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