root/drivers/memory/of_memory.c

DEFINITIONS

1. of_get_min_tck
2. of_do_get_timings
3. of_get_ddr_timings

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * OpenFirmware helpers for memory drivers
   4  *
   5  * Copyright (C) 2012 Texas Instruments, Inc.
   6  */
   7 
   8 #include <linux/device.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/list.h>
  11 #include <linux/of.h>
  12 #include <linux/gfp.h>
  13 #include <linux/export.h>
  14 
  15 #include "jedec_ddr.h"
  16 #include "of_memory.h"
  17 
  18 /**
  19  * of_get_min_tck() - extract min timing values for ddr
  20  * @np: pointer to ddr device tree node
  21  * @device: device requesting for min timing values
  22  *
  23  * Populates the lpddr2_min_tck structure by extracting data
  24  * from device tree node. Returns a pointer to the populated
  25  * structure. If any error in populating the structure, returns
  26  * default min timings provided by JEDEC.
  27  */
  28 const struct lpddr2_min_tck *of_get_min_tck(struct device_node *np,
  29                 struct device *dev)
  30 {
  31         int                     ret = 0;
  32         struct lpddr2_min_tck   *min;
  33 
  34         min = devm_kzalloc(dev, sizeof(*min), GFP_KERNEL);
  35         if (!min)
  36                 goto default_min_tck;
  37 
  38         ret |= of_property_read_u32(np, "tRPab-min-tck", &min->tRPab);
  39         ret |= of_property_read_u32(np, "tRCD-min-tck", &min->tRCD);
  40         ret |= of_property_read_u32(np, "tWR-min-tck", &min->tWR);
  41         ret |= of_property_read_u32(np, "tRASmin-min-tck", &min->tRASmin);
  42         ret |= of_property_read_u32(np, "tRRD-min-tck", &min->tRRD);
  43         ret |= of_property_read_u32(np, "tWTR-min-tck", &min->tWTR);
  44         ret |= of_property_read_u32(np, "tXP-min-tck", &min->tXP);
  45         ret |= of_property_read_u32(np, "tRTP-min-tck", &min->tRTP);
  46         ret |= of_property_read_u32(np, "tCKE-min-tck", &min->tCKE);
  47         ret |= of_property_read_u32(np, "tCKESR-min-tck", &min->tCKESR);
  48         ret |= of_property_read_u32(np, "tFAW-min-tck", &min->tFAW);
  49 
  50         if (ret) {
  51                 devm_kfree(dev, min);
  52                 goto default_min_tck;
  53         }
  54 
  55         return min;
  56 
  57 default_min_tck:
  58         dev_warn(dev, "%s: using default min-tck values\n", __func__);
  59         return &lpddr2_jedec_min_tck;
  60 }
  61 EXPORT_SYMBOL(of_get_min_tck);
  62 
  63 static int of_do_get_timings(struct device_node *np,
  64                 struct lpddr2_timings *tim)
  65 {
  66         int ret;
  67 
  68         ret = of_property_read_u32(np, "max-freq", &tim->max_freq);
  69         ret |= of_property_read_u32(np, "min-freq", &tim->min_freq);
  70         ret |= of_property_read_u32(np, "tRPab", &tim->tRPab);
  71         ret |= of_property_read_u32(np, "tRCD", &tim->tRCD);
  72         ret |= of_property_read_u32(np, "tWR", &tim->tWR);
  73         ret |= of_property_read_u32(np, "tRAS-min", &tim->tRAS_min);
  74         ret |= of_property_read_u32(np, "tRRD", &tim->tRRD);
  75         ret |= of_property_read_u32(np, "tWTR", &tim->tWTR);
  76         ret |= of_property_read_u32(np, "tXP", &tim->tXP);
  77         ret |= of_property_read_u32(np, "tRTP", &tim->tRTP);
  78         ret |= of_property_read_u32(np, "tCKESR", &tim->tCKESR);
  79         ret |= of_property_read_u32(np, "tDQSCK-max", &tim->tDQSCK_max);
  80         ret |= of_property_read_u32(np, "tFAW", &tim->tFAW);
  81         ret |= of_property_read_u32(np, "tZQCS", &tim->tZQCS);
  82         ret |= of_property_read_u32(np, "tZQCL", &tim->tZQCL);
  83         ret |= of_property_read_u32(np, "tZQinit", &tim->tZQinit);
  84         ret |= of_property_read_u32(np, "tRAS-max-ns", &tim->tRAS_max_ns);
  85         ret |= of_property_read_u32(np, "tDQSCK-max-derated",
  86                 &tim->tDQSCK_max_derated);
  87 
  88         return ret;
  89 }
  90 
  91 /**
  92  * of_get_ddr_timings() - extracts the ddr timings and updates no of
  93  * frequencies available.
  94  * @np_ddr: Pointer to ddr device tree node
  95  * @dev: Device requesting for ddr timings
  96  * @device_type: Type of ddr(LPDDR2 S2/S4)
  97  * @nr_frequencies: No of frequencies available for ddr
  98  * (updated by this function)
  99  *
 100  * Populates lpddr2_timings structure by extracting data from device
 101  * tree node. Returns pointer to populated structure. If any error
 102  * while populating, returns default timings provided by JEDEC.
 103  */
 104 const struct lpddr2_timings *of_get_ddr_timings(struct device_node *np_ddr,
 105                 struct device *dev, u32 device_type, u32 *nr_frequencies)
 106 {
 107         struct lpddr2_timings   *timings = NULL;
 108         u32                     arr_sz = 0, i = 0;
 109         struct device_node      *np_tim;
 110         char                    *tim_compat = NULL;
 111 
 112         switch (device_type) {
 113         case DDR_TYPE_LPDDR2_S2:
 114         case DDR_TYPE_LPDDR2_S4:
 115                 tim_compat = "jedec,lpddr2-timings";
 116                 break;
 117         default:
 118                 dev_warn(dev, "%s: un-supported memory type\n", __func__);
 119         }
 120 
 121         for_each_child_of_node(np_ddr, np_tim)
 122                 if (of_device_is_compatible(np_tim, tim_compat))
 123                         arr_sz++;
 124 
 125         if (arr_sz)
 126                 timings = devm_kcalloc(dev, arr_sz, sizeof(*timings),
 127                                        GFP_KERNEL);
 128 
 129         if (!timings)
 130                 goto default_timings;
 131 
 132         for_each_child_of_node(np_ddr, np_tim) {
 133                 if (of_device_is_compatible(np_tim, tim_compat)) {
 134                         if (of_do_get_timings(np_tim, &timings[i])) {
 135                                 devm_kfree(dev, timings);
 136                                 goto default_timings;
 137                         }
 138                         i++;
 139                 }
 140         }
 141 
 142         *nr_frequencies = arr_sz;
 143 
 144         return timings;
 145 
 146 default_timings:
 147         dev_warn(dev, "%s: using default timings\n", __func__);
 148         *nr_frequencies = ARRAY_SIZE(lpddr2_jedec_timings);
 149         return lpddr2_jedec_timings;
 150 }
 151 EXPORT_SYMBOL(of_get_ddr_timings);