habanalabs: add context and ASID modules

This patch adds two modules - ASID and context.

Each user process that opens a device's file must have at least one
context before it is able to "work" with the device. Each context has its
own device address-space and contains information about its runtime state
(its active command submissions).

To have address-space separation between contexts, each context is assigned
a unique ASID, which stands for "address-space id". Goya supports up to
1024 ASIDs.

Currently, the driver doesn't support multiple contexts. Therefore, the
user doesn't need to actively create a context. A "primary context" is
created automatically when the user opens the device's file.

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, 57 insertions, 0 deletions

diff --git a/drivers/misc/habanalabs/asid.c b/drivers/misc/habanalabs/asid.c
new file mode 100644
index 000000000000..f54e7971a762
--- /dev/null
+++ b/drivers/misc/habanalabs/asid.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2016-2019 HabanaLabs, Ltd.
+ * All Rights Reserved.
+ */
+
+#include "habanalabs.h"
+
+#include <linux/slab.h>
+
+int hl_asid_init(struct hl_device *hdev)
+{
+	hdev->asid_bitmap = kcalloc(BITS_TO_LONGS(hdev->asic_prop.max_asid),
+					sizeof(*hdev->asid_bitmap), GFP_KERNEL);
+	if (!hdev->asid_bitmap)
+		return -ENOMEM;
+
+	mutex_init(&hdev->asid_mutex);
+
+	/* ASID 0 is reserved for KMD */
+	set_bit(0, hdev->asid_bitmap);
+
+	return 0;
+}
+
+void hl_asid_fini(struct hl_device *hdev)
+{
+	mutex_destroy(&hdev->asid_mutex);
+	kfree(hdev->asid_bitmap);
+}
+
+unsigned long hl_asid_alloc(struct hl_device *hdev)
+{
+	unsigned long found;
+
+	mutex_lock(&hdev->asid_mutex);
+
+	found = find_first_zero_bit(hdev->asid_bitmap,
+					hdev->asic_prop.max_asid);
+	if (found == hdev->asic_prop.max_asid)
+		found = 0;
+	else
+		set_bit(found, hdev->asid_bitmap);
+
+	mutex_unlock(&hdev->asid_mutex);
+
+	return found;
+}
+
+void hl_asid_free(struct hl_device *hdev, unsigned long asid)
+{
+	if (WARN((asid == 0 || asid >= hdev->asic_prop.max_asid),
+						"Invalid ASID %lu", asid))
+		return;
+	clear_bit(asid, hdev->asid_bitmap);
+}