linux/drivers/gpio/gpio-loongson1.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

96 lines
2.3 KiB
C

/*
* GPIO Driver for Loongson 1 SoC
*
* Copyright (C) 2015-2016 Zhang, Keguang <keguang.zhang@gmail.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/module.h>
#include <linux/gpio/driver.h>
#include <linux/platform_device.h>
#include <linux/bitops.h>
/* Loongson 1 GPIO Register Definitions */
#define GPIO_CFG 0x0
#define GPIO_DIR 0x10
#define GPIO_DATA 0x20
#define GPIO_OUTPUT 0x30
static void __iomem *gpio_reg_base;
static int ls1x_gpio_request(struct gpio_chip *gc, unsigned int offset)
{
unsigned long flags;
raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
__raw_writel(__raw_readl(gpio_reg_base + GPIO_CFG) | BIT(offset),
gpio_reg_base + GPIO_CFG);
raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
return 0;
}
static void ls1x_gpio_free(struct gpio_chip *gc, unsigned int offset)
{
unsigned long flags;
raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
__raw_writel(__raw_readl(gpio_reg_base + GPIO_CFG) & ~BIT(offset),
gpio_reg_base + GPIO_CFG);
raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}
static int ls1x_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct gpio_chip *gc;
int ret;
gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
if (!gc)
return -ENOMEM;
gpio_reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(gpio_reg_base))
return PTR_ERR(gpio_reg_base);
ret = bgpio_init(gc, dev, 4, gpio_reg_base + GPIO_DATA,
gpio_reg_base + GPIO_OUTPUT, NULL,
NULL, gpio_reg_base + GPIO_DIR, 0);
if (ret)
goto err;
gc->owner = THIS_MODULE;
gc->request = ls1x_gpio_request;
gc->free = ls1x_gpio_free;
gc->base = pdev->id * 32;
ret = devm_gpiochip_add_data(dev, gc, NULL);
if (ret)
goto err;
platform_set_drvdata(pdev, gc);
dev_info(dev, "Loongson1 GPIO driver registered\n");
return 0;
err:
dev_err(dev, "failed to register GPIO device\n");
return ret;
}
static struct platform_driver ls1x_gpio_driver = {
.probe = ls1x_gpio_probe,
.driver = {
.name = "ls1x-gpio",
},
};
module_platform_driver(ls1x_gpio_driver);
MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
MODULE_DESCRIPTION("Loongson1 GPIO driver");
MODULE_LICENSE("GPL");