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linux-stable/drivers/gpio/gpio-pl061.c
Julia Cartwright 99b9b45de8 gpio: pl061: make use of raw_spinlock variants 
The pl061 gpio driver currently implements an irq_chip for handling
interrupts; due to how irq_chip handling is done, it's necessary for the
irq_chip methods to be invoked from hardirq context, even on a a
real-time kernel.  Because the spinlock_t type becomes a "sleeping"
spinlock w/ RT kernels, it is not suitable to be used with irq_chips.

A quick audit of the operations under the lock reveal that they do only
minimal, bounded work, and are therefore safe to do under a raw spinlock.

Signed-off-by: Julia Cartwright <julia@ni.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-03-16 21:52:09 +01:00

431 lines
11 KiB
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/*
* Copyright (C) 2008, 2009 Provigent Ltd.
*
* Author: Baruch Siach <baruch@tkos.co.il>
*
* 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.
*
* Driver for the ARM PrimeCell(tm) General Purpose Input/Output (PL061)
*
* Data sheet: ARM DDI 0190B, September 2000
*/
#include <linux/spinlock.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/bitops.h>
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/amba/bus.h>
#include <linux/slab.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pm.h>
#define GPIODIR 0x400
#define GPIOIS 0x404
#define GPIOIBE 0x408
#define GPIOIEV 0x40C
#define GPIOIE 0x410
#define GPIORIS 0x414
#define GPIOMIS 0x418
#define GPIOIC 0x41C
#define PL061_GPIO_NR 8
#ifdef CONFIG_PM
struct pl061_context_save_regs {
u8 gpio_data;
u8 gpio_dir;
u8 gpio_is;
u8 gpio_ibe;
u8 gpio_iev;
u8 gpio_ie;
};
#endif
struct pl061 {
raw_spinlock_t lock;
void __iomem *base;
struct gpio_chip gc;
int parent_irq;
#ifdef CONFIG_PM
struct pl061_context_save_regs csave_regs;
#endif
};
static int pl061_get_direction(struct gpio_chip *gc, unsigned offset)
{
struct pl061 *pl061 = gpiochip_get_data(gc);
return !(readb(pl061->base + GPIODIR) & BIT(offset));
}
static int pl061_direction_input(struct gpio_chip *gc, unsigned offset)
{
struct pl061 *pl061 = gpiochip_get_data(gc);
unsigned long flags;
unsigned char gpiodir;
raw_spin_lock_irqsave(&pl061->lock, flags);
gpiodir = readb(pl061->base + GPIODIR);
gpiodir &= ~(BIT(offset));
writeb(gpiodir, pl061->base + GPIODIR);
raw_spin_unlock_irqrestore(&pl061->lock, flags);
return 0;
}
static int pl061_direction_output(struct gpio_chip *gc, unsigned offset,
int value)
{
struct pl061 *pl061 = gpiochip_get_data(gc);
unsigned long flags;
unsigned char gpiodir;
raw_spin_lock_irqsave(&pl061->lock, flags);
writeb(!!value << offset, pl061->base + (BIT(offset + 2)));
gpiodir = readb(pl061->base + GPIODIR);
gpiodir |= BIT(offset);
writeb(gpiodir, pl061->base + GPIODIR);
/*
* gpio value is set again, because pl061 doesn't allow to set value of
* a gpio pin before configuring it in OUT mode.
*/
writeb(!!value << offset, pl061->base + (BIT(offset + 2)));
raw_spin_unlock_irqrestore(&pl061->lock, flags);
return 0;
}
static int pl061_get_value(struct gpio_chip *gc, unsigned offset)
{
struct pl061 *pl061 = gpiochip_get_data(gc);
return !!readb(pl061->base + (BIT(offset + 2)));
}
static void pl061_set_value(struct gpio_chip *gc, unsigned offset, int value)
{
struct pl061 *pl061 = gpiochip_get_data(gc);
writeb(!!value << offset, pl061->base + (BIT(offset + 2)));
}
static int pl061_irq_type(struct irq_data *d, unsigned trigger)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct pl061 *pl061 = gpiochip_get_data(gc);
int offset = irqd_to_hwirq(d);
unsigned long flags;
u8 gpiois, gpioibe, gpioiev;
u8 bit = BIT(offset);
if (offset < 0 || offset >= PL061_GPIO_NR)
return -EINVAL;
if ((trigger & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) &&
(trigger & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING)))
{
dev_err(gc->parent,
"trying to configure line %d for both level and edge "
"detection, choose one!\n",
offset);
return -EINVAL;
}
raw_spin_lock_irqsave(&pl061->lock, flags);
gpioiev = readb(pl061->base + GPIOIEV);
gpiois = readb(pl061->base + GPIOIS);
gpioibe = readb(pl061->base + GPIOIBE);
if (trigger & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) {
bool polarity = trigger & IRQ_TYPE_LEVEL_HIGH;
/* Disable edge detection */
gpioibe &= ~bit;
/* Enable level detection */
gpiois |= bit;
/* Select polarity */
if (polarity)
gpioiev |= bit;
else
gpioiev &= ~bit;
irq_set_handler_locked(d, handle_level_irq);
dev_dbg(gc->parent, "line %d: IRQ on %s level\n",
offset,
polarity ? "HIGH" : "LOW");
} else if ((trigger & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH) {
/* Disable level detection */
gpiois &= ~bit;
/* Select both edges, setting this makes GPIOEV be ignored */
gpioibe |= bit;
irq_set_handler_locked(d, handle_edge_irq);
dev_dbg(gc->parent, "line %d: IRQ on both edges\n", offset);
} else if ((trigger & IRQ_TYPE_EDGE_RISING) ||
(trigger & IRQ_TYPE_EDGE_FALLING)) {
bool rising = trigger & IRQ_TYPE_EDGE_RISING;
/* Disable level detection */
gpiois &= ~bit;
/* Clear detection on both edges */
gpioibe &= ~bit;
/* Select edge */
if (rising)
gpioiev |= bit;
else
gpioiev &= ~bit;
irq_set_handler_locked(d, handle_edge_irq);
dev_dbg(gc->parent, "line %d: IRQ on %s edge\n",
offset,
rising ? "RISING" : "FALLING");
} else {
/* No trigger: disable everything */
gpiois &= ~bit;
gpioibe &= ~bit;
gpioiev &= ~bit;
irq_set_handler_locked(d, handle_bad_irq);
dev_warn(gc->parent, "no trigger selected for line %d\n",
offset);
}
writeb(gpiois, pl061->base + GPIOIS);
writeb(gpioibe, pl061->base + GPIOIBE);
writeb(gpioiev, pl061->base + GPIOIEV);
raw_spin_unlock_irqrestore(&pl061->lock, flags);
return 0;
}
static void pl061_irq_handler(struct irq_desc *desc)
{
unsigned long pending;
int offset;
struct gpio_chip *gc = irq_desc_get_handler_data(desc);
struct pl061 *pl061 = gpiochip_get_data(gc);
struct irq_chip *irqchip = irq_desc_get_chip(desc);
chained_irq_enter(irqchip, desc);
pending = readb(pl061->base + GPIOMIS);
if (pending) {
for_each_set_bit(offset, &pending, PL061_GPIO_NR)
generic_handle_irq(irq_find_mapping(gc->irqdomain,
offset));
}
chained_irq_exit(irqchip, desc);
}
static void pl061_irq_mask(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct pl061 *pl061 = gpiochip_get_data(gc);
u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
u8 gpioie;
raw_spin_lock(&pl061->lock);
gpioie = readb(pl061->base + GPIOIE) & ~mask;
writeb(gpioie, pl061->base + GPIOIE);
raw_spin_unlock(&pl061->lock);
}
static void pl061_irq_unmask(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct pl061 *pl061 = gpiochip_get_data(gc);
u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
u8 gpioie;
raw_spin_lock(&pl061->lock);
gpioie = readb(pl061->base + GPIOIE) | mask;
writeb(gpioie, pl061->base + GPIOIE);
raw_spin_unlock(&pl061->lock);
}
/**
* pl061_irq_ack() - ACK an edge IRQ
* @d: IRQ data for this IRQ
*
* This gets called from the edge IRQ handler to ACK the edge IRQ
* in the GPIOIC (interrupt-clear) register. For level IRQs this is
* not needed: these go away when the level signal goes away.
*/
static void pl061_irq_ack(struct irq_data *d)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct pl061 *pl061 = gpiochip_get_data(gc);
u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR);
raw_spin_lock(&pl061->lock);
writeb(mask, pl061->base + GPIOIC);
raw_spin_unlock(&pl061->lock);
}
static int pl061_irq_set_wake(struct irq_data *d, unsigned int state)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
struct pl061 *pl061 = gpiochip_get_data(gc);
return irq_set_irq_wake(pl061->parent_irq, state);
}
static struct irq_chip pl061_irqchip = {
.name = "pl061",
.irq_ack = pl061_irq_ack,
.irq_mask = pl061_irq_mask,
.irq_unmask = pl061_irq_unmask,
.irq_set_type = pl061_irq_type,
.irq_set_wake = pl061_irq_set_wake,
};
static int pl061_probe(struct amba_device *adev, const struct amba_id *id)
{
struct device *dev = &adev->dev;
struct pl061 *pl061;
int ret, irq;
pl061 = devm_kzalloc(dev, sizeof(*pl061), GFP_KERNEL);
if (pl061 == NULL)
return -ENOMEM;
pl061->base = devm_ioremap_resource(dev, &adev->res);
if (IS_ERR(pl061->base))
return PTR_ERR(pl061->base);
raw_spin_lock_init(&pl061->lock);
if (of_property_read_bool(dev->of_node, "gpio-ranges")) {
pl061->gc.request = gpiochip_generic_request;
pl061->gc.free = gpiochip_generic_free;
}
pl061->gc.base = -1;
pl061->gc.get_direction = pl061_get_direction;
pl061->gc.direction_input = pl061_direction_input;
pl061->gc.direction_output = pl061_direction_output;
pl061->gc.get = pl061_get_value;
pl061->gc.set = pl061_set_value;
pl061->gc.ngpio = PL061_GPIO_NR;
pl061->gc.label = dev_name(dev);
pl061->gc.parent = dev;
pl061->gc.owner = THIS_MODULE;
ret = gpiochip_add_data(&pl061->gc, pl061);
if (ret)
return ret;
/*
* irq_chip support
*/
writeb(0, pl061->base + GPIOIE); /* disable irqs */
irq = adev->irq[0];
if (irq < 0) {
dev_err(&adev->dev, "invalid IRQ\n");
return -ENODEV;
}
pl061->parent_irq = irq;
ret = gpiochip_irqchip_add(&pl061->gc, &pl061_irqchip,
0, handle_bad_irq,
IRQ_TYPE_NONE);
if (ret) {
dev_info(&adev->dev, "could not add irqchip\n");
return ret;
}
gpiochip_set_chained_irqchip(&pl061->gc, &pl061_irqchip,
irq, pl061_irq_handler);
amba_set_drvdata(adev, pl061);
dev_info(&adev->dev, "PL061 GPIO chip @%pa registered\n",
&adev->res.start);
return 0;
}
#ifdef CONFIG_PM
static int pl061_suspend(struct device *dev)
{
struct pl061 *pl061 = dev_get_drvdata(dev);
int offset;
pl061->csave_regs.gpio_data = 0;
pl061->csave_regs.gpio_dir = readb(pl061->base + GPIODIR);
pl061->csave_regs.gpio_is = readb(pl061->base + GPIOIS);
pl061->csave_regs.gpio_ibe = readb(pl061->base + GPIOIBE);
pl061->csave_regs.gpio_iev = readb(pl061->base + GPIOIEV);
pl061->csave_regs.gpio_ie = readb(pl061->base + GPIOIE);
for (offset = 0; offset < PL061_GPIO_NR; offset++) {
if (pl061->csave_regs.gpio_dir & (BIT(offset)))
pl061->csave_regs.gpio_data |=
pl061_get_value(&pl061->gc, offset) << offset;
}
return 0;
}
static int pl061_resume(struct device *dev)
{
struct pl061 *pl061 = dev_get_drvdata(dev);
int offset;
for (offset = 0; offset < PL061_GPIO_NR; offset++) {
if (pl061->csave_regs.gpio_dir & (BIT(offset)))
pl061_direction_output(&pl061->gc, offset,
pl061->csave_regs.gpio_data &
(BIT(offset)));
else
pl061_direction_input(&pl061->gc, offset);
}
writeb(pl061->csave_regs.gpio_is, pl061->base + GPIOIS);
writeb(pl061->csave_regs.gpio_ibe, pl061->base + GPIOIBE);
writeb(pl061->csave_regs.gpio_iev, pl061->base + GPIOIEV);
writeb(pl061->csave_regs.gpio_ie, pl061->base + GPIOIE);
return 0;
}
static const struct dev_pm_ops pl061_dev_pm_ops = {
.suspend = pl061_suspend,
.resume = pl061_resume,
.freeze = pl061_suspend,
.restore = pl061_resume,
};
#endif
static struct amba_id pl061_ids[] = {
{
.id = 0x00041061,
.mask = 0x000fffff,
},
{ 0, 0 },
};
static struct amba_driver pl061_gpio_driver = {
.drv = {
.name = "pl061_gpio",
#ifdef CONFIG_PM
.pm = &pl061_dev_pm_ops,
#endif
},
.id_table = pl061_ids,
.probe = pl061_probe,
};
static int __init pl061_gpio_init(void)
{
return amba_driver_register(&pl061_gpio_driver);
}
device_initcall(pl061_gpio_init);
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