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linux-next/arch/arm/mach-tegra/irq.c
Joseph Lo 7e8b15dbc3 ARM: tegra114: Reprogram GIC CPU interface to bypass IRQ on CPU PM entry 
There is a difference between GICv1 and v2 when CPU in power management
mode (aka CPU power down on Tegra). For GICv1, IRQ/FIQ interrupt lines
going to CPU are same lines which are also used for wake-interrupt.
Therefore, we cannot disable the GIC CPU interface if we need to use same
interrupts for CPU wake purpose. This creates a race condition for CPU
power off entry. Also, in GICv1, disabling GICv1 CPU interface puts GICv1
into bypass mode such that incoming legacy IRQ/FIQ are sent to CPU, which
means disabling GIC CPU interface doesn't really disable IRQ/FIQ to CPU.

GICv2 provides a wake IRQ/FIQ (for wake-event purpose), which are not
disabled by GIC CPU interface. This is done by adding a bypass override
capability when the interrupts are disabled at the CPU interface. To
support this, there are four bits about IRQ/FIQ BypassDisable in CPU
interface Control Register. When the IRQ/FIQ not being driver by the
CPU interface, each interrupt output signal can be deasserted rather
than being driven by the legacy interrupt input.

So the wake-event can be used as wakeup signals to SoC (system power
controller).

To prevent race conditions and ensure proper interrupt routing on
Cortex-A15 CPUs when they are power-gated, add a CPU PM notifier
call-back to reprogram the GIC CPU interface on PM entry. The
GIC CPU interface will be reset back to its normal state by
the common GIC CPU PM exit callback when the CPU wakes up.

Based on the work by: Scott Williams <scwilliams@nvidia.com>

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
2013-07-19 10:07:14 -06:00

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/*
* Copyright (C) 2011 Google, Inc.
*
* Author:
* Colin Cross <ccross@android.com>
*
* Copyright (C) 2010,2013, NVIDIA Corporation
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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/kernel.h>
#include <linux/cpu_pm.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/irqchip/arm-gic.h>
#include <linux/syscore_ops.h>
#include "board.h"
#include "iomap.h"
#define ICTLR_CPU_IEP_VFIQ 0x08
#define ICTLR_CPU_IEP_FIR 0x14
#define ICTLR_CPU_IEP_FIR_SET 0x18
#define ICTLR_CPU_IEP_FIR_CLR 0x1c
#define ICTLR_CPU_IER 0x20
#define ICTLR_CPU_IER_SET 0x24
#define ICTLR_CPU_IER_CLR 0x28
#define ICTLR_CPU_IEP_CLASS 0x2C
#define ICTLR_COP_IER 0x30
#define ICTLR_COP_IER_SET 0x34
#define ICTLR_COP_IER_CLR 0x38
#define ICTLR_COP_IEP_CLASS 0x3c
#define FIRST_LEGACY_IRQ 32
#define TEGRA_MAX_NUM_ICTLRS 5
#define SGI_MASK 0xFFFF
static int num_ictlrs;
static void __iomem *ictlr_reg_base[] = {
IO_ADDRESS(TEGRA_PRIMARY_ICTLR_BASE),
IO_ADDRESS(TEGRA_SECONDARY_ICTLR_BASE),
IO_ADDRESS(TEGRA_TERTIARY_ICTLR_BASE),
IO_ADDRESS(TEGRA_QUATERNARY_ICTLR_BASE),
IO_ADDRESS(TEGRA_QUINARY_ICTLR_BASE),
};
#ifdef CONFIG_PM_SLEEP
static u32 cop_ier[TEGRA_MAX_NUM_ICTLRS];
static u32 cop_iep[TEGRA_MAX_NUM_ICTLRS];
static u32 cpu_ier[TEGRA_MAX_NUM_ICTLRS];
static u32 cpu_iep[TEGRA_MAX_NUM_ICTLRS];
static u32 ictlr_wake_mask[TEGRA_MAX_NUM_ICTLRS];
static void __iomem *tegra_gic_cpu_base;
#endif
bool tegra_pending_sgi(void)
{
u32 pending_set;
void __iomem *distbase = IO_ADDRESS(TEGRA_ARM_INT_DIST_BASE);
pending_set = readl_relaxed(distbase + GIC_DIST_PENDING_SET);
if (pending_set & SGI_MASK)
return true;
return false;
}
static inline void tegra_irq_write_mask(unsigned int irq, unsigned long reg)
{
void __iomem *base;
u32 mask;
BUG_ON(irq < FIRST_LEGACY_IRQ ||
irq >= FIRST_LEGACY_IRQ + num_ictlrs * 32);
base = ictlr_reg_base[(irq - FIRST_LEGACY_IRQ) / 32];
mask = BIT((irq - FIRST_LEGACY_IRQ) % 32);
__raw_writel(mask, base + reg);
}
static void tegra_mask(struct irq_data *d)
{
if (d->irq < FIRST_LEGACY_IRQ)
return;
tegra_irq_write_mask(d->irq, ICTLR_CPU_IER_CLR);
}
static void tegra_unmask(struct irq_data *d)
{
if (d->irq < FIRST_LEGACY_IRQ)
return;
tegra_irq_write_mask(d->irq, ICTLR_CPU_IER_SET);
}
static void tegra_ack(struct irq_data *d)
{
if (d->irq < FIRST_LEGACY_IRQ)
return;
tegra_irq_write_mask(d->irq, ICTLR_CPU_IEP_FIR_CLR);
}
static void tegra_eoi(struct irq_data *d)
{
if (d->irq < FIRST_LEGACY_IRQ)
return;
tegra_irq_write_mask(d->irq, ICTLR_CPU_IEP_FIR_CLR);
}
static int tegra_retrigger(struct irq_data *d)
{
if (d->irq < FIRST_LEGACY_IRQ)
return 0;
tegra_irq_write_mask(d->irq, ICTLR_CPU_IEP_FIR_SET);
return 1;
}
#ifdef CONFIG_PM_SLEEP
static int tegra_set_wake(struct irq_data *d, unsigned int enable)
{
u32 irq = d->irq;
u32 index, mask;
if (irq < FIRST_LEGACY_IRQ ||
irq >= FIRST_LEGACY_IRQ + num_ictlrs * 32)
return -EINVAL;
index = ((irq - FIRST_LEGACY_IRQ) / 32);
mask = BIT((irq - FIRST_LEGACY_IRQ) % 32);
if (enable)
ictlr_wake_mask[index] |= mask;
else
ictlr_wake_mask[index] &= ~mask;
return 0;
}
static int tegra_legacy_irq_suspend(void)
{
unsigned long flags;
int i;
local_irq_save(flags);
for (i = 0; i < num_ictlrs; i++) {
void __iomem *ictlr = ictlr_reg_base[i];
/* Save interrupt state */
cpu_ier[i] = readl_relaxed(ictlr + ICTLR_CPU_IER);
cpu_iep[i] = readl_relaxed(ictlr + ICTLR_CPU_IEP_CLASS);
cop_ier[i] = readl_relaxed(ictlr + ICTLR_COP_IER);
cop_iep[i] = readl_relaxed(ictlr + ICTLR_COP_IEP_CLASS);
/* Disable COP interrupts */
writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
/* Disable CPU interrupts */
writel_relaxed(~0ul, ictlr + ICTLR_CPU_IER_CLR);
/* Enable the wakeup sources of ictlr */
writel_relaxed(ictlr_wake_mask[i], ictlr + ICTLR_CPU_IER_SET);
}
local_irq_restore(flags);
return 0;
}
static void tegra_legacy_irq_resume(void)
{
unsigned long flags;
int i;
local_irq_save(flags);
for (i = 0; i < num_ictlrs; i++) {
void __iomem *ictlr = ictlr_reg_base[i];
writel_relaxed(cpu_iep[i], ictlr + ICTLR_CPU_IEP_CLASS);
writel_relaxed(~0ul, ictlr + ICTLR_CPU_IER_CLR);
writel_relaxed(cpu_ier[i], ictlr + ICTLR_CPU_IER_SET);
writel_relaxed(cop_iep[i], ictlr + ICTLR_COP_IEP_CLASS);
writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
writel_relaxed(cop_ier[i], ictlr + ICTLR_COP_IER_SET);
}
local_irq_restore(flags);
}
static struct syscore_ops tegra_legacy_irq_syscore_ops = {
.suspend = tegra_legacy_irq_suspend,
.resume = tegra_legacy_irq_resume,
};
int tegra_legacy_irq_syscore_init(void)
{
register_syscore_ops(&tegra_legacy_irq_syscore_ops);
return 0;
}
static int tegra_gic_notifier(struct notifier_block *self,
unsigned long cmd, void *v)
{
switch (cmd) {
case CPU_PM_ENTER:
writel_relaxed(0x1E0, tegra_gic_cpu_base + GIC_CPU_CTRL);
break;
}
return NOTIFY_OK;
}
static struct notifier_block tegra_gic_notifier_block = {
.notifier_call = tegra_gic_notifier,
};
static const struct of_device_id tegra114_dt_gic_match[] __initconst = {
{ .compatible = "arm,cortex-a15-gic" },
{ }
};
static void tegra114_gic_cpu_pm_registration(void)
{
struct device_node *dn;
dn = of_find_matching_node(NULL, tegra114_dt_gic_match);
if (!dn)
return;
tegra_gic_cpu_base = of_iomap(dn, 1);
cpu_pm_register_notifier(&tegra_gic_notifier_block);
}
#else
#define tegra_set_wake NULL
static void tegra114_gic_cpu_pm_registration(void) { }
#endif
void __init tegra_init_irq(void)
{
int i;
void __iomem *distbase;
distbase = IO_ADDRESS(TEGRA_ARM_INT_DIST_BASE);
num_ictlrs = readl_relaxed(distbase + GIC_DIST_CTR) & 0x1f;
if (num_ictlrs > ARRAY_SIZE(ictlr_reg_base)) {
WARN(1, "Too many (%d) interrupt controllers found. Maximum is %d.",
num_ictlrs, ARRAY_SIZE(ictlr_reg_base));
num_ictlrs = ARRAY_SIZE(ictlr_reg_base);
}
for (i = 0; i < num_ictlrs; i++) {
void __iomem *ictlr = ictlr_reg_base[i];
writel(~0, ictlr + ICTLR_CPU_IER_CLR);
writel(0, ictlr + ICTLR_CPU_IEP_CLASS);
}
gic_arch_extn.irq_ack = tegra_ack;
gic_arch_extn.irq_eoi = tegra_eoi;
gic_arch_extn.irq_mask = tegra_mask;
gic_arch_extn.irq_unmask = tegra_unmask;
gic_arch_extn.irq_retrigger = tegra_retrigger;
gic_arch_extn.irq_set_wake = tegra_set_wake;
gic_arch_extn.flags = IRQCHIP_MASK_ON_SUSPEND;
/*
* Check if there is a devicetree present, since the GIC will be
* initialized elsewhere under DT.
*/
if (!of_have_populated_dt())
gic_init(0, 29, distbase,
IO_ADDRESS(TEGRA_ARM_PERIF_BASE + 0x100));
tegra114_gic_cpu_pm_registration();
}
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