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
tegra210_emc_table_device_init(struct reserved_mem * rmem,struct device * dev)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
tegra210_emc_table_device_release(struct reserved_mem * rmem,struct device * dev)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
tegra210_emc_table_init(struct reserved_mem * rmem)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);
91