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 */ 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 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 */ 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_kzalloc(dev, sizeof(*timings) * arr_sz, 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