tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 void __iomem *at91_shdwc_base;
55static struct clk *sclk;
56static void __iomem *mpddrc_base;
57
58static void __init at91_wakeup_status(void)
59{
60 u32 reg = readl(at91_shdwc_base + AT91_SHDW_SR);
61 char *reason = "unknown";
62
63 /* Simple power-on, just bail out */
64 if (!reg)
65 return;
66
67 if (reg & AT91_SHDW_RTTWK)
68 reason = "RTT";
69 else if (reg & AT91_SHDW_RTCWK)
70 reason = "RTC";
71
72 pr_info("AT91: Wake-Up source: %s\n", reason);
73}
74
75static void at91_poweroff(void)
76{
77 writel(AT91_SHDW_KEY | AT91_SHDW_SHDW, at91_shdwc_base + AT91_SHDW_CR);
78}
79
80static void at91_lpddr_poweroff(void)
81{
82 asm volatile(
83 /* Align to cache lines */
84 ".balign 32\n\t"
85
86 /* Ensure AT91_SHDW_CR is in the TLB by reading it */
87 " ldr r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
88
89 /* Power down SDRAM0 */
90 " str %1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
91 /* Shutdown CPU */
92 " str %3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
93
94 " b .\n\t"
95 :
96 : "r" (mpddrc_base),
97 "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF),
98 "r" (at91_shdwc_base),
99 "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW)
100 : "r6");
101}
102
103static int at91_poweroff_get_wakeup_mode(struct device_node *np)
104{
105 const char *pm;
106 unsigned int i;
107 int err;
108
109 err = of_property_read_string(np, "atmel,wakeup-mode", &pm);
110 if (err < 0)
111 return AT91_SHDW_WKMODE0_ANYLEVEL;
112
113 for (i = 0; i < ARRAY_SIZE(shdwc_wakeup_modes); i++)
114 if (!strcasecmp(pm, shdwc_wakeup_modes[i]))
115 return i;
116
117 return -ENODEV;
118}
119
120static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
121{
122 struct device_node *np = pdev->dev.of_node;
123 int wakeup_mode;
124 u32 mode = 0, tmp;
125
126 wakeup_mode = at91_poweroff_get_wakeup_mode(np);
127 if (wakeup_mode < 0) {
128 dev_warn(&pdev->dev, "shdwc unknown wakeup mode\n");
129 return;
130 }
131
132 if (!of_property_read_u32(np, "atmel,wakeup-counter", &tmp)) {
133 if (tmp > AT91_SHDW_CPTWK0_MAX) {
134 dev_warn(&pdev->dev,
135 "shdwc wakeup counter 0x%x > 0x%x reduce it to 0x%x\n",
136 tmp, AT91_SHDW_CPTWK0_MAX, AT91_SHDW_CPTWK0_MAX);
137 tmp = AT91_SHDW_CPTWK0_MAX;
138 }
139 mode |= AT91_SHDW_CPTWK0_(tmp);
140 }
141
142 if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
143 mode |= AT91_SHDW_RTCWKEN;
144
145 if (of_property_read_bool(np, "atmel,wakeup-rtt-timer"))
146 mode |= AT91_SHDW_RTTWKEN;
147
148 writel(wakeup_mode | mode, at91_shdwc_base + AT91_SHDW_MR);
149}
150
151static int __init at91_poweroff_probe(struct platform_device *pdev)
152{
153 struct resource *res;
154 struct device_node *np;
155 u32 ddr_type;
156 int ret;
157
158 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
159 at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
160 if (IS_ERR(at91_shdwc_base)) {
161 dev_err(&pdev->dev, "Could not map reset controller address\n");
162 return PTR_ERR(at91_shdwc_base);
163 }
164
165 sclk = devm_clk_get(&pdev->dev, NULL);
166 if (IS_ERR(sclk))
167 return PTR_ERR(sclk);
168
169 ret = clk_prepare_enable(sclk);
170 if (ret) {
171 dev_err(&pdev->dev, "Could not enable slow clock\n");
172 return ret;
173 }
174
175 at91_wakeup_status();
176
177 if (pdev->dev.of_node)
178 at91_poweroff_dt_set_wakeup_mode(pdev);
179
180 pm_power_off = at91_poweroff;
181
182 np = of_find_compatible_node(NULL, NULL, "atmel,sama5d3-ddramc");
183 if (!np)
184 return 0;
185
186 mpddrc_base = of_iomap(np, 0);
187 of_node_put(np);
188
189 if (!mpddrc_base)
190 return 0;
191
192 ddr_type = readl(mpddrc_base + AT91_DDRSDRC_MDR) & AT91_DDRSDRC_MD;
193 if ((ddr_type == AT91_DDRSDRC_MD_LPDDR2) ||
194 (ddr_type == AT91_DDRSDRC_MD_LPDDR3))
195 pm_power_off = at91_lpddr_poweroff;
196 else
197 iounmap(mpddrc_base);
198
199 return 0;
200}
201
202static int __exit at91_poweroff_remove(struct platform_device *pdev)
203{
204 if (pm_power_off == at91_poweroff ||
205 pm_power_off == at91_lpddr_poweroff)
206 pm_power_off = NULL;
207
208 clk_disable_unprepare(sclk);
209
210 return 0;
211}
212
213static const struct of_device_id at91_ramc_of_match[] = {
214 { .compatible = "atmel,sama5d3-ddramc", },
215 { /* sentinel */ }
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");