diff options
author | Eryk Brol <eryk.brol@amd.com> | 2018-12-07 18:25:13 +0300 |
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committer | Alex Deucher <alexander.deucher@amd.com> | 2019-01-26 00:15:36 +0300 |
commit | b9708648766d8b15003a543ca36863e731b7b1ba (patch) | |
tree | 442d46c39b114fc2fd107466795d8445d8a88188 /drivers/gpu/drm/amd/display/dc/core/dc_vm_helper.c | |
parent | 89c4f84b602544e580684fff9a7f869e9b1e4ae5 (diff) | |
download | linux-b9708648766d8b15003a543ca36863e731b7b1ba.tar.xz |
drm/amd/display: Introduce DC VM interface
Virtual memory allows display to support flipping to surfaces which
are not allocated contiguously in memory with physical addresses,
instead a 1-4 level page table is used.
This is beneficial because it allows the scattering of large surfaces
to improve memory efficiency and security.
Signed-off-by: Eryk Brol <eryk.brol@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/amd/display/dc/core/dc_vm_helper.c')
-rw-r--r-- | drivers/gpu/drm/amd/display/dc/core/dc_vm_helper.c | 127 |
1 files changed, 127 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..e54b8ac339b2 --- /dev/null +++ b/drivers/gpu/drm/amd/display/dc/core/dc_vm_helper.c @@ -0,0 +1,127 @@ +/* + * 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; +} + +struct vm_helper init_vm_helper(unsigned int num_vmid, unsigned int num_hubp) +{ + static uint64_t ptb_assigned_to_vmid[MAX_VMID]; + static struct vmid_usage hubp_vmid_usage[MAX_HUBP]; + + return (struct vm_helper){ + .num_vmid = num_vmid, + .num_hubp = num_hubp, + .num_vmids_available = num_vmid - 1, + .ptb_assigned_to_vmid = ptb_assigned_to_vmid, + .hubp_vmid_usage = hubp_vmid_usage + }; +} |