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1/*2 * Atmel AT91 SAM9 SoCs reset code3 *4 * Copyright (C) 2007 Atmel Corporation.5 * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>6 * Copyright (C) 2014 Free Electrons7 *8 * This file is licensed under the terms of the GNU General Public9 * License version 2. This program is licensed "as is" without any10 * 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 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 else74 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 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 void 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 216static const struct of_device_id at91_poweroff_of_match[] = {217 { .compatible = "atmel,at91sam9260-shdwc", },218 { .compatible = "atmel,at91sam9rl-shdwc", },219 { .compatible = "atmel,at91sam9x5-shdwc", },220 { /*sentinel*/ }221};222MODULE_DEVICE_TABLE(of, at91_poweroff_of_match);223 224static struct platform_driver at91_poweroff_driver = {225 .probe = at91_poweroff_probe,226 .remove_new = at91_poweroff_remove,227 .driver = {228 .name = "at91-poweroff",229 .of_match_table = at91_poweroff_of_match,230 },231};232module_platform_driver(at91_poweroff_driver);233 234MODULE_AUTHOR("Atmel Corporation");235MODULE_DESCRIPTION("Shutdown driver for Atmel SoCs");236MODULE_LICENSE("GPL v2");237