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	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
54out:
55	/* keep track of which table this is */
56	rmem->priv = timings;
57
58	return 0;
59}
60
61static 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
75static 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
80static 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}
89RESERVEDMEM_OF_DECLARE(tegra210_emc_table, "nvidia,tegra210-emc-table",
90		       tegra210_emc_table_init);