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 000000000000..339be5a3ae6a
--- /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(&current->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 */