--- /dev/null
+/*
+ * arch/ubicom32/kernel/irq.c
+ * Ubicom32 architecture IRQ support.
+ *
+ * (C) Copyright 2009, Ubicom, Inc.
+ * (C) Copyright 2007, Greg Ungerer <gerg@snapgear.com>
+ *
+ * This file is part of the Ubicom32 Linux Kernel Port.
+ *
+ * The Ubicom32 Linux Kernel Port 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, either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * The Ubicom32 Linux Kernel Port 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 the Ubicom32 Linux Kernel Port. If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Ubicom32 implementation derived from (with many thanks):
+ * arch/m68knommu
+ * arch/blackfin
+ * arch/parisc
+ */
+
+#include <linux/types.h>
+#include <linux/irq.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/proc_fs.h>
+#include <asm/system.h>
+#include <asm/traps.h>
+#include <asm/ldsr.h>
+#include <asm/ip5000.h>
+#include <asm/machdep.h>
+#include <asm/asm-offsets.h>
+#include <asm/thread.h>
+#include <asm/devtree.h>
+
+unsigned int irq_soft_avail;
+static struct irqaction ubicom32_reserve_action[NR_IRQS];
+
+#if !defined(CONFIG_DEBUG_IRQMEASURE)
+#define IRQ_DECLARE_MEASUREMENT
+#define IRQ_MEASUREMENT_START()
+#define IRQ_MEASUREMENT_END(irq)
+#else
+#define IRQ_DECLARE_MEASUREMENT \
+ int __diff; \
+ unsigned int __tstart;
+
+#define IRQ_MEASUREMENT_START() \
+ __tstart = UBICOM32_IO_TIMER->sysval;
+
+#define IRQ_MEASUREMENT_END(irq) \
+ __diff = (int)UBICOM32_IO_TIMER->sysval - (int)__tstart; \
+ irq_measurement_update((irq), __diff);
+
+/*
+ * We keep track of the time spent in both irq_enter()
+ * and irq_exit().
+ */
+#define IRQ_WEIGHT 32
+
+struct irq_measurement {
+ volatile unsigned int min;
+ volatile unsigned int avg;
+ volatile unsigned int max;
+};
+
+static DEFINE_SPINLOCK(irq_measurement_lock);
+
+/*
+ * Add 1 in for softirq (irq_exit());
+ */
+static struct irq_measurement irq_measurements[NR_IRQS + 1];
+
+/*
+ * irq_measurement_update()
+ * Update an entry in the measurement array for this irq.
+ */
+static void irq_measurement_update(int irq, int sample)
+{
+ struct irq_measurement *im = &irq_measurements[irq];
+ spin_lock(&irq_measurement_lock);
+ if ((im->min == 0) || (im->min > sample)) {
+ im->min = sample;
+ }
+ if (im->max < sample) {
+ im->max = sample;
+ }
+ im->avg = ((im->avg * (IRQ_WEIGHT - 1)) + sample) / IRQ_WEIGHT;
+ spin_unlock(&irq_measurement_lock);
+}
+#endif
+
+/*
+ * irq_kernel_stack_check()
+ * See if the kernel stack is within STACK_WARN of the end.
+ */
+static void irq_kernel_stack_check(int irq, struct pt_regs *regs)
+{
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+ unsigned long sp;
+
+ /*
+ * Make sure that we are not close to the top of the stack and thus
+ * can not really service this interrupt.
+ */
+ asm volatile (
+ "and.4 %0, SP, %1 \n\t"
+ : "=d" (sp)
+ : "d" (THREAD_SIZE - 1)
+ : "cc"
+ );
+
+ if (sp < (sizeof(struct thread_info) + STACK_WARN)) {
+ printk(KERN_WARNING
+ "cpu[%d]: possible overflow detected sp remain: %p, "
+ "irq: %d, regs: %p\n",
+ thread_get_self(), (void *)sp, irq, regs);
+ dump_stack();
+ }
+
+ if (sp < (sizeof(struct thread_info) + 16)) {
+ THREAD_STALL;
+ }
+#endif
+}
+
+/*
+ * irq_get_lsb()
+ * Get the LSB set in value
+ */
+static int irq_get_lsb(unsigned int value)
+{
+ static unsigned char irq_bits[8] = {
+ 3, 0, 1, 0, 2, 0, 1, 0
+ };
+ u32_t nextbit = 0;
+
+ value = (value >> nextbit) | (value << ((sizeof(value) * 8) - nextbit));
+
+ /*
+ * It's unlikely that we find that we execute the body of this while
+ * loop. 50% of the time we won't take this at all and then of the
+ * cases where we do about 50% of those we only execute once.
+ */
+ if (!(value & 0xffff)) {
+ nextbit += 0x10;
+ value >>= 16;
+ }
+
+ if (!(value & 0xff)) {
+ nextbit += 0x08;
+ value >>= 8;
+ }
+
+ if (!(value & 0xf)) {
+ nextbit += 0x04;
+ value >>= 4;
+ }
+
+ nextbit += irq_bits[value & 0x7];
+ if (nextbit > 63) {
+ panic("nextbit out of range: %d\n", nextbit);
+ }
+ return nextbit;
+}
+
+/*
+ * ubicom32_reserve_handler()
+ * Bogus handler associated with pre-reserved IRQ(s).
+ */
+static irqreturn_t ubicom32_reserve_handler(int irq, void *dev_id)
+{
+ BUG();
+ return IRQ_HANDLED;
+}
+
+/*
+ * __irq_disable_vector()
+ * Disable the interrupt by clearing the appropriate bit in the
+ * LDSR Mask Register.
+ */
+static void __irq_disable_vector(unsigned int irq)
+{
+ ldsr_disable_vector(irq);
+}
+
+/*
+ * __irq_ack_vector()
+ * Acknowledge the specific interrupt by clearing the associate bit in
+ * hardware
+ */
+static void __irq_ack_vector(unsigned int irq)
+{
+ if (irq < 32) {
+ asm volatile ("move.4 INT_CLR0, %0" : : "d" (1 << irq));
+ } else {
+ asm volatile ("move.4 INT_CLR1, %0" : : "d" (1 << (irq - 32)));
+ }
+}
+
+/*
+ * __irq_enable_vector()
+ * Clean and then enable the interrupt by setting the appropriate bit in
+ * the LDSR Mask Register.
+ */
+static void __irq_enable_vector(unsigned int irq)
+{
+ /*
+ * Acknowledge, really clear the vector.
+ */
+ __irq_ack_vector(irq);
+ ldsr_enable_vector(irq);
+}
+
+/*
+ * __irq_mask_vector()
+ */
+static void __irq_mask_vector(unsigned int irq)
+{
+ ldsr_mask_vector(irq);
+}
+
+/*
+ * __irq_unmask_vector()
+ */
+static void __irq_unmask_vector(unsigned int irq)
+{
+ ldsr_unmask_vector(irq);
+}
+
+/*
+ * __irq_end_vector()
+ * Called once an interrupt is completed (reset the LDSR mask).
+ */
+static void __irq_end_vector(unsigned int irq)
+{
+ ldsr_unmask_vector(irq);
+}
+
+#if defined(CONFIG_SMP)
+/*
+ * __irq_set_affinity()
+ * Set the cpu affinity for this interrupt.
+ * affinity container allocated at boot
+ */
+static void __irq_set_affinity(unsigned int irq, const struct cpumask *dest)
+{
+ smp_set_affinity(irq, dest);
+ cpumask_copy(irq_desc[irq].affinity, dest);
+}
+#endif
+
+/*
+ * On-Chip Generic Interrupt function handling.
+ */
+static struct irq_chip ubicom32_irq_chip = {
+ .name = "Ubicom32",
+ .startup = NULL,
+ .shutdown = NULL,
+ .enable = __irq_enable_vector,
+ .disable = __irq_disable_vector,
+ .ack = __irq_ack_vector,
+ .mask = __irq_mask_vector,
+ .unmask = __irq_unmask_vector,
+ .end = __irq_end_vector,
+#if defined(CONFIG_SMP)
+ .set_affinity = __irq_set_affinity,
+#endif
+};
+
+/*
+ * do_IRQ()
+ * Primary interface for handling IRQ() requests.
+ */
+asmlinkage void do_IRQ(int irq, struct pt_regs *regs)
+{
+ struct pt_regs *oldregs;
+ struct thread_info *ti = current_thread_info();
+
+ IRQ_DECLARE_MEASUREMENT;
+
+ /*
+ * Mark that we are inside of an interrupt and
+ * that interrupts are disabled.
+ */
+ oldregs = set_irq_regs(regs);
+ ti->interrupt_nesting++;
+ trace_hardirqs_off();
+ irq_kernel_stack_check(irq, regs);
+
+ /*
+ * Start the interrupt sequence
+ */
+ irq_enter();
+
+ /*
+ * Execute the IRQ handler and any pending SoftIRQ requests.
+ */
+ BUG_ON(!irqs_disabled());
+ IRQ_MEASUREMENT_START();
+ __do_IRQ(irq);
+ IRQ_MEASUREMENT_END(irq);
+ BUG_ON(!irqs_disabled());
+
+ /*
+ * TODO: Since IRQ's are disabled when calling irq_exit()
+ * modify Kconfig to set __ARCH_IRQ_EXIT_IRQS_DISABLED flag.
+ * This will slightly improve performance by enabling
+ * softirq handling to avoid disabling/disabled interrupts.
+ */
+ IRQ_MEASUREMENT_START();
+ irq_exit();
+ IRQ_MEASUREMENT_END(NR_IRQS);
+ BUG_ON(!irqs_disabled());
+
+ /*
+ * Outside of an interrupt (or nested exit).
+ */
+ set_irq_regs(oldregs);
+ trace_hardirqs_on();
+ ti->interrupt_nesting--;
+}
+
+/*
+ * irq_soft_alloc()
+ * Allocate a soft IRQ.
+ */
+int irq_soft_alloc(unsigned int *soft)
+{
+ if (irq_soft_avail == 0) {
+ printk(KERN_NOTICE "no soft irqs to allocate\n");
+ return -EFAULT;
+ }
+
+ *soft = irq_get_lsb(irq_soft_avail);
+ irq_soft_avail &= ~(1 << *soft);
+ return 0;
+}
+
+/*
+ * ack_bad_irq()
+ * Called to handle an bad irq request.
+ */
+void ack_bad_irq(unsigned int irq)
+{
+ printk(KERN_ERR "IRQ: unexpected irq=%d\n", irq);
+ __irq_end_vector(irq);
+}
+
+/*
+ * show_interrupts()
+ * Return a string that displays the state of each of the interrupts.
+ */
+int show_interrupts(struct seq_file *p, void *v)
+{
+ struct irqaction *ap;
+ int irq = *((loff_t *) v);
+ int j;
+
+ if (irq >= NR_IRQS) {
+ return 0;
+ }
+
+ if (irq == 0) {
+ seq_puts(p, " ");
+ for_each_online_cpu(j) {
+ seq_printf(p, "CPU%d ", j);
+ }
+ seq_putc(p, '\n');
+ }
+
+ ap = irq_desc[irq].action;
+ if (ap) {
+ seq_printf(p, "%3d: ", irq);
+ for_each_online_cpu(j) {
+ seq_printf(p, "%10u ", kstat_irqs_cpu(irq, j));
+ }
+ seq_printf(p, "%14s ", irq_desc[irq].chip->name);
+ seq_printf(p, "%s", ap->name);
+ for (ap = ap->next; ap; ap = ap->next) {
+ seq_printf(p, ", %s", ap->name);
+ }
+ seq_putc(p, '\n');
+ }
+ return 0;
+}
+
+#if defined(CONFIG_DEBUG_IRQMEASURE)
+static unsigned int irq_cycles_to_micro(unsigned int cycles, unsigned int frequency)
+{
+ unsigned int micro = (cycles / (frequency / 1000000));
+ return micro;
+}
+
+/*
+ * irq_measurement_show()
+ * Print out the min, avg, max values for each IRQ
+ *
+ * By request, the max value is reset after each dump.
+ */
+static int irq_measurement_show(struct seq_file *p, void *v)
+{
+ struct irqaction *ap;
+ unsigned int freq = processor_frequency();
+ int irq = *((loff_t *) v);
+
+
+ if (irq == 0) {
+ seq_puts(p, "\tmin\tavg\tmax\t(micro-seconds)\n");
+ }
+
+ if (irq > NR_IRQS) {
+ return 0;
+ }
+
+ if (irq == NR_IRQS) {
+ unsigned int min, avg, max;
+ spin_lock(&irq_measurement_lock);
+ min = irq_cycles_to_micro(irq_measurements[irq].min, freq);
+ avg = irq_cycles_to_micro(irq_measurements[irq].avg, freq);
+ max = irq_cycles_to_micro(irq_measurements[irq].max, freq);
+ irq_measurements[irq].max = 0;
+ spin_unlock(&irq_measurement_lock);
+ seq_printf(p, " \t%u\t%u\t%u\tsoftirq\n", min, avg, max);
+ return 0;
+ }
+
+ ap = irq_desc[irq].action;
+ if (ap) {
+ unsigned int min, avg, max;
+ spin_lock(&irq_measurement_lock);
+ min = irq_cycles_to_micro(irq_measurements[irq].min, freq);
+ avg = irq_cycles_to_micro(irq_measurements[irq].avg, freq);
+ max = irq_cycles_to_micro(irq_measurements[irq].max, freq);
+ irq_measurements[irq].max = 0;
+ spin_unlock(&irq_measurement_lock);
+ seq_printf(p, "%2u:\t%u\t%u\t%u\t%s\n", irq, min, avg, max, ap->name);
+ }
+ return 0;
+}
+
+static void *irq_measurement_start(struct seq_file *f, loff_t *pos)
+{
+ return (*pos <= NR_IRQS) ? pos : NULL;
+}
+
+static void *irq_measurement_next(struct seq_file *f, void *v, loff_t *pos)
+{
+ (*pos)++;
+ if (*pos > NR_IRQS)
+ return NULL;
+ return pos;
+}
+
+static void irq_measurement_stop(struct seq_file *f, void *v)
+{
+ /* Nothing to do */
+}
+
+static const struct seq_operations irq_measurement_seq_ops = {
+ .start = irq_measurement_start,
+ .next = irq_measurement_next,
+ .stop = irq_measurement_stop,
+ .show = irq_measurement_show,
+};
+
+static int irq_measurement_open(struct inode *inode, struct file *filp)
+{
+ return seq_open(filp, &irq_measurement_seq_ops);
+}
+
+static const struct file_operations irq_measurement_fops = {
+ .open = irq_measurement_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static int __init irq_measurement_init(void)
+{
+ proc_create("irq_measurements", 0, NULL, &irq_measurement_fops);
+ return 0;
+}
+module_init(irq_measurement_init);
+#endif
+
+/*
+ * init_IRQ(void)
+ * Initialize the on-chip IRQ subsystem.
+ */
+void __init init_IRQ(void)
+{
+ int irq;
+ struct devtree_node *p = NULL;
+ struct devtree_node *iter = NULL;
+ unsigned int mask = 0;
+ unsigned int reserved = 0;
+
+ /*
+ * Pull out the list of software interrupts that are avialable to
+ * Linux and provide an allocation function for them. The first
+ * 24 interrupts of INT0 are software interrupts.
+ */
+ irq_soft_avail = 0;
+ if (processor_interrupts(&irq_soft_avail, NULL) < 0) {
+ printk(KERN_WARNING "No Soft IRQ(s) available\n");
+ }
+ irq_soft_avail &= ((1 << 24) - 1);
+
+ /*
+ * Initialize all of the on-chip interrupt handling
+ * to use a common set of interrupt functions.
+ */
+ for (irq = 0; irq < NR_IRQS; irq++) {
+ irq_desc[irq].status = IRQ_DISABLED;
+ irq_desc[irq].action = NULL;
+ irq_desc[irq].depth = 1;
+ set_irq_chip(irq, &ubicom32_irq_chip);
+ }
+
+ /*
+ * The sendirq of a devnode is not registered within Linux but instead
+ * is used by the software I/O thread. These interrupts are reserved.
+ * The recvirq is used by Linux and registered by a device driver, these
+ * are not reserved.
+ *
+ * recvirq(s) that are in the software interrupt range are not supposed
+ * to be marked as reserved. We track this while we scan the device
+ * nodes.
+ */
+ p = devtree_find_next(&iter);
+ while (p) {
+ unsigned char sendirq, recvirq;
+ devtree_irq(p, &sendirq, &recvirq);
+
+ /*
+ * If the sendirq is valid, mark that irq as taken by the
+ * devtree node.
+ */
+ if (sendirq < NR_IRQS) {
+ ubicom32_reserve_action[sendirq].handler =
+ ubicom32_reserve_handler;
+ ubicom32_reserve_action[sendirq].name = p->name;
+ irq_desc[sendirq].action =
+ &ubicom32_reserve_action[sendirq];
+ mask |= (1 << sendirq);
+ }
+
+ /*
+ * Track the relevant recieve IRQ(s)
+ */
+ if (recvirq < 24) {
+ mask |= (1 << recvirq);
+ }
+
+ /*
+ * Move to the next node.
+ */
+ p = devtree_find_next(&iter);
+ }
+
+ /*
+ * Remove these bits from the irq_soft_avail list and then use the
+ * result as the list of pre-reserved IRQ(s).
+ */
+ reserved = ~irq_soft_avail & ~mask;
+ for (irq = 0; irq < 24; irq++) {
+ if ((reserved & (1 << irq))) {
+ ubicom32_reserve_action[irq].handler =
+ ubicom32_reserve_handler;
+ ubicom32_reserve_action[irq].name = "reserved";
+ irq_desc[irq].action = &ubicom32_reserve_action[irq];
+ }
+ }
+
+ /*
+ * Initialize the LDSR which is the Ubicom32 programmable
+ * interrupt controller.
+ */
+ ldsr_init();
+
+ /*
+ * The Ubicom trap code needs a 2nd init after IRQ(s) are setup.
+ */
+ trap_init_interrupt();
+}
projects / openwrt.git / blobdiff