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 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
tegra210_emc_table_device_release(struct reserved_mem * rmem,struct device * dev)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
tegra210_emc_table_init(struct reserved_mem * rmem)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);
89