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 #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_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);