1/*
2 * Atmel AT91 SAM9 SoCs reset code
3 *
4 * Copyright (C) 2007 Atmel Corporation.
5 * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
6 * Copyright (C) 2014 Free Electrons
7 *
8 * This file is licensed under the terms of the GNU General Public
9 * License version 2.  This program is licensed "as is" without any
10 * warranty of any kind, whether express or implied.
11 */
12
13#include <linux/clk.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/platform_device.h>
19#include <linux/printk.h>
20
21#include <soc/at91/at91sam9_ddrsdr.h>
22
23#define AT91_SHDW_CR	0x00		/* Shut Down Control Register */
24#define AT91_SHDW_SHDW		BIT(0)			/* Shut Down command */
25#define AT91_SHDW_KEY		(0xa5 << 24)		/* KEY Password */
26
27#define AT91_SHDW_MR	0x04		/* Shut Down Mode Register */
28#define AT91_SHDW_WKMODE0	GENMASK(2, 0)		/* Wake-up 0 Mode Selection */
29#define AT91_SHDW_CPTWK0_MAX	0xf			/* Maximum Counter On Wake Up 0 */
30#define AT91_SHDW_CPTWK0	(AT91_SHDW_CPTWK0_MAX << 4) /* Counter On Wake Up 0 */
31#define AT91_SHDW_CPTWK0_(x)	((x) << 4)
32#define AT91_SHDW_RTTWKEN	BIT(16)			/* Real Time Timer Wake-up Enable */
33#define AT91_SHDW_RTCWKEN	BIT(17)			/* Real Time Clock Wake-up Enable */
34
35#define AT91_SHDW_SR	0x08		/* Shut Down Status Register */
36#define AT91_SHDW_WAKEUP0	BIT(0)			/* Wake-up 0 Status */
37#define AT91_SHDW_RTTWK		BIT(16)			/* Real-time Timer Wake-up */
38#define AT91_SHDW_RTCWK		BIT(17)			/* Real-time Clock Wake-up [SAM9RL] */
39
40enum wakeup_type {
41	AT91_SHDW_WKMODE0_NONE		= 0,
42	AT91_SHDW_WKMODE0_HIGH		= 1,
43	AT91_SHDW_WKMODE0_LOW		= 2,
44	AT91_SHDW_WKMODE0_ANYLEVEL	= 3,
45};
46
47static const char *shdwc_wakeup_modes[] = {
48	[AT91_SHDW_WKMODE0_NONE]	= "none",
49	[AT91_SHDW_WKMODE0_HIGH]	= "high",
50	[AT91_SHDW_WKMODE0_LOW]		= "low",
51	[AT91_SHDW_WKMODE0_ANYLEVEL]	= "any",
52};
53
54static struct shdwc {
55	struct clk *sclk;
56	void __iomem *shdwc_base;
57	void __iomem *mpddrc_base;
58} at91_shdwc;
59
60static void __init at91_wakeup_status(struct platform_device *pdev)
61{
62	const char *reason;
63	u32 reg = readl(at91_shdwc.shdwc_base + AT91_SHDW_SR);
64
65	/* Simple power-on, just bail out */
66	if (!reg)
67		return;
68
69	if (reg & AT91_SHDW_RTTWK)
70		reason = "RTT";
71	else if (reg & AT91_SHDW_RTCWK)
72		reason = "RTC";
73	else
74		reason = "unknown";
75
76	dev_info(&pdev->dev, "Wake-Up source: %s\n", reason);
77}
78
79static void at91_poweroff(void)
80{
81	asm volatile(
82		/* Align to cache lines */
83		".balign 32\n\t"
84
85		/* Ensure AT91_SHDW_CR is in the TLB by reading it */
86		"	ldr	r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
87
88		/* Power down SDRAM0 */
89		"	tst	%0, #0\n\t"
90		"	beq	1f\n\t"
91		"	str	%1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
92		/* Shutdown CPU */
93		"1:	str	%3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
94
95		"	b	.\n\t"
96		:
97		: "r" (at91_shdwc.mpddrc_base),
98		  "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF),
99		  "r" (at91_shdwc.shdwc_base),
100		  "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW)
101		: "r6");
102}
103
104static int at91_poweroff_get_wakeup_mode(struct device_node *np)
105{
106	const char *pm;
107	unsigned int i;
108	int err;
109
110	err = of_property_read_string(np, "atmel,wakeup-mode", &pm);
111	if (err < 0)
112		return AT91_SHDW_WKMODE0_ANYLEVEL;
113
114	for (i = 0; i < ARRAY_SIZE(shdwc_wakeup_modes); i++)
115		if (!strcasecmp(pm, shdwc_wakeup_modes[i]))
116			return i;
117
118	return -ENODEV;
119}
120
121static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
122{
123	struct device_node *np = pdev->dev.of_node;
124	int wakeup_mode;
125	u32 mode = 0, tmp;
126
127	wakeup_mode = at91_poweroff_get_wakeup_mode(np);
128	if (wakeup_mode < 0) {
129		dev_warn(&pdev->dev, "shdwc unknown wakeup mode\n");
130		return;
131	}
132
133	if (!of_property_read_u32(np, "atmel,wakeup-counter", &tmp)) {
134		if (tmp > AT91_SHDW_CPTWK0_MAX) {
135			dev_warn(&pdev->dev,
136				 "shdwc wakeup counter 0x%x > 0x%x reduce it to 0x%x\n",
137				 tmp, AT91_SHDW_CPTWK0_MAX, AT91_SHDW_CPTWK0_MAX);
138			tmp = AT91_SHDW_CPTWK0_MAX;
139		}
140		mode |= AT91_SHDW_CPTWK0_(tmp);
141	}
142
143	if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
144			mode |= AT91_SHDW_RTCWKEN;
145
146	if (of_property_read_bool(np, "atmel,wakeup-rtt-timer"))
147			mode |= AT91_SHDW_RTTWKEN;
148
149	writel(wakeup_mode | mode, at91_shdwc.shdwc_base + AT91_SHDW_MR);
150}
151
152static int __init at91_poweroff_probe(struct platform_device *pdev)
153{
154	struct device_node *np;
155	u32 ddr_type;
156	int ret;
157
158	at91_shdwc.shdwc_base = devm_platform_ioremap_resource(pdev, 0);
159	if (IS_ERR(at91_shdwc.shdwc_base))
160		return PTR_ERR(at91_shdwc.shdwc_base);
161
162	at91_shdwc.sclk = devm_clk_get(&pdev->dev, NULL);
163	if (IS_ERR(at91_shdwc.sclk))
164		return PTR_ERR(at91_shdwc.sclk);
165
166	ret = clk_prepare_enable(at91_shdwc.sclk);
167	if (ret) {
168		dev_err(&pdev->dev, "Could not enable slow clock\n");
169		return ret;
170	}
171
172	at91_wakeup_status(pdev);
173
174	if (pdev->dev.of_node)
175		at91_poweroff_dt_set_wakeup_mode(pdev);
176
177	np = of_find_compatible_node(NULL, NULL, "atmel,sama5d3-ddramc");
178	if (np) {
179		at91_shdwc.mpddrc_base = of_iomap(np, 0);
180		of_node_put(np);
181
182		if (!at91_shdwc.mpddrc_base) {
183			ret = -ENOMEM;
184			goto clk_disable;
185		}
186
187		ddr_type = readl(at91_shdwc.mpddrc_base + AT91_DDRSDRC_MDR) &
188				 AT91_DDRSDRC_MD;
189		if (ddr_type != AT91_DDRSDRC_MD_LPDDR2 &&
190		    ddr_type != AT91_DDRSDRC_MD_LPDDR3) {
191			iounmap(at91_shdwc.mpddrc_base);
192			at91_shdwc.mpddrc_base = NULL;
193		}
194	}
195
196	pm_power_off = at91_poweroff;
197
198	return 0;
199
200clk_disable:
201	clk_disable_unprepare(at91_shdwc.sclk);
202	return ret;
203}
204
205static int __exit at91_poweroff_remove(struct platform_device *pdev)
206{
207	if (pm_power_off == at91_poweroff)
208		pm_power_off = NULL;
209
210	if (at91_shdwc.mpddrc_base)
211		iounmap(at91_shdwc.mpddrc_base);
212
213	clk_disable_unprepare(at91_shdwc.sclk);
214
215	return 0;
216}
217
218static const struct of_device_id at91_poweroff_of_match[] = {
219	{ .compatible = "atmel,at91sam9260-shdwc", },
220	{ .compatible = "atmel,at91sam9rl-shdwc", },
221	{ .compatible = "atmel,at91sam9x5-shdwc", },
222	{ /*sentinel*/ }
223};
224MODULE_DEVICE_TABLE(of, at91_poweroff_of_match);
225
226static struct platform_driver at91_poweroff_driver = {
227	.remove = __exit_p(at91_poweroff_remove),
228	.driver = {
229		.name = "at91-poweroff",
230		.of_match_table = at91_poweroff_of_match,
231	},
232};
233module_platform_driver_probe(at91_poweroff_driver, at91_poweroff_probe);
234
235MODULE_AUTHOR("Atmel Corporation");
236MODULE_DESCRIPTION("Shutdown driver for Atmel SoCs");
237MODULE_LICENSE("GPL v2");
238