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linux-next/drivers/gpio/gpio-104-idi-48.c
Linus Torvalds 291b38a756 Annotation of module parameters that specify device settings
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Merge tag 'hwparam-20170420' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull hw lockdown support from David Howells:
 "Annotation of module parameters that configure hardware resources
  including ioports, iomem addresses, irq lines and dma channels.

  This allows a future patch to prohibit the use of such module
  parameters to prevent that hardware from being abused to gain access
  to the running kernel image as part of locking the kernel down under
  UEFI secure boot conditions.

  Annotations are made by changing:

        module_param(n, t, p)
        module_param_named(n, v, t, p)
        module_param_array(n, t, m, p)

  to:

        module_param_hw(n, t, hwtype, p)
        module_param_hw_named(n, v, t, hwtype, p)
        module_param_hw_array(n, t, hwtype, m, p)

  where the module parameter refers to a hardware setting

  hwtype specifies the type of the resource being configured. This can
  be one of:

        ioport          Module parameter configures an I/O port
        iomem           Module parameter configures an I/O mem address
        ioport_or_iomem Module parameter could be either (runtime set)
        irq             Module parameter configures an I/O port
        dma             Module parameter configures a DMA channel
        dma_addr        Module parameter configures a DMA buffer address
        other           Module parameter configures some other value

  Note that the hwtype is compile checked, but not currently stored (the
  lockdown code probably won't require it). It is, however, there for
  future use.

  A bonus is that the hwtype can also be used for grepping.

  The intention is for the kernel to ignore or reject attempts to set
  annotated module parameters if lockdown is enabled. This applies to
  options passed on the boot command line, passed to insmod/modprobe or
  direct twiddling in /sys/module/ parameter files.

  The module initialisation then needs to handle the parameter not being
  set, by (1) giving an error, (2) probing for a value or (3) using a
  reasonable default.

  What I can't do is just reject a module out of hand because it may
  take a hardware setting in the module parameters. Some important
  modules, some ipmi stuff for instance, both probe for hardware and
  allow hardware to be manually specified; if the driver is aborts with
  any error, you don't get any ipmi hardware.

  Further, trying to do this entirely in the module initialisation code
  doesn't protect against sysfs twiddling.

  [!] Note that in and of itself, this series of patches should have no
      effect on the the size of the kernel or code execution - that is
      left to a patch in the next series to effect. It does mark
      annotated kernel parameters with a KERNEL_PARAM_FL_HWPARAM flag in
      an already existing field"

* tag 'hwparam-20170420' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (38 commits)
  Annotate hardware config module parameters in sound/pci/
  Annotate hardware config module parameters in sound/oss/
  Annotate hardware config module parameters in sound/isa/
  Annotate hardware config module parameters in sound/drivers/
  Annotate hardware config module parameters in fs/pstore/
  Annotate hardware config module parameters in drivers/watchdog/
  Annotate hardware config module parameters in drivers/video/
  Annotate hardware config module parameters in drivers/tty/
  Annotate hardware config module parameters in drivers/staging/vme/
  Annotate hardware config module parameters in drivers/staging/speakup/
  Annotate hardware config module parameters in drivers/staging/media/
  Annotate hardware config module parameters in drivers/scsi/
  Annotate hardware config module parameters in drivers/pcmcia/
  Annotate hardware config module parameters in drivers/pci/hotplug/
  Annotate hardware config module parameters in drivers/parport/
  Annotate hardware config module parameters in drivers/net/wireless/
  Annotate hardware config module parameters in drivers/net/wan/
  Annotate hardware config module parameters in drivers/net/irda/
  Annotate hardware config module parameters in drivers/net/hamradio/
  Annotate hardware config module parameters in drivers/net/ethernet/
  ...
2017-05-10 19:13:03 -07:00

302 lines
8.0 KiB
C

/*
* GPIO driver for the ACCES 104-IDI-48 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-IDI-48A,
* 104-IDI-48AC, 104-IDI-48B, and 104-IDI-48BC.
*/
#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 IDI_48_EXTENT 8
#define MAX_NUM_IDI_48 max_num_isa_dev(IDI_48_EXTENT)
static unsigned int base[MAX_NUM_IDI_48];
static unsigned int num_idi_48;
module_param_hw_array(base, uint, ioport, &num_idi_48, 0);
MODULE_PARM_DESC(base, "ACCES 104-IDI-48 base addresses");
static unsigned int irq[MAX_NUM_IDI_48];
module_param_hw_array(irq, uint, irq, NULL, 0);
MODULE_PARM_DESC(irq, "ACCES 104-IDI-48 interrupt line numbers");
/**
* struct idi_48_gpio - GPIO device private data structure
* @chip: instance of the gpio_chip
* @lock: synchronization lock to prevent I/O race conditions
* @ack_lock: synchronization lock to prevent IRQ handler race conditions
* @irq_mask: input bits affected by interrupts
* @base: base port address of the GPIO device
* @cos_enb: Change-Of-State IRQ enable boundaries mask
*/
struct idi_48_gpio {
struct gpio_chip chip;
raw_spinlock_t lock;
spinlock_t ack_lock;
unsigned char irq_mask[6];
unsigned base;
unsigned char cos_enb;
};
static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
return 1;
}
static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
return 0;
}
static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
unsigned i;
const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
unsigned base_offset;
unsigned mask;
for (i = 0; i < 48; i += 8)
if (offset < i + 8) {
base_offset = register_offset[i / 8];
mask = BIT(offset - i);
return !!(inb(idi48gpio->base + base_offset) & mask);
}
/* The following line should never execute since offset < 48 */
return 0;
}
static void idi_48_irq_ack(struct irq_data *data)
{
}
static void idi_48_irq_mask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
const unsigned offset = irqd_to_hwirq(data);
unsigned i;
unsigned mask;
unsigned boundary;
unsigned long flags;
for (i = 0; i < 48; i += 8)
if (offset < i + 8) {
mask = BIT(offset - i);
boundary = i / 8;
idi48gpio->irq_mask[boundary] &= ~mask;
if (!idi48gpio->irq_mask[boundary]) {
idi48gpio->cos_enb &= ~BIT(boundary);
raw_spin_lock_irqsave(&idi48gpio->lock, flags);
outb(idi48gpio->cos_enb, idi48gpio->base + 7);
raw_spin_unlock_irqrestore(&idi48gpio->lock,
flags);
}
return;
}
}
static void idi_48_irq_unmask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
const unsigned offset = irqd_to_hwirq(data);
unsigned i;
unsigned mask;
unsigned boundary;
unsigned prev_irq_mask;
unsigned long flags;
for (i = 0; i < 48; i += 8)
if (offset < i + 8) {
mask = BIT(offset - i);
boundary = i / 8;
prev_irq_mask = idi48gpio->irq_mask[boundary];
idi48gpio->irq_mask[boundary] |= mask;
if (!prev_irq_mask) {
idi48gpio->cos_enb |= BIT(boundary);
raw_spin_lock_irqsave(&idi48gpio->lock, flags);
outb(idi48gpio->cos_enb, idi48gpio->base + 7);
raw_spin_unlock_irqrestore(&idi48gpio->lock,
flags);
}
return;
}
}
static int idi_48_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 idi_48_irqchip = {
.name = "104-idi-48",
.irq_ack = idi_48_irq_ack,
.irq_mask = idi_48_irq_mask,
.irq_unmask = idi_48_irq_unmask,
.irq_set_type = idi_48_irq_set_type
};
static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
{
struct idi_48_gpio *const idi48gpio = dev_id;
unsigned long cos_status;
unsigned long boundary;
unsigned long irq_mask;
unsigned long bit_num;
unsigned long gpio;
struct gpio_chip *const chip = &idi48gpio->chip;
spin_lock(&idi48gpio->ack_lock);
raw_spin_lock(&idi48gpio->lock);
cos_status = inb(idi48gpio->base + 7);
raw_spin_unlock(&idi48gpio->lock);
/* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
if (cos_status & BIT(6)) {
spin_unlock(&idi48gpio->ack_lock);
return IRQ_NONE;
}
/* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
cos_status &= 0x3F;
for_each_set_bit(boundary, &cos_status, 6) {
irq_mask = idi48gpio->irq_mask[boundary];
for_each_set_bit(bit_num, &irq_mask, 8) {
gpio = bit_num + boundary * 8;
generic_handle_irq(irq_find_mapping(chip->irqdomain,
gpio));
}
}
spin_unlock(&idi48gpio->ack_lock);
return IRQ_HANDLED;
}
#define IDI48_NGPIO 48
static const char *idi48_names[IDI48_NGPIO] = {
"Bit 0 A", "Bit 1 A", "Bit 2 A", "Bit 3 A", "Bit 4 A", "Bit 5 A",
"Bit 6 A", "Bit 7 A", "Bit 8 A", "Bit 9 A", "Bit 10 A", "Bit 11 A",
"Bit 12 A", "Bit 13 A", "Bit 14 A", "Bit 15 A", "Bit 16 A", "Bit 17 A",
"Bit 18 A", "Bit 19 A", "Bit 20 A", "Bit 21 A", "Bit 22 A", "Bit 23 A",
"Bit 0 B", "Bit 1 B", "Bit 2 B", "Bit 3 B", "Bit 4 B", "Bit 5 B",
"Bit 6 B", "Bit 7 B", "Bit 8 B", "Bit 9 B", "Bit 10 B", "Bit 11 B",
"Bit 12 B", "Bit 13 B", "Bit 14 B", "Bit 15 B", "Bit 16 B", "Bit 17 B",
"Bit 18 B", "Bit 19 B", "Bit 20 B", "Bit 21 B", "Bit 22 B", "Bit 23 B"
};
static int idi_48_probe(struct device *dev, unsigned int id)
{
struct idi_48_gpio *idi48gpio;
const char *const name = dev_name(dev);
int err;
idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
if (!idi48gpio)
return -ENOMEM;
if (!devm_request_region(dev, base[id], IDI_48_EXTENT, name)) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
base[id], base[id] + IDI_48_EXTENT);
return -EBUSY;
}
idi48gpio->chip.label = name;
idi48gpio->chip.parent = dev;
idi48gpio->chip.owner = THIS_MODULE;
idi48gpio->chip.base = -1;
idi48gpio->chip.ngpio = IDI48_NGPIO;
idi48gpio->chip.names = idi48_names;
idi48gpio->chip.get_direction = idi_48_gpio_get_direction;
idi48gpio->chip.direction_input = idi_48_gpio_direction_input;
idi48gpio->chip.get = idi_48_gpio_get;
idi48gpio->base = base[id];
raw_spin_lock_init(&idi48gpio->lock);
spin_lock_init(&idi48gpio->ack_lock);
err = devm_gpiochip_add_data(dev, &idi48gpio->chip, idi48gpio);
if (err) {
dev_err(dev, "GPIO registering failed (%d)\n", err);
return err;
}
/* Disable IRQ by default */
outb(0, base[id] + 7);
inb(base[id] + 7);
err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_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], idi_48_irq_handler, IRQF_SHARED,
name, idi48gpio);
if (err) {
dev_err(dev, "IRQ handler registering failed (%d)\n", err);
return err;
}
return 0;
}
static struct isa_driver idi_48_driver = {
.probe = idi_48_probe,
.driver = {
.name = "104-idi-48"
},
};
module_isa_driver(idi_48_driver, num_idi_48);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
MODULE_LICENSE("GPL v2");