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Soren Brinkmann0beb2bd2014-09-02 14:19:09 -07001/*
2 * Zynq power management
3 *
4 * Copyright (C) 2012 - 2014 Xilinx
5 *
6 * Sören Brinkmann <soren.brinkmann@xilinx.com>
7 *
8 * This program is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22#include <linux/io.h>
23#include <linux/of_address.h>
24#include <linux/of_device.h>
25#include "common.h"
26
27/* register offsets */
28#define DDRC_CTRL_REG1_OFFS 0x60
29#define DDRC_DRAM_PARAM_REG3_OFFS 0x20
30
31/* bitfields */
32#define DDRC_CLOCKSTOP_MASK BIT(23)
33#define DDRC_SELFREFRESH_MASK BIT(12)
34
35static void __iomem *ddrc_base;
36
37/**
38 * zynq_pm_ioremap() - Create IO mappings
39 * @comp: DT compatible string
40 * Return: Pointer to the mapped memory or NULL.
41 *
42 * Remap the memory region for a compatible DT node.
43 */
44static void __iomem *zynq_pm_ioremap(const char *comp)
45{
46 struct device_node *np;
47 void __iomem *base = NULL;
48
49 np = of_find_compatible_node(NULL, NULL, comp);
50 if (np) {
51 base = of_iomap(np, 0);
52 of_node_put(np);
53 } else {
54 pr_warn("%s: no compatible node found for '%s'\n", __func__,
55 comp);
56 }
57
58 return base;
59}
60
61/**
62 * zynq_pm_late_init() - Power management init
63 *
64 * Initialization of power management related featurs and infrastructure.
65 */
66void __init zynq_pm_late_init(void)
67{
68 u32 reg;
69
70 ddrc_base = zynq_pm_ioremap("xlnx,zynq-ddrc-a05");
71 if (!ddrc_base) {
72 pr_warn("%s: Unable to map DDRC IO memory.\n", __func__);
73 } else {
74 /*
75 * Enable DDRC clock stop feature. The HW takes care of
76 * entering/exiting the correct mode depending
77 * on activity state.
78 */
79 reg = readl(ddrc_base + DDRC_DRAM_PARAM_REG3_OFFS);
80 reg |= DDRC_CLOCKSTOP_MASK;
81 writel(reg, ddrc_base + DDRC_DRAM_PARAM_REG3_OFFS);
82 }
83}