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 	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 
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 
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