drivers/memory/tegra/tegra210-emc-table.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
   4  */
   5
   6 #include <linux/of_reserved_mem.h>
   7
   8 #include "tegra210-emc.h"
   9
  10 #define TEGRA_EMC_MAX_FREQS             16
  11
  12 static int tegra210_emc_table_device_init(struct reserved_mem *rmem,
  13                                           struct device *dev)
  14 {
  15         struct tegra210_emc *emc = dev_get_drvdata(dev);
  16         struct tegra210_emc_timing *timings;
  17         unsigned int i, count = 0;
  18
  19         timings = memremap(rmem->base, rmem->size, MEMREMAP_WB);
  20         if (!timings) {
  21                 dev_err(dev, "failed to map EMC table\n");
  22                 return -ENOMEM;
  23         }
  24
  25         for (i = 0; i < TEGRA_EMC_MAX_FREQS; i++) {
  26                 if (timings[i].revision == 0)
  27                         break;
  28
  29                 count++;
  30         }
  31
  32         /* only the nominal and derated tables are expected */
  33         if (emc->derated) {
  34                 dev_warn(dev, "excess EMC table '%s'\n", rmem->name);
  35                 goto out;
  36         }
  37
  38         if (emc->nominal) {
  39                 if (count != emc->num_timings) {
  40                         dev_warn(dev, "%u derated vs. %u nominal entries\n",
  41                                  count, emc->num_timings);
  42                         memunmap(timings);
  43                         return -EINVAL;
  44                 }
  45
  46                 emc->derated = timings;
  47         } else {
  48                 emc->num_timings = count;
  49                 emc->nominal = timings;
  50         }
  51
  52 out:
  53         /* keep track of which table this is */
  54         rmem->priv = timings;
  55
  56         return 0;
  57 }
  58
  59 static void tegra210_emc_table_device_release(struct reserved_mem *rmem,
  60                                               struct device *dev)
  61 {
  62         struct tegra210_emc_timing *timings = rmem->priv;
  63         struct tegra210_emc *emc = dev_get_drvdata(dev);
  64
  65         if ((emc->nominal && timings != emc->nominal) &&
  66             (emc->derated && timings != emc->derated))
  67                 dev_warn(dev, "trying to release unassigned EMC table '%s'\n",
  68                          rmem->name);
  69
  70         memunmap(timings);
  71 }
  72
  73 static const struct reserved_mem_ops tegra210_emc_table_ops = {
  74         .device_init = tegra210_emc_table_device_init,
  75         .device_release = tegra210_emc_table_device_release,
  76 };
  77
  78 static int tegra210_emc_table_init(struct reserved_mem *rmem)
  79 {
  80         pr_debug("Tegra210 EMC table at %pa, size %lu bytes\n", &rmem->base,
  81                  (unsigned long)rmem->size);
  82
  83         rmem->ops = &tegra210_emc_table_ops;
  84
  85         return 0;
  86 }
  87 RESERVEDMEM_OF_DECLARE(tegra210_emc_table, "nvidia,tegra210-emc-table",
  88                        tegra210_emc_table_init);