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// SPDX-License-Identifier: GPL-2.0
/*
* ip27-irq.c: Highlevel interrupt handling for IP27 architecture.
*
* Copyright (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 1999 - 2001 Kanoj Sarcar
*/
#undef DEBUG
#include <linux/irq.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/timex.h>
#include <linux/smp.h>
#include <linux/random.h>
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <asm/bootinfo.h>
#include <asm/io.h>
#include <asm/mipsregs.h>
#include <asm/processor.h>
#include <asm/pci/bridge.h>
#include <asm/sn/addrs.h>
#include <asm/sn/agent.h>
#include <asm/sn/arch.h>
#include <asm/sn/hub.h>
#include <asm/sn/intr.h>
/*
* Linux has a controller-independent x86 interrupt architecture.
* every controller has a 'controller-template', that is used
* by the main code to do the right thing. Each driver-visible
* interrupt source is transparently wired to the appropriate
* controller. Thus drivers need not be aware of the
* interrupt-controller.
*
* Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
* PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
* (IO-APICs assumed to be messaging to Pentium local-APICs)
*
* the code is designed to be easily extended with new/different
* interrupt controllers, without having to do assembly magic.
*/
extern struct bridge_controller *irq_to_bridge[];
extern int irq_to_slot[];
/*
* use these macros to get the encoded nasid and widget id
* from the irq value
*/
#define IRQ_TO_BRIDGE(i) irq_to_bridge[(i)]
#define SLOT_FROM_PCI_IRQ(i) irq_to_slot[i]
static inline int alloc_level(int cpu, int irq)
{
struct hub_data *hub = hub_data(cpu_to_node(cpu));
struct slice_data *si = cpu_data[cpu].data;
int level;
level = find_first_zero_bit(hub->irq_alloc_mask, LEVELS_PER_SLICE);
if (level >= LEVELS_PER_SLICE)
panic("Cpu %d flooded with devices", cpu);
__set_bit(level, hub->irq_alloc_mask);
si->level_to_irq[level] = irq;
return level;
}
static inline int find_level(cpuid_t *cpunum, int irq)
{
int cpu, i;
for_each_online_cpu(cpu) {
struct slice_data *si = cpu_data[cpu].data;
for (i = BASE_PCI_IRQ; i < LEVELS_PER_SLICE; i++)
if (si->level_to_irq[i] == irq) {
*cpunum = cpu;
return i;
}
}
panic("Could not identify cpu/level for irq %d", irq);
}
static int intr_connect_level(int cpu, int bit)
{
nasid_t nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
struct slice_data *si = cpu_data[cpu].data;
set_bit(bit, si->irq_enable_mask);
if (!cputoslice(cpu)) {
REMOTE_HUB_S(nasid, PI_INT_MASK0_A, si->irq_enable_mask[0]);
REMOTE_HUB_S(nasid, PI_INT_MASK1_A, si->irq_enable_mask[1]);
} else {
REMOTE_HUB_S(nasid, PI_INT_MASK0_B, si->irq_enable_mask[0]);
REMOTE_HUB_S(nasid, PI_INT_MASK1_B, si->irq_enable_mask[1]);
}
return 0;
}
static int intr_disconnect_level(int cpu, int bit)
{
nasid_t nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
struct slice_data *si = cpu_data[cpu].data;
clear_bit(bit, si->irq_enable_mask);
if (!cputoslice(cpu)) {
REMOTE_HUB_S(nasid, PI_INT_MASK0_A, si->irq_enable_mask[0]);
REMOTE_HUB_S(nasid, PI_INT_MASK1_A, si->irq_enable_mask[1]);
} else {
REMOTE_HUB_S(nasid, PI_INT_MASK0_B, si->irq_enable_mask[0]);
REMOTE_HUB_S(nasid, PI_INT_MASK1_B, si->irq_enable_mask[1]);
}
return 0;
}
/* Startup one of the (PCI ...) IRQs routes over a bridge. */
static unsigned int startup_bridge_irq(struct irq_data *d)
{
struct bridge_controller *bc;
int pin, swlevel;
cpuid_t cpu;
u64 device;
pin = SLOT_FROM_PCI_IRQ(d->irq);
bc = IRQ_TO_BRIDGE(d->irq);
pr_debug("bridge_startup(): irq= 0x%x pin=%d\n", d->irq, pin);
/*
* "map" irq to a swlevel greater than 6 since the first 6 bits
* of INT_PEND0 are taken
*/
swlevel = find_level(&cpu, d->irq);
bridge_write(bc, b_int_addr[pin].addr,
(0x20000 | swlevel | (bc->nasid << 8)));
bridge_set(bc, b_int_enable, (1 << pin));
bridge_set(bc, b_int_enable, 0x7ffffe00); /* more stuff in int_enable */
/*
* Enable sending of an interrupt clear packt to the hub on a high to
* low transition of the interrupt pin.
*
* IRIX sets additional bits in the address which are documented as
* reserved in the bridge docs.
*/
bridge_set(bc, b_int_mode, (1UL << pin));
/*
* We assume the bridge to have a 1:1 mapping between devices
* (slots) and intr pins.
*/
device = bridge_read(bc, b_int_device);
device &= ~(7 << (pin*3));
device |= (pin << (pin*3));
bridge_write(bc, b_int_device, device);
bridge_read(bc, b_wid_tflush);
intr_connect_level(cpu, swlevel);
return 0; /* Never anything pending. */
}
/* Shutdown one of the (PCI ...) IRQs routes over a bridge. */
static void shutdown_bridge_irq(struct irq_data *d)
{
struct bridge_controller *bc = IRQ_TO_BRIDGE(d->irq);
int pin, swlevel;
cpuid_t cpu;
pr_debug("bridge_shutdown: irq 0x%x\n", d->irq);
pin = SLOT_FROM_PCI_IRQ(d->irq);
/*
* map irq to a swlevel greater than 6 since the first 6 bits
* of INT_PEND0 are taken
*/
swlevel = find_level(&cpu, d->irq);
intr_disconnect_level(cpu, swlevel);
bridge_clr(bc, b_int_enable, (1 << pin));
bridge_read(bc, b_wid_tflush);
}
static inline void enable_bridge_irq(struct irq_data *d)
{
cpuid_t cpu;
int swlevel;
swlevel = find_level(&cpu, d->irq); /* Criminal offence */
intr_connect_level(cpu, swlevel);
}
static inline void disable_bridge_irq(struct irq_data *d)
{
cpuid_t cpu;
int swlevel;
swlevel = find_level(&cpu, d->irq); /* Criminal offence */
intr_disconnect_level(cpu, swlevel);
}
static struct irq_chip bridge_irq_type = {
.name = "bridge",
.irq_startup = startup_bridge_irq,
.irq_shutdown = shutdown_bridge_irq,
.irq_mask = disable_bridge_irq,
.irq_unmask = enable_bridge_irq,
};
void register_bridge_irq(unsigned int irq)
{
irq_set_chip_and_handler(irq, &bridge_irq_type, handle_level_irq);
}
int request_bridge_irq(struct bridge_controller *bc)
{
int irq = allocate_irqno();
int swlevel, cpu;
nasid_t nasid;
if (irq < 0)
return irq;
/*
* "map" irq to a swlevel greater than 6 since the first 6 bits
* of INT_PEND0 are taken
*/
cpu = bc->irq_cpu;
swlevel = alloc_level(cpu, irq);
if (unlikely(swlevel < 0)) {
free_irqno(irq);
return -EAGAIN;
}
/* Make sure it's not already pending when we connect it. */
nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
REMOTE_HUB_CLR_INTR(nasid, swlevel);
intr_connect_level(cpu, swlevel);
register_bridge_irq(irq);
return irq;
}
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