diff options
Diffstat (limited to 'arch/blackfin/kernel/ipipe.c')
| -rw-r--r-- | arch/blackfin/kernel/ipipe.c | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/arch/blackfin/kernel/ipipe.c b/arch/blackfin/kernel/ipipe.c new file mode 100644 index 00000000000..339be5a3ae6 --- /dev/null +++ b/arch/blackfin/kernel/ipipe.c @@ -0,0 +1,428 @@ +/* -*- linux-c -*- + * linux/arch/blackfin/kernel/ipipe.c + * + * Copyright (C) 2005-2007 Philippe Gerum. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139, + * USA; either version 2 of the License, or (at your option) any later + * version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Architecture-dependent I-pipe support for the Blackfin. + */ + +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/percpu.h> +#include <linux/bitops.h> +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/kthread.h> +#include <asm/unistd.h> +#include <asm/system.h> +#include <asm/atomic.h> +#include <asm/io.h> + +static int create_irq_threads; + +DEFINE_PER_CPU(struct pt_regs, __ipipe_tick_regs); + +static DEFINE_PER_CPU(unsigned long, pending_irqthread_mask); + +static DEFINE_PER_CPU(int [IVG13 + 1], pending_irq_count); + +asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs); + +static void __ipipe_no_irqtail(void); + +unsigned long __ipipe_irq_tail_hook = (unsigned long)&__ipipe_no_irqtail; +EXPORT_SYMBOL(__ipipe_irq_tail_hook); + +unsigned long __ipipe_core_clock; +EXPORT_SYMBOL(__ipipe_core_clock); + +unsigned long __ipipe_freq_scale; +EXPORT_SYMBOL(__ipipe_freq_scale); + +atomic_t __ipipe_irq_lvdepth[IVG15 + 1]; + +unsigned long __ipipe_irq_lvmask = __all_masked_irq_flags; +EXPORT_SYMBOL(__ipipe_irq_lvmask); + +static void __ipipe_ack_irq(unsigned irq, struct irq_desc *desc) +{ + desc->ipipe_ack(irq, desc); +} + +/* + * __ipipe_enable_pipeline() -- We are running on the boot CPU, hw + * interrupts are off, and secondary CPUs are still lost in space. + */ +void __ipipe_enable_pipeline(void) +{ + unsigned irq; + + __ipipe_core_clock = get_cclk(); /* Fetch this once. */ + __ipipe_freq_scale = 1000000000UL / __ipipe_core_clock; + + for (irq = 0; irq < NR_IRQS; ++irq) + ipipe_virtualize_irq(ipipe_root_domain, + irq, + (ipipe_irq_handler_t)&asm_do_IRQ, + NULL, + &__ipipe_ack_irq, + IPIPE_HANDLE_MASK | IPIPE_PASS_MASK); +} + +/* + * __ipipe_handle_irq() -- IPIPE's generic IRQ handler. An optimistic + * interrupt protection log is maintained here for each domain. Hw + * interrupts are masked on entry. + */ +void __ipipe_handle_irq(unsigned irq, struct pt_regs *regs) +{ + struct ipipe_domain *this_domain, *next_domain; + struct list_head *head, *pos; + int m_ack, s = -1; + + /* + * Software-triggered IRQs do not need any ack. The contents + * of the register frame should only be used when processing + * the timer interrupt, but not for handling any other + * interrupt. + */ + m_ack = (regs == NULL || irq == IRQ_SYSTMR || irq == IRQ_CORETMR); + + this_domain = ipipe_current_domain; + + if (unlikely(test_bit(IPIPE_STICKY_FLAG, &this_domain->irqs[irq].control))) + head = &this_domain->p_link; + else { + head = __ipipe_pipeline.next; + next_domain = list_entry(head, struct ipipe_domain, p_link); + if (likely(test_bit(IPIPE_WIRED_FLAG, &next_domain->irqs[irq].control))) { + if (!m_ack && next_domain->irqs[irq].acknowledge != NULL) + next_domain->irqs[irq].acknowledge(irq, irq_desc + irq); + if (test_bit(IPIPE_ROOTLOCK_FLAG, &ipipe_root_domain->flags)) + s = __test_and_set_bit(IPIPE_STALL_FLAG, + &ipipe_root_cpudom_var(status)); + __ipipe_dispatch_wired(next_domain, irq); + goto finalize; + return; + } + } + + /* Ack the interrupt. */ + + pos = head; + + while (pos != &__ipipe_pipeline) { + next_domain = list_entry(pos, struct ipipe_domain, p_link); + /* + * For each domain handling the incoming IRQ, mark it + * as pending in its log. + */ + if (test_bit(IPIPE_HANDLE_FLAG, &next_domain->irqs[irq].control)) { + /* + * Domains that handle this IRQ are polled for + * acknowledging it by decreasing priority + * order. The interrupt must be made pending + * _first_ in the domain's status flags before + * the PIC is unlocked. + */ + __ipipe_set_irq_pending(next_domain, irq); + + if (!m_ack && next_domain->irqs[irq].acknowledge != NULL) { + next_domain->irqs[irq].acknowledge(irq, irq_desc + irq); + m_ack = 1; + } + } + + /* + * If the domain does not want the IRQ to be passed + * down the interrupt pipe, exit the loop now. + */ + if (!test_bit(IPIPE_PASS_FLAG, &next_domain->irqs[irq].control)) + break; + + pos = next_domain->p_link.next; + } + + /* + * Now walk the pipeline, yielding control to the highest + * priority domain that has pending interrupt(s) or + * immediately to the current domain if the interrupt has been + * marked as 'sticky'. This search does not go beyond the + * current domain in the pipeline. We also enforce the + * additional root stage lock (blackfin-specific). */ + + if (test_bit(IPIPE_ROOTLOCK_FLAG, &ipipe_root_domain->flags)) + s = __test_and_set_bit(IPIPE_STALL_FLAG, + &ipipe_root_cpudom_var(status)); +finalize: + + __ipipe_walk_pipeline(head); + + if (!s) + __clear_bit(IPIPE_STALL_FLAG, + &ipipe_root_cpudom_var(status)); +} + +int __ipipe_check_root(void) +{ + return ipipe_root_domain_p; +} + +void __ipipe_enable_irqdesc(struct ipipe_domain *ipd, unsigned irq) +{ + struct irq_desc *desc = irq_desc + irq; + int prio = desc->ic_prio; + + desc->depth = 0; + if (ipd != &ipipe_root && + atomic_inc_return(&__ipipe_irq_lvdepth[prio]) == 1) + __set_bit(prio, &__ipipe_irq_lvmask); +} +EXPORT_SYMBOL(__ipipe_enable_irqdesc); + +void __ipipe_disable_irqdesc(struct ipipe_domain *ipd, unsigned irq) +{ + struct irq_desc *desc = irq_desc + irq; + int prio = desc->ic_prio; + + if (ipd != &ipipe_root && + atomic_dec_and_test(&__ipipe_irq_lvdepth[prio])) + __clear_bit(prio, &__ipipe_irq_lvmask); +} +EXPORT_SYMBOL(__ipipe_disable_irqdesc); + +void __ipipe_stall_root_raw(void) +{ + /* + * This code is called by the ins{bwl} routines (see + * arch/blackfin/lib/ins.S), which are heavily used by the + * network stack. It masks all interrupts but those handled by + * non-root domains, so that we keep decent network transfer + * rates for Linux without inducing pathological jitter for + * the real-time domain. + */ + __asm__ __volatile__ ("sti %0;" : : "d"(__ipipe_irq_lvmask)); + + __set_bit(IPIPE_STALL_FLAG, + &ipipe_root_cpudom_var(status)); +} + +void __ipipe_unstall_root_raw(void) +{ + __clear_bit(IPIPE_STALL_FLAG, + &ipipe_root_cpudom_var(status)); + + __asm__ __volatile__ ("sti %0;" : : "d"(bfin_irq_flags)); +} + +int __ipipe_syscall_root(struct pt_regs *regs) +{ + unsigned long flags; + + /* We need to run the IRQ tail hook whenever we don't + * propagate a syscall to higher domains, because we know that + * important operations might be pending there (e.g. Xenomai + * deferred rescheduling). */ + + if (!__ipipe_syscall_watched_p(current, regs->orig_p0)) { + void (*hook)(void) = (void (*)(void))__ipipe_irq_tail_hook; + hook(); + return 0; + } + + /* + * This routine either returns: + * 0 -- if the syscall is to be passed to Linux; + * 1 -- if the syscall should not be passed to Linux, and no + * tail work should be performed; + * -1 -- if the syscall should not be passed to Linux but the + * tail work has to be performed (for handling signals etc). + */ + + if (__ipipe_event_monitored_p(IPIPE_EVENT_SYSCALL) && + __ipipe_dispatch_event(IPIPE_EVENT_SYSCALL, regs) > 0) { + if (ipipe_root_domain_p && !in_atomic()) { + /* + * Sync pending VIRQs before _TIF_NEED_RESCHED + * is tested. + */ + local_irq_save_hw(flags); + if ((ipipe_root_cpudom_var(irqpend_himask) & IPIPE_IRQMASK_VIRT) != 0) + __ipipe_sync_pipeline(IPIPE_IRQMASK_VIRT); + local_irq_restore_hw(flags); + return -1; + } + return 1; + } + + return 0; +} + +unsigned long ipipe_critical_enter(void (*syncfn) (void)) +{ + unsigned long flags; + + local_irq_save_hw(flags); + + return flags; +} + +void ipipe_critical_exit(unsigned long flags) +{ + local_irq_restore_hw(flags); +} + +static void __ipipe_no_irqtail(void) +{ +} + +int ipipe_get_sysinfo(struct ipipe_sysinfo *info) +{ + info->ncpus = num_online_cpus(); + info->cpufreq = ipipe_cpu_freq(); + info->archdep.tmirq = IPIPE_TIMER_IRQ; + info->archdep.tmfreq = info->cpufreq; + + return 0; +} + +/* + * ipipe_trigger_irq() -- Push the interrupt at front of the pipeline + * just like if it has been actually received from a hw source. Also + * works for virtual interrupts. + */ +int ipipe_trigger_irq(unsigned irq) +{ + unsigned long flags; + + if (irq >= IPIPE_NR_IRQS || + (ipipe_virtual_irq_p(irq) + && !test_bit(irq - IPIPE_VIRQ_BASE, &__ipipe_virtual_irq_map))) + return -EINVAL; + + local_irq_save_hw(flags); + + __ipipe_handle_irq(irq, NULL); + + local_irq_restore_hw(flags); + + return 1; +} + +/* Move Linux IRQ to threads. */ + +static int do_irqd(void *__desc) +{ + struct irq_desc *desc = __desc; + unsigned irq = desc - irq_desc; + int thrprio = desc->thr_prio; + int thrmask = 1 << thrprio; + int cpu = smp_processor_id(); + cpumask_t cpumask; + + sigfillset(¤t->blocked); + current->flags |= PF_NOFREEZE; + cpumask = cpumask_of_cpu(cpu); + set_cpus_allowed(current, cpumask); + ipipe_setscheduler_root(current, SCHED_FIFO, 50 + thrprio); + + while (!kthread_should_stop()) { + local_irq_disable(); + if (!(desc->status & IRQ_SCHEDULED)) { + set_current_state(TASK_INTERRUPTIBLE); +resched: + local_irq_enable(); + schedule(); + local_irq_disable(); + } + __set_current_state(TASK_RUNNING); + /* + * If higher priority interrupt servers are ready to + * run, reschedule immediately. We need this for the + * GPIO demux IRQ handler to unmask the interrupt line + * _last_, after all GPIO IRQs have run. + */ + if (per_cpu(pending_irqthread_mask, cpu) & ~(thrmask|(thrmask-1))) + goto resched; + if (--per_cpu(pending_irq_count[thrprio], cpu) == 0) + per_cpu(pending_irqthread_mask, cpu) &= ~thrmask; + desc->status &= ~IRQ_SCHEDULED; + desc->thr_handler(irq, &__raw_get_cpu_var(__ipipe_tick_regs)); + local_irq_enable(); + } + __set_current_state(TASK_RUNNING); + return 0; +} + +static void kick_irqd(unsigned irq, void *cookie) +{ + struct irq_desc *desc = irq_desc + irq; + int thrprio = desc->thr_prio; + int thrmask = 1 << thrprio; + int cpu = smp_processor_id(); + + if (!(desc->status & IRQ_SCHEDULED)) { + desc->status |= IRQ_SCHEDULED; + per_cpu(pending_irqthread_mask, cpu) |= thrmask; + ++per_cpu(pending_irq_count[thrprio], cpu); + wake_up_process(desc->thread); + } +} + +int ipipe_start_irq_thread(unsigned irq, struct irq_desc *desc) +{ + if (desc->thread || !create_irq_threads) + return 0; + + desc->thread = kthread_create(do_irqd, desc, "IRQ %d", irq); + if (desc->thread == NULL) { + printk(KERN_ERR "irqd: could not create IRQ thread %d!\n", irq); + return -ENOMEM; + } + + wake_up_process(desc->thread); + + desc->thr_handler = ipipe_root_domain->irqs[irq].handler; + ipipe_root_domain->irqs[irq].handler = &kick_irqd; + + return 0; +} + +void __init ipipe_init_irq_threads(void) +{ + unsigned irq; + struct irq_desc *desc; + + create_irq_threads = 1; + + for (irq = 0; irq < NR_IRQS; irq++) { + desc = irq_desc + irq; + if (desc->action != NULL || + (desc->status & IRQ_NOREQUEST) != 0) + ipipe_start_irq_thread(irq, desc); + } +} + +EXPORT_SYMBOL(show_stack); + +#ifdef CONFIG_IPIPE_TRACE_MCOUNT +void notrace _mcount(void); +EXPORT_SYMBOL(_mcount); +#endif /* CONFIG_IPIPE_TRACE_MCOUNT */ |