xref: /openbmc/linux/drivers/gpu/drm/i915/intel_step.c (revision 35267cea)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2020,2021 Intel Corporation
4  */
5 
6 #include "i915_drv.h"
7 #include "intel_step.h"
8 
9 /*
10  * KBL revision ID ordering is bizarre; higher revision ID's map to lower
11  * steppings in some cases.  So rather than test against the revision ID
12  * directly, let's map that into our own range of increasing ID's that we
13  * can test against in a regular manner.
14  */
15 
16 
17 /* FIXME: what about REVID_E0 */
18 static const struct intel_step_info kbl_revids[] = {
19 	[0] = { .gt_step = STEP_A0, .display_step = STEP_A0 },
20 	[1] = { .gt_step = STEP_B0, .display_step = STEP_B0 },
21 	[2] = { .gt_step = STEP_C0, .display_step = STEP_B0 },
22 	[3] = { .gt_step = STEP_D0, .display_step = STEP_B0 },
23 	[4] = { .gt_step = STEP_F0, .display_step = STEP_C0 },
24 	[5] = { .gt_step = STEP_C0, .display_step = STEP_B1 },
25 	[6] = { .gt_step = STEP_D1, .display_step = STEP_B1 },
26 	[7] = { .gt_step = STEP_G0, .display_step = STEP_C0 },
27 };
28 
29 static const struct intel_step_info tgl_uy_revid_step_tbl[] = {
30 	[0] = { .gt_step = STEP_A0, .display_step = STEP_A0 },
31 	[1] = { .gt_step = STEP_B0, .display_step = STEP_C0 },
32 	[2] = { .gt_step = STEP_B1, .display_step = STEP_C0 },
33 	[3] = { .gt_step = STEP_C0, .display_step = STEP_D0 },
34 };
35 
36 /* Same GT stepping between tgl_uy_revids and tgl_revids don't mean the same HW */
37 static const struct intel_step_info tgl_revid_step_tbl[] = {
38 	[0] = { .gt_step = STEP_A0, .display_step = STEP_B0 },
39 	[1] = { .gt_step = STEP_B0, .display_step = STEP_D0 },
40 };
41 
42 static const struct intel_step_info adls_revid_step_tbl[] = {
43 	[0x0] = { .gt_step = STEP_A0, .display_step = STEP_A0 },
44 	[0x1] = { .gt_step = STEP_A0, .display_step = STEP_A2 },
45 	[0x4] = { .gt_step = STEP_B0, .display_step = STEP_B0 },
46 	[0x8] = { .gt_step = STEP_C0, .display_step = STEP_B0 },
47 	[0xC] = { .gt_step = STEP_D0, .display_step = STEP_C0 },
48 };
49 
50 static const struct intel_step_info adlp_revid_step_tbl[] = {
51 	[0x0] = { .gt_step = STEP_A0, .display_step = STEP_A0 },
52 	[0x4] = { .gt_step = STEP_B0, .display_step = STEP_B0 },
53 	[0x8] = { .gt_step = STEP_C0, .display_step = STEP_C0 },
54 	[0xC] = { .gt_step = STEP_C0, .display_step = STEP_D0 },
55 };
56 
57 void intel_step_init(struct drm_i915_private *i915)
58 {
59 	const struct intel_step_info *revids = NULL;
60 	int size = 0;
61 	int revid = INTEL_REVID(i915);
62 	struct intel_step_info step = {};
63 
64 	if (IS_ALDERLAKE_P(i915)) {
65 		revids = adlp_revid_step_tbl;
66 		size = ARRAY_SIZE(adlp_revid_step_tbl);
67 	} else if (IS_ALDERLAKE_S(i915)) {
68 		revids = adls_revid_step_tbl;
69 		size = ARRAY_SIZE(adls_revid_step_tbl);
70 	} else if (IS_TGL_U(i915) || IS_TGL_Y(i915)) {
71 		revids = tgl_uy_revid_step_tbl;
72 		size = ARRAY_SIZE(tgl_uy_revid_step_tbl);
73 	} else if (IS_TIGERLAKE(i915)) {
74 		revids = tgl_revid_step_tbl;
75 		size = ARRAY_SIZE(tgl_revid_step_tbl);
76 	} else if (IS_KABYLAKE(i915)) {
77 		revids = kbl_revids;
78 		size = ARRAY_SIZE(kbl_revids);
79 	}
80 
81 	/* Not using the stepping scheme for the platform yet. */
82 	if (!revids)
83 		return;
84 
85 	if (revid < size && revids[revid].gt_step != STEP_NONE) {
86 		step = revids[revid];
87 	} else {
88 		drm_warn(&i915->drm, "Unknown revid 0x%02x\n", revid);
89 
90 		/*
91 		 * If we hit a gap in the revid array, use the information for
92 		 * the next revid.
93 		 *
94 		 * This may be wrong in all sorts of ways, especially if the
95 		 * steppings in the array are not monotonically increasing, but
96 		 * it's better than defaulting to 0.
97 		 */
98 		while (revid < size && revids[revid].gt_step == STEP_NONE)
99 			revid++;
100 
101 		if (revid < size) {
102 			drm_dbg(&i915->drm, "Using steppings for revid 0x%02x\n",
103 				revid);
104 			step = revids[revid];
105 		} else {
106 			drm_dbg(&i915->drm, "Using future steppings\n");
107 			step.gt_step = STEP_FUTURE;
108 			step.display_step = STEP_FUTURE;
109 		}
110 	}
111 
112 	if (drm_WARN_ON(&i915->drm, step.gt_step == STEP_NONE))
113 		return;
114 
115 	RUNTIME_INFO(i915)->step = step;
116 }
117