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drivers/power/reset/at91-reset.c
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/* |
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* Atmel AT91 SAM9 & SAMA5 SoCs reset code |
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* * Copyright (C) 2007 Atmel Corporation. * Copyright (C) BitBox Ltd 2010 * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcosoft.com> * Copyright (C) 2014 Free Electrons * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ |
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#include <linux/clk.h> |
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#include <linux/io.h> #include <linux/module.h> #include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/reboot.h> |
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#include <soc/at91/at91sam9_ddrsdr.h> #include <soc/at91/at91sam9_sdramc.h> |
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#define AT91_RSTC_CR 0x00 /* Reset Controller Control Register */ #define AT91_RSTC_PROCRST BIT(0) /* Processor Reset */ #define AT91_RSTC_PERRST BIT(2) /* Peripheral Reset */ #define AT91_RSTC_EXTRST BIT(3) /* External Reset */ #define AT91_RSTC_KEY (0xa5 << 24) /* KEY Password */ #define AT91_RSTC_SR 0x04 /* Reset Controller Status Register */ #define AT91_RSTC_URSTS BIT(0) /* User Reset Status */ #define AT91_RSTC_RSTTYP GENMASK(10, 8) /* Reset Type */ #define AT91_RSTC_NRSTL BIT(16) /* NRST Pin Level */ #define AT91_RSTC_SRCMP BIT(17) /* Software Reset Command in Progress */ #define AT91_RSTC_MR 0x08 /* Reset Controller Mode Register */ #define AT91_RSTC_URSTEN BIT(0) /* User Reset Enable */ #define AT91_RSTC_URSTIEN BIT(4) /* User Reset Interrupt Enable */ #define AT91_RSTC_ERSTL GENMASK(11, 8) /* External Reset Length */ enum reset_type { RESET_TYPE_GENERAL = 0, RESET_TYPE_WAKEUP = 1, RESET_TYPE_WATCHDOG = 2, RESET_TYPE_SOFTWARE = 3, RESET_TYPE_USER = 4, }; static void __iomem *at91_ramc_base[2], *at91_rstc_base; |
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static struct clk *sclk; |
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/* * unless the SDRAM is cleanly shutdown before we hit the * reset register it can be left driving the data bus and * killing the chance of a subsequent boot from NAND */ |
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static int at91sam9260_restart(struct notifier_block *this, unsigned long mode, void *cmd) |
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{ asm volatile( /* Align to cache lines */ ".balign 32 \t" /* Disable SDRAM accesses */ "str %2, [%0, #" __stringify(AT91_SDRAMC_TR) "] \t" /* Power down SDRAM */ "str %3, [%0, #" __stringify(AT91_SDRAMC_LPR) "] \t" /* Reset CPU */ "str %4, [%1, #" __stringify(AT91_RSTC_CR) "] \t" "b . \t" : : "r" (at91_ramc_base[0]), "r" (at91_rstc_base), "r" (1), |
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"r" cpu_to_le32(AT91_SDRAMC_LPCB_POWER_DOWN), "r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST)); |
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return NOTIFY_DONE; |
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} |
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static int at91sam9g45_restart(struct notifier_block *this, unsigned long mode, void *cmd) |
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{ asm volatile( /* * Test wether we have a second RAM controller to care * about. * * First, test that we can dereference the virtual address. */ "cmp %1, #0 \t" "beq 1f \t" /* Then, test that the RAM controller is enabled */ "ldr r0, [%1] \t" "cmp r0, #0 \t" /* Align to cache lines */ ".balign 32 \t" /* Disable SDRAM0 accesses */ "1: str %3, [%0, #" __stringify(AT91_DDRSDRC_RTR) "] \t" /* Power down SDRAM0 */ |
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" str %4, [%0, #" __stringify(AT91_DDRSDRC_LPR) "] \t" |
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/* Disable SDRAM1 accesses */ " strne %3, [%1, #" __stringify(AT91_DDRSDRC_RTR) "] \t" /* Power down SDRAM1 */ |
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" strne %4, [%1, #" __stringify(AT91_DDRSDRC_LPR) "] \t" |
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/* Reset CPU */ " str %5, [%2, #" __stringify(AT91_RSTC_CR) "] \t" " b . \t" : : "r" (at91_ramc_base[0]), "r" (at91_ramc_base[1]), "r" (at91_rstc_base), "r" (1), |
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"r" cpu_to_le32(AT91_DDRSDRC_LPCB_POWER_DOWN), "r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST) |
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: "r0"); |
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return NOTIFY_DONE; |
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} |
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static int sama5d3_restart(struct notifier_block *this, unsigned long mode, void *cmd) { writel(cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST), at91_rstc_base); return NOTIFY_DONE; } |
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static void __init at91_reset_status(struct platform_device *pdev) { u32 reg = readl(at91_rstc_base + AT91_RSTC_SR); char *reason; switch ((reg & AT91_RSTC_RSTTYP) >> 8) { case RESET_TYPE_GENERAL: reason = "general reset"; break; case RESET_TYPE_WAKEUP: reason = "wakeup"; break; case RESET_TYPE_WATCHDOG: reason = "watchdog reset"; break; case RESET_TYPE_SOFTWARE: reason = "software reset"; break; case RESET_TYPE_USER: reason = "user reset"; break; default: reason = "unknown reset"; break; } pr_info("AT91: Starting after %s ", reason); } |
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static const struct of_device_id at91_ramc_of_match[] = { |
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{ .compatible = "atmel,at91sam9260-sdramc", }, { .compatible = "atmel,at91sam9g45-ddramc", }, |
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{ /* sentinel */ } }; |
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static const struct of_device_id at91_reset_of_match[] = { |
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{ .compatible = "atmel,at91sam9260-rstc", .data = at91sam9260_restart }, { .compatible = "atmel,at91sam9g45-rstc", .data = at91sam9g45_restart }, |
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{ .compatible = "atmel,sama5d3-rstc", .data = sama5d3_restart }, |
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{ /* sentinel */ } }; |
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static struct notifier_block at91_restart_nb = { .priority = 192, }; |
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static int __init at91_reset_probe(struct platform_device *pdev) |
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{ const struct of_device_id *match; struct device_node *np; |
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int ret, idx = 0; |
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at91_rstc_base = of_iomap(pdev->dev.of_node, 0); if (!at91_rstc_base) { dev_err(&pdev->dev, "Could not map reset controller address "); return -ENODEV; } |
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if (!of_device_is_compatible(pdev->dev.of_node, "atmel,sama5d3-rstc")) { /* we need to shutdown the ddr controller, so get ramc base */ for_each_matching_node(np, at91_ramc_of_match) { at91_ramc_base[idx] = of_iomap(np, 0); if (!at91_ramc_base[idx]) { dev_err(&pdev->dev, "Could not map ram controller address "); |
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of_node_put(np); |
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return -ENODEV; } idx++; |
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} |
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} match = of_match_node(at91_reset_of_match, pdev->dev.of_node); |
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at91_restart_nb.notifier_call = match->data; |
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sclk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(sclk)) return PTR_ERR(sclk); ret = clk_prepare_enable(sclk); if (ret) { dev_err(&pdev->dev, "Could not enable slow clock "); return ret; } |
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ret = register_restart_handler(&at91_restart_nb); |
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if (ret) { clk_disable_unprepare(sclk); |
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return ret; |
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} |
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at91_reset_status(pdev); return 0; } |
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static int __exit at91_reset_remove(struct platform_device *pdev) { unregister_restart_handler(&at91_restart_nb); |
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clk_disable_unprepare(sclk); |
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return 0; } |
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static const struct platform_device_id at91_reset_plat_match[] = { |
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{ "at91-sam9260-reset", (unsigned long)at91sam9260_restart }, { "at91-sam9g45-reset", (unsigned long)at91sam9g45_restart }, { /* sentinel */ } }; static struct platform_driver at91_reset_driver = { |
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.remove = __exit_p(at91_reset_remove), |
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.driver = { .name = "at91-reset", .of_match_table = at91_reset_of_match, }, .id_table = at91_reset_plat_match, }; |
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module_platform_driver_probe(at91_reset_driver, at91_reset_probe); MODULE_AUTHOR("Atmel Corporation"); MODULE_DESCRIPTION("Reset driver for Atmel SoCs"); MODULE_LICENSE("GPL v2"); |