/*
* Copyright (C) 2015 - Ben Herrenschmidt, IBM Corp.
*
* Driver for Aspeed "new" VIC as found in SoC generation 3 and later
*
* Based on irq-vic.c:
*
* Copyright (C) 1999 - 2003 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd
*
* 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.
*
*/
#include <linux/export.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/syscore_ops.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <asm/exception.h>
#include <asm/irq.h>
/* These definitions correspond to the "new mapping" of the
* register set that interleaves "high" and "low". The offsets
* below are for the "low" register, add 4 to get to the high one
*/
#define AVIC_IRQ_STATUS 0x00
#define AVIC_FIQ_STATUS 0x08
#define AVIC_RAW_STATUS 0x10
#define AVIC_INT_SELECT 0x18
#define AVIC_INT_ENABLE 0x20
#define AVIC_INT_ENABLE_CLR 0x28
#define AVIC_INT_TRIGGER 0x30
#define AVIC_INT_TRIGGER_CLR 0x38
#define AVIC_INT_SENSE 0x40
#define AVIC_INT_DUAL_EDGE 0x48
#define AVIC_INT_EVENT 0x50
#define AVIC_EDGE_CLR 0x58
#define AVIC_EDGE_STATUS 0x60
#define NUM_IRQS 64
struct aspeed_vic {
void __iomem *base;
u32 edge_sources[2];
struct irq_domain *dom;
};
static struct aspeed_vic *system_avic;
static void vic_init_hw(struct aspeed_vic *vic)
{
u32 sense;
/* Disable all interrupts */
writel(0xffffffff, vic->base + AVIC_INT_ENABLE_CLR);
writel(0xffffffff, vic->base + AVIC_INT_ENABLE_CLR + 4);
/* Make sure no soft trigger is on */
writel(0xffffffff, vic->base + AVIC_INT_TRIGGER_CLR);
writel(0xffffffff, vic->base + AVIC_INT_TRIGGER_CLR + 4);
/* Set everything to be IRQ */
writel(0, vic->base + AVIC_INT_SELECT);
writel(0, vic->base + AVIC_INT_SELECT + 4);
/* Some interrupts have a programable high/low level trigger
* (4 GPIO direct inputs), for now we assume this was configured
* by firmware. We read which ones are edge now.
*/
sense = readl(vic->base + AVIC_INT_SENSE);
vic->edge_sources[0] = ~sense;
sense = readl(vic->base + AVIC_INT_SENSE + 4);
vic->edge_sources[1] = ~sense;
/* Clear edge detection latches */
writel(0xffffffff, vic->base + AVIC_EDGE_CLR);
writel(0xffffffff, vic->base + AVIC_EDGE_CLR + 4);
}
static void __exception_irq_entry avic_handle_irq(struct pt_regs *regs)
{
struct aspeed_vic *vic = system_avic;
u32 stat, irq;
for (;;) {
irq = 0;
stat = readl_relaxed(vic->base + AVIC_IRQ_STATUS);
if (!stat) {
stat = readl_relaxed(vic->base + AVIC_IRQ_STATUS + 4);
irq = 32;
}
if (stat == 0)
break;
irq += ffs(stat) - 1;
handle_domain_irq(vic->dom, irq, regs);
}
}
static void avic_ack_irq(struct irq_data *d)
{
struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
unsigned int sidx = d->hwirq >> 5;
unsigned int sbit = 1u << (d->hwirq & 0x1f);
/* Clear edge latch for edge interrupts, nop for level */
if (vic->edge_sources[sidx] & sbit)
writel(sbit, vic->base + AVIC_EDGE_CLR + sidx * 4);
}
static void avic_mask_irq(struct irq_data *d)
{
struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
unsigned int sidx = d->hwirq >> 5;
unsigned int sbit = 1u << (d->hwirq & 0x1f);
writel(sbit, vic->base + AVIC_INT_ENABLE_CLR + sidx * 4);
}
static void avic_unmask_irq(struct irq_data *d)
{
struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
unsigned int sidx = d->hwirq >> 5;
unsigned int sbit = 1u << (d->hwirq & 0x1f);
writel(sbit, vic->base + AVIC_INT_ENABLE + sidx * 4);
}
/* For level irq, faster than going through a nop "ack" and mask */
static void avic_mask_ack_irq(struct irq_data *d)
{
struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
unsigned int sidx = d->hwirq >> 5;
unsigned int sbit = 1u << (d->hwirq & 0x1f);
/* First mask */
writel(sbit, vic->base + AVIC_INT_ENABLE_CLR + sidx * 4);
/* Then clear edge latch for edge interrupts */
if (vic->edge_sources[sidx] & sbit)
writel(sbit, vic->base + AVIC_EDGE_CLR + sidx * 4);
}
static struct irq_chip avic_chip = {
.name = "AVIC",
.irq_ack = avic_ack_irq,
.irq_mask = avic_mask_irq,
.irq_unmask = avic_unmask_irq,
.irq_mask_ack = avic_mask_ack_irq,
};
static int avic_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
struct aspeed_vic *vic = d->host_data;
unsigned int sidx = hwirq >> 5;
unsigned int sbit = 1u << (hwirq & 0x1f);
/* Check if interrupt exists */
if (sidx > 1)
return -EPERM;
if (vic->edge_sources[sidx] & sbit)
irq_set_chip_and_handler(irq, &avic_chip, handle_edge_irq);
else
irq_set_chip_and_handler(irq, &avic_chip, handle_level_irq);
irq_set_chip_data(irq, vic);
irq_set_probe(irq);
return 0;
}
static struct irq_domain_ops avic_dom_ops = {
.map = avic_map,
.xlate = irq_domain_xlate_onetwocell,
};
static int __init avic_of_init(struct device_node *node,
struct device_node *parent)
{
void __iomem *regs;
struct aspeed_vic *vic;
if (WARN(parent, "non-root Aspeed VIC not supported"))
return -EINVAL;
if (WARN(system_avic, "duplicate Aspeed VIC not supported"))
return -EINVAL;
regs = of_iomap(node, 0);
if (WARN_ON(!regs))
return -EIO;
vic = kzalloc(sizeof(struct aspeed_vic), GFP_KERNEL);
if (WARN_ON(!vic)) {
iounmap(regs);
return -ENOMEM;
}
vic->base = regs;
/* Initialize soures, all masked */
vic_init_hw(vic);
/* Ready to receive interrupts */
system_avic = vic;
set_handle_irq(avic_handle_irq);
/* Register our domain */
vic->dom = irq_domain_add_simple(node, NUM_IRQS, 0,
&avic_dom_ops, vic);
return 0;
}
IRQCHIP_DECLARE(aspeed_new_vic, "aspeed,ast2400-vic", avic_of_init);