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
10static 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
36static 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
84u64 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