2 * Atmel AT91 SAM9 & SAMA5 SoCs reset code
4 * Copyright (C) 2007 Atmel Corporation.
5 * Copyright (C) BitBox Ltd 2010
6 * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcosoft.com>
7 * Copyright (C) 2014 Free Electrons
9 * This file is licensed under the terms of the GNU General Public
10 * License version 2. This program is licensed "as is" without any
11 * warranty of any kind, whether express or implied.
14 #include <linux/clk.h>
16 #include <linux/module.h>
17 #include <linux/of_address.h>
18 #include <linux/platform_device.h>
19 #include <linux/reboot.h>
21 #include <soc/at91/at91sam9_ddrsdr.h>
22 #include <soc/at91/at91sam9_sdramc.h>
24 #define AT91_RSTC_CR 0x00 /* Reset Controller Control Register */
25 #define AT91_RSTC_PROCRST BIT(0) /* Processor Reset */
26 #define AT91_RSTC_PERRST BIT(2) /* Peripheral Reset */
27 #define AT91_RSTC_EXTRST BIT(3) /* External Reset */
28 #define AT91_RSTC_KEY (0xa5 << 24) /* KEY Password */
30 #define AT91_RSTC_SR 0x04 /* Reset Controller Status Register */
31 #define AT91_RSTC_URSTS BIT(0) /* User Reset Status */
32 #define AT91_RSTC_RSTTYP GENMASK(10, 8) /* Reset Type */
33 #define AT91_RSTC_NRSTL BIT(16) /* NRST Pin Level */
34 #define AT91_RSTC_SRCMP BIT(17) /* Software Reset Command in Progress */
36 #define AT91_RSTC_MR 0x08 /* Reset Controller Mode Register */
37 #define AT91_RSTC_URSTEN BIT(0) /* User Reset Enable */
38 #define AT91_RSTC_URSTIEN BIT(4) /* User Reset Interrupt Enable */
39 #define AT91_RSTC_ERSTL GENMASK(11, 8) /* External Reset Length */
42 RESET_TYPE_GENERAL = 0,
43 RESET_TYPE_WAKEUP = 1,
44 RESET_TYPE_WATCHDOG = 2,
45 RESET_TYPE_SOFTWARE = 3,
47 RESET_TYPE_CPU_FAIL = 6,
48 RESET_TYPE_XTAL_FAIL = 7,
53 void __iomem *rstc_base;
54 void __iomem *ramc_base[2];
56 struct notifier_block nb;
60 * unless the SDRAM is cleanly shutdown before we hit the
61 * reset register it can be left driving the data bus and
62 * killing the chance of a subsequent boot from NAND
64 static int at91sam9260_restart(struct notifier_block *this, unsigned long mode,
67 struct at91_reset *reset = container_of(this, struct at91_reset, nb);
70 /* Align to cache lines */
73 /* Disable SDRAM accesses */
74 "str %2, [%0, #" __stringify(AT91_SDRAMC_TR) "]\n\t"
76 /* Power down SDRAM */
77 "str %3, [%0, #" __stringify(AT91_SDRAMC_LPR) "]\n\t"
80 "str %4, [%1, #" __stringify(AT91_RSTC_CR) "]\n\t"
84 : "r" (reset->ramc_base[0]),
85 "r" (reset->rstc_base),
87 "r" cpu_to_le32(AT91_SDRAMC_LPCB_POWER_DOWN),
88 "r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST));
93 static int at91sam9g45_restart(struct notifier_block *this, unsigned long mode,
96 struct at91_reset *reset = container_of(this, struct at91_reset, nb);
100 * Test wether we have a second RAM controller to care
103 * First, test that we can dereference the virtual address.
108 /* Then, test that the RAM controller is enabled */
112 /* Align to cache lines */
115 /* Disable SDRAM0 accesses */
116 "1: str %3, [%0, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
117 /* Power down SDRAM0 */
118 " str %4, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
119 /* Disable SDRAM1 accesses */
120 " strne %3, [%1, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
121 /* Power down SDRAM1 */
122 " strne %4, [%1, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
124 " str %5, [%2, #" __stringify(AT91_RSTC_CR) "]\n\t"
128 : "r" (reset->ramc_base[0]),
129 "r" (reset->ramc_base[1]),
130 "r" (reset->rstc_base),
132 "r" cpu_to_le32(AT91_DDRSDRC_LPCB_POWER_DOWN),
133 "r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST)
139 static int sama5d3_restart(struct notifier_block *this, unsigned long mode,
142 struct at91_reset *reset = container_of(this, struct at91_reset, nb);
144 writel(cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST),
150 static int samx7_restart(struct notifier_block *this, unsigned long mode,
153 struct at91_reset *reset = container_of(this, struct at91_reset, nb);
155 writel(cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PROCRST),
161 static void __init at91_reset_status(struct platform_device *pdev,
165 u32 reg = readl(base + AT91_RSTC_SR);
167 switch ((reg & AT91_RSTC_RSTTYP) >> 8) {
168 case RESET_TYPE_GENERAL:
169 reason = "general reset";
171 case RESET_TYPE_WAKEUP:
174 case RESET_TYPE_WATCHDOG:
175 reason = "watchdog reset";
177 case RESET_TYPE_SOFTWARE:
178 reason = "software reset";
180 case RESET_TYPE_USER:
181 reason = "user reset";
183 case RESET_TYPE_CPU_FAIL:
184 reason = "CPU clock failure detection";
186 case RESET_TYPE_XTAL_FAIL:
187 reason = "32.768 kHz crystal failure detection";
189 case RESET_TYPE_ULP2:
190 reason = "ULP2 reset";
193 reason = "unknown reset";
197 dev_info(&pdev->dev, "Starting after %s\n", reason);
200 static const struct of_device_id at91_ramc_of_match[] = {
201 { .compatible = "atmel,at91sam9260-sdramc", },
202 { .compatible = "atmel,at91sam9g45-ddramc", },
206 static const struct of_device_id at91_reset_of_match[] = {
207 { .compatible = "atmel,at91sam9260-rstc", .data = at91sam9260_restart },
208 { .compatible = "atmel,at91sam9g45-rstc", .data = at91sam9g45_restart },
209 { .compatible = "atmel,sama5d3-rstc", .data = sama5d3_restart },
210 { .compatible = "atmel,samx7-rstc", .data = samx7_restart },
211 { .compatible = "microchip,sam9x60-rstc", .data = samx7_restart },
214 MODULE_DEVICE_TABLE(of, at91_reset_of_match);
216 static int __init at91_reset_probe(struct platform_device *pdev)
218 const struct of_device_id *match;
219 struct at91_reset *reset;
220 struct device_node *np;
223 reset = devm_kzalloc(&pdev->dev, sizeof(*reset), GFP_KERNEL);
227 reset->rstc_base = of_iomap(pdev->dev.of_node, 0);
228 if (!reset->rstc_base) {
229 dev_err(&pdev->dev, "Could not map reset controller address\n");
233 if (!of_device_is_compatible(pdev->dev.of_node, "atmel,sama5d3-rstc")) {
234 /* we need to shutdown the ddr controller, so get ramc base */
235 for_each_matching_node(np, at91_ramc_of_match) {
236 reset->ramc_base[idx] = of_iomap(np, 0);
237 if (!reset->ramc_base[idx]) {
238 dev_err(&pdev->dev, "Could not map ram controller address\n");
246 match = of_match_node(at91_reset_of_match, pdev->dev.of_node);
247 reset->nb.notifier_call = match->data;
248 reset->nb.priority = 192;
250 reset->sclk = devm_clk_get(&pdev->dev, NULL);
251 if (IS_ERR(reset->sclk))
252 return PTR_ERR(reset->sclk);
254 ret = clk_prepare_enable(reset->sclk);
256 dev_err(&pdev->dev, "Could not enable slow clock\n");
260 platform_set_drvdata(pdev, reset);
262 ret = register_restart_handler(&reset->nb);
264 clk_disable_unprepare(reset->sclk);
268 at91_reset_status(pdev, reset->rstc_base);
273 static int __exit at91_reset_remove(struct platform_device *pdev)
275 struct at91_reset *reset = platform_get_drvdata(pdev);
277 unregister_restart_handler(&reset->nb);
278 clk_disable_unprepare(reset->sclk);
283 static struct platform_driver at91_reset_driver = {
284 .remove = __exit_p(at91_reset_remove),
286 .name = "at91-reset",
287 .of_match_table = at91_reset_of_match,
290 module_platform_driver_probe(at91_reset_driver, at91_reset_probe);
292 MODULE_AUTHOR("Atmel Corporation");
293 MODULE_DESCRIPTION("Reset driver for Atmel SoCs");
294 MODULE_LICENSE("GPL v2");