arch/mips/sibyte/sb1250/irq.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) 2000, 2001, 2002, 2003 Broadcom Corporation
  *
  * 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; 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.
  */
 #include <linux/config.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/linkage.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/smp.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/kernel_stat.h>

 #include <asm/errno.h>
 #include <asm/signal.h>
 #include <asm/system.h>
 #include <asm/ptrace.h>
 #include <asm/io.h>

 #include <asm/sibyte/sb1250_regs.h>
 #include <asm/sibyte/sb1250_int.h>
 #include <asm/sibyte/sb1250_uart.h>
 #include <asm/sibyte/sb1250_scd.h>
 #include <asm/sibyte/sb1250.h>

 /*
  * These are the routines that handle all the low level interrupt stuff.
  * Actions handled here are: initialization of the interrupt map, requesting of
  * interrupt lines by handlers, dispatching if interrupts to handlers, probing
  * for interrupt lines
  */


 #define shutdown_sb1250_irq	disable_sb1250_irq
 static void end_sb1250_irq(unsigned int irq);
 static void enable_sb1250_irq(unsigned int irq);
 static void disable_sb1250_irq(unsigned int irq);
 static unsigned int startup_sb1250_irq(unsigned int irq);
 static void ack_sb1250_irq(unsigned int irq);
 #ifdef CONFIG_SMP
 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask);
 #endif

 #ifdef CONFIG_SIBYTE_HAS_LDT
 extern unsigned long ldt_eoi_space;
 #endif

 #ifdef CONFIG_KGDB
 static int kgdb_irq;

 /* Default to UART1 */
 int kgdb_port = 1;
 #ifdef CONFIG_SIBYTE_SB1250_DUART
 extern char sb1250_duart_present[];
 #endif
 #endif

 static struct hw_interrupt_type sb1250_irq_type = {
 	.typename = "SB1250-IMR",
 	.startup = startup_sb1250_irq,
 	.shutdown = shutdown_sb1250_irq,
 	.enable = enable_sb1250_irq,
 	.disable = disable_sb1250_irq,
 	.ack = ack_sb1250_irq,
 	.end = end_sb1250_irq,
 #ifdef CONFIG_SMP
 	.set_affinity = sb1250_set_affinity
 #endif
 };

 /* Store the CPU id (not the logical number) */
 int sb1250_irq_owner[SB1250_NR_IRQS];

 DEFINE_SPINLOCK(sb1250_imr_lock);

 void sb1250_mask_irq(int cpu, int irq)
 {
 	unsigned long flags;
 	u64 cur_ints;

 	spin_lock_irqsave(&sb1250_imr_lock, flags);
 	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 					R_IMR_INTERRUPT_MASK));
 	cur_ints |= (((u64) 1) << irq);
 	____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 					R_IMR_INTERRUPT_MASK));
 	spin_unlock_irqrestore(&sb1250_imr_lock, flags);
 }

 void sb1250_unmask_irq(int cpu, int irq)
 {
 	unsigned long flags;
 	u64 cur_ints;

 	spin_lock_irqsave(&sb1250_imr_lock, flags);
 	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 					R_IMR_INTERRUPT_MASK));
 	cur_ints &= ~(((u64) 1) << irq);
 	____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 					R_IMR_INTERRUPT_MASK));
 	spin_unlock_irqrestore(&sb1250_imr_lock, flags);
 }

 #ifdef CONFIG_SMP
 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask)
 {
 	int i = 0, old_cpu, cpu, int_on;
 	u64 cur_ints;
 	irq_desc_t *desc = irq_desc + irq;
 	unsigned long flags;

 	i = first_cpu(mask);

 	if (cpus_weight(mask) > 1) {
 		printk("attempted to set irq affinity for irq %d to multiple CPUs\n", irq);
 		return;
 	}

 	/* Convert logical CPU to physical CPU */
 	cpu = cpu_logical_map(i);

 	/* Protect against other affinity changers and IMR manipulation */
 	spin_lock_irqsave(&desc->lock, flags);
 	spin_lock(&sb1250_imr_lock);

 	/* Swizzle each CPU's IMR (but leave the IP selection alone) */
 	old_cpu = sb1250_irq_owner[irq];
 	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(old_cpu) +
 					R_IMR_INTERRUPT_MASK));
 	int_on = !(cur_ints & (((u64) 1) << irq));
 	if (int_on) {
 		/* If it was on, mask it */
 		cur_ints |= (((u64) 1) << irq);
 		____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(old_cpu) +
 					R_IMR_INTERRUPT_MASK));
 	}
 	sb1250_irq_owner[irq] = cpu;
 	if (int_on) {
 		/* unmask for the new CPU */
 		cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 					R_IMR_INTERRUPT_MASK));
 		cur_ints &= ~(((u64) 1) << irq);
 		____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 					R_IMR_INTERRUPT_MASK));
 	}
 	spin_unlock(&sb1250_imr_lock);
 	spin_unlock_irqrestore(&desc->lock, flags);
 }
 #endif

 /*****************************************************************************/

 static unsigned int startup_sb1250_irq(unsigned int irq)
 {
 	sb1250_unmask_irq(sb1250_irq_owner[irq], irq);

 	return 0;		/* never anything pending */
 }


 static void disable_sb1250_irq(unsigned int irq)
 {
 	sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 }

 static void enable_sb1250_irq(unsigned int irq)
 {
 	sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 }


 static void ack_sb1250_irq(unsigned int irq)
 {
 #ifdef CONFIG_SIBYTE_HAS_LDT
 	u64 pending;

 	/*
 	 * If the interrupt was an HT interrupt, now is the time to
 	 * clear it.  NOTE: we assume the HT bridge was set up to
 	 * deliver the interrupts to all CPUs (which makes affinity
 	 * changing easier for us)
 	 */
 	pending = __raw_readq(IOADDR(A_IMR_REGISTER(sb1250_irq_owner[irq],
 						    R_IMR_LDT_INTERRUPT)));
 	pending &= ((u64)1 << (irq));
 	if (pending) {
 		int i;
 		for (i=0; i<NR_CPUS; i++) {
 			int cpu;
 #ifdef CONFIG_SMP
 			cpu = cpu_logical_map(i);
 #else
 			cpu = i;
 #endif
 			/*
 			 * Clear for all CPUs so an affinity switch
 			 * doesn't find an old status
 			 */
 			__raw_writeq(pending,
 				     IOADDR(A_IMR_REGISTER(cpu,
 						R_IMR_LDT_INTERRUPT_CLR)));
 		}

 		/*
 		 * Generate EOI.  For Pass 1 parts, EOI is a nop.  For
 		 * Pass 2, the LDT world may be edge-triggered, but
 		 * this EOI shouldn't hurt.  If they are
 		 * level-sensitive, the EOI is required.
 		 */
 		*(uint32_t *)(ldt_eoi_space+(irq<<16)+(7<<2)) = 0;
 	}
 #endif
 	sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 }


 static void end_sb1250_irq(unsigned int irq)
 {
 	if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 		sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 	}
 }


 void __init init_sb1250_irqs(void)
 {
 	int i;

 	for (i = 0; i < NR_IRQS; i++) {
 		irq_desc[i].status = IRQ_DISABLED;
 		irq_desc[i].action = 0;
 		irq_desc[i].depth = 1;
 		if (i < SB1250_NR_IRQS) {
 			irq_desc[i].handler = &sb1250_irq_type;
 			sb1250_irq_owner[i] = 0;
 		} else {
 			irq_desc[i].handler = &no_irq_type;
 		}
 	}
 }


 static irqreturn_t  sb1250_dummy_handler(int irq, void *dev_id,
 	struct pt_regs *regs)
 {
 	return IRQ_NONE;
 }

 static struct irqaction sb1250_dummy_action = {
 	.handler = sb1250_dummy_handler,
 	.flags   = 0,
 	.mask    = CPU_MASK_NONE,
 	.name    = "sb1250-private",
 	.next    = NULL,
 	.dev_id  = 0
 };

 int sb1250_steal_irq(int irq)
 {
 	irq_desc_t *desc = irq_desc + irq;
 	unsigned long flags;
 	int retval = 0;

 	if (irq >= SB1250_NR_IRQS)
 		return -EINVAL;

 	spin_lock_irqsave(&desc->lock,flags);
 	/* Don't allow sharing at all for these */
 	if (desc->action != NULL)
 		retval = -EBUSY;
 	else {
 		desc->action = &sb1250_dummy_action;
 		desc->depth = 0;
 	}
 	spin_unlock_irqrestore(&desc->lock,flags);
 	return 0;
 }

 /*
  *  arch_init_irq is called early in the boot sequence from init/main.c via
  *  init_IRQ.  It is responsible for setting up the interrupt mapper and
  *  installing the handler that will be responsible for dispatching interrupts
  *  to the "right" place.
  */
 /*
  * For now, map all interrupts to IP[2].  We could save
  * some cycles by parceling out system interrupts to different
  * IP lines, but keep it simple for bringup.  We'll also direct
  * all interrupts to a single CPU; we should probably route
  * PCI and LDT to one cpu and everything else to the other
  * to balance the load a bit.
  *
  * On the second cpu, everything is set to IP5, which is
  * ignored, EXCEPT the mailbox interrupt.  That one is
  * set to IP[2] so it is handled.  This is needed so we
  * can do cross-cpu function calls, as requred by SMP
  */

 #define IMR_IP2_VAL	K_INT_MAP_I0
 #define IMR_IP3_VAL	K_INT_MAP_I1
 #define IMR_IP4_VAL	K_INT_MAP_I2
 #define IMR_IP5_VAL	K_INT_MAP_I3
 #define IMR_IP6_VAL	K_INT_MAP_I4

 void __init arch_init_irq(void)
 {

 	unsigned int i;
 	u64 tmp;
 	unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
 		STATUSF_IP1 | STATUSF_IP0;

 	/* Default everything to IP2 */
 	for (i = 0; i < SB1250_NR_IRQS; i++) {	/* was I0 */
 		__raw_writeq(IMR_IP2_VAL,
 			     IOADDR(A_IMR_REGISTER(0,
 						   R_IMR_INTERRUPT_MAP_BASE) +
 				    (i << 3)));
 		__raw_writeq(IMR_IP2_VAL,
 			     IOADDR(A_IMR_REGISTER(1,
 						   R_IMR_INTERRUPT_MAP_BASE) +
 				    (i << 3)));
 	}

 	init_sb1250_irqs();

 	/*
 	 * Map the high 16 bits of the mailbox registers to IP[3], for
 	 * inter-cpu messages
 	 */
 	/* Was I1 */
 	__raw_writeq(IMR_IP3_VAL,
 		     IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
 			    (K_INT_MBOX_0 << 3)));
 	__raw_writeq(IMR_IP3_VAL,
 		     IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MAP_BASE) +
 			    (K_INT_MBOX_0 << 3)));

 	/* Clear the mailboxes.  The firmware may leave them dirty */
 	__raw_writeq(0xffffffffffffffffULL,
 		     IOADDR(A_IMR_REGISTER(0, R_IMR_MAILBOX_CLR_CPU)));
 	__raw_writeq(0xffffffffffffffffULL,
 		     IOADDR(A_IMR_REGISTER(1, R_IMR_MAILBOX_CLR_CPU)));

 	/* Mask everything except the mailbox registers for both cpus */
 	tmp = ~((u64) 0) ^ (((u64) 1) << K_INT_MBOX_0);
 	__raw_writeq(tmp, IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MASK)));
 	__raw_writeq(tmp, IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MASK)));

 	sb1250_steal_irq(K_INT_MBOX_0);

 	/*
 	 * Note that the timer interrupts are also mapped, but this is
 	 * done in sb1250_time_init().  Also, the profiling driver
 	 * does its own management of IP7.
 	 */

 #ifdef CONFIG_KGDB
 	imask |= STATUSF_IP6;
 #endif
 	/* Enable necessary IPs, disable the rest */
 	change_c0_status(ST0_IM, imask);

 #ifdef CONFIG_KGDB
 	if (kgdb_flag) {
 		kgdb_irq = K_INT_UART_0 + kgdb_port;

 #ifdef CONFIG_SIBYTE_SB1250_DUART
 		sb1250_duart_present[kgdb_port] = 0;
 #endif
 		/* Setup uart 1 settings, mapper */
 		__raw_writeq(M_DUART_IMR_BRK,
 			     IOADDR(A_DUART_IMRREG(kgdb_port)));

 		sb1250_steal_irq(kgdb_irq);
 		__raw_writeq(IMR_IP6_VAL,
 			     IOADDR(A_IMR_REGISTER(0,
 						   R_IMR_INTERRUPT_MAP_BASE) +
 				    (kgdb_irq << 3)));
 		sb1250_unmask_irq(0, kgdb_irq);
 	}
 #endif
 }

 #ifdef CONFIG_KGDB

 #include <linux/delay.h>

 #define duart_out(reg, val)     csr_out32(val, IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 #define duart_in(reg)           csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))

 static void sb1250_kgdb_interrupt(struct pt_regs *regs)
 {
 	/*
 	 * Clear break-change status (allow some time for the remote
 	 * host to stop the break, since we would see another
 	 * interrupt on the end-of-break too)
 	 */
 	kstat_this_cpu.irqs[kgdb_irq]++;
 	mdelay(500);
 	duart_out(R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT |
 				M_DUART_RX_EN | M_DUART_TX_EN);
 	set_async_breakpoint(&regs->cp0_epc);
 }

 #endif 	/* CONFIG_KGDB */

 static inline int dclz(unsigned long long x)
 {
 	int lz;

 	__asm__ (
 	"	.set	push						\n"
 	"	.set	mips64						\n"
 	"	dclz	%0, %1						\n"
 	"	.set	pop						\n"
 	: "=r" (lz)
 	: "r" (x));

 	return lz;
 }

 extern void sb1250_timer_interrupt(struct pt_regs *regs);
 extern void sb1250_mailbox_interrupt(struct pt_regs *regs);
 extern void sb1250_kgdb_interrupt(struct pt_regs *regs);

 asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
 {
 	unsigned int pending;

 #ifdef CONFIG_SIBYTE_SB1250_PROF
 	/* Set compare to count to silence count/compare timer interrupts */
 	write_c0_compare(read_c0_count());
 #endif

 	/*
 	 * What a pain. We have to be really careful saving the upper 32 bits
 	 * of any * register across function calls if we don't want them
 	 * trashed--since were running in -o32, the calling routing never saves
 	 * the full 64 bits of a register across a function call.  Being the
 	 * interrupt handler, we're guaranteed that interrupts are disabled
 	 * during this code so we don't have to worry about random interrupts
 	 * blasting the high 32 bits.
 	 */

 	pending = read_c0_cause();

 #ifdef CONFIG_SIBYTE_SB1250_PROF
 	if (pending & CAUSEF_IP7) { /* Cpu performance counter interrupt */
 		sbprof_cpu_intr(exception_epc(regs));
 	}
 #endif

 	if (pending & CAUSEF_IP4)
 		sb1250_timer_interrupt(regs);

 #ifdef CONFIG_SMP
 	if (pending & CAUSEF_IP3)
 		sb1250_mailbox_interrupt(regs);
 #endif

 #ifdef CONFIG_KGDB
 	if (pending & CAUSEF_IP6)			/* KGDB (uart 1) */
 		sb1250_kgdb_interrupt(regs);
 #endif

 	if (pending & CAUSEF_IP2) {
 		unsigned long long mask;

 		/*
 		 * Default...we've hit an IP[2] interrupt, which means we've
 		 * got to check the 1250 interrupt registers to figure out what
 		 * to do.  Need to detect which CPU we're on, now that
 		 * smp_affinity is supported.
 		 */
 		mask = __raw_readq(IOADDR(A_IMR_REGISTER(smp_processor_id(),
 		                              R_IMR_INTERRUPT_STATUS_BASE)));
 		if (mask)
 			do_IRQ(63 - dclz(mask), regs);
 	}
 }
	/*
	* Copyright (C) 2000, 2001, 2002, 2003 Broadcom Corporation
	*
	* 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; 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.
	*/
	#include <linux/config.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/linkage.h>
	#include <linux/interrupt.h>
	#include <linux/spinlock.h>
	#include <linux/smp.h>
	#include <linux/mm.h>
	#include <linux/slab.h>
	#include <linux/kernel_stat.h>

	#include <asm/errno.h>
	#include <asm/signal.h>
	#include <asm/system.h>
	#include <asm/ptrace.h>
	#include <asm/io.h>

	#include <asm/sibyte/sb1250_regs.h>
	#include <asm/sibyte/sb1250_int.h>
	#include <asm/sibyte/sb1250_uart.h>
	#include <asm/sibyte/sb1250_scd.h>
	#include <asm/sibyte/sb1250.h>

	/*
	* These are the routines that handle all the low level interrupt stuff.
	* Actions handled here are: initialization of the interrupt map, requesting of
	* interrupt lines by handlers, dispatching if interrupts to handlers, probing
	* for interrupt lines
	*/


	#define shutdown_sb1250_irq disable_sb1250_irq
	static void end_sb1250_irq(unsigned int irq);
	static void enable_sb1250_irq(unsigned int irq);
	static void disable_sb1250_irq(unsigned int irq);
	static unsigned int startup_sb1250_irq(unsigned int irq);
	static void ack_sb1250_irq(unsigned int irq);
	#ifdef CONFIG_SMP
	static void sb1250_set_affinity(unsigned int irq, cpumask_t mask);
	#endif

	#ifdef CONFIG_SIBYTE_HAS_LDT
	extern unsigned long ldt_eoi_space;
	#endif

	#ifdef CONFIG_KGDB
	static int kgdb_irq;

	/* Default to UART1 */
	int kgdb_port = 1;
	#ifdef CONFIG_SIBYTE_SB1250_DUART
	extern char sb1250_duart_present[];
	#endif
	#endif

	static struct hw_interrupt_type sb1250_irq_type = {
	.typename = "SB1250-IMR",
	.startup = startup_sb1250_irq,
	.shutdown = shutdown_sb1250_irq,
	.enable = enable_sb1250_irq,
	.disable = disable_sb1250_irq,
	.ack = ack_sb1250_irq,
	.end = end_sb1250_irq,
	#ifdef CONFIG_SMP
	.set_affinity = sb1250_set_affinity
	#endif
	};

	/* Store the CPU id (not the logical number) */
	int sb1250_irq_owner[SB1250_NR_IRQS];

	DEFINE_SPINLOCK(sb1250_imr_lock);

	void sb1250_mask_irq(int cpu, int irq)
	{
	unsigned long flags;
	u64 cur_ints;

	spin_lock_irqsave(&sb1250_imr_lock, flags);
	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
	R_IMR_INTERRUPT_MASK));
	cur_ints \|= (((u64) 1) << irq);
	____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
	R_IMR_INTERRUPT_MASK));
	spin_unlock_irqrestore(&sb1250_imr_lock, flags);
	}

	void sb1250_unmask_irq(int cpu, int irq)
	{
	unsigned long flags;
	u64 cur_ints;

	spin_lock_irqsave(&sb1250_imr_lock, flags);
	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
	R_IMR_INTERRUPT_MASK));
	cur_ints &= ~(((u64) 1) << irq);
	____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
	R_IMR_INTERRUPT_MASK));
	spin_unlock_irqrestore(&sb1250_imr_lock, flags);
	}

	#ifdef CONFIG_SMP
	static void sb1250_set_affinity(unsigned int irq, cpumask_t mask)
	{
	int i = 0, old_cpu, cpu, int_on;
	u64 cur_ints;
	irq_desc_t *desc = irq_desc + irq;
	unsigned long flags;

	i = first_cpu(mask);

	if (cpus_weight(mask) > 1) {
	printk("attempted to set irq affinity for irq %d to multiple CPUs\n", irq);
	return;
	}

	/* Convert logical CPU to physical CPU */
	cpu = cpu_logical_map(i);

	/* Protect against other affinity changers and IMR manipulation */
	spin_lock_irqsave(&desc->lock, flags);
	spin_lock(&sb1250_imr_lock);

	/* Swizzle each CPU's IMR (but leave the IP selection alone) */
	old_cpu = sb1250_irq_owner[irq];
	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(old_cpu) +
	R_IMR_INTERRUPT_MASK));
	int_on = !(cur_ints & (((u64) 1) << irq));
	if (int_on) {
	/* If it was on, mask it */
	cur_ints \|= (((u64) 1) << irq);
	____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(old_cpu) +
	R_IMR_INTERRUPT_MASK));
	}
	sb1250_irq_owner[irq] = cpu;
	if (int_on) {
	/* unmask for the new CPU */
	cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
	R_IMR_INTERRUPT_MASK));
	cur_ints &= ~(((u64) 1) << irq);
	____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
	R_IMR_INTERRUPT_MASK));
	}
	spin_unlock(&sb1250_imr_lock);
	spin_unlock_irqrestore(&desc->lock, flags);
	}
	#endif

	/*****************************************************************************/

	static unsigned int startup_sb1250_irq(unsigned int irq)
	{
	sb1250_unmask_irq(sb1250_irq_owner[irq], irq);

	return 0; /* never anything pending */
	}


	static void disable_sb1250_irq(unsigned int irq)
	{
	sb1250_mask_irq(sb1250_irq_owner[irq], irq);
	}

	static void enable_sb1250_irq(unsigned int irq)
	{
	sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
	}


	static void ack_sb1250_irq(unsigned int irq)
	{
	#ifdef CONFIG_SIBYTE_HAS_LDT
	u64 pending;

	/*
	* If the interrupt was an HT interrupt, now is the time to
	* clear it. NOTE: we assume the HT bridge was set up to
	* deliver the interrupts to all CPUs (which makes affinity
	* changing easier for us)
	*/
	pending = __raw_readq(IOADDR(A_IMR_REGISTER(sb1250_irq_owner[irq],
	R_IMR_LDT_INTERRUPT)));
	pending &= ((u64)1 << (irq));
	if (pending) {
	int i;
	for (i=0; i<NR_CPUS; i++) {
	int cpu;
	#ifdef CONFIG_SMP
	cpu = cpu_logical_map(i);
	#else
	cpu = i;
	#endif
	/*
	* Clear for all CPUs so an affinity switch
	* doesn't find an old status
	*/
	__raw_writeq(pending,
	IOADDR(A_IMR_REGISTER(cpu,
	R_IMR_LDT_INTERRUPT_CLR)));
	}

	/*
	* Generate EOI. For Pass 1 parts, EOI is a nop. For
	* Pass 2, the LDT world may be edge-triggered, but
	* this EOI shouldn't hurt. If they are
	* level-sensitive, the EOI is required.
	*/
	(uint32_t )(ldt_eoi_space+(irq<<16)+(7<<2)) = 0;
	}
	#endif
	sb1250_mask_irq(sb1250_irq_owner[irq], irq);
	}


	static void end_sb1250_irq(unsigned int irq)
	{
	if (!(irq_desc[irq].status & (IRQ_DISABLED \| IRQ_INPROGRESS))) {
	sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
	}
	}


	void __init init_sb1250_irqs(void)
	{
	int i;

	for (i = 0; i < NR_IRQS; i++) {
	irq_desc[i].status = IRQ_DISABLED;
	irq_desc[i].action = 0;
	irq_desc[i].depth = 1;
	if (i < SB1250_NR_IRQS) {
	irq_desc[i].handler = &sb1250_irq_type;
	sb1250_irq_owner[i] = 0;
	} else {
	irq_desc[i].handler = &no_irq_type;
	}
	}
	}


	static irqreturn_t sb1250_dummy_handler(int irq, void *dev_id,
	struct pt_regs *regs)
	{
	return IRQ_NONE;
	}

	static struct irqaction sb1250_dummy_action = {
	.handler = sb1250_dummy_handler,
	.flags = 0,
	.mask = CPU_MASK_NONE,
	.name = "sb1250-private",
	.next = NULL,
	.dev_id = 0
	};

	int sb1250_steal_irq(int irq)
	{
	irq_desc_t *desc = irq_desc + irq;
	unsigned long flags;
	int retval = 0;

	if (irq >= SB1250_NR_IRQS)
	return -EINVAL;

	spin_lock_irqsave(&desc->lock,flags);
	/* Don't allow sharing at all for these */
	if (desc->action != NULL)
	retval = -EBUSY;
	else {
	desc->action = &sb1250_dummy_action;
	desc->depth = 0;
	}
	spin_unlock_irqrestore(&desc->lock,flags);
	return 0;
	}

	/*
	* arch_init_irq is called early in the boot sequence from init/main.c via
	* init_IRQ. It is responsible for setting up the interrupt mapper and
	* installing the handler that will be responsible for dispatching interrupts
	* to the "right" place.
	*/
	/*
	* For now, map all interrupts to IP[2]. We could save
	* some cycles by parceling out system interrupts to different
	* IP lines, but keep it simple for bringup. We'll also direct
	* all interrupts to a single CPU; we should probably route
	* PCI and LDT to one cpu and everything else to the other
	* to balance the load a bit.
	*
	* On the second cpu, everything is set to IP5, which is
	* ignored, EXCEPT the mailbox interrupt. That one is
	* set to IP[2] so it is handled. This is needed so we
	* can do cross-cpu function calls, as requred by SMP
	*/

	#define IMR_IP2_VAL K_INT_MAP_I0
	#define IMR_IP3_VAL K_INT_MAP_I1
	#define IMR_IP4_VAL K_INT_MAP_I2
	#define IMR_IP5_VAL K_INT_MAP_I3
	#define IMR_IP6_VAL K_INT_MAP_I4

	void __init arch_init_irq(void)
	{

	unsigned int i;
	u64 tmp;
	unsigned int imask = STATUSF_IP4 \| STATUSF_IP3 \| STATUSF_IP2 \|
	STATUSF_IP1 \| STATUSF_IP0;

	/* Default everything to IP2 */
	for (i = 0; i < SB1250_NR_IRQS; i++) { /* was I0 */
	__raw_writeq(IMR_IP2_VAL,
	IOADDR(A_IMR_REGISTER(0,
	R_IMR_INTERRUPT_MAP_BASE) +
	(i << 3)));
	__raw_writeq(IMR_IP2_VAL,
	IOADDR(A_IMR_REGISTER(1,
	R_IMR_INTERRUPT_MAP_BASE) +
	(i << 3)));
	}

	init_sb1250_irqs();

	/*
	* Map the high 16 bits of the mailbox registers to IP[3], for
	* inter-cpu messages
	*/
	/* Was I1 */
	__raw_writeq(IMR_IP3_VAL,
	IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
	(K_INT_MBOX_0 << 3)));
	__raw_writeq(IMR_IP3_VAL,
	IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MAP_BASE) +
	(K_INT_MBOX_0 << 3)));

	/* Clear the mailboxes. The firmware may leave them dirty */
	__raw_writeq(0xffffffffffffffffULL,
	IOADDR(A_IMR_REGISTER(0, R_IMR_MAILBOX_CLR_CPU)));
	__raw_writeq(0xffffffffffffffffULL,
	IOADDR(A_IMR_REGISTER(1, R_IMR_MAILBOX_CLR_CPU)));

	/* Mask everything except the mailbox registers for both cpus */
	tmp = ~((u64) 0) ^ (((u64) 1) << K_INT_MBOX_0);
	__raw_writeq(tmp, IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MASK)));
	__raw_writeq(tmp, IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MASK)));

	sb1250_steal_irq(K_INT_MBOX_0);

	/*
	* Note that the timer interrupts are also mapped, but this is
	* done in sb1250_time_init(). Also, the profiling driver
	* does its own management of IP7.
	*/

	#ifdef CONFIG_KGDB
	imask \|= STATUSF_IP6;
	#endif
	/* Enable necessary IPs, disable the rest */
	change_c0_status(ST0_IM, imask);

	#ifdef CONFIG_KGDB
	if (kgdb_flag) {
	kgdb_irq = K_INT_UART_0 + kgdb_port;

	#ifdef CONFIG_SIBYTE_SB1250_DUART
	sb1250_duart_present[kgdb_port] = 0;
	#endif
	/* Setup uart 1 settings, mapper */
	__raw_writeq(M_DUART_IMR_BRK,
	IOADDR(A_DUART_IMRREG(kgdb_port)));

	sb1250_steal_irq(kgdb_irq);
	__raw_writeq(IMR_IP6_VAL,
	IOADDR(A_IMR_REGISTER(0,
	R_IMR_INTERRUPT_MAP_BASE) +
	(kgdb_irq << 3)));
	sb1250_unmask_irq(0, kgdb_irq);
	}
	#endif
	}

	#ifdef CONFIG_KGDB

	#include <linux/delay.h>

	#define duart_out(reg, val) csr_out32(val, IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
	#define duart_in(reg) csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))

	static void sb1250_kgdb_interrupt(struct pt_regs *regs)
	{
	/*
	* Clear break-change status (allow some time for the remote
	* host to stop the break, since we would see another
	* interrupt on the end-of-break too)
	*/
	kstat_this_cpu.irqs[kgdb_irq]++;
	mdelay(500);
	duart_out(R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT \|
	M_DUART_RX_EN \| M_DUART_TX_EN);
	set_async_breakpoint(&regs->cp0_epc);
	}

	#endif /* CONFIG_KGDB */

	static inline int dclz(unsigned long long x)
	{
	int lz;

	__asm__ (
	" .set push \n"
	" .set mips64 \n"
	" dclz %0, %1 \n"
	" .set pop \n"
	: "=r" (lz)
	: "r" (x));

	return lz;
	}

	extern void sb1250_timer_interrupt(struct pt_regs *regs);
	extern void sb1250_mailbox_interrupt(struct pt_regs *regs);
	extern void sb1250_kgdb_interrupt(struct pt_regs *regs);

	asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
	{
	unsigned int pending;

	#ifdef CONFIG_SIBYTE_SB1250_PROF
	/* Set compare to count to silence count/compare timer interrupts */
	write_c0_compare(read_c0_count());
	#endif

	/*
	* What a pain. We have to be really careful saving the upper 32 bits
	* of any * register across function calls if we don't want them
	* trashed--since were running in -o32, the calling routing never saves
	* the full 64 bits of a register across a function call. Being the
	* interrupt handler, we're guaranteed that interrupts are disabled
	* during this code so we don't have to worry about random interrupts
	* blasting the high 32 bits.
	*/

	pending = read_c0_cause();

	#ifdef CONFIG_SIBYTE_SB1250_PROF
	if (pending & CAUSEF_IP7) { /* Cpu performance counter interrupt */
	sbprof_cpu_intr(exception_epc(regs));
	}
	#endif

	if (pending & CAUSEF_IP4)
	sb1250_timer_interrupt(regs);

	#ifdef CONFIG_SMP
	if (pending & CAUSEF_IP3)
	sb1250_mailbox_interrupt(regs);
	#endif

	#ifdef CONFIG_KGDB
	if (pending & CAUSEF_IP6) /* KGDB (uart 1) */
	sb1250_kgdb_interrupt(regs);
	#endif

	if (pending & CAUSEF_IP2) {
	unsigned long long mask;

	/*
	* Default...we've hit an IP[2] interrupt, which means we've
	* got to check the 1250 interrupt registers to figure out what
	* to do. Need to detect which CPU we're on, now that
	* smp_affinity is supported.
	*/
	mask = __raw_readq(IOADDR(A_IMR_REGISTER(smp_processor_id(),
	R_IMR_INTERRUPT_STATUS_BASE)));
	if (mask)
	do_IRQ(63 - dclz(mask), regs);
	}
	}