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         count = 0;
  26
  27         for (i = 0; i < TEGRA_EMC_MAX_FREQS; i++) {
  28                 if (timings[i].revision == 0)
  29                         break;
  30
  31                 count++;
  32         }
  33
  34         /* only the nominal and derated tables are expected */
  35         if (emc->derated) {
  36                 dev_warn(dev, "excess EMC table '%s'\n", rmem->name);
  37                 goto out;
  38         }
  39
  40         if (emc->nominal) {
  41                 if (count != emc->num_timings) {
  42                         dev_warn(dev, "%u derated vs. %u nominal entries\n",
  43                                  count, emc->num_timings);
  44                         memunmap(timings);
  45                         return -EINVAL;
  46                 }
  47
  48                 emc->derated = timings;
  49         } else {
  50                 emc->num_timings = count;
  51                 emc->nominal = timings;
  52         }
  53
  54 out:
  55         /* keep track of which table this is */
  56         rmem->priv = timings;
  57
  58         return 0;
  59 }
  60
  61 static void tegra210_emc_table_device_release(struct reserved_mem *rmem,
  62                                               struct device *dev)
  63 {
  64         struct tegra210_emc_timing *timings = rmem->priv;
  65         struct tegra210_emc *emc = dev_get_drvdata(dev);
  66
  67         if ((emc->nominal && timings != emc->nominal) &&
  68             (emc->derated && timings != emc->derated))
  69                 dev_warn(dev, "trying to release unassigned EMC table '%s'\n",
  70                          rmem->name);
  71
  72         memunmap(timings);
  73 }
  74
  75 static const struct reserved_mem_ops tegra210_emc_table_ops = {
  76         .device_init = tegra210_emc_table_device_init,
  77         .device_release = tegra210_emc_table_device_release,
  78 };
  79
  80 static int tegra210_emc_table_init(struct reserved_mem *rmem)
  81 {
  82         pr_debug("Tegra210 EMC table at %pa, size %lu bytes\n", &rmem->base,
  83                  (unsigned long)rmem->size);
  84
  85         rmem->ops = &tegra210_emc_table_ops;
  86
  87         return 0;
  88 }
  89 RESERVEDMEM_OF_DECLARE(tegra210_emc_table, "nvidia,tegra210-emc-table",
  90                        tegra210_emc_table_init);