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linux/drivers/gpio/gpio-amd8111.c
Xiongfeng Wang 45fecdb9f6 gpio: amd8111: Fix PCI device reference count leak 
for_each_pci_dev() is implemented by pci_get_device(). The comment of
pci_get_device() says that it will increase the reference count for the
returned pci_dev and also decrease the reference count for the input
pci_dev @from if it is not NULL.

If we break for_each_pci_dev() loop with pdev not NULL, we need to call
pci_dev_put() to decrease the reference count. Add the missing
pci_dev_put() after the 'out' label. Since pci_dev_put() can handle NULL
input parameter, there is no problem for the 'Device not found' branch.
For the normal path, add pci_dev_put() in amd_gpio_exit().

Fixes: f942a7de04 ("gpio: add a driver for GPIO pins found on AMD-8111 south bridge chips")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2022-11-30 17:18:35 +01:00

249 lines
6.7 KiB
C
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// SPDX-License-Identifier: GPL-2.0
/*
* GPIO driver for AMD 8111 south bridges
*
* Copyright (c) 2012 Dmitry Eremin-Solenikov
*
* Based on the AMD RNG driver:
* Copyright 2005 (c) MontaVista Software, Inc.
* with the majority of the code coming from:
*
* Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
* (c) Copyright 2003 Red Hat Inc <jgarzik@redhat.com>
*
* derived from
*
* Hardware driver for the AMD 768 Random Number Generator (RNG)
* (c) Copyright 2001 Red Hat Inc
*
* derived from
*
* Hardware driver for Intel i810 Random Number Generator (RNG)
* Copyright 2000,2001 Jeff Garzik <jgarzik@pobox.com>
* Copyright 2000,2001 Philipp Rumpf <prumpf@mandrakesoft.com>
*/
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/gpio/driver.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#define PMBASE_OFFSET 0xb0
#define PMBASE_SIZE 0x30
#define AMD_REG_GPIO(i) (0x10 + (i))
#define AMD_GPIO_LTCH_STS 0x40 /* Latch status, w1 */
#define AMD_GPIO_RTIN 0x20 /* Real Time in, ro */
#define AMD_GPIO_DEBOUNCE 0x10 /* Debounce, rw */
#define AMD_GPIO_MODE_MASK 0x0c /* Pin Mode Select, rw */
#define AMD_GPIO_MODE_IN 0x00
#define AMD_GPIO_MODE_OUT 0x04
/* Enable alternative (e.g. clkout, IRQ, etc) function of the pin */
#define AMD_GPIO_MODE_ALTFN 0x08 /* Or 0x09 */
#define AMD_GPIO_X_MASK 0x03 /* In/Out specific, rw */
#define AMD_GPIO_X_IN_ACTIVEHI 0x01 /* Active High */
#define AMD_GPIO_X_IN_LATCH 0x02 /* Latched version is selected */
#define AMD_GPIO_X_OUT_LOW 0x00
#define AMD_GPIO_X_OUT_HI 0x01
#define AMD_GPIO_X_OUT_CLK0 0x02
#define AMD_GPIO_X_OUT_CLK1 0x03
/*
* Data for PCI driver interface
*
* This data only exists for exporting the supported
* PCI ids via MODULE_DEVICE_TABLE. We do not actually
* register a pci_driver, because someone else might one day
* want to register another driver on the same PCI id.
*/
static const struct pci_device_id pci_tbl[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8111_SMBUS), 0 },
{ 0, }, /* terminate list */
};
MODULE_DEVICE_TABLE(pci, pci_tbl);
struct amd_gpio {
struct gpio_chip chip;
u32 pmbase;
void __iomem *pm;
struct pci_dev *pdev;
spinlock_t lock; /* guards hw registers and orig table */
u8 orig[32];
};
static int amd_gpio_request(struct gpio_chip *chip, unsigned offset)
{
struct amd_gpio *agp = gpiochip_get_data(chip);
agp->orig[offset] = ioread8(agp->pm + AMD_REG_GPIO(offset)) &
(AMD_GPIO_DEBOUNCE | AMD_GPIO_MODE_MASK | AMD_GPIO_X_MASK);
dev_dbg(&agp->pdev->dev, "Requested gpio %d, data %x\n", offset, agp->orig[offset]);
return 0;
}
static void amd_gpio_free(struct gpio_chip *chip, unsigned offset)
{
struct amd_gpio *agp = gpiochip_get_data(chip);
dev_dbg(&agp->pdev->dev, "Freed gpio %d, data %x\n", offset, agp->orig[offset]);
iowrite8(agp->orig[offset], agp->pm + AMD_REG_GPIO(offset));
}
static void amd_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct amd_gpio *agp = gpiochip_get_data(chip);
u8 temp;
unsigned long flags;
spin_lock_irqsave(&agp->lock, flags);
temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_OUT | (value ? AMD_GPIO_X_OUT_HI : AMD_GPIO_X_OUT_LOW);
iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
spin_unlock_irqrestore(&agp->lock, flags);
dev_dbg(&agp->pdev->dev, "Setting gpio %d, value %d, reg=%02x\n", offset, !!value, temp);
}
static int amd_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct amd_gpio *agp = gpiochip_get_data(chip);
u8 temp;
temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
dev_dbg(&agp->pdev->dev, "Getting gpio %d, reg=%02x\n", offset, temp);
return (temp & AMD_GPIO_RTIN) ? 1 : 0;
}
static int amd_gpio_dirout(struct gpio_chip *chip, unsigned offset, int value)
{
struct amd_gpio *agp = gpiochip_get_data(chip);
u8 temp;
unsigned long flags;
spin_lock_irqsave(&agp->lock, flags);
temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_OUT | (value ? AMD_GPIO_X_OUT_HI : AMD_GPIO_X_OUT_LOW);
iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
spin_unlock_irqrestore(&agp->lock, flags);
dev_dbg(&agp->pdev->dev, "Dirout gpio %d, value %d, reg=%02x\n", offset, !!value, temp);
return 0;
}
static int amd_gpio_dirin(struct gpio_chip *chip, unsigned offset)
{
struct amd_gpio *agp = gpiochip_get_data(chip);
u8 temp;
unsigned long flags;
spin_lock_irqsave(&agp->lock, flags);
temp = ioread8(agp->pm + AMD_REG_GPIO(offset));
temp = (temp & AMD_GPIO_DEBOUNCE) | AMD_GPIO_MODE_IN;
iowrite8(temp, agp->pm + AMD_REG_GPIO(offset));
spin_unlock_irqrestore(&agp->lock, flags);
dev_dbg(&agp->pdev->dev, "Dirin gpio %d, reg=%02x\n", offset, temp);
return 0;
}
static struct amd_gpio gp = {
.chip = {
.label = "AMD GPIO",
.owner = THIS_MODULE,
.base = -1,
.ngpio = 32,
.request = amd_gpio_request,
.free = amd_gpio_free,
.set = amd_gpio_set,
.get = amd_gpio_get,
.direction_output = amd_gpio_dirout,
.direction_input = amd_gpio_dirin,
},
};
static int __init amd_gpio_init(void)
{
int err = -ENODEV;
struct pci_dev *pdev = NULL;
const struct pci_device_id *ent;
/* We look for our device - AMD South Bridge
* I don't know about a system with two such bridges,
* so we can assume that there is max. one device.
*
* We can't use plain pci_driver mechanism,
* as the device is really a multiple function device,
* main driver that binds to the pci_device is an smbus
* driver and have to find & bind to the device this way.
*/
for_each_pci_dev(pdev) {
ent = pci_match_id(pci_tbl, pdev);
if (ent)
goto found;
}
/* Device not found. */
goto out;
found:
err = pci_read_config_dword(pdev, 0x58, &gp.pmbase);
if (err)
goto out;
err = -EIO;
gp.pmbase &= 0x0000FF00;
if (gp.pmbase == 0)
goto out;
if (!devm_request_region(&pdev->dev, gp.pmbase + PMBASE_OFFSET,
PMBASE_SIZE, "AMD GPIO")) {
dev_err(&pdev->dev, "AMD GPIO region 0x%x already in use!\n",
gp.pmbase + PMBASE_OFFSET);
err = -EBUSY;
goto out;
}
gp.pm = ioport_map(gp.pmbase + PMBASE_OFFSET, PMBASE_SIZE);
if (!gp.pm) {
dev_err(&pdev->dev, "Couldn't map io port into io memory\n");
err = -ENOMEM;
goto out;
}
gp.pdev = pdev;
gp.chip.parent = &pdev->dev;
spin_lock_init(&gp.lock);
dev_info(&pdev->dev, "AMD-8111 GPIO detected\n");
err = gpiochip_add_data(&gp.chip, &gp);
if (err) {
dev_err(&pdev->dev, "GPIO registering failed (%d)\n", err);
ioport_unmap(gp.pm);
goto out;
}
return 0;
out:
pci_dev_put(pdev);
return err;
}
static void __exit amd_gpio_exit(void)
{
gpiochip_remove(&gp.chip);
ioport_unmap(gp.pm);
pci_dev_put(gp.pdev);
}
module_init(amd_gpio_init);
module_exit(amd_gpio_exit);
MODULE_AUTHOR("The Linux Kernel team");
MODULE_DESCRIPTION("GPIO driver for AMD chipsets");
MODULE_LICENSE("GPL");
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