1 /*
2 * OpenFirmware helpers for memory drivers
3 *
4 * Copyright (C) 2012 Texas Instruments, Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 */
11
12 #include <linux/device.h>
13 #include <linux/platform_device.h>
14 #include <linux/list.h>
15 #include <linux/of.h>
16 #include <linux/gfp.h>
17 #include <memory/jedec_ddr.h>
18 #include <linux/export.h>
19 #include "of_memory.h"
20
21 /**
22 * of_get_min_tck() - extract min timing values for ddr
23 * @np: pointer to ddr device tree node
24 * @device: device requesting for min timing values
25 *
26 * Populates the lpddr2_min_tck structure by extracting data
27 * from device tree node. Returns a pointer to the populated
28 * structure. If any error in populating the structure, returns
29 * default min timings provided by JEDEC.
30 */
of_get_min_tck(struct device_node * np,struct device * dev)31 const struct lpddr2_min_tck *of_get_min_tck(struct device_node *np,
32 struct device *dev)
33 {
34 int ret = 0;
35 struct lpddr2_min_tck *min;
36
37 min = devm_kzalloc(dev, sizeof(*min), GFP_KERNEL);
38 if (!min)
39 goto default_min_tck;
40
41 ret |= of_property_read_u32(np, "tRPab-min-tck", &min->tRPab);
42 ret |= of_property_read_u32(np, "tRCD-min-tck", &min->tRCD);
43 ret |= of_property_read_u32(np, "tWR-min-tck", &min->tWR);
44 ret |= of_property_read_u32(np, "tRASmin-min-tck", &min->tRASmin);
45 ret |= of_property_read_u32(np, "tRRD-min-tck", &min->tRRD);
46 ret |= of_property_read_u32(np, "tWTR-min-tck", &min->tWTR);
47 ret |= of_property_read_u32(np, "tXP-min-tck", &min->tXP);
48 ret |= of_property_read_u32(np, "tRTP-min-tck", &min->tRTP);
49 ret |= of_property_read_u32(np, "tCKE-min-tck", &min->tCKE);
50 ret |= of_property_read_u32(np, "tCKESR-min-tck", &min->tCKESR);
51 ret |= of_property_read_u32(np, "tFAW-min-tck", &min->tFAW);
52
53 if (ret) {
54 devm_kfree(dev, min);
55 goto default_min_tck;
56 }
57
58 return min;
59
60 default_min_tck:
61 dev_warn(dev, "%s: using default min-tck values\n", __func__);
62 return &lpddr2_jedec_min_tck;
63 }
64 EXPORT_SYMBOL(of_get_min_tck);
65
of_do_get_timings(struct device_node * np,struct lpddr2_timings * tim)66 static int of_do_get_timings(struct device_node *np,
67 struct lpddr2_timings *tim)
68 {
69 int ret;
70
71 ret = of_property_read_u32(np, "max-freq", &tim->max_freq);
72 ret |= of_property_read_u32(np, "min-freq", &tim->min_freq);
73 ret |= of_property_read_u32(np, "tRPab", &tim->tRPab);
74 ret |= of_property_read_u32(np, "tRCD", &tim->tRCD);
75 ret |= of_property_read_u32(np, "tWR", &tim->tWR);
76 ret |= of_property_read_u32(np, "tRAS-min", &tim->tRAS_min);
77 ret |= of_property_read_u32(np, "tRRD", &tim->tRRD);
78 ret |= of_property_read_u32(np, "tWTR", &tim->tWTR);
79 ret |= of_property_read_u32(np, "tXP", &tim->tXP);
80 ret |= of_property_read_u32(np, "tRTP", &tim->tRTP);
81 ret |= of_property_read_u32(np, "tCKESR", &tim->tCKESR);
82 ret |= of_property_read_u32(np, "tDQSCK-max", &tim->tDQSCK_max);
83 ret |= of_property_read_u32(np, "tFAW", &tim->tFAW);
84 ret |= of_property_read_u32(np, "tZQCS", &tim->tZQCS);
85 ret |= of_property_read_u32(np, "tZQCL", &tim->tZQCL);
86 ret |= of_property_read_u32(np, "tZQinit", &tim->tZQinit);
87 ret |= of_property_read_u32(np, "tRAS-max-ns", &tim->tRAS_max_ns);
88 ret |= of_property_read_u32(np, "tDQSCK-max-derated",
89 &tim->tDQSCK_max_derated);
90
91 return ret;
92 }
93
94 /**
95 * of_get_ddr_timings() - extracts the ddr timings and updates no of
96 * frequencies available.
97 * @np_ddr: Pointer to ddr device tree node
98 * @dev: Device requesting for ddr timings
99 * @device_type: Type of ddr(LPDDR2 S2/S4)
100 * @nr_frequencies: No of frequencies available for ddr
101 * (updated by this function)
102 *
103 * Populates lpddr2_timings structure by extracting data from device
104 * tree node. Returns pointer to populated structure. If any error
105 * while populating, returns default timings provided by JEDEC.
106 */
of_get_ddr_timings(struct device_node * np_ddr,struct device * dev,u32 device_type,u32 * nr_frequencies)107 const struct lpddr2_timings *of_get_ddr_timings(struct device_node *np_ddr,
108 struct device *dev, u32 device_type, u32 *nr_frequencies)
109 {
110 struct lpddr2_timings *timings = NULL;
111 u32 arr_sz = 0, i = 0;
112 struct device_node *np_tim;
113 char *tim_compat = NULL;
114
115 switch (device_type) {
116 case DDR_TYPE_LPDDR2_S2:
117 case DDR_TYPE_LPDDR2_S4:
118 tim_compat = "jedec,lpddr2-timings";
119 break;
120 default:
121 dev_warn(dev, "%s: un-supported memory type\n", __func__);
122 }
123
124 for_each_child_of_node(np_ddr, np_tim)
125 if (of_device_is_compatible(np_tim, tim_compat))
126 arr_sz++;
127
128 if (arr_sz)
129 timings = devm_kcalloc(dev, arr_sz, sizeof(*timings),
130 GFP_KERNEL);
131
132 if (!timings)
133 goto default_timings;
134
135 for_each_child_of_node(np_ddr, np_tim) {
136 if (of_device_is_compatible(np_tim, tim_compat)) {
137 if (of_do_get_timings(np_tim, &timings[i])) {
138 devm_kfree(dev, timings);
139 goto default_timings;
140 }
141 i++;
142 }
143 }
144
145 *nr_frequencies = arr_sz;
146
147 return timings;
148
149 default_timings:
150 dev_warn(dev, "%s: using default timings\n", __func__);
151 *nr_frequencies = ARRAY_SIZE(lpddr2_jedec_timings);
152 return lpddr2_jedec_timings;
153 }
154 EXPORT_SYMBOL(of_get_ddr_timings);
155
