dmaengine: idxd: add interrupt handling for event log

An event log interrupt is raised in the misc interrupt INTCAUSE register
when an event is written by the hardware. Add basic event log processing
support to the interrupt handler. The event log is a ring where the
hardware owns the tail and the software owns the head. The hardware will
advance the tail index when an additional event has been pushed to memory.
The software will process the log entry and then advances the head. The
log is full when (tail + 1) % log_size = head. The hardware will stop
writing when the log is full. The user is expected to create a log size
large enough to handle all the expected events.

Tested-by: Tony Zhu <tony.zhu@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-5-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 0d639303b515..52b8b7d9db22 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -217,6 +217,49 @@ static void idxd_int_handle_revoke(struct work_struct *work)
 	kfree(revoke);
 }
 
+static void process_evl_entry(struct idxd_device *idxd, struct __evl_entry *entry_head)
+{
+	struct device *dev = &idxd->pdev->dev;
+	u8 status;
+
+	status = DSA_COMP_STATUS(entry_head->error);
+	dev_warn_ratelimited(dev, "Device error %#x operation: %#x fault addr: %#llx\n",
+			     status, entry_head->operation, entry_head->fault_addr);
+}
+
+static void process_evl_entries(struct idxd_device *idxd)
+{
+	union evl_status_reg evl_status;
+	unsigned int h, t;
+	struct idxd_evl *evl = idxd->evl;
+	struct __evl_entry *entry_head;
+	unsigned int ent_size = evl_ent_size(idxd);
+	u32 size;
+
+	evl_status.bits = 0;
+	evl_status.int_pending = 1;
+
+	spin_lock(&evl->lock);
+	/* Clear interrupt pending bit */
+	iowrite32(evl_status.bits_upper32,
+		  idxd->reg_base + IDXD_EVLSTATUS_OFFSET + sizeof(u32));
+	h = evl->head;
+	evl_status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
+	t = evl_status.tail;
+	size = idxd->evl->size;
+
+	while (h != t) {
+		entry_head = (struct __evl_entry *)(evl->log + (h * ent_size));
+		process_evl_entry(idxd, entry_head);
+		h = (h + 1) % size;
+	}
+
+	evl->head = h;
+	evl_status.head = h;
+	iowrite32(evl_status.bits_lower32, idxd->reg_base + IDXD_EVLSTATUS_OFFSET);
+	spin_unlock(&evl->lock);
+}
+
 irqreturn_t idxd_misc_thread(int vec, void *data)
 {
 	struct idxd_irq_entry *irq_entry = data;
@@ -304,6 +347,11 @@ irqreturn_t idxd_misc_thread(int vec, void *data)
 		perfmon_counter_overflow(idxd);
 	}
 
+	if (cause & IDXD_INTC_EVL) {
+		val |= IDXD_INTC_EVL;
+		process_evl_entries(idxd);
+	}
+
 	val ^= cause;
 	if (val)
 		dev_warn_once(dev, "Unexpected interrupt cause bits set: %#x\n",