1/*
2 * Copyright 2011 Freescale Semiconductor, Inc.
3 * Copyright 2011 Linaro Ltd.
4 *
5 * The code contained herein is licensed under the GNU General Public
6 * License. You may obtain a copy of the GNU General Public License
7 * Version 2 or later at the following locations:
8 *
9 * http://www.opensource.org/licenses/gpl-license.html
10 * http://www.gnu.org/copyleft/gpl.html
11 */
12
13#include <linux/init.h>
14#include <linux/io.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18#include <linux/of_device.h>
19
20#include "common.h"
21
22#define MMDC_MAPSR		0x404
23#define BP_MMDC_MAPSR_PSD	0
24#define BP_MMDC_MAPSR_PSS	4
25
26#define MMDC_MDMISC		0x18
27#define BM_MMDC_MDMISC_DDR_TYPE	0x18
28#define BP_MMDC_MDMISC_DDR_TYPE	0x3
29
30static int ddr_type;
31
32static int imx_mmdc_probe(struct platform_device *pdev)
33{
34	struct device_node *np = pdev->dev.of_node;
35	void __iomem *mmdc_base, *reg;
36	u32 val;
37	int timeout = 0x400;
38
39	mmdc_base = of_iomap(np, 0);
40	WARN_ON(!mmdc_base);
41
42	reg = mmdc_base + MMDC_MDMISC;
43	/* Get ddr type */
44	val = readl_relaxed(reg);
45	ddr_type = (val & BM_MMDC_MDMISC_DDR_TYPE) >>
46		 BP_MMDC_MDMISC_DDR_TYPE;
47
48	reg = mmdc_base + MMDC_MAPSR;
49
50	/* Enable automatic power saving */
51	val = readl_relaxed(reg);
52	val &= ~(1 << BP_MMDC_MAPSR_PSD);
53	writel_relaxed(val, reg);
54
55	/* Ensure it's successfully enabled */
56	while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout)
57		cpu_relax();
58
59	if (unlikely(!timeout)) {
60		pr_warn("%s: failed to enable automatic power saving\n",
61			__func__);
62		return -EBUSY;
63	}
64
65	return 0;
66}
67
68int imx_mmdc_get_ddr_type(void)
69{
70	return ddr_type;
71}
72
73static const struct of_device_id imx_mmdc_dt_ids[] = {
74	{ .compatible = "fsl,imx6q-mmdc", },
75	{ /* sentinel */ }
76};
77
78static struct platform_driver imx_mmdc_driver = {
79	.driver		= {
80		.name	= "imx-mmdc",
81		.of_match_table = imx_mmdc_dt_ids,
82	},
83	.probe		= imx_mmdc_probe,
84};
85
86static int __init imx_mmdc_init(void)
87{
88	return platform_driver_register(&imx_mmdc_driver);
89}
90postcore_initcall(imx_mmdc_init);
91