From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/mips/sibyte/sb1250/irq.c | 337 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 337 insertions(+)
 create mode 100644 arch/mips/sibyte/sb1250/irq.c

(limited to 'arch/mips/sibyte/sb1250/irq.c')

diff --git a/arch/mips/sibyte/sb1250/irq.c b/arch/mips/sibyte/sb1250/irq.c
new file mode 100644
index 000000000..6d8dba5cf
--- /dev/null
+++ b/arch/mips/sibyte/sb1250/irq.c
@@ -0,0 +1,337 @@
+/*
+ * 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/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/kernel_stat.h>
+
+#include <asm/errno.h>
+#include <asm/signal.h>
+#include <asm/time.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
+ */
+
+#ifdef CONFIG_SIBYTE_HAS_LDT
+extern unsigned long ldt_eoi_space;
+#endif
+
+/* Store the CPU id (not the logical number) */
+int sb1250_irq_owner[SB1250_NR_IRQS];
+
+static DEFINE_RAW_SPINLOCK(sb1250_imr_lock);
+
+void sb1250_mask_irq(int cpu, int irq)
+{
+	unsigned long flags;
+	u64 cur_ints;
+
+	raw_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));
+	raw_spin_unlock_irqrestore(&sb1250_imr_lock, flags);
+}
+
+void sb1250_unmask_irq(int cpu, int irq)
+{
+	unsigned long flags;
+	u64 cur_ints;
+
+	raw_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));
+	raw_spin_unlock_irqrestore(&sb1250_imr_lock, flags);
+}
+
+#ifdef CONFIG_SMP
+static int sb1250_set_affinity(struct irq_data *d, const struct cpumask *mask,
+			       bool force)
+{
+	int i = 0, old_cpu, cpu, int_on;
+	unsigned int irq = d->irq;
+	u64 cur_ints;
+	unsigned long flags;
+
+	i = cpumask_first_and(mask, cpu_online_mask);
+
+	/* Convert logical CPU to physical CPU */
+	cpu = cpu_logical_map(i);
+
+	/* Protect against other affinity changers and IMR manipulation */
+	raw_spin_lock_irqsave(&sb1250_imr_lock, flags);
+
+	/* 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));
+	}
+	raw_spin_unlock_irqrestore(&sb1250_imr_lock, flags);
+
+	return 0;
+}
+#endif
+
+static void disable_sb1250_irq(struct irq_data *d)
+{
+	unsigned int irq = d->irq;
+
+	sb1250_mask_irq(sb1250_irq_owner[irq], irq);
+}
+
+static void enable_sb1250_irq(struct irq_data *d)
+{
+	unsigned int irq = d->irq;
+
+	sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
+}
+
+
+static void ack_sb1250_irq(struct irq_data *d)
+{
+	unsigned int irq = d->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 struct irq_chip sb1250_irq_type = {
+	.name = "SB1250-IMR",
+	.irq_mask_ack = ack_sb1250_irq,
+	.irq_unmask = enable_sb1250_irq,
+	.irq_mask = disable_sb1250_irq,
+#ifdef CONFIG_SMP
+	.irq_set_affinity = sb1250_set_affinity
+#endif
+};
+
+void __init init_sb1250_irqs(void)
+{
+	int i;
+
+	for (i = 0; i < SB1250_NR_IRQS; i++) {
+		irq_set_chip_and_handler(i, &sb1250_irq_type,
+					 handle_level_irq);
+		sb1250_irq_owner[i] = 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 required 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)));
+
+	/*
+	 * 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.
+	 */
+
+	/* Enable necessary IPs, disable the rest */
+	change_c0_status(ST0_IM, imask);
+}
+
+extern void sb1250_mailbox_interrupt(void);
+
+static inline void dispatch_ip2(void)
+{
+	unsigned int cpu = smp_processor_id();
+	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(cpu,
+				  R_IMR_INTERRUPT_STATUS_BASE)));
+	if (mask)
+		do_IRQ(fls64(mask) - 1);
+}
+
+asmlinkage void plat_irq_dispatch(void)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned int pending;
+
+	/*
+	 * 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() & read_c0_status() & ST0_IM;
+
+	if (pending & CAUSEF_IP7) /* CPU performance counter interrupt */
+		do_IRQ(MIPS_CPU_IRQ_BASE + 7);
+	else if (pending & CAUSEF_IP4)
+		do_IRQ(K_INT_TIMER_0 + cpu);	/* sb1250_timer_interrupt() */
+
+#ifdef CONFIG_SMP
+	else if (pending & CAUSEF_IP3)
+		sb1250_mailbox_interrupt();
+#endif
+
+	else if (pending & CAUSEF_IP2)
+		dispatch_ip2();
+	else
+		spurious_interrupt();
+}
-- 
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