--- /dev/null
+/*
+ * Atmel AT91 SAM9 SoCs reset code
+ *
+ * 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.
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+
+#include <soc/at91/at91sam9_ddrsdr.h>
+#include <soc/at91/at91sam9_sdramc.h>
+
+#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;
+
+/*
+* 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
+*/
+static int at91sam9260_restart(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ asm volatile(
+ /* Align to cache lines */
+ ".balign 32\n\t"
+
+ /* Disable SDRAM accesses */
+ "str %2, [%0, #" __stringify(AT91_SDRAMC_TR) "]\n\t"
+
+ /* Power down SDRAM */
+ "str %3, [%0, #" __stringify(AT91_SDRAMC_LPR) "]\n\t"
+
+ /* Reset CPU */
+ "str %4, [%1, #" __stringify(AT91_RSTC_CR) "]\n\t"
+
+ "b .\n\t"
+ :
+ : "r" (at91_ramc_base[0]),
+ "r" (at91_rstc_base),
+ "r" (1),
+ "r" cpu_to_le32(AT91_SDRAMC_LPCB_POWER_DOWN),
+ "r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST));
+
+ return NOTIFY_DONE;
+}
+
+static int at91sam9g45_restart(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ 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\n\t"
+ "beq 1f\n\t"
+
+ /* Then, test that the RAM controller is enabled */
+ "ldr r0, [%1]\n\t"
+ "cmp r0, #0\n\t"
+
+ /* Align to cache lines */
+ ".balign 32\n\t"
+
+ /* Disable SDRAM0 accesses */
+ "1: str %3, [%0, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
+ /* Power down SDRAM0 */
+ " str %4, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
+ /* Disable SDRAM1 accesses */
+ " strne %3, [%1, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
+ /* Power down SDRAM1 */
+ " strne %4, [%1, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
+ /* Reset CPU */
+ " str %5, [%2, #" __stringify(AT91_RSTC_CR) "]\n\t"
+
+ " b .\n\t"
+ :
+ : "r" (at91_ramc_base[0]),
+ "r" (at91_ramc_base[1]),
+ "r" (at91_rstc_base),
+ "r" (1),
+ "r" cpu_to_le32(AT91_DDRSDRC_LPCB_POWER_DOWN),
+ "r" cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST)
+ : "r0");
+
+ return NOTIFY_DONE;
+}
+
+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\n", reason);
+}
+
+static const struct of_device_id at91_ramc_of_match[] = {
+ { .compatible = "atmel,at91sam9260-sdramc", },
+ { .compatible = "atmel,at91sam9g45-ddramc", },
+ { .compatible = "atmel,sama5d3-ddramc", },
+ { /* sentinel */ }
+};
+
+static const struct of_device_id at91_reset_of_match[] = {
+ { .compatible = "atmel,at91sam9260-rstc", .data = at91sam9260_restart },
+ { .compatible = "atmel,at91sam9g45-rstc", .data = at91sam9g45_restart },
+ { /* sentinel */ }
+};
+
+static struct notifier_block at91_restart_nb = {
+ .priority = 192,
+};
+
+static int at91_reset_of_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+ struct device_node *np;
+ int idx = 0;
+
+ at91_rstc_base = of_iomap(pdev->dev.of_node, 0);
+ if (!at91_rstc_base) {
+ dev_err(&pdev->dev, "Could not map reset controller address\n");
+ return -ENODEV;
+ }
+
+ 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\n");
+ return -ENODEV;
+ }
+ idx++;
+ }
+
+ match = of_match_node(at91_reset_of_match, pdev->dev.of_node);
+ at91_restart_nb.notifier_call = match->data;
+ return register_restart_handler(&at91_restart_nb);
+}
+
+static int at91_reset_platform_probe(struct platform_device *pdev)
+{
+ const struct platform_device_id *match;
+ struct resource *res;
+ int idx = 0;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ at91_rstc_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(at91_rstc_base)) {
+ dev_err(&pdev->dev, "Could not map reset controller address\n");
+ return PTR_ERR(at91_rstc_base);
+ }
+
+ for (idx = 0; idx < 2; idx++) {
+ res = platform_get_resource(pdev, IORESOURCE_MEM, idx + 1 );
+ at91_ramc_base[idx] = devm_ioremap(&pdev->dev, res->start,
+ resource_size(res));
+ if (!at91_ramc_base[idx]) {
+ dev_err(&pdev->dev, "Could not map ram controller address\n");
+ return -ENOMEM;
+ }
+ }
+
+ match = platform_get_device_id(pdev);
+ at91_restart_nb.notifier_call =
+ (int (*)(struct notifier_block *,
+ unsigned long, void *)) match->driver_data;
+
+ return register_restart_handler(&at91_restart_nb);
+}
+
+static int at91_reset_probe(struct platform_device *pdev)
+{
+ int ret;
+
+ if (pdev->dev.of_node)
+ ret = at91_reset_of_probe(pdev);
+ else
+ ret = at91_reset_platform_probe(pdev);
+
+ if (ret)
+ return ret;
+
+ at91_reset_status(pdev);
+
+ return 0;
+}
+
+static struct platform_device_id at91_reset_plat_match[] = {
+ { "at91-sam9260-reset", (unsigned long)at91sam9260_restart },
+ { "at91-sam9g45-reset", (unsigned long)at91sam9g45_restart },
+ { /* sentinel */ }
+};
+
+static struct platform_driver at91_reset_driver = {
+ .probe = at91_reset_probe,
+ .driver = {
+ .name = "at91-reset",
+ .of_match_table = at91_reset_of_match,
+ },
+ .id_table = at91_reset_plat_match,
+};
+module_platform_driver(at91_reset_driver);
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