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linux-next/drivers/irqchip/irq-gic-common.c
Liviu Dudau fb7e7deb7f irqchip: gic: Allow interrupt level to be set for PPIs
During a recent cleanup of the arm64 DTs it has become clear that
the handling of PPIs in xxxx_set_type() is incorrect. The ARM TRMs
for GICv2 and later allow for "implementation defined" support for
setting the edge or level type of the PPI interrupts and don't restrict
the activation level of the signal. Current ARM implementations
do restrict the PPI level type to IRQ_TYPE_LEVEL_LOW, but licensees
of the IP can decide to shoot themselves in the foot at any time.

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Acked-by: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: LAKML <linux-arm-kernel@lists.infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Haojian Zhuang <haojian.zhuang@linaro.org>
Link: http://lkml.kernel.org/r/1421772779-25764-1-git-send-email-Liviu.Dudau@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-01-26 11:38:23 +01:00

125 lines
3.3 KiB
C

/*
* Copyright (C) 2002 ARM Limited, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqchip/arm-gic.h>
#include "irq-gic-common.h"
int gic_configure_irq(unsigned int irq, unsigned int type,
void __iomem *base, void (*sync_access)(void))
{
u32 enablemask = 1 << (irq % 32);
u32 enableoff = (irq / 32) * 4;
u32 confmask = 0x2 << ((irq % 16) * 2);
u32 confoff = (irq / 16) * 4;
bool enabled = false;
u32 val, oldval;
int ret = 0;
/*
* Read current configuration register, and insert the config
* for "irq", depending on "type".
*/
val = oldval = readl_relaxed(base + GIC_DIST_CONFIG + confoff);
if (type & IRQ_TYPE_LEVEL_MASK)
val &= ~confmask;
else if (type & IRQ_TYPE_EDGE_BOTH)
val |= confmask;
/*
* As recommended by the spec, disable the interrupt before changing
* the configuration
*/
if (readl_relaxed(base + GIC_DIST_ENABLE_SET + enableoff) & enablemask) {
writel_relaxed(enablemask, base + GIC_DIST_ENABLE_CLEAR + enableoff);
if (sync_access)
sync_access();
enabled = true;
}
/*
* Write back the new configuration, and possibly re-enable
* the interrupt. If we tried to write a new configuration and failed,
* return an error.
*/
writel_relaxed(val, base + GIC_DIST_CONFIG + confoff);
if (readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val && val != oldval)
ret = -EINVAL;
if (enabled)
writel_relaxed(enablemask, base + GIC_DIST_ENABLE_SET + enableoff);
if (sync_access)
sync_access();
return ret;
}
void __init gic_dist_config(void __iomem *base, int gic_irqs,
void (*sync_access)(void))
{
unsigned int i;
/*
* Set all global interrupts to be level triggered, active low.
*/
for (i = 32; i < gic_irqs; i += 16)
writel_relaxed(GICD_INT_ACTLOW_LVLTRIG,
base + GIC_DIST_CONFIG + i / 4);
/*
* Set priority on all global interrupts.
*/
for (i = 32; i < gic_irqs; i += 4)
writel_relaxed(GICD_INT_DEF_PRI_X4, base + GIC_DIST_PRI + i);
/*
* Disable all interrupts. Leave the PPI and SGIs alone
* as they are enabled by redistributor registers.
*/
for (i = 32; i < gic_irqs; i += 32)
writel_relaxed(GICD_INT_EN_CLR_X32,
base + GIC_DIST_ENABLE_CLEAR + i / 8);
if (sync_access)
sync_access();
}
void gic_cpu_config(void __iomem *base, void (*sync_access)(void))
{
int i;
/*
* Deal with the banked PPI and SGI interrupts - disable all
* PPI interrupts, ensure all SGI interrupts are enabled.
*/
writel_relaxed(GICD_INT_EN_CLR_PPI, base + GIC_DIST_ENABLE_CLEAR);
writel_relaxed(GICD_INT_EN_SET_SGI, base + GIC_DIST_ENABLE_SET);
/*
* Set priority on PPI and SGI interrupts
*/
for (i = 0; i < 32; i += 4)
writel_relaxed(GICD_INT_DEF_PRI_X4,
base + GIC_DIST_PRI + i * 4 / 4);
if (sync_access)
sync_access();
}