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);
91