drivers/memory/of_memory.c

   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);