Subject: Re: [PATCH v7 06/11] leds: trigger: netdev: add hardware control support

From: Alexander Stein <[email-masked]>
Date: Thu, 15 Dec 2022 16:27:17 +0100

Hi,

thanks for the v7 series.

Am Donnerstag, 15. Dezember 2022, 00:54:33 CET schrieb Christian Marangi:
> Add hardware control support for the Netdev trigger.
> The trigger on config change will check if the requested trigger can set
> to blink mode using LED hardware mode and if every blink mode is supported,
> the trigger will enable hardware mode with the requested configuration.
> If there is at least one trigger that is not supported and can't run in
> hardware mode, then software mode will be used instead.
> A validation is done on every value change and on fail the old value is
> restored and -EINVAL is returned.
> 
> Signed-off-by: Christian Marangi <[email-masked]>
> ---
>  drivers/leds/trigger/ledtrig-netdev.c | 155 +++++++++++++++++++++++++-
>  1 file changed, 149 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/leds/trigger/ledtrig-netdev.c
> b/drivers/leds/trigger/ledtrig-netdev.c index dd63cadb896e..ed019cb5867c
> 100644
> --- a/drivers/leds/trigger/ledtrig-netdev.c
> +++ b/drivers/leds/trigger/ledtrig-netdev.c
> @@ -37,6 +37,7 @@
>   */
> 
>  struct led_netdev_data {
> +	enum led_blink_modes blink_mode;
>  	spinlock_t lock;
> 
>  	struct delayed_work work;
> @@ -53,11 +54,105 @@ struct led_netdev_data {
>  	bool carrier_link_up;
>  };
> 
> +struct netdev_led_attr_detail {
> +	char *name;
> +	bool hardware_only;
> +	enum led_trigger_netdev_modes bit;
> +};
> +
> +static struct netdev_led_attr_detail attr_details[] = {
> +	{ .name = "link", .bit = TRIGGER_NETDEV_LINK},
> +	{ .name = "tx", .bit = TRIGGER_NETDEV_TX},
> +	{ .name = "rx", .bit = TRIGGER_NETDEV_RX},
> +};
> +
> +static bool validate_baseline_state(struct led_netdev_data *trigger_data)
> +{
> +	struct led_classdev *led_cdev = trigger_data->led_cdev;
> +	struct netdev_led_attr_detail *detail;
> +	u32 hw_blink_mode_supported = 0;
> +	bool force_sw = false;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(attr_details); i++) {
> +		detail = &attr_details[i];
> +
> +		/* Mode not active, skip */
> +		if (!test_bit(detail->bit, &trigger_data->mode))
> +			continue;
> +
> +		/* Hardware only mode enabled on software controlled led 
*/
> +		if (led_cdev->blink_mode == SOFTWARE_CONTROLLED &&
> +		    detail->hardware_only)
> +			return false;
> +
> +		/* Check if the mode supports hardware mode */
> +		if (led_cdev->blink_mode != SOFTWARE_CONTROLLED) {
> +			/* With a net dev set, force software mode.
> +			 * With modes are handled by hardware, led will 
blink
> +			 * based on his own events and will ignore any 
event
> +			 * from the provided dev.
> +			 */
> +			if (trigger_data->net_dev) {
> +				force_sw = true;
> +				continue;
> +			}
> +
> +			/* With empty dev, check if the mode is 
supported */
> +			if 
(led_trigger_blink_mode_is_supported(led_cdev, detail->bit))
> +				hw_blink_mode_supported |= BIT(detail-
>bit);

Shouldn't this be BIT(detail->bit)?

> +		}
> +	}
> +
> +	/* We can't run modes handled by both software and hardware.
> +	 * Check if we run hardware modes and check if all the modes
> +	 * can be handled by hardware.
> +	 */
> +	if (hw_blink_mode_supported && hw_blink_mode_supported !=
> trigger_data->mode) +		return false;
> +
> +	/* Modes are valid. Decide now the running mode to later
> +	 * set the baseline.
> +	 * Software mode is enforced with net_dev set. With an empty
> +	 * one hardware mode is selected by default (if supported).
> +	 */
> +	if (force_sw || led_cdev->blink_mode == SOFTWARE_CONTROLLED)

IMHO '|| !hw_blink_mode_supported' should be added here for blink_modes. This 
might happen if a PHY LED is SOFTWARE_HARDWARE_CONTROLLED, but some blink mode 
is not supported by hardware, thus hw_blink_mode_supported=0.

Best regards,
Alexander

> +		trigger_data->blink_mode = SOFTWARE_CONTROLLED;
> +	else
> +		trigger_data->blink_mode = HARDWARE_CONTROLLED;
> +
> +	return true;
> +}
> +
>  static void set_baseline_state(struct led_netdev_data *trigger_data)
>  {
> +	int i;
>  	int current_brightness;
> +	struct netdev_led_attr_detail *detail;
>  	struct led_classdev *led_cdev = trigger_data->led_cdev;
> 
> +	/* Modes already validated. Directly apply hw trigger modes */
> +	if (trigger_data->blink_mode == HARDWARE_CONTROLLED) {
> +		/* We are refreshing the blink modes. Reset them */
> +		led_cdev->hw_control_configure(led_cdev, 
BIT(TRIGGER_NETDEV_LINK),
> +					       BLINK_MODE_ZERO);
> +
> +		for (i = 0; i < ARRAY_SIZE(attr_details); i++) {
> +			detail = &attr_details[i];
> +
> +			if (!test_bit(detail->bit, &trigger_data->mode))
> +				continue;
> +
> +			led_cdev->hw_control_configure(led_cdev, 
BIT(detail->bit),
> +						       
BLINK_MODE_ENABLE);

Shouldn't this be BIT(detail->bit)?

> +		}
> +
> +		led_cdev->hw_control_start(led_cdev);
> +
> +		return;
> +	}
> +
> +	/* Handle trigger modes by software */
>  	current_brightness = led_cdev->brightness;
>  	if (current_brightness)
>  		led_cdev->blink_brightness = current_brightness;
> @@ -100,10 +195,15 @@ static ssize_t device_name_store(struct device *dev,
>  				 size_t size)
>  {
>  	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
> +	struct net_device *old_net = trigger_data->net_dev;
> +	char old_device_name[IFNAMSIZ];
> 
>  	if (size >= IFNAMSIZ)
>  		return -EINVAL;
> 
> +	/* Backup old device name */
> +	memcpy(old_device_name, trigger_data->device_name, IFNAMSIZ);
> +
>  	cancel_delayed_work_sync(&trigger_data->work);
> 
>  	spin_lock_bh(&trigger_data->lock);
> @@ -122,6 +222,19 @@ static ssize_t device_name_store(struct device *dev,
>  		trigger_data->net_dev =
>  		    dev_get_by_name(&init_net, trigger_data->device_name);
> 
> +	if (!validate_baseline_state(trigger_data)) {
> +		/* Restore old net_dev and device_name */
> +		if (trigger_data->net_dev)
> +			dev_put(trigger_data->net_dev);
> +
> +		dev_hold(old_net);
> +		trigger_data->net_dev = old_net;
> +		memcpy(trigger_data->device_name, old_device_name, 
IFNAMSIZ);
> +
> +		spin_unlock_bh(&trigger_data->lock);
> +		return -EINVAL;
> +	}
> +
>  	trigger_data->carrier_link_up = false;
>  	if (trigger_data->net_dev != NULL)
>  		trigger_data->carrier_link_up = 
netif_carrier_ok(trigger_data->net_dev);
> @@ -159,7 +272,7 @@ static ssize_t netdev_led_attr_store(struct device *dev,
> const char *buf, size_t size, enum led_trigger_netdev_modes attr)
>  {
>  	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
> -	unsigned long state;
> +	unsigned long state, old_mode = trigger_data->mode;
>  	int ret;
>  	int bit;
> 
> @@ -184,6 +297,12 @@ static ssize_t netdev_led_attr_store(struct device
> *dev, const char *buf, else
>  		clear_bit(bit, &trigger_data->mode);
> 
> +	if (!validate_baseline_state(trigger_data)) {
> +		/* Restore old mode on validation fail */
> +		trigger_data->mode = old_mode;
> +		return -EINVAL;
> +	}
> +
>  	set_baseline_state(trigger_data);
> 
>  	return size;
> @@ -220,6 +339,8 @@ static ssize_t interval_store(struct device *dev,
>  			      size_t size)
>  {
>  	struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
> +	int old_interval = atomic_read(&trigger_data->interval);
> +	u32 old_mode = trigger_data->mode;
>  	unsigned long value;
>  	int ret;
> 
> @@ -228,13 +349,22 @@ static ssize_t interval_store(struct device *dev,
>  		return ret;
> 
>  	/* impose some basic bounds on the timer interval */
> -	if (value >= 5 && value <= 10000) {
> -		cancel_delayed_work_sync(&trigger_data->work);
> +	if (value < 5 || value > 10000)
> +		return -EINVAL;
> +
> +	cancel_delayed_work_sync(&trigger_data->work);
> +
> +	atomic_set(&trigger_data->interval, msecs_to_jiffies(value));
> 
> -		atomic_set(&trigger_data->interval, 
msecs_to_jiffies(value));
> -		set_baseline_state(trigger_data);	/* resets timer 
*/
> +	if (!validate_baseline_state(trigger_data)) {
> +		/* Restore old interval on validation error */
> +		atomic_set(&trigger_data->interval, old_interval);
> +		trigger_data->mode = old_mode;
> +		return -EINVAL;
>  	}
> 
> +	set_baseline_state(trigger_data);	/* resets timer */
> +
>  	return size;
>  }
> 
> @@ -368,13 +498,25 @@ static int netdev_trig_activate(struct led_classdev
> *led_cdev) trigger_data->mode = 0;
>  	atomic_set(&trigger_data->interval, msecs_to_jiffies(50));
>  	trigger_data->last_activity = 0;
> +	if (led_cdev->blink_mode != SOFTWARE_CONTROLLED) {
> +		/* With hw mode enabled reset any rule set by default */
> +		if (led_cdev->hw_control_status(led_cdev)) {
> +			rc = led_cdev->hw_control_configure(led_cdev, 
BIT(TRIGGER_NETDEV_LINK),
> +							    
BLINK_MODE_ZERO);
> +			if (rc)
> +				goto err;
> +		}
> +	}
> 
>  	led_set_trigger_data(led_cdev, trigger_data);
> 
>  	rc = register_netdevice_notifier(&trigger_data->notifier);
>  	if (rc)
> -		kfree(trigger_data);
> +		goto err;
> 
> +	return 0;
> +err:
> +	kfree(trigger_data);
>  	return rc;
>  }
> 
> @@ -394,6 +536,7 @@ static void netdev_trig_deactivate(struct led_classdev
> *led_cdev)
> 
>  static struct led_trigger netdev_led_trigger = {
>  	.name = "netdev",
> +	.supported_blink_modes = SOFTWARE_HARDWARE,
>  	.activate = netdev_trig_activate,
>  	.deactivate = netdev_trig_deactivate,
>  	.groups = netdev_trig_groups,