1 files changed, 123 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_vm_helper.c b/drivers/gpu/drm/amd/display/dc/core/dc_vm_helper.c
new file mode 100644
index 000000000000..6ce87b682a32
--- /dev/null
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_vm_helper.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2018 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: AMD
+ *
+ */
+
+#include "vm_helper.h"
+
+static void mark_vmid_used(struct vm_helper *vm_helper, unsigned int pos, uint8_t hubp_idx)
+{
+	struct vmid_usage vmids = vm_helper->hubp_vmid_usage[hubp_idx];
+
+	vmids.vmid_usage[0] = vmids.vmid_usage[1];
+	vmids.vmid_usage[1] = 1 << pos;
+}
+
+static void add_ptb_to_table(struct vm_helper *vm_helper, unsigned int vmid, uint64_t ptb)
+{
+	vm_helper->ptb_assigned_to_vmid[vmid] = ptb;
+	vm_helper->num_vmids_available--;
+}
+
+static void clear_entry_from_vmid_table(struct vm_helper *vm_helper, unsigned int vmid)
+{
+	vm_helper->ptb_assigned_to_vmid[vmid] = 0;
+	vm_helper->num_vmids_available++;
+}
+
+static void evict_vmids(struct vm_helper *vm_helper)
+{
+	int i;
+	uint16_t ord = 0;
+
+	for (i = 0; i < vm_helper->num_vmid; i++)
+		ord |= vm_helper->hubp_vmid_usage[i].vmid_usage[0] | vm_helper->hubp_vmid_usage[i].vmid_usage[1];
+
+	// At this point any positions with value 0 are unused vmids, evict them
+	for (i = 1; i < vm_helper->num_vmid; i++) {
+		if (ord & (1u << i))
+			clear_entry_from_vmid_table(vm_helper, i);
+	}
+}
+
+// Return value of -1 indicates vmid table unitialized or ptb dne in the table
+static int get_existing_vmid_for_ptb(struct vm_helper *vm_helper, uint64_t ptb)
+{
+	int i;
+
+	for (i = 0; i < vm_helper->num_vmid; i++) {
+		if (vm_helper->ptb_assigned_to_vmid[i] == ptb)
+			return i;
+	}
+
+	return -1;
+}
+
+// Expected to be called only when there's an available vmid
+static int get_next_available_vmid(struct vm_helper *vm_helper)
+{
+	int i;
+
+	for (i = 1; i < vm_helper->num_vmid; i++) {
+		if (vm_helper->ptb_assigned_to_vmid[i] == 0)
+			return i;
+	}
+
+	return -1;
+}
+
+uint8_t get_vmid_for_ptb(struct vm_helper *vm_helper, int64_t ptb, uint8_t hubp_idx)
+{
+	unsigned int vmid = 0;
+	int vmid_exists = -1;
+
+	// Physical address gets vmid 0
+	if (ptb == 0)
+		return 0;
+
+	vmid_exists = get_existing_vmid_for_ptb(vm_helper, ptb);
+
+	if (vmid_exists != -1) {
+		mark_vmid_used(vm_helper, vmid_exists, hubp_idx);
+		vmid = vmid_exists;
+	} else {
+		if (vm_helper->num_vmids_available == 0)
+			evict_vmids(vm_helper);
+
+		vmid = get_next_available_vmid(vm_helper);
+		mark_vmid_used(vm_helper, vmid, hubp_idx);
+		add_ptb_to_table(vm_helper, vmid, ptb);
+	}
+
+	return vmid;
+}
+
+void init_vm_helper(struct vm_helper *vm_helper, unsigned int num_vmid, unsigned int num_hubp)
+{
+	vm_helper->num_vmid = num_vmid;
+	vm_helper->num_hubp = num_hubp;
+	vm_helper->num_vmids_available = num_vmid - 1;
+
+	memset(vm_helper->hubp_vmid_usage, 0, sizeof(vm_helper->hubp_vmid_usage[0]) * MAX_HUBP);
+	memset(vm_helper->ptb_assigned_to_vmid, 0, sizeof(vm_helper->ptb_assigned_to_vmid[0]) * MAX_VMID);
+}