[PATCH 1/2] libata: add ledtrig support

[Aditya Prayoga]

From: Daniel Golle <daniel@xxxxxxxxxxxxxx>

This adds a LED trigger for each ATA port indicating disk activity.

As this is needed only on specific platforms (NAS SoCs and such),
these platforms should define ARCH_WANTS_LIBATA_LEDS if there
are boards with LED(s) intended to indicate ATA disk activity and
need the OS to take care of that.
In that way, if not selected, LED trigger support not will be
included in libata-core and both, codepaths and structures remain
untouched.

I'm currently deploying this for the oxnas target in OpenWrt
https://dev.openwrt.org/changeset/43675/

v2: rebased to kernel/git/tj/libata.git
    plus small corrections and comments added

Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
URL: https://patchwork.ozlabs.org/patch/420733/
[Aditya Prayoga:
* Port forward
* Change ATA_LEDS default to no
* Reduce performance impact by moving ata_led_act() call from
    ata_qc_new() to ata_qc_complete()]
Signed-off-by: Aditya Prayoga <aditya@xxxxxxxx>

---

If there is anything fundamentally wrong with that approach, I'd be
glad for some advise on how to do it better.
I conciously choose an #ifdev approach to make sure performance will
not be affected for non-users of that code.

Thanks

Daniel

---
---
 drivers/ata/Kconfig       | 16 ++++++++++++++
 drivers/ata/libata-core.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/libata.h    |  7 ++++++
 3 files changed, 79 insertions(+)

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 39b181d..a2c64ce 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -46,6 +46,22 @@ config ATA_VERBOSE_ERROR
 
 	  If unsure, say Y.
 
+config ARCH_WANT_LIBATA_LEDS
+	bool
+
+config ATA_LEDS
+	bool "support ATA port LED triggers"
+	depends on ARCH_WANT_LIBATA_LEDS
+	select NEW_LEDS
+	select LEDS_CLASS
+	select LEDS_TRIGGERS
+	default n
+	help
+	  This option adds a LED trigger for each registered ATA port.
+	  It is used to drive disk activity leds connected via GPIO.
+
+	  If unsure, say N.
+
 config ATA_ACPI
 	bool "ATA ACPI Support"
 	depends on ACPI
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 599e01b..65228f5 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5105,6 +5105,30 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
 }
 
 /**
+ *	ata_led_act - Trigger port activity LED
+ *	@ap: indicating port
+ *
+ *	Blinks any LEDs registered to the trigger.
+ *	Commonly used with leds-gpio on NAS systems with disk activity
+ *	indicator LEDs.
+ *
+ *	LOCKING:
+ *	None.
+ */
+static inline void ata_led_act(struct ata_port *ap)
+{
+#ifdef CONFIG_ATA_LEDS
+#define LIBATA_BLINK_DELAY 20 /* ms */
+	unsigned long led_delay = LIBATA_BLINK_DELAY;
+
+	if (unlikely(!ap->ledtrig))
+		return;
+
+	led_trigger_blink_oneshot(ap->ledtrig, &led_delay, &led_delay, 0);
+#endif /* CONFIG_ATA_LEDS */
+}
+
+/**
  *	ata_qc_new_init - Request an available ATA command, and initialize it
  *	@dev: Device from whom we request an available command structure
  *	@tag: tag
@@ -5249,6 +5273,10 @@ void ata_qc_complete(struct ata_queued_cmd *qc)
 	/* Trigger the LED (if available) */
 	ledtrig_disk_activity(!!(qc->tf.flags & ATA_TFLAG_WRITE));
 
+#ifdef CONFIG_ATA_LEDS
+	ata_led_act(ap);
+#endif
+
 	/* XXX: New EH and old EH use different mechanisms to
 	 * synchronize EH with regular execution path.
 	 *
@@ -6028,6 +6056,9 @@ struct ata_port *ata_port_alloc(struct ata_host *host)
 	ap->stats.unhandled_irq = 1;
 	ap->stats.idle_irq = 1;
 #endif
+#ifdef CONFIG_ATA_LEDS
+	ap->ledtrig = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
+#endif
 	ata_sff_port_init(ap);
 
 	return ap;
@@ -6063,6 +6094,12 @@ static void ata_host_release(struct kref *kref)
 
 		kfree(ap->pmp_link);
 		kfree(ap->slave_link);
+#ifdef CONFIG_ATA_LEDS
+		if (ap->ledtrig) {
+			led_trigger_unregister(ap->ledtrig);
+			kfree(ap->ledtrig);
+		};
+#endif
 		kfree(ap);
 		host->ports[i] = NULL;
 	}
@@ -6527,6 +6564,25 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
 		host->ports[i]->local_port_no = i + 1;
 	}
 
+#ifdef CONFIG_ATA_LEDS
+	/* register LED triggers for all ports */
+	for (i = 0; i < host->n_ports; i++) {
+		if (unlikely(!host->ports[i]->ledtrig))
+			continue;
+
+		snprintf(host->ports[i]->ledtrig_name,
+			sizeof(host->ports[i]->ledtrig_name), "ata%u",
+			host->ports[i]->print_id);
+
+		host->ports[i]->ledtrig->name = host->ports[i]->ledtrig_name;
+
+		if (led_trigger_register(host->ports[i]->ledtrig)) {
+			kfree(host->ports[i]->ledtrig);
+			host->ports[i]->ledtrig = NULL;
+		}
+	}
+#endif
+
 	/* Create associated sysfs transport objects  */
 	for (i = 0; i < host->n_ports; i++) {
 		rc = ata_tport_add(host->dev,host->ports[i]);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 38c95d6..3cc5f63 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -38,6 +38,7 @@
 #include <linux/acpi.h>
 #include <linux/cdrom.h>
 #include <linux/sched.h>
+#include <linux/leds.h>
 
 /*
  * Define if arch has non-standard setup.  This is a _PCI_ standard
@@ -893,6 +894,12 @@ struct ata_port {
 #ifdef CONFIG_ATA_ACPI
 	struct ata_acpi_gtm	__acpi_init_gtm; /* use ata_acpi_init_gtm() */
 #endif
+
+#ifdef CONFIG_ATA_LEDS
+	struct led_trigger	*ledtrig;
+	char			ledtrig_name[8];
+#endif
+
 	/* owned by EH */
 	u8			sector_buf[ATA_SECT_SIZE] ____cacheline_aligned;
 };
-- 
2.7.4