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
12static 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
52out:
53	/* keep track of which table this is */
54	rmem->priv = timings;
55
56	return 0;
57}
58
59static 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
73static 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
78static 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}
87RESERVEDMEM_OF_DECLARE(tegra210_emc_table, "nvidia,tegra210-emc-table",
88		       tegra210_emc_table_init);
89