[PATCH RFC v2 01/14] nvme: Add NVME_AER_ONE_SHOT callback handler

[Joel Granados]

Handle NVME_AER_ONE_SHOT asynchronous event notifications by extracting
the event parameter from the 64-bit result and passing it to the
handler.

Stub nvme_handle_aen_oneshot() with warnings for now; it will be
extended by subsequent patches to handle specific one-shot event types
like CDQ tail pointer events.

Signed-off-by: Joel Granados <joel.granados at kernel.org>
---
 drivers/nvme/host/core.c | 29 +++++++++++++++++++++++++++++
 include/linux/nvme.h     |  7 +++++++
 2 files changed, 36 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index fb13f85dd7844331566f05915dda21d91abfea30..6e7533ccf24bfe3df7188f442986ec18a3200660 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4748,6 +4748,30 @@ static u32 nvme_aer_subtype(u32 result)
 	return (result & 0xff00) >> 8;
 }
 
+static bool nvme_handle_aen_oneshot(struct nvme_ctrl *ctrl, u32 result, u32 event_param)
+{
+	u32 aer_subtype = nvme_aer_subtype(result);
+
+	switch (aer_subtype) {
+	case NVME_AER_ONE_SHOT_CDQ_TAIL_PTR:
+		WARN_ONCE(1, "CDQ Tail Pointer one shot event ignored");
+		break;
+	case NVME_AER_ONE_SHOT_CDQ_FULL:
+		WARN_ONCE(1, "CDQ Full Error one shot event ignored");
+		break;
+	case NVME_AER_ONE_SHOT_PWR_TH:
+		WARN_ONCE(1, "Power Threshold Exceeded one shot event ignored");
+		break;
+	default:
+		WARN_ONCE(1, "Unrecognized One Shot Async Event %d (ignored)",
+			  aer_subtype);
+		break;
+	}
+
+	/* Return true in all cases to reque after handling */
+	return true;
+}
+
 static bool nvme_handle_aen_notice(struct nvme_ctrl *ctrl, u32 result)
 {
 	u32 aer_notice_type = nvme_aer_subtype(result);
@@ -4796,6 +4820,7 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
 		volatile union nvme_result *res)
 {
 	u32 result = le32_to_cpu(res->u32);
+	u32 event_param = 0;
 	u32 aer_type = nvme_aer_type(result);
 	u32 aer_subtype = nvme_aer_subtype(result);
 	bool requeue = true;
@@ -4808,6 +4833,10 @@ void nvme_complete_async_event(struct nvme_ctrl *ctrl, __le16 status,
 	case NVME_AER_NOTICE:
 		requeue = nvme_handle_aen_notice(ctrl, result);
 		break;
+	case NVME_AER_ONE_SHOT:
+		event_param = le64_to_cpu(res->u64) >> 32;
+		requeue = nvme_handle_aen_oneshot(ctrl, result, event_param);
+		break;
 	case NVME_AER_ERROR:
 		/*
 		 * For a persistent internal error, don't run async_event_work
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 69a8c48faa6ce19e695286d15be2585a4d4401d4..60fb5b6808615ff7388f30e12ffe6ed5da2ef4f6 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -862,6 +862,7 @@ enum {
 	NVME_AER_ERROR			= 0,
 	NVME_AER_SMART			= 1,
 	NVME_AER_NOTICE			= 2,
+	NVME_AER_ONE_SHOT		= 4,
 	NVME_AER_CSS			= 6,
 	NVME_AER_VS			= 7,
 };
@@ -877,6 +878,12 @@ enum {
 	NVME_AER_NOTICE_DISC_CHANGED	= 0xf0,
 };
 
+enum {
+	NVME_AER_ONE_SHOT_CDQ_TAIL_PTR	= 0x00,
+	NVME_AER_ONE_SHOT_CDQ_FULL	= 0x01,
+	NVME_AER_ONE_SHOT_PWR_TH	= 0x02,
+};
+
 enum {
 	NVME_AEN_BIT_NS_ATTR		= 8,
 	NVME_AEN_BIT_FW_ACT		= 9,

-- 
2.50.1