Re: [PATCH v4 2/5] gpio: Add support for Intel LJCA USB GPIO driver

Oliver Neukum
2023-03-09T13:40:22Z

On 09.03.23 08:10, Ye Xiang wrote:

> +#define LJCA_GPIO_BUF_SIZE 60
> +struct ljca_gpio_dev {
> + struct platform_device *pdev;
> + struct gpio_chip gc;
> + struct ljca_gpio_info *gpio_info;
> + DECLARE_BITMAP(unmasked_irqs, LJCA_MAX_GPIO_NUM);
> + DECLARE_BITMAP(enabled_irqs, LJCA_MAX_GPIO_NUM);
> + DECLARE_BITMAP(reenable_irqs, LJCA_MAX_GPIO_NUM);
> + u8 *connect_mode;
> + /* mutex to protect irq bus */
> + struct mutex irq_lock;
> + struct work_struct work;
> + /* lock to protect package transfer to Hardware */
> + struct mutex trans_lock;
> +
> + u8 obuf[LJCA_GPIO_BUF_SIZE];
> + u8 ibuf[LJCA_GPIO_BUF_SIZE];

And here we have a violation of DMA coherency rules.
Basically you cannot embed buffers into other data structures
if they can be subject to DMA.

> +static int ljca_gpio_remove(struct platform_device *pdev)
> +{
> + struct ljca_gpio_dev *ljca_gpio = platform_get_drvdata(pdev);
> +
> + gpiochip_remove(&ljca_gpio->gc);
> + ljca_unregister_event_cb(ljca_gpio->gpio_info->ljca);
> + mutex_destroy(&ljca_gpio->irq_lock);
> + mutex_destroy(&ljca_gpio->trans_lock);

At this time, what has made sure that no work is scheduled?

> + return 0;
> +}

Regards
Oliver