linux-stable/drivers/gpio/gpio-amdpt.c
Schspa Shi 3c938cc5ce gpio: use raw spinlock for gpio chip shadowed data
In case of PREEMPT_RT, there is a raw_spinlock -> spinlock dependency
as the lockdep report shows.

__irq_set_handler
  irq_get_desc_buslock
    __irq_get_desc_lock
      raw_spin_lock_irqsave(&desc->lock, *flags);  // raw spinlock get here
  __irq_do_set_handler
    mask_ack_irq
      dwapb_irq_ack
        spin_lock_irqsave(&gc->bgpio_lock, flags); // sleep able spinlock
  irq_put_desc_busunlock

Replace with a raw lock to avoid BUGs. This lock is only used to access
registers, and It's safe to replace with the raw lock without bad
influence.

[   15.090359][    T1] =============================
[   15.090365][    T1] [ BUG: Invalid wait context ]
[   15.090373][    T1] 5.10.59-rt52-00983-g186a6841c682-dirty #3 Not tainted
[   15.090386][    T1] -----------------------------
[   15.090392][    T1] swapper/0/1 is trying to lock:
[   15.090402][    T1] 70ff00018507c188 (&gc->bgpio_lock){....}-{3:3}, at: _raw_spin_lock_irqsave+0x1c/0x28
[   15.090470][    T1] other info that might help us debug this:
[   15.090477][    T1] context-{5:5}
[   15.090485][    T1] 3 locks held by swapper/0/1:
[   15.090497][    T1]  #0: c2ff0001816de1a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock+0x98/0x104
[   15.090553][    T1]  #1: ffff90001485b4b8 (irq_domain_mutex){+.+.}-{4:4}, at: irq_domain_associate+0xbc/0x6d4
[   15.090606][    T1]  #2: 4bff000185d7a8e0 (lock_class){....}-{2:2}, at: _raw_spin_lock_irqsave+0x1c/0x28
[   15.090654][    T1] stack backtrace:
[   15.090661][    T1] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.10.59-rt52-00983-g186a6841c682-dirty #3
[   15.090682][    T1] Hardware name: Horizon Robotics Journey 5 DVB (DT)
[   15.090692][    T1] Call trace:
......
[   15.090811][    T1]  _raw_spin_lock_irqsave+0x1c/0x28
[   15.090828][    T1]  dwapb_irq_ack+0xb4/0x300
[   15.090846][    T1]  __irq_do_set_handler+0x494/0xb2c
[   15.090864][    T1]  __irq_set_handler+0x74/0x114
[   15.090881][    T1]  irq_set_chip_and_handler_name+0x44/0x58
[   15.090900][    T1]  gpiochip_irq_map+0x210/0x644

Signed-off-by: Schspa Shi <schspa@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Doug Berger <opendmb@gmail.com>
Acked-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-04-25 12:10:02 +02:00

155 lines
3.8 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* AMD Promontory GPIO driver
*
* Copyright (C) 2015 ASMedia Technology Inc.
* Author: YD Tseng <yd_tseng@asmedia.com.tw>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/gpio/driver.h>
#include <linux/spinlock.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
#define PT_TOTAL_GPIO 8
#define PT_TOTAL_GPIO_EX 24
/* PCI-E MMIO register offsets */
#define PT_DIRECTION_REG 0x00
#define PT_INPUTDATA_REG 0x04
#define PT_OUTPUTDATA_REG 0x08
#define PT_CLOCKRATE_REG 0x0C
#define PT_SYNC_REG 0x28
struct pt_gpio_chip {
struct gpio_chip gc;
void __iomem *reg_base;
};
static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
{
struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
unsigned long flags;
u32 using_pins;
dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
if (using_pins & BIT(offset)) {
dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
offset);
raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
return -EINVAL;
}
writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
return 0;
}
static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
{
struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
unsigned long flags;
u32 using_pins;
raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
using_pins &= ~BIT(offset);
writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
}
static int pt_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct pt_gpio_chip *pt_gpio;
int ret = 0;
if (!ACPI_COMPANION(dev)) {
dev_err(dev, "PT GPIO device node not found\n");
return -ENODEV;
}
pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
if (!pt_gpio)
return -ENOMEM;
pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pt_gpio->reg_base)) {
dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
return PTR_ERR(pt_gpio->reg_base);
}
ret = bgpio_init(&pt_gpio->gc, dev, 4,
pt_gpio->reg_base + PT_INPUTDATA_REG,
pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
BGPIOF_READ_OUTPUT_REG_SET);
if (ret) {
dev_err(dev, "bgpio_init failed\n");
return ret;
}
pt_gpio->gc.owner = THIS_MODULE;
pt_gpio->gc.request = pt_gpio_request;
pt_gpio->gc.free = pt_gpio_free;
pt_gpio->gc.ngpio = (uintptr_t)device_get_match_data(dev);
ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio);
if (ret) {
dev_err(dev, "Failed to register GPIO lib\n");
return ret;
}
platform_set_drvdata(pdev, pt_gpio);
/* initialize register setting */
writel(0, pt_gpio->reg_base + PT_SYNC_REG);
writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
dev_dbg(dev, "PT GPIO driver loaded\n");
return ret;
}
static int pt_gpio_remove(struct platform_device *pdev)
{
struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
gpiochip_remove(&pt_gpio->gc);
return 0;
}
static const struct acpi_device_id pt_gpio_acpi_match[] = {
{ "AMDF030", PT_TOTAL_GPIO },
{ "AMDIF030", PT_TOTAL_GPIO },
{ "AMDIF031", PT_TOTAL_GPIO_EX },
{ },
};
MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
static struct platform_driver pt_gpio_driver = {
.driver = {
.name = "pt-gpio",
.acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
},
.probe = pt_gpio_probe,
.remove = pt_gpio_remove,
};
module_platform_driver(pt_gpio_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
MODULE_DESCRIPTION("AMD Promontory GPIO Driver");