1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright(c) 2022 Intel Corporation. All rights reserved. */
3 
4 #include <cxl.h>
5 #include "core.h"
6 
7 #define CREATE_TRACE_POINTS
8 #include "trace.h"
9 
cxl_is_hpa_in_range(u64 hpa,struct cxl_region * cxlr,int pos)10 static bool cxl_is_hpa_in_range(u64 hpa, struct cxl_region *cxlr, int pos)
11 {
12 	struct cxl_region_params *p = &cxlr->params;
13 	int gran = p->interleave_granularity;
14 	int ways = p->interleave_ways;
15 	u64 offset;
16 
17 	/* Is the hpa within this region at all */
18 	if (hpa < p->res->start || hpa > p->res->end) {
19 		dev_dbg(&cxlr->dev,
20 			"Addr trans fail: hpa 0x%llx not in region\n", hpa);
21 		return false;
22 	}
23 
24 	/* Is the hpa in an expected chunk for its pos(-ition) */
25 	offset = hpa - p->res->start;
26 	offset = do_div(offset, gran * ways);
27 	if ((offset >= pos * gran) && (offset < (pos + 1) * gran))
28 		return true;
29 
30 	dev_dbg(&cxlr->dev,
31 		"Addr trans fail: hpa 0x%llx not in expected chunk\n", hpa);
32 
33 	return false;
34 }
35 
cxl_dpa_to_hpa(u64 dpa,struct cxl_region * cxlr,struct cxl_endpoint_decoder * cxled)36 static u64 cxl_dpa_to_hpa(u64 dpa,  struct cxl_region *cxlr,
37 			  struct cxl_endpoint_decoder *cxled)
38 {
39 	u64 dpa_offset, hpa_offset, bits_upper, mask_upper, hpa;
40 	struct cxl_region_params *p = &cxlr->params;
41 	int pos = cxled->pos;
42 	u16 eig = 0;
43 	u8 eiw = 0;
44 
45 	ways_to_eiw(p->interleave_ways, &eiw);
46 	granularity_to_eig(p->interleave_granularity, &eig);
47 
48 	/*
49 	 * The device position in the region interleave set was removed
50 	 * from the offset at HPA->DPA translation. To reconstruct the
51 	 * HPA, place the 'pos' in the offset.
52 	 *
53 	 * The placement of 'pos' in the HPA is determined by interleave
54 	 * ways and granularity and is defined in the CXL Spec 3.0 Section
55 	 * 8.2.4.19.13 Implementation Note: Device Decode Logic
56 	 */
57 
58 	/* Remove the dpa base */
59 	dpa_offset = dpa - cxl_dpa_resource_start(cxled);
60 
61 	mask_upper = GENMASK_ULL(51, eig + 8);
62 
63 	if (eiw < 8) {
64 		hpa_offset = (dpa_offset & mask_upper) << eiw;
65 		hpa_offset |= pos << (eig + 8);
66 	} else {
67 		bits_upper = (dpa_offset & mask_upper) >> (eig + 8);
68 		bits_upper = bits_upper * 3;
69 		hpa_offset = ((bits_upper << (eiw - 8)) + pos) << (eig + 8);
70 	}
71 
72 	/* The lower bits remain unchanged */
73 	hpa_offset |= dpa_offset & GENMASK_ULL(eig + 7, 0);
74 
75 	/* Apply the hpa_offset to the region base address */
76 	hpa = hpa_offset + p->res->start;
77 
78 	if (!cxl_is_hpa_in_range(hpa, cxlr, cxled->pos))
79 		return ULLONG_MAX;
80 
81 	return hpa;
82 }
83 
cxl_trace_hpa(struct cxl_region * cxlr,struct cxl_memdev * cxlmd,u64 dpa)84 u64 cxl_trace_hpa(struct cxl_region *cxlr, struct cxl_memdev *cxlmd,
85 		  u64 dpa)
86 {
87 	struct cxl_region_params *p = &cxlr->params;
88 	struct cxl_endpoint_decoder *cxled = NULL;
89 
90 	for (int i = 0; i <  p->nr_targets; i++) {
91 		cxled = p->targets[i];
92 		if (cxlmd == cxled_to_memdev(cxled))
93 			break;
94 	}
95 	if (!cxled || cxlmd != cxled_to_memdev(cxled))
96 		return ULLONG_MAX;
97 
98 	return cxl_dpa_to_hpa(dpa, cxlr, cxled);
99 }
100