1 /*
2  * System controller support for Armada 370 and XP platforms.
3  *
4  * Copyright (C) 2012 Marvell
5  *
6  * Lior Amsalem <alior@marvell.com>
7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
9  *
10  * This file is licensed under the terms of the GNU General Public
11  * License version 2.  This program is licensed "as is" without any
12  * warranty of any kind, whether express or implied.
13  *
14  * The Armada 370 and Armada XP SoCs both have a range of
15  * miscellaneous registers, that do not belong to a particular device,
16  * but rather provide system-level features. This basic
17  * system-controller driver provides a device tree binding for those
18  * registers, and implements utility functions offering various
19  * features related to those registers.
20  *
21  * For now, the feature set is limited to restarting the platform by a
22  * soft-reset, but it might be extended in the future.
23  */
24 
25 #include <linux/kernel.h>
26 #include <linux/init.h>
27 #include <linux/of_address.h>
28 #include <linux/io.h>
29 
30 static void __iomem *system_controller_base;
31 
32 struct mvebu_system_controller {
33 	u32 rstoutn_mask_offset;
34 	u32 system_soft_reset_offset;
35 
36 	u32 rstoutn_mask_reset_out_en;
37 	u32 system_soft_reset;
38 };
39 static struct mvebu_system_controller *mvebu_sc;
40 
41 const struct mvebu_system_controller armada_370_xp_system_controller = {
42 	.rstoutn_mask_offset = 0x60,
43 	.system_soft_reset_offset = 0x64,
44 	.rstoutn_mask_reset_out_en = 0x1,
45 	.system_soft_reset = 0x1,
46 };
47 
48 const struct mvebu_system_controller orion_system_controller = {
49 	.rstoutn_mask_offset = 0x108,
50 	.system_soft_reset_offset = 0x10c,
51 	.rstoutn_mask_reset_out_en = 0x4,
52 	.system_soft_reset = 0x1,
53 };
54 
55 static struct of_device_id of_system_controller_table[] = {
56 	{
57 		.compatible = "marvell,orion-system-controller",
58 		.data = (void *) &orion_system_controller,
59 	}, {
60 		.compatible = "marvell,armada-370-xp-system-controller",
61 		.data = (void *) &armada_370_xp_system_controller,
62 	},
63 	{ /* end of list */ },
64 };
65 
66 void mvebu_restart(char mode, const char *cmd)
67 {
68 	if (!system_controller_base) {
69 		pr_err("Cannot restart, system-controller not available: check the device tree\n");
70 	} else {
71 		/*
72 		 * Enable soft reset to assert RSTOUTn.
73 		 */
74 		writel(mvebu_sc->rstoutn_mask_reset_out_en,
75 			system_controller_base +
76 			mvebu_sc->rstoutn_mask_offset);
77 		/*
78 		 * Assert soft reset.
79 		 */
80 		writel(mvebu_sc->system_soft_reset,
81 			system_controller_base +
82 			mvebu_sc->system_soft_reset_offset);
83 	}
84 
85 	while (1)
86 		;
87 }
88 
89 static int __init mvebu_system_controller_init(void)
90 {
91 	struct device_node *np;
92 
93 	np = of_find_matching_node(NULL, of_system_controller_table);
94 	if (np) {
95 		const struct of_device_id *match =
96 		    of_match_node(of_system_controller_table, np);
97 		BUG_ON(!match);
98 		system_controller_base = of_iomap(np, 0);
99 		mvebu_sc = (struct mvebu_system_controller *)match->data;
100 	}
101 
102 	return 0;
103 }
104 
105 arch_initcall(mvebu_system_controller_init);
106