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#define MMDC_MAPSR		0x404
21#define BP_MMDC_MAPSR_PSD	0
22#define BP_MMDC_MAPSR_PSS	4
23
24#define MMDC_MDMISC		0x18
25#define BM_MMDC_MDMISC_DDR_TYPE	0x18
26#define BP_MMDC_MDMISC_DDR_TYPE	0x3
27
28static int ddr_type;
29
30static int imx_mmdc_probe(struct platform_device *pdev)
31{
32	struct device_node *np = pdev->dev.of_node;
33	void __iomem *mmdc_base, *reg;
34	u32 val;
35	int timeout = 0x400;
36
37	mmdc_base = of_iomap(np, 0);
38	WARN_ON(!mmdc_base);
39
40	reg = mmdc_base + MMDC_MDMISC;
41	/* Get ddr type */
42	val = readl_relaxed(reg);
43	ddr_type = (val & BM_MMDC_MDMISC_DDR_TYPE) >>
44		 BP_MMDC_MDMISC_DDR_TYPE;
45
46	reg = mmdc_base + MMDC_MAPSR;
47
48	/* Enable automatic power saving */
49	val = readl_relaxed(reg);
50	val &= ~(1 << BP_MMDC_MAPSR_PSD);
51	writel_relaxed(val, reg);
52
53	/* Ensure it's successfully enabled */
54	while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout)
55		cpu_relax();
56
57	if (unlikely(!timeout)) {
58		pr_warn("%s: failed to enable automatic power saving\n",
59			__func__);
60		return -EBUSY;
61	}
62
63	return 0;
64}
65
66int imx_mmdc_get_ddr_type(void)
67{
68	return ddr_type;
69}
70
71static const struct of_device_id imx_mmdc_dt_ids[] = {
72	{ .compatible = "fsl,imx6q-mmdc", },
73	{ /* sentinel */ }
74};
75
76static struct platform_driver imx_mmdc_driver = {
77	.driver		= {
78		.name	= "imx-mmdc",
79		.of_match_table = imx_mmdc_dt_ids,
80	},
81	.probe		= imx_mmdc_probe,
82};
83
84static int __init imx_mmdc_init(void)
85{
86	return platform_driver_register(&imx_mmdc_driver);
87}
88postcore_initcall(imx_mmdc_init);
89