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linux_dsm_epyc7002/drivers/gpio/gpio-104-idio-16.c
David Howells d759f90679 Annotate hardware config module parameters in drivers/gpio/ 
When the kernel is running in secure boot mode, we lock down the kernel to
prevent userspace from modifying the running kernel image.  Whilst this
includes prohibiting access to things like /dev/mem, it must also prevent
access by means of configuring driver modules in such a way as to cause a
device to access or modify the kernel image.

To this end, annotate module_param* statements that refer to hardware
configuration and indicate for future reference what type of parameter they
specify.  The parameter parser in the core sees this information and can
skip such parameters with an error message if the kernel is locked down.
The module initialisation then runs as normal, but just sees whatever the
default values for those parameters is.

Note that we do still need to do the module initialisation because some
drivers have viable defaults set in case parameters aren't specified and
some drivers support automatic configuration (e.g. PNP or PCI) in addition
to manually coded parameters.

This patch annotates drivers in drivers/gpio/.

Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
cc: Alexandre Courbot <gnurou@gmail.com>
cc: linux-gpio@vger.kernel.org
2017-04-20 12:02:32 +01:00

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/*
* GPIO driver for the ACCES 104-IDIO-16 family
* Copyright (C) 2015 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-IDIO-16,
* 104-IDIO-16E, 104-IDO-16, 104-IDIO-8, 104-IDIO-8E, and 104-IDO-8.
*/
#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 IDIO_16_EXTENT 8
#define MAX_NUM_IDIO_16 max_num_isa_dev(IDIO_16_EXTENT)
static unsigned int base[MAX_NUM_IDIO_16];
static unsigned int num_idio_16;
module_param_hw_array(base, uint, ioport, &num_idio_16, 0);
MODULE_PARM_DESC(base, "ACCES 104-IDIO-16 base addresses");
static unsigned int irq[MAX_NUM_IDIO_16];
module_param_hw_array(irq, uint, irq, NULL, 0);
MODULE_PARM_DESC(irq, "ACCES 104-IDIO-16 interrupt line numbers");
/**
* struct idio_16_gpio - GPIO device private data structure
* @chip: instance of the gpio_chip
* @lock: synchronization lock to prevent I/O race conditions
* @irq_mask: I/O bits affected by interrupts
* @base: base port address of the GPIO device
* @out_state: output bits state
*/
struct idio_16_gpio {
struct gpio_chip chip;
spinlock_t lock;
unsigned long irq_mask;
unsigned base;
unsigned out_state;
};
static int idio_16_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
if (offset > 15)
return 1;
return 0;
}
static int idio_16_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
return 0;
}
static int idio_16_gpio_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
chip->set(chip, offset, value);
return 0;
}
static int idio_16_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
const unsigned mask = BIT(offset-16);
if (offset < 16)
return -EINVAL;
if (offset < 24)
return !!(inb(idio16gpio->base + 1) & mask);
return !!(inb(idio16gpio->base + 5) & (mask>>8));
}
static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
const unsigned mask = BIT(offset);
unsigned long flags;
if (offset > 15)
return;
spin_lock_irqsave(&idio16gpio->lock, flags);
if (value)
idio16gpio->out_state |= mask;
else
idio16gpio->out_state &= ~mask;
if (offset > 7)
outb(idio16gpio->out_state >> 8, idio16gpio->base + 4);
else
outb(idio16gpio->out_state, idio16gpio->base);
spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
unsigned long flags;
spin_lock_irqsave(&idio16gpio->lock, flags);
idio16gpio->out_state &= ~*mask;
idio16gpio->out_state |= *mask & *bits;
if (*mask & 0xFF)
outb(idio16gpio->out_state, idio16gpio->base);
if ((*mask >> 8) & 0xFF)
outb(idio16gpio->out_state >> 8, idio16gpio->base + 4);
spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
static void idio_16_irq_ack(struct irq_data *data)
{
}
static void idio_16_irq_mask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
const unsigned long mask = BIT(irqd_to_hwirq(data));
unsigned long flags;
idio16gpio->irq_mask &= ~mask;
if (!idio16gpio->irq_mask) {
spin_lock_irqsave(&idio16gpio->lock, flags);
outb(0, idio16gpio->base + 2);
spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
}
static void idio_16_irq_unmask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
const unsigned long mask = BIT(irqd_to_hwirq(data));
const unsigned long prev_irq_mask = idio16gpio->irq_mask;
unsigned long flags;
idio16gpio->irq_mask |= mask;
if (!prev_irq_mask) {
spin_lock_irqsave(&idio16gpio->lock, flags);
inb(idio16gpio->base + 2);
spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
}
static int idio_16_irq_set_type(struct irq_data *data, unsigned flow_type)
{
/* The only valid irq types are none and both-edges */
if (flow_type != IRQ_TYPE_NONE &&
(flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
return -EINVAL;
return 0;
}
static struct irq_chip idio_16_irqchip = {
.name = "104-idio-16",
.irq_ack = idio_16_irq_ack,
.irq_mask = idio_16_irq_mask,
.irq_unmask = idio_16_irq_unmask,
.irq_set_type = idio_16_irq_set_type
};
static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
{
struct idio_16_gpio *const idio16gpio = dev_id;
struct gpio_chip *const chip = &idio16gpio->chip;
int gpio;
for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
generic_handle_irq(irq_find_mapping(chip->irqdomain, gpio));
spin_lock(&idio16gpio->lock);
outb(0, idio16gpio->base + 1);
spin_unlock(&idio16gpio->lock);
return IRQ_HANDLED;
}
#define IDIO_16_NGPIO 32
static const char *idio_16_names[IDIO_16_NGPIO] = {
"OUT0", "OUT1", "OUT2", "OUT3", "OUT4", "OUT5", "OUT6", "OUT7",
"OUT8", "OUT9", "OUT10", "OUT11", "OUT12", "OUT13", "OUT14", "OUT15",
"IIN0", "IIN1", "IIN2", "IIN3", "IIN4", "IIN5", "IIN6", "IIN7",
"IIN8", "IIN9", "IIN10", "IIN11", "IIN12", "IIN13", "IIN14", "IIN15"
};
static int idio_16_probe(struct device *dev, unsigned int id)
{
struct idio_16_gpio *idio16gpio;
const char *const name = dev_name(dev);
int err;
idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
if (!idio16gpio)
return -ENOMEM;
if (!devm_request_region(dev, base[id], IDIO_16_EXTENT, name)) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
base[id], base[id] + IDIO_16_EXTENT);
return -EBUSY;
}
idio16gpio->chip.label = name;
idio16gpio->chip.parent = dev;
idio16gpio->chip.owner = THIS_MODULE;
idio16gpio->chip.base = -1;
idio16gpio->chip.ngpio = IDIO_16_NGPIO;
idio16gpio->chip.names = idio_16_names;
idio16gpio->chip.get_direction = idio_16_gpio_get_direction;
idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
idio16gpio->chip.get = idio_16_gpio_get;
idio16gpio->chip.set = idio_16_gpio_set;
idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
idio16gpio->base = base[id];
idio16gpio->out_state = 0xFFFF;
spin_lock_init(&idio16gpio->lock);
err = devm_gpiochip_add_data(dev, &idio16gpio->chip, idio16gpio);
if (err) {
dev_err(dev, "GPIO registering failed (%d)\n", err);
return err;
}
/* Disable IRQ by default */
outb(0, base[id] + 2);
outb(0, base[id] + 1);
err = gpiochip_irqchip_add(&idio16gpio->chip, &idio_16_irqchip, 0,
handle_edge_irq, IRQ_TYPE_NONE);
if (err) {
dev_err(dev, "Could not add irqchip (%d)\n", err);
return err;
}
err = devm_request_irq(dev, irq[id], idio_16_irq_handler, 0, name,
idio16gpio);
if (err) {
dev_err(dev, "IRQ handler registering failed (%d)\n", err);
return err;
}
return 0;
}
static struct isa_driver idio_16_driver = {
.probe = idio_16_probe,
.driver = {
.name = "104-idio-16"
},
};
module_isa_driver(idio_16_driver, num_idio_16);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES 104-IDIO-16 GPIO driver");
MODULE_LICENSE("GPL v2");
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