCHEDULED)) {
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set_current_state(TASK_INTERRUPTIBLE);
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resched:
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local_irq_enable();
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schedule();
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local_irq_disable();
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}
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__set_current_state(TASK_RUNNING);
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/*
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* If higher priority interrupt servers are ready to
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* run, reschedule immediately. We need this for the
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* GPIO demux IRQ handler to unmask the interrupt line
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* _last_, after all GPIO IRQs have run.
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*/
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if (per_cpu(pending_irqthread_mask, cpu) & ~(thrmask|(thrmask-1)))
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goto resched;
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if (--per_cpu(pending_irq_count[thrprio], cpu) == 0)
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per_cpu(pending_irqthread_mask, cpu) &= ~thrmask;
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desc->status &= ~IRQ_SCHEDULED;
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desc->thr_handler(irq, &__raw_get_cpu_var(__ipipe_tick_regs));
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local_irq_enable();
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}
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__set_current_state(TASK_RUNNING);
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return 0;
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}
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static void kick_irqd(unsigned irq, void *cookie)
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{
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struct irq_desc *desc = irq_desc + irq;
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int thrprio = desc->thr_prio;
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int thrmask = 1 << thrprio;
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int cpu = smp_processor_id();
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if (!(desc->status & IRQ_SCHEDULED)) {
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desc->status |= IRQ_SCHEDULED;
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per_cpu(pending_irqthread_mask, cpu) |= thrmask;
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++per_cpu(pending_irq_count[thrprio], cpu);
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wake_up_process(desc->thread);
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}
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}
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int ipipe_start_irq_thread(unsigned irq, struct irq_desc *desc)
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{
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if (desc->thread || !create_irq_threads)
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return 0;
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desc->thread = kthread_create(do_irqd, desc, "IRQ %d", irq);
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if (desc->thread == NULL) {
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printk(KERN_ERR "irqd: could not create IRQ thread %d!\n", irq);
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return -ENOMEM;
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}
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wake_up_process(desc->thread);
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desc->thr_handler = ipipe_root_domain->irqs[irq].handler;
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ipipe_root_domain->irqs[irq].handler = &kick_irqd;
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return 0;
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}
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void __init ipipe_init_irq_threads(void)
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{
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unsigned irq;
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struct irq_desc *desc;
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create_irq_threads = 1;
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for (irq = 0; irq < NR_IRQS; irq++) {
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desc = irq_desc + irq;
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if (desc->action != NULL ||
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(desc->status & IRQ_NOREQUEST) != 0)
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ipipe_start_irq_thread(irq, desc);
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}
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}
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EXPORT_SYMBOL(show_stack);
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#ifdef CONFIG_IPIPE_TRACE_MCOUNT
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void notrace _mcount(void);
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EXPORT_SYMBOL(_mcount);
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#endif /* CONFIG_IPIPE_TRACE_MCOUNT */
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