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linux/drivers/gpio/gpio-104-dio-48e.c
William Breathitt Gray d15d6cf916 gpio: 104-dio-48e: Fix control port offset computation off-by-one error 
There are only two control ports, each controlling three distinct I/O
ports. To compute the control port address offset for a respective I/O
port, the I/O port address offset should be divided by 3; dividing by 2
may result in not only the wrong address offset but possibly also an
out-of-bounds array memory access for a non-existent third control port.

Fixes: 1b06d64f73 ("gpio: Add GPIO support for the ACCES 104-DIO-48E")
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-06-08 10:08:12 +02:00

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/*
* GPIO driver for the ACCES 104-DIO-48E series
* Copyright (C) 2016 William Breathitt Gray
*
* 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.
*
* This driver supports the following ACCES devices: 104-DIO-48E and
* 104-DIO-24E.
*/
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/irqdesc.h>
#include <linux/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#define DIO48E_EXTENT 16
#define MAX_NUM_DIO48E max_num_isa_dev(DIO48E_EXTENT)
static unsigned int base[MAX_NUM_DIO48E];
static unsigned int num_dio48e;
module_param_array(base, uint, &num_dio48e, 0);
MODULE_PARM_DESC(base, "ACCES 104-DIO-48E base addresses");
static unsigned int irq[MAX_NUM_DIO48E];
module_param_array(irq, uint, NULL, 0);
MODULE_PARM_DESC(irq, "ACCES 104-DIO-48E interrupt line numbers");
/**
* struct dio48e_gpio - GPIO device private data structure
* @chip: instance of the gpio_chip
* @io_state: bit I/O state (whether bit is set to input or output)
* @out_state: output bits state
* @control: Control registers state
* @lock: synchronization lock to prevent I/O race conditions
* @base: base port address of the GPIO device
* @irq: Interrupt line number
* @irq_mask: I/O bits affected by interrupts
*/
struct dio48e_gpio {
struct gpio_chip chip;
unsigned char io_state[6];
unsigned char out_state[6];
unsigned char control[2];
spinlock_t lock;
unsigned base;
unsigned irq;
unsigned char irq_mask;
};
static int dio48e_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
return !!(dio48egpio->io_state[port] & mask);
}
static int dio48e_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned io_port = offset / 8;
const unsigned int control_port = io_port / 3;
const unsigned control_addr = dio48egpio->base + 3 + control_port*4;
unsigned long flags;
unsigned control;
spin_lock_irqsave(&dio48egpio->lock, flags);
/* Check if configuring Port C */
if (io_port == 2 || io_port == 5) {
/* Port C can be configured by nibble */
if (offset % 8 > 3) {
dio48egpio->io_state[io_port] |= 0xF0;
dio48egpio->control[control_port] |= BIT(3);
} else {
dio48egpio->io_state[io_port] |= 0x0F;
dio48egpio->control[control_port] |= BIT(0);
}
} else {
dio48egpio->io_state[io_port] |= 0xFF;
if (io_port == 0 || io_port == 3)
dio48egpio->control[control_port] |= BIT(4);
else
dio48egpio->control[control_port] |= BIT(1);
}
control = BIT(7) | dio48egpio->control[control_port];
outb(control, control_addr);
control &= ~BIT(7);
outb(control, control_addr);
spin_unlock_irqrestore(&dio48egpio->lock, flags);
return 0;
}
static int dio48e_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
int value)
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned io_port = offset / 8;
const unsigned int control_port = io_port / 3;
const unsigned mask = BIT(offset % 8);
const unsigned control_addr = dio48egpio->base + 3 + control_port*4;
const unsigned out_port = (io_port > 2) ? io_port + 1 : io_port;
unsigned long flags;
unsigned control;
spin_lock_irqsave(&dio48egpio->lock, flags);
/* Check if configuring Port C */
if (io_port == 2 || io_port == 5) {
/* Port C can be configured by nibble */
if (offset % 8 > 3) {
dio48egpio->io_state[io_port] &= 0x0F;
dio48egpio->control[control_port] &= ~BIT(3);
} else {
dio48egpio->io_state[io_port] &= 0xF0;
dio48egpio->control[control_port] &= ~BIT(0);
}
} else {
dio48egpio->io_state[io_port] &= 0x00;
if (io_port == 0 || io_port == 3)
dio48egpio->control[control_port] &= ~BIT(4);
else
dio48egpio->control[control_port] &= ~BIT(1);
}
if (value)
dio48egpio->out_state[io_port] |= mask;
else
dio48egpio->out_state[io_port] &= ~mask;
control = BIT(7) | dio48egpio->control[control_port];
outb(control, control_addr);
outb(dio48egpio->out_state[io_port], dio48egpio->base + out_port);
control &= ~BIT(7);
outb(control, control_addr);
spin_unlock_irqrestore(&dio48egpio->lock, flags);
return 0;
}
static int dio48e_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
const unsigned in_port = (port > 2) ? port + 1 : port;
unsigned long flags;
unsigned port_state;
spin_lock_irqsave(&dio48egpio->lock, flags);
/* ensure that GPIO is set for input */
if (!(dio48egpio->io_state[port] & mask)) {
spin_unlock_irqrestore(&dio48egpio->lock, flags);
return -EINVAL;
}
port_state = inb(dio48egpio->base + in_port);
spin_unlock_irqrestore(&dio48egpio->lock, flags);
return !!(port_state & mask);
}
static void dio48e_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
const unsigned out_port = (port > 2) ? port + 1 : port;
unsigned long flags;
spin_lock_irqsave(&dio48egpio->lock, flags);
if (value)
dio48egpio->out_state[port] |= mask;
else
dio48egpio->out_state[port] &= ~mask;
outb(dio48egpio->out_state[port], dio48egpio->base + out_port);
spin_unlock_irqrestore(&dio48egpio->lock, flags);
}
static void dio48e_irq_ack(struct irq_data *data)
{
}
static void dio48e_irq_mask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned long offset = irqd_to_hwirq(data);
unsigned long flags;
/* only bit 3 on each respective Port C supports interrupts */
if (offset != 19 && offset != 43)
return;
spin_lock_irqsave(&dio48egpio->lock, flags);
if (offset == 19)
dio48egpio->irq_mask &= ~BIT(0);
else
dio48egpio->irq_mask &= ~BIT(1);
if (!dio48egpio->irq_mask)
/* disable interrupts */
inb(dio48egpio->base + 0xB);
spin_unlock_irqrestore(&dio48egpio->lock, flags);
}
static void dio48e_irq_unmask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
const unsigned long offset = irqd_to_hwirq(data);
unsigned long flags;
/* only bit 3 on each respective Port C supports interrupts */
if (offset != 19 && offset != 43)
return;
spin_lock_irqsave(&dio48egpio->lock, flags);
if (!dio48egpio->irq_mask) {
/* enable interrupts */
outb(0x00, dio48egpio->base + 0xF);
outb(0x00, dio48egpio->base + 0xB);
}
if (offset == 19)
dio48egpio->irq_mask |= BIT(0);
else
dio48egpio->irq_mask |= BIT(1);
spin_unlock_irqrestore(&dio48egpio->lock, flags);
}
static int dio48e_irq_set_type(struct irq_data *data, unsigned flow_type)
{
const unsigned long offset = irqd_to_hwirq(data);
/* only bit 3 on each respective Port C supports interrupts */
if (offset != 19 && offset != 43)
return -EINVAL;
if (flow_type != IRQ_TYPE_NONE && flow_type != IRQ_TYPE_EDGE_RISING)
return -EINVAL;
return 0;
}
static struct irq_chip dio48e_irqchip = {
.name = "104-dio-48e",
.irq_ack = dio48e_irq_ack,
.irq_mask = dio48e_irq_mask,
.irq_unmask = dio48e_irq_unmask,
.irq_set_type = dio48e_irq_set_type
};
static irqreturn_t dio48e_irq_handler(int irq, void *dev_id)
{
struct dio48e_gpio *const dio48egpio = dev_id;
struct gpio_chip *const chip = &dio48egpio->chip;
const unsigned long irq_mask = dio48egpio->irq_mask;
unsigned long gpio;
for_each_set_bit(gpio, &irq_mask, 2)
generic_handle_irq(irq_find_mapping(chip->irqdomain,
19 + gpio*24));
spin_lock(&dio48egpio->lock);
outb(0x00, dio48egpio->base + 0xF);
spin_unlock(&dio48egpio->lock);
return IRQ_HANDLED;
}
static int dio48e_probe(struct device *dev, unsigned int id)
{
struct dio48e_gpio *dio48egpio;
const char *const name = dev_name(dev);
int err;
dio48egpio = devm_kzalloc(dev, sizeof(*dio48egpio), GFP_KERNEL);
if (!dio48egpio)
return -ENOMEM;
if (!devm_request_region(dev, base[id], DIO48E_EXTENT, name)) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
base[id], base[id] + DIO48E_EXTENT);
return -EBUSY;
}
dio48egpio->chip.label = name;
dio48egpio->chip.parent = dev;
dio48egpio->chip.owner = THIS_MODULE;
dio48egpio->chip.base = -1;
dio48egpio->chip.ngpio = 48;
dio48egpio->chip.get_direction = dio48e_gpio_get_direction;
dio48egpio->chip.direction_input = dio48e_gpio_direction_input;
dio48egpio->chip.direction_output = dio48e_gpio_direction_output;
dio48egpio->chip.get = dio48e_gpio_get;
dio48egpio->chip.set = dio48e_gpio_set;
dio48egpio->base = base[id];
dio48egpio->irq = irq[id];
spin_lock_init(&dio48egpio->lock);
dev_set_drvdata(dev, dio48egpio);
err = gpiochip_add_data(&dio48egpio->chip, dio48egpio);
if (err) {
dev_err(dev, "GPIO registering failed (%d)\n", err);
return err;
}
/* initialize all GPIO as output */
outb(0x80, base[id] + 3);
outb(0x00, base[id]);
outb(0x00, base[id] + 1);
outb(0x00, base[id] + 2);
outb(0x00, base[id] + 3);
outb(0x80, base[id] + 7);
outb(0x00, base[id] + 4);
outb(0x00, base[id] + 5);
outb(0x00, base[id] + 6);
outb(0x00, base[id] + 7);
/* disable IRQ by default */
inb(base[id] + 0xB);
err = gpiochip_irqchip_add(&dio48egpio->chip, &dio48e_irqchip, 0,
handle_edge_irq, IRQ_TYPE_NONE);
if (err) {
dev_err(dev, "Could not add irqchip (%d)\n", err);
goto err_gpiochip_remove;
}
err = request_irq(irq[id], dio48e_irq_handler, 0, name, dio48egpio);
if (err) {
dev_err(dev, "IRQ handler registering failed (%d)\n", err);
goto err_gpiochip_remove;
}
return 0;
err_gpiochip_remove:
gpiochip_remove(&dio48egpio->chip);
return err;
}
static int dio48e_remove(struct device *dev, unsigned int id)
{
struct dio48e_gpio *const dio48egpio = dev_get_drvdata(dev);
free_irq(dio48egpio->irq, dio48egpio);
gpiochip_remove(&dio48egpio->chip);
return 0;
}
static struct isa_driver dio48e_driver = {
.probe = dio48e_probe,
.driver = {
.name = "104-dio-48e"
},
.remove = dio48e_remove
};
module_isa_driver(dio48e_driver, num_dio48e);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES 104-DIO-48E GPIO driver");
MODULE_LICENSE("GPL v2");
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