linux/drivers/memory/of_memory.c
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   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 */
  30const 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
  59default_min_tck:
  60        dev_warn(dev, "%s: using default min-tck values\n", __func__);
  61        return &lpddr2_jedec_min_tck;
  62}
  63EXPORT_SYMBOL(of_get_min_tck);
  64
  65static 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 */
 106const 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
 148default_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}
 153EXPORT_SYMBOL(of_get_ddr_timings);
 154
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