1#include <asm/byteorder.h>
2#include "vphn.h"
3
4/*
5 * The associativity domain numbers are returned from the hypervisor as a
6 * stream of mixed 16-bit and 32-bit fields. The stream is terminated by the
7 * special value of "all ones" (aka. 0xffff) and its size may not exceed 48
8 * bytes.
9 *
10 *    --- 16-bit fields -->
11 *  _________________________
12 *  |  0  |  1  |  2  |  3  |   be_packed[0]
13 *  ------+-----+-----+------
14 *  _________________________
15 *  |  4  |  5  |  6  |  7  |   be_packed[1]
16 *  -------------------------
17 *            ...
18 *  _________________________
19 *  | 20  | 21  | 22  | 23  |   be_packed[5]
20 *  -------------------------
21 *
22 * Convert to the sequence they would appear in the ibm,associativity property.
23 */
24int vphn_unpack_associativity(const long *packed, __be32 *unpacked)
25{
26	__be64 be_packed[VPHN_REGISTER_COUNT];
27	int i, nr_assoc_doms = 0;
28	const __be16 *field = (const __be16 *) be_packed;
29	u16 last = 0;
30	bool is_32bit = false;
31
32#define VPHN_FIELD_UNUSED	(0xffff)
33#define VPHN_FIELD_MSB		(0x8000)
34#define VPHN_FIELD_MASK		(~VPHN_FIELD_MSB)
35
36	/* Let's fix the values returned by plpar_hcall9() */
37	for (i = 0; i < VPHN_REGISTER_COUNT; i++)
38		be_packed[i] = cpu_to_be64(packed[i]);
39
40	for (i = 1; i < VPHN_ASSOC_BUFSIZE; i++) {
41		u16 new = be16_to_cpup(field++);
42
43		if (is_32bit) {
44			/* Let's concatenate the 16 bits of this field to the
45			 * 15 lower bits of the previous field
46			 */
47			unpacked[++nr_assoc_doms] =
48				cpu_to_be32(last << 16 | new);
49			is_32bit = false;
50		} else if (new == VPHN_FIELD_UNUSED)
51			/* This is the list terminator */
52			break;
53		else if (new & VPHN_FIELD_MSB) {
54			/* Data is in the lower 15 bits of this field */
55			unpacked[++nr_assoc_doms] =
56				cpu_to_be32(new & VPHN_FIELD_MASK);
57		} else {
58			/* Data is in the lower 15 bits of this field
59			 * concatenated with the next 16 bit field
60			 */
61			last = new;
62			is_32bit = true;
63		}
64	}
65
66	/* The first cell contains the length of the property */
67	unpacked[0] = cpu_to_be32(nr_assoc_doms);
68
69	return nr_assoc_doms;
70}
71