habanalabs: add h/w queues module

This patch adds the H/W queues module and the code to initialize Goya's
various compute and DMA engines and their queues.

Goya has 5 DMA channels, 8 TPC engines and a single MME engine. For each
channel/engine, there is a H/W queue logic which is used to pass commands
from the user to the H/W. That logic is called QMAN.

There are two types of QMANs: external and internal. The DMA QMANs are
considered external while the TPC and MME QMANs are considered internal.
For each external queue there is a completion queue, which is located on
the Host memory.

The differences between external and internal QMANs are:

1. The location of the queue's memory. External QMANs are located on the
   Host memory while internal QMANs are located on the on-chip memory.

2. The external QMAN write an entry to a completion queue and sends an
   MSI-X interrupt upon completion of a command buffer that was given to
   it. The internal QMAN doesn't do that.

Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 149 insertions, 0 deletions

diff --git a/drivers/misc/habanalabs/irq.c b/drivers/misc/habanalabs/irq.c
new file mode 100644
index 000000000000..6b7d35f6af08
--- /dev/null
+++ b/drivers/misc/habanalabs/irq.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2016-2019 HabanaLabs, Ltd.
+ * All Rights Reserved.
+ */
+
+#include "habanalabs.h"
+
+#include <linux/irqreturn.h>
+
+/*
+ * hl_cq_inc_ptr - increment ci or pi of cq
+ *
+ * @ptr: the current ci or pi value of the completion queue
+ *
+ * Increment ptr by 1. If it reaches the number of completion queue
+ * entries, set it to 0
+ */
+inline u32 hl_cq_inc_ptr(u32 ptr)
+{
+	ptr++;
+	if (unlikely(ptr == HL_CQ_LENGTH))
+		ptr = 0;
+	return ptr;
+}
+
+/*
+ * hl_irq_handler_cq - irq handler for completion queue
+ *
+ * @irq: irq number
+ * @arg: pointer to completion queue structure
+ *
+ */
+irqreturn_t hl_irq_handler_cq(int irq, void *arg)
+{
+	struct hl_cq *cq = arg;
+	struct hl_device *hdev = cq->hdev;
+	struct hl_hw_queue *queue;
+	struct hl_cs_job *job;
+	bool shadow_index_valid;
+	u16 shadow_index;
+	u32 *cq_entry;
+	u32 *cq_base;
+
+	if (hdev->disabled) {
+		dev_dbg(hdev->dev,
+			"Device disabled but received IRQ %d for CQ %d\n",
+			irq, cq->hw_queue_id);
+		return IRQ_HANDLED;
+	}
+
+	cq_base = (u32 *) (uintptr_t) cq->kernel_address;
+
+	while (1) {
+		bool entry_ready = ((cq_base[cq->ci] & CQ_ENTRY_READY_MASK)
+						>> CQ_ENTRY_READY_SHIFT);
+
+		if (!entry_ready)
+			break;
+
+		cq_entry = (u32 *) &cq_base[cq->ci];
+
+		/*
+		 * Make sure we read CQ entry contents after we've
+		 * checked the ownership bit.
+		 */
+		dma_rmb();
+
+		shadow_index_valid =
+			((*cq_entry & CQ_ENTRY_SHADOW_INDEX_VALID_MASK)
+					>> CQ_ENTRY_SHADOW_INDEX_VALID_SHIFT);
+
+		shadow_index = (u16)
+			((*cq_entry & CQ_ENTRY_SHADOW_INDEX_MASK)
+					>> CQ_ENTRY_SHADOW_INDEX_SHIFT);
+
+		queue = &hdev->kernel_queues[cq->hw_queue_id];
+
+		if ((shadow_index_valid) && (!hdev->disabled)) {
+			job = queue->shadow_queue[hl_pi_2_offset(shadow_index)];
+			queue_work(hdev->cq_wq, &job->finish_work);
+		}
+
+		/*
+		 * Update ci of the context's queue. There is no
+		 * need to protect it with spinlock because this update is
+		 * done only inside IRQ and there is a different IRQ per
+		 * queue
+		 */
+		queue->ci = hl_queue_inc_ptr(queue->ci);
+
+		/* Clear CQ entry ready bit */
+		cq_base[cq->ci] &= ~CQ_ENTRY_READY_MASK;
+
+		cq->ci = hl_cq_inc_ptr(cq->ci);
+
+		/* Increment free slots */
+		atomic_inc(&cq->free_slots_cnt);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * hl_cq_init - main initialization function for an cq object
+ *
+ * @hdev: pointer to device structure
+ * @q: pointer to cq structure
+ * @hw_queue_id: The H/W queue ID this completion queue belongs to
+ *
+ * Allocate dma-able memory for the completion queue and initialize fields
+ * Returns 0 on success
+ */
+int hl_cq_init(struct hl_device *hdev, struct hl_cq *q, u32 hw_queue_id)
+{
+	void *p;
+
+	BUILD_BUG_ON(HL_CQ_SIZE_IN_BYTES > HL_PAGE_SIZE);
+
+	p = hdev->asic_funcs->dma_alloc_coherent(hdev, HL_CQ_SIZE_IN_BYTES,
+				&q->bus_address, GFP_KERNEL | __GFP_ZERO);
+	if (!p)
+		return -ENOMEM;
+
+	q->hdev = hdev;
+	q->kernel_address = (u64) (uintptr_t) p;
+	q->hw_queue_id = hw_queue_id;
+	q->ci = 0;
+	q->pi = 0;
+
+	atomic_set(&q->free_slots_cnt, HL_CQ_LENGTH);
+
+	return 0;
+}
+
+/*
+ * hl_cq_fini - destroy completion queue
+ *
+ * @hdev: pointer to device structure
+ * @q: pointer to cq structure
+ *
+ * Free the completion queue memory
+ */
+void hl_cq_fini(struct hl_device *hdev, struct hl_cq *q)
+{
+	hdev->asic_funcs->dma_free_coherent(hdev, HL_CQ_SIZE_IN_BYTES,
+			(void *) (uintptr_t) q->kernel_address, q->bus_address);
+}