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 #include <linux/reboot.h>
30 
31 static void __iomem *system_controller_base;
32 
33 struct mvebu_system_controller {
34 	u32 rstoutn_mask_offset;
35 	u32 system_soft_reset_offset;
36 
37 	u32 rstoutn_mask_reset_out_en;
38 	u32 system_soft_reset;
39 };
40 static struct mvebu_system_controller *mvebu_sc;
41 
42 const struct mvebu_system_controller armada_370_xp_system_controller = {
43 	.rstoutn_mask_offset = 0x60,
44 	.system_soft_reset_offset = 0x64,
45 	.rstoutn_mask_reset_out_en = 0x1,
46 	.system_soft_reset = 0x1,
47 };
48 
49 const struct mvebu_system_controller orion_system_controller = {
50 	.rstoutn_mask_offset = 0x108,
51 	.system_soft_reset_offset = 0x10c,
52 	.rstoutn_mask_reset_out_en = 0x4,
53 	.system_soft_reset = 0x1,
54 };
55 
56 static struct of_device_id of_system_controller_table[] = {
57 	{
58 		.compatible = "marvell,orion-system-controller",
59 		.data = (void *) &orion_system_controller,
60 	}, {
61 		.compatible = "marvell,armada-370-xp-system-controller",
62 		.data = (void *) &armada_370_xp_system_controller,
63 	},
64 	{ /* end of list */ },
65 };
66 
67 void mvebu_restart(enum reboot_mode mode, const char *cmd)
68 {
69 	if (!system_controller_base) {
70 		pr_err("Cannot restart, system-controller not available: check the device tree\n");
71 	} else {
72 		/*
73 		 * Enable soft reset to assert RSTOUTn.
74 		 */
75 		writel(mvebu_sc->rstoutn_mask_reset_out_en,
76 			system_controller_base +
77 			mvebu_sc->rstoutn_mask_offset);
78 		/*
79 		 * Assert soft reset.
80 		 */
81 		writel(mvebu_sc->system_soft_reset,
82 			system_controller_base +
83 			mvebu_sc->system_soft_reset_offset);
84 	}
85 
86 	while (1)
87 		;
88 }
89 
90 static int __init mvebu_system_controller_init(void)
91 {
92 	struct device_node *np;
93 
94 	np = of_find_matching_node(NULL, of_system_controller_table);
95 	if (np) {
96 		const struct of_device_id *match =
97 		    of_match_node(of_system_controller_table, np);
98 		BUG_ON(!match);
99 		system_controller_base = of_iomap(np, 0);
100 		mvebu_sc = (struct mvebu_system_controller *)match->data;
101 		of_node_put(np);
102 	}
103 
104 	return 0;
105 }
106 
107 arch_initcall(mvebu_system_controller_init);
108