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 */ 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 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 */ 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