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, 400 insertions, 0 deletions

diff --git a/drivers/misc/habanalabs/hw_queue.c b/drivers/misc/habanalabs/hw_queue.c
new file mode 100644
index 000000000000..2ec43f36cdb8
--- /dev/null
+++ b/drivers/misc/habanalabs/hw_queue.c
@@ -0,0 +1,400 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2016-2019 HabanaLabs, Ltd.
+ * All Rights Reserved.
+ */
+
+#include "habanalabs.h"
+
+#include <linux/slab.h>
+
+/*
+ * hl_queue_add_ptr - add to pi or ci and checks if it wraps around
+ *
+ * @ptr: the current pi/ci value
+ * @val: the amount to add
+ *
+ * Add val to ptr. It can go until twice the queue length.
+ */
+inline u32 hl_hw_queue_add_ptr(u32 ptr, u16 val)
+{
+	ptr += val;
+	ptr &= ((HL_QUEUE_LENGTH << 1) - 1);
+	return ptr;
+}
+
+static inline int queue_free_slots(struct hl_hw_queue *q, u32 queue_len)
+{
+	int delta = (q->pi - q->ci);
+
+	if (delta >= 0)
+		return (queue_len - delta);
+	else
+		return (abs(delta) - queue_len);
+}
+
+/*
+ * ext_queue_submit_bd - Submit a buffer descriptor to an external queue
+ *
+ * @hdev: pointer to habanalabs device structure
+ * @q: pointer to habanalabs queue structure
+ * @ctl: BD's control word
+ * @len: BD's length
+ * @ptr: BD's pointer
+ *
+ * This function assumes there is enough space on the queue to submit a new
+ * BD to it. It initializes the next BD and calls the device specific
+ * function to set the pi (and doorbell)
+ *
+ * This function must be called when the scheduler mutex is taken
+ *
+ */
+static void ext_queue_submit_bd(struct hl_device *hdev, struct hl_hw_queue *q,
+				u32 ctl, u32 len, u64 ptr)
+{
+	struct hl_bd *bd;
+
+	bd = (struct hl_bd *) (uintptr_t) q->kernel_address;
+	bd += hl_pi_2_offset(q->pi);
+	bd->ctl = ctl;
+	bd->len = len;
+	bd->ptr = ptr + hdev->asic_prop.host_phys_base_address;
+
+	q->pi = hl_queue_inc_ptr(q->pi);
+	hdev->asic_funcs->ring_doorbell(hdev, q->hw_queue_id, q->pi);
+}
+
+/*
+ * ext_queue_sanity_checks - perform some sanity checks on external queue
+ *
+ * @hdev              : pointer to hl_device structure
+ * @q                 :	pointer to hl_hw_queue structure
+ * @num_of_entries    : how many entries to check for space
+ * @reserve_cq_entry  :	whether to reserve an entry in the cq
+ *
+ * H/W queues spinlock should be taken before calling this function
+ *
+ * Perform the following:
+ * - Make sure we have enough space in the h/w queue
+ * - Make sure we have enough space in the completion queue
+ * - Reserve space in the completion queue (needs to be reversed if there
+ *   is a failure down the road before the actual submission of work). Only
+ *   do this action if reserve_cq_entry is true
+ *
+ */
+static int ext_queue_sanity_checks(struct hl_device *hdev,
+				struct hl_hw_queue *q, int num_of_entries,
+				bool reserve_cq_entry)
+{
+	atomic_t *free_slots =
+			&hdev->completion_queue[q->hw_queue_id].free_slots_cnt;
+	int free_slots_cnt;
+
+	/* Check we have enough space in the queue */
+	free_slots_cnt = queue_free_slots(q, HL_QUEUE_LENGTH);
+
+	if (free_slots_cnt < num_of_entries) {
+		dev_dbg(hdev->dev, "Queue %d doesn't have room for %d CBs\n",
+			q->hw_queue_id, num_of_entries);
+		return -EAGAIN;
+	}
+
+	if (reserve_cq_entry) {
+		/*
+		 * Check we have enough space in the completion queue
+		 * Add -1 to counter (decrement) unless counter was already 0
+		 * In that case, CQ is full so we can't submit a new CB because
+		 * we won't get ack on its completion
+		 * atomic_add_unless will return 0 if counter was already 0
+		 */
+		if (atomic_add_negative(num_of_entries * -1, free_slots)) {
+			dev_dbg(hdev->dev, "No space for %d on CQ %d\n",
+				num_of_entries, q->hw_queue_id);
+			atomic_add(num_of_entries, free_slots);
+			return -EAGAIN;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * hl_hw_queue_send_cb_no_cmpl - send a single CB (not a JOB) without completion
+ *
+ * @hdev: pointer to hl_device structure
+ * @hw_queue_id: Queue's type
+ * @cb_size: size of CB
+ * @cb_ptr: pointer to CB location
+ *
+ * This function sends a single CB, that must NOT generate a completion entry
+ *
+ */
+int hl_hw_queue_send_cb_no_cmpl(struct hl_device *hdev, u32 hw_queue_id,
+				u32 cb_size, u64 cb_ptr)
+{
+	struct hl_hw_queue *q = &hdev->kernel_queues[hw_queue_id];
+	int rc;
+
+	/*
+	 * The CPU queue is a synchronous queue with an effective depth of
+	 * a single entry (although it is allocated with room for multiple
+	 * entries). Therefore, there is a different lock, called
+	 * send_cpu_message_lock, that serializes accesses to the CPU queue.
+	 * As a result, we don't need to lock the access to the entire H/W
+	 * queues module when submitting a JOB to the CPU queue
+	 */
+	if (q->queue_type != QUEUE_TYPE_CPU)
+		hdev->asic_funcs->hw_queues_lock(hdev);
+
+	if (hdev->disabled) {
+		rc = -EPERM;
+		goto out;
+	}
+
+	rc = ext_queue_sanity_checks(hdev, q, 1, false);
+	if (rc)
+		goto out;
+
+	ext_queue_submit_bd(hdev, q, 0, cb_size, cb_ptr);
+
+out:
+	if (q->queue_type != QUEUE_TYPE_CPU)
+		hdev->asic_funcs->hw_queues_unlock(hdev);
+
+	return rc;
+}
+
+/*
+ * hl_hw_queue_inc_ci_kernel - increment ci for kernel's queue
+ *
+ * @hdev: pointer to hl_device structure
+ * @hw_queue_id: which queue to increment its ci
+ */
+void hl_hw_queue_inc_ci_kernel(struct hl_device *hdev, u32 hw_queue_id)
+{
+	struct hl_hw_queue *q = &hdev->kernel_queues[hw_queue_id];
+
+	q->ci = hl_queue_inc_ptr(q->ci);
+}
+
+static int ext_and_cpu_hw_queue_init(struct hl_device *hdev,
+					struct hl_hw_queue *q)
+{
+	void *p;
+	int rc;
+
+	p = hdev->asic_funcs->dma_alloc_coherent(hdev,
+				HL_QUEUE_SIZE_IN_BYTES,
+				&q->bus_address, GFP_KERNEL | __GFP_ZERO);
+	if (!p)
+		return -ENOMEM;
+
+	q->kernel_address = (u64) (uintptr_t) p;
+
+	q->shadow_queue = kmalloc_array(HL_QUEUE_LENGTH,
+					sizeof(*q->shadow_queue),
+					GFP_KERNEL);
+	if (!q->shadow_queue) {
+		dev_err(hdev->dev,
+			"Failed to allocate shadow queue for H/W queue %d\n",
+			q->hw_queue_id);
+		rc = -ENOMEM;
+		goto free_queue;
+	}
+
+	/* Make sure read/write pointers are initialized to start of queue */
+	q->ci = 0;
+	q->pi = 0;
+
+	return 0;
+
+free_queue:
+	hdev->asic_funcs->dma_free_coherent(hdev, HL_QUEUE_SIZE_IN_BYTES,
+			(void *) (uintptr_t) q->kernel_address, q->bus_address);
+
+	return rc;
+}
+
+static int int_hw_queue_init(struct hl_device *hdev, struct hl_hw_queue *q)
+{
+	void *p;
+
+	p = hdev->asic_funcs->get_int_queue_base(hdev, q->hw_queue_id,
+					&q->bus_address, &q->int_queue_len);
+	if (!p) {
+		dev_err(hdev->dev,
+			"Failed to get base address for internal queue %d\n",
+			q->hw_queue_id);
+		return -EFAULT;
+	}
+
+	q->kernel_address = (u64) (uintptr_t) p;
+	q->pi = 0;
+	q->ci = 0;
+
+	return 0;
+}
+
+static int cpu_hw_queue_init(struct hl_device *hdev, struct hl_hw_queue *q)
+{
+	return ext_and_cpu_hw_queue_init(hdev, q);
+}
+
+static int ext_hw_queue_init(struct hl_device *hdev, struct hl_hw_queue *q)
+{
+	return ext_and_cpu_hw_queue_init(hdev, q);
+}
+
+/*
+ * hw_queue_init - main initialization function for H/W queue object
+ *
+ * @hdev: pointer to hl_device device structure
+ * @q: pointer to hl_hw_queue queue structure
+ * @hw_queue_id: The id of the H/W queue
+ *
+ * Allocate dma-able memory for the queue and initialize fields
+ * Returns 0 on success
+ */
+static int hw_queue_init(struct hl_device *hdev, struct hl_hw_queue *q,
+			u32 hw_queue_id)
+{
+	int rc;
+
+	BUILD_BUG_ON(HL_QUEUE_SIZE_IN_BYTES > HL_PAGE_SIZE);
+
+	q->hw_queue_id = hw_queue_id;
+
+	switch (q->queue_type) {
+	case QUEUE_TYPE_EXT:
+		rc = ext_hw_queue_init(hdev, q);
+		break;
+
+	case QUEUE_TYPE_INT:
+		rc = int_hw_queue_init(hdev, q);
+		break;
+
+	case QUEUE_TYPE_CPU:
+		rc = cpu_hw_queue_init(hdev, q);
+		break;
+
+	case QUEUE_TYPE_NA:
+		q->valid = 0;
+		return 0;
+
+	default:
+		dev_crit(hdev->dev, "wrong queue type %d during init\n",
+			q->queue_type);
+		rc = -EINVAL;
+		break;
+	}
+
+	if (rc)
+		return rc;
+
+	q->valid = 1;
+
+	return 0;
+}
+
+/*
+ * hw_queue_fini - destroy queue
+ *
+ * @hdev: pointer to hl_device device structure
+ * @q: pointer to hl_hw_queue queue structure
+ *
+ * Free the queue memory
+ */
+static void hw_queue_fini(struct hl_device *hdev, struct hl_hw_queue *q)
+{
+	if (!q->valid)
+		return;
+
+	/*
+	 * If we arrived here, there are no jobs waiting on this queue
+	 * so we can safely remove it.
+	 * This is because this function can only called when:
+	 * 1. Either a context is deleted, which only can occur if all its
+	 *    jobs were finished
+	 * 2. A context wasn't able to be created due to failure or timeout,
+	 *    which means there are no jobs on the queue yet
+	 *
+	 * The only exception are the queues of the kernel context, but
+	 * if they are being destroyed, it means that the entire module is
+	 * being removed. If the module is removed, it means there is no open
+	 * user context. It also means that if a job was submitted by
+	 * the kernel driver (e.g. context creation), the job itself was
+	 * released by the kernel driver when a timeout occurred on its
+	 * Completion. Thus, we don't need to release it again.
+	 */
+
+	if (q->queue_type == QUEUE_TYPE_INT)
+		return;
+
+	kfree(q->shadow_queue);
+
+	hdev->asic_funcs->dma_free_coherent(hdev, HL_QUEUE_SIZE_IN_BYTES,
+			(void *) (uintptr_t) q->kernel_address, q->bus_address);
+}
+
+int hl_hw_queues_create(struct hl_device *hdev)
+{
+	struct asic_fixed_properties *asic = &hdev->asic_prop;
+	struct hl_hw_queue *q;
+	int i, rc, q_ready_cnt;
+
+	hdev->kernel_queues = kcalloc(HL_MAX_QUEUES,
+				sizeof(*hdev->kernel_queues), GFP_KERNEL);
+
+	if (!hdev->kernel_queues) {
+		dev_err(hdev->dev, "Not enough memory for H/W queues\n");
+		return -ENOMEM;
+	}
+
+	/* Initialize the H/W queues */
+	for (i = 0, q_ready_cnt = 0, q = hdev->kernel_queues;
+			i < HL_MAX_QUEUES ; i++, q_ready_cnt++, q++) {
+
+		q->queue_type = asic->hw_queues_props[i].type;
+		rc = hw_queue_init(hdev, q, i);
+		if (rc) {
+			dev_err(hdev->dev,
+				"failed to initialize queue %d\n", i);
+			goto release_queues;
+		}
+	}
+
+	return 0;
+
+release_queues:
+	for (i = 0, q = hdev->kernel_queues ; i < q_ready_cnt ; i++, q++)
+		hw_queue_fini(hdev, q);
+
+	kfree(hdev->kernel_queues);
+
+	return rc;
+}
+
+void hl_hw_queues_destroy(struct hl_device *hdev)
+{
+	struct hl_hw_queue *q;
+	int i;
+
+	for (i = 0, q = hdev->kernel_queues ; i < HL_MAX_QUEUES ; i++, q++)
+		hw_queue_fini(hdev, q);
+
+	kfree(hdev->kernel_queues);
+}
+
+void hl_hw_queue_reset(struct hl_device *hdev, bool hard_reset)
+{
+	struct hl_hw_queue *q;
+	int i;
+
+	for (i = 0, q = hdev->kernel_queues ; i < HL_MAX_QUEUES ; i++, q++) {
+		if ((!q->valid) ||
+			((!hard_reset) && (q->queue_type == QUEUE_TYPE_CPU)))
+			continue;
+		q->pi = q->ci = 0;
+	}
+}