Subject: Re: [PATCH 2/4] irqchip/meson-gpio: support more than 8 channels gpio irq line

From: Marc Zyngier <[email-masked]>
Date: Sat, 08 Jan 2022 10:37:52 +0000

On Sat, 08 Jan 2022 08:42:16 +0000,
Qianggui Song <[email-masked]> wrote:
> 
> Current meson gpio irqchip driver only support 8 channels for gpio irq
> line, later chips may have more then 8 channels, so need to modify code
> to support more.
> 
> Signed-off-by: Qianggui Song <[email-masked]>
> ---
>  drivers/irqchip/irq-meson-gpio.c | 33 +++++++++++++++++++++++---------
>  1 file changed, 24 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-meson-gpio.c b/drivers/irqchip/irq-meson-gpio.c
> index d90ff0b92480..6a7b4fb13452 100644
> --- a/drivers/irqchip/irq-meson-gpio.c
> +++ b/drivers/irqchip/irq-meson-gpio.c
> @@ -16,7 +16,6 @@
>  #include <linux/of.h>
>  #include <linux/of_address.h>
>  
> -#define NUM_CHANNEL 8
>  #define MAX_INPUT_MUX 256
>  
>  #define REG_EDGE_POL	0x00
> @@ -60,6 +59,7 @@ struct irq_ctl_ops {
>  
>  struct meson_gpio_irq_params {
>  	unsigned int nr_hwirq;
> +	unsigned int channel_num;

For consistency, please name this nr_channels.

>  	bool support_edge_both;
>  	unsigned int edge_both_offset;
>  	unsigned int edge_single_offset;
> @@ -81,6 +81,7 @@ struct meson_gpio_irq_params {
>  	.edge_single_offset = 0,				\
>  	.pol_low_offset = 16,					\
>  	.pin_sel_mask = 0xff,					\
> +	.channel_num = 8,					\
>  
>  #define INIT_MESON_A1_COMMON_DATA(irqs)				\
>  	INIT_MESON_COMMON(irqs, meson_a1_gpio_irq_init,		\
> @@ -90,6 +91,7 @@ struct meson_gpio_irq_params {
>  	.edge_single_offset = 8,				\
>  	.pol_low_offset = 0,					\
>  	.pin_sel_mask = 0x7f,					\
> +	.channel_num = 8,					\
>  
>  static const struct meson_gpio_irq_params meson8_params = {
>  	INIT_MESON8_COMMON_DATA(134)
> @@ -136,8 +138,9 @@ static const struct of_device_id meson_irq_gpio_matches[] = {
>  struct meson_gpio_irq_controller {
>  	const struct meson_gpio_irq_params *params;
>  	void __iomem *base;
> -	u32 channel_irqs[NUM_CHANNEL];
> -	DECLARE_BITMAP(channel_map, NUM_CHANNEL);
> +	u32 *channel_irqs;
> +	unsigned long *channel_map;
> +	u8 channel_num;

Same thing. Though this is completely superfluous, see below.

>  	spinlock_t lock;
>  };
>  
> @@ -207,8 +210,8 @@ meson_gpio_irq_request_channel(struct meson_gpio_irq_controller *ctl,
>  	spin_lock_irqsave(&ctl->lock, flags);
>  
>  	/* Find a free channel */
> -	idx = find_first_zero_bit(ctl->channel_map, NUM_CHANNEL);
> -	if (idx >= NUM_CHANNEL) {
> +	idx = find_first_zero_bit(ctl->channel_map, ctl->channel_num);
> +	if (idx >= ctl->channel_num) {
>  		spin_unlock_irqrestore(&ctl->lock, flags);
>  		pr_err("No channel available\n");
>  		return -ENOSPC;
> @@ -447,13 +450,25 @@ static int meson_gpio_irq_parse_dt(struct device_node *node, struct meson_gpio_i
>  
>  	ctl->params = match->data;
>  
> +	ctl->channel_num = ctl->params->channel_num;

Since you already have a pointer to params, why do you need to
duplicate this information?

> +	ctl->channel_irqs = kcalloc(ctl->channel_num,
> +				    sizeof(*ctl->channel_irqs), GFP_KERNEL);
> +	if (!ctl->channel_irqs)
> +		return -ENOMEM;
> +
> +	ctl->channel_map = bitmap_zalloc(ctl->params->channel_num, GFP_KERNEL);
> +	if (!ctl->channel_map) {
> +		kfree(ctl->channel_irqs);
> +		return -ENOMEM;
> +	}
> +
>  	ret = of_property_read_variable_u32_array(node,
>  						  "amlogic,channel-interrupts",
>  						  ctl->channel_irqs,
> -						  NUM_CHANNEL,
> -						  NUM_CHANNEL);
> +						  ctl->channel_num,
> +						  ctl->channel_num);
>  	if (ret < 0) {
> -		pr_err("can't get %d channel interrupts\n", NUM_CHANNEL);
> +		pr_err("can't get %d channel interrupts\n", ctl->channel_num);
>  		return ret;

You are now leaking the bitmap and channel_map allocations.

	M.

-- 
Without deviation from the norm, progress is not possible.

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