/*
* Copyright 2010 Broadcom
* Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren
*
* 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.
*
* Quirk 1: Shortcut interrupts don't set the bank 1/2 register pending bits
*
* If an interrupt fires on bank 1 that isn't in the shortcuts list, bit 8
* on bank 0 is set to signify that an interrupt in bank 1 has fired, and
* to look in the bank 1 status register for more information.
*
* If an interrupt fires on bank 1 that _is_ in the shortcuts list, its
* shortcut bit in bank 0 is set as well as its interrupt bit in the bank 1
* status register, but bank 0 bit 8 is _not_ set.
*
* Quirk 2: You can't mask the register 1/2 pending interrupts
*
* In a proper cascaded interrupt controller, the interrupt lines with
* cascaded interrupt controllers on them are just normal interrupt lines.
* You can mask the interrupts and get on with things. With this controller
* you can't do that.
*
* Quirk 3: The shortcut interrupts can't be (un)masked in bank 0
*
* Those interrupts that have shortcuts can only be masked/unmasked in
* their respective banks' enable/disable registers. Doing so in the bank 0
* enable/disable registers has no effect.
*
* The FIQ control register:
* Bits 0-6: IRQ (index in order of interrupts from banks 1, 2, then 0)
* Bit 7: Enable FIQ generation
* Bits 8+: Unused
*
* An interrupt must be disabled before configuring it for FIQ generation
* otherwise both handlers will fire at the same time!
*/
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/irqdomain.h>
#include <linux/irqchip/bcm2835.h>
#include <asm/exception.h>
/* Put the bank and irq (32 bits) into the hwirq */
#define MAKE_HWIRQ(b, n) ((b << 5) | (n))
#define HWIRQ_BANK(i) (i >> 5)
#define HWIRQ_BIT(i) BIT(i & 0x1f)
#define NR_IRQS_BANK0 8
#define BANK0_HWIRQ_MASK 0xff
/* Shortcuts can't be disabled so any unknown new ones need to be masked */
#define SHORTCUT1_MASK 0x00007c00
#define SHORTCUT2_MASK 0x001f8000
#define SHORTCUT_SHIFT 10
#define BANK1_HWIRQ BIT(8)
#define BANK2_HWIRQ BIT(9)
#define BANK0_VALID_MASK (BANK0_HWIRQ_MASK | BANK1_HWIRQ | BANK2_HWIRQ \
| SHORTCUT1_MASK | SHORTCUT2_MASK)
#define REG_FIQ_CONTROL 0x0c
#define NR_BANKS 3
#define IRQS_PER_BANK 32
static int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
static int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
static int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 };
static int bank_irqs[] __initconst = { 8, 32, 32 };
static const int shortcuts[] = {
7, 9, 10, 18, 19, /* Bank 1 */
21, 22, 23, 24, 25, 30 /* Bank 2 */
};
struct armctrl_ic {
void __iomem *base;
void __iomem *pending[NR_BANKS];
void __iomem *enable[NR_BANKS];
void __iomem *disable[NR_BANKS];
struct irq_domain *domain;
};
static struct armctrl_ic intc __read_mostly;
static void armctrl_mask_irq(struct irq_data *d)
{
writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]);
}
static void armctrl_unmask_irq(struct irq_data *d)
{
writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]);
}
static struct irq_chip armctrl_chip = {
.name = "ARMCTRL-level",
.irq_mask = armctrl_mask_irq,
.irq_unmask = armctrl_unmask_irq
};
static int armctrl_xlate(struct irq_domain *d, struct device_node *ctrlr,
const u32 *intspec, unsigned int intsize,
unsigned long *out_hwirq, unsigned int *out_type)
{
if (WARN_ON(intsize != 2))
return -EINVAL;
if (WARN_ON(intspec[0] >= NR_BANKS))
return -EINVAL;
if (WARN_ON(intspec[1] >= IRQS_PER_BANK))
return -EINVAL;
if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0))
return -EINVAL;
*out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]);
*out_type = IRQ_TYPE_NONE;
return 0;
}
static struct irq_domain_ops armctrl_ops = {
.xlate = armctrl_xlate
};
static int __init armctrl_of_init(struct device_node *node,
struct device_node *parent)
{
void __iomem *base;
int irq, b, i;
base = of_iomap(node, 0);
if (!base)
panic("%s: unable to map IC registers\n",
node->full_name);
intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
&armctrl_ops, NULL);
if (!intc.domain)
panic("%s: unable to create IRQ domain\n", node->full_name);
for (b = 0; b < NR_BANKS; b++) {
intc.pending[b] = base + reg_pending[b];
intc.enable[b] = base + reg_enable[b];
intc.disable[b] = base + reg_disable[b];
for (i = 0; i < bank_irqs[b]; i++) {
irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i));
BUG_ON(irq <= 0);
irq_set_chip_and_handler(irq, &armctrl_chip,
handle_level_irq);
set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
}
}
return 0;
}
static struct of_device_id irq_of_match[] __initconst = {
{ .compatible = "brcm,bcm2835-armctrl-ic", .data = armctrl_of_init }
};
void __init bcm2835_init_irq(void)
{
of_irq_init(irq_of_match);
}
/*
* Handle each interrupt across the entire interrupt controller. This reads the
* status register before handling each interrupt, which is necessary given that
* handle_IRQ may briefly re-enable interrupts for soft IRQ handling.
*/
static void armctrl_handle_bank(int bank, struct pt_regs *regs)
{
u32 stat, irq;
while ((stat = readl_relaxed(intc.pending[bank]))) {
irq = MAKE_HWIRQ(bank, ffs(stat) - 1);
handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
}
}
static void armctrl_handle_shortcut(int bank, struct pt_regs *regs,
u32 stat)
{
u32 irq = MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]);
handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
}
asmlinkage void __exception_irq_entry bcm2835_handle_irq(
struct pt_regs *regs)
{
u32 stat, irq;
while ((stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK)) {
if (stat & BANK0_HWIRQ_MASK) {
irq = MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1);
handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
} else if (stat & SHORTCUT1_MASK) {
armctrl_handle_shortcut(1, regs, stat & SHORTCUT1_MASK);
} else if (stat & SHORTCUT2_MASK) {
armctrl_handle_shortcut(2, regs, stat & SHORTCUT2_MASK);
} else if (stat & BANK1_HWIRQ) {
armctrl_handle_bank(1, regs);
} else if (stat & BANK2_HWIRQ) {
armctrl_handle_bank(2, regs);
} else {
BUG();
}
}
}
