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Diffstat (limited to 'drivers/power/reset/at91-reset.c')
-rw-r--r--drivers/power/reset/at91-reset.c425
1 files changed, 425 insertions, 0 deletions
diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
new file mode 100644
index 000000000..741e44a01
--- /dev/null
+++ b/drivers/power/reset/at91-reset.c
@@ -0,0 +1,425 @@
+/*
+ * Atmel AT91 SAM9 & SAMA5 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/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/reset-controller.h>
+
+#include <soc/at91/at91sam9_ddrsdr.h>
+#include <soc/at91/at91sam9_sdramc.h>
+
+#include <dt-bindings/reset/sama7g5-reset.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_URSTASYNC BIT(2) /* User Reset Asynchronous Control */
+#define AT91_RSTC_URSTIEN BIT(4) /* User Reset Interrupt Enable */
+#define AT91_RSTC_ERSTL GENMASK(11, 8) /* External Reset Length */
+
+/**
+ * enum reset_type - reset types
+ * @RESET_TYPE_GENERAL: first power-up reset
+ * @RESET_TYPE_WAKEUP: return from backup mode
+ * @RESET_TYPE_WATCHDOG: watchdog fault
+ * @RESET_TYPE_SOFTWARE: processor reset required by software
+ * @RESET_TYPE_USER: NRST pin detected low
+ * @RESET_TYPE_CPU_FAIL: CPU clock failure detection
+ * @RESET_TYPE_XTAL_FAIL: 32KHz crystal failure dectection fault
+ * @RESET_TYPE_ULP2: ULP2 reset
+ */
+enum reset_type {
+ RESET_TYPE_GENERAL = 0,
+ RESET_TYPE_WAKEUP = 1,
+ RESET_TYPE_WATCHDOG = 2,
+ RESET_TYPE_SOFTWARE = 3,
+ RESET_TYPE_USER = 4,
+ RESET_TYPE_CPU_FAIL = 6,
+ RESET_TYPE_XTAL_FAIL = 7,
+ RESET_TYPE_ULP2 = 8,
+};
+
+/**
+ * struct at91_reset - AT91 reset specific data structure
+ * @rstc_base: base address for system reset
+ * @ramc_base: array with base addresses of RAM controllers
+ * @dev_base: base address for devices reset
+ * @sclk: slow clock
+ * @data: platform specific reset data
+ * @rcdev: reset controller device
+ * @lock: lock for devices reset register access
+ * @nb: reset notifier block
+ * @args: SoC specific system reset arguments
+ * @ramc_lpr: SDRAM Controller Low Power Register
+ */
+struct at91_reset {
+ void __iomem *rstc_base;
+ void __iomem *ramc_base[2];
+ void __iomem *dev_base;
+ struct clk *sclk;
+ const struct at91_reset_data *data;
+ struct reset_controller_dev rcdev;
+ spinlock_t lock;
+ struct notifier_block nb;
+ u32 args;
+ u32 ramc_lpr;
+};
+
+#define to_at91_reset(r) container_of(r, struct at91_reset, rcdev)
+
+/**
+ * struct at91_reset_data - AT91 reset data
+ * @reset_args: SoC specific system reset arguments
+ * @n_device_reset: number of device resets
+ * @device_reset_min_id: min id for device reset
+ * @device_reset_max_id: max id for device reset
+ */
+struct at91_reset_data {
+ u32 reset_args;
+ u32 n_device_reset;
+ u8 device_reset_min_id;
+ u8 device_reset_max_id;
+};
+
+/*
+* 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 at91_reset(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ struct at91_reset *reset = container_of(this, struct at91_reset, nb);
+
+ asm volatile(
+ /* Align to cache lines */
+ ".balign 32\n\t"
+
+ /* Disable SDRAM0 accesses */
+ " tst %0, #0\n\t"
+ " beq 1f\n\t"
+ " str %3, [%0, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
+ /* Power down SDRAM0 */
+ " str %4, [%0, %6]\n\t"
+ /* Disable SDRAM1 accesses */
+ "1: tst %1, #0\n\t"
+ " beq 2f\n\t"
+ " strne %3, [%1, #" __stringify(AT91_DDRSDRC_RTR) "]\n\t"
+ /* Power down SDRAM1 */
+ " strne %4, [%1, %6]\n\t"
+ /* Reset CPU */
+ "2: str %5, [%2, #" __stringify(AT91_RSTC_CR) "]\n\t"
+
+ " b .\n\t"
+ :
+ : "r" (reset->ramc_base[0]),
+ "r" (reset->ramc_base[1]),
+ "r" (reset->rstc_base),
+ "r" (1),
+ "r" cpu_to_le32(AT91_DDRSDRC_LPCB_POWER_DOWN),
+ "r" (reset->data->reset_args),
+ "r" (reset->ramc_lpr)
+ : "r4");
+
+ return NOTIFY_DONE;
+}
+
+static void __init at91_reset_status(struct platform_device *pdev,
+ void __iomem *base)
+{
+ const char *reason;
+ u32 reg = readl(base + AT91_RSTC_SR);
+
+ 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;
+ case RESET_TYPE_CPU_FAIL:
+ reason = "CPU clock failure detection";
+ break;
+ case RESET_TYPE_XTAL_FAIL:
+ reason = "32.768 kHz crystal failure detection";
+ break;
+ case RESET_TYPE_ULP2:
+ reason = "ULP2 reset";
+ break;
+ default:
+ reason = "unknown reset";
+ break;
+ }
+
+ dev_info(&pdev->dev, "Starting after %s\n", reason);
+}
+
+static const struct of_device_id at91_ramc_of_match[] = {
+ {
+ .compatible = "atmel,at91sam9260-sdramc",
+ .data = (void *)AT91_SDRAMC_LPR,
+ },
+ {
+ .compatible = "atmel,at91sam9g45-ddramc",
+ .data = (void *)AT91_DDRSDRC_LPR,
+ },
+ { /* sentinel */ }
+};
+
+static const struct at91_reset_data sam9260 = {
+ .reset_args = AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST,
+};
+
+static const struct at91_reset_data samx7 = {
+ .reset_args = AT91_RSTC_KEY | AT91_RSTC_PROCRST,
+};
+
+static const struct at91_reset_data sama7g5 = {
+ .reset_args = AT91_RSTC_KEY | AT91_RSTC_PROCRST,
+ .n_device_reset = 3,
+ .device_reset_min_id = SAMA7G5_RESET_USB_PHY1,
+ .device_reset_max_id = SAMA7G5_RESET_USB_PHY3,
+};
+
+static const struct of_device_id at91_reset_of_match[] = {
+ {
+ .compatible = "atmel,at91sam9260-rstc",
+ .data = &sam9260,
+ },
+ {
+ .compatible = "atmel,at91sam9g45-rstc",
+ .data = &sam9260,
+ },
+ {
+ .compatible = "atmel,sama5d3-rstc",
+ .data = &sam9260,
+ },
+ {
+ .compatible = "atmel,samx7-rstc",
+ .data = &samx7,
+ },
+ {
+ .compatible = "microchip,sam9x60-rstc",
+ .data = &samx7,
+ },
+ {
+ .compatible = "microchip,sama7g5-rstc",
+ .data = &sama7g5,
+ },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, at91_reset_of_match);
+
+static int at91_reset_update(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ struct at91_reset *reset = to_at91_reset(rcdev);
+ unsigned long flags;
+ u32 val;
+
+ spin_lock_irqsave(&reset->lock, flags);
+ val = readl_relaxed(reset->dev_base);
+ if (assert)
+ val |= BIT(id);
+ else
+ val &= ~BIT(id);
+ writel_relaxed(val, reset->dev_base);
+ spin_unlock_irqrestore(&reset->lock, flags);
+
+ return 0;
+}
+
+static int at91_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return at91_reset_update(rcdev, id, true);
+}
+
+static int at91_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return at91_reset_update(rcdev, id, false);
+}
+
+static int at91_reset_dev_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct at91_reset *reset = to_at91_reset(rcdev);
+ u32 val;
+
+ val = readl_relaxed(reset->dev_base);
+
+ return !!(val & BIT(id));
+}
+
+static const struct reset_control_ops at91_reset_ops = {
+ .assert = at91_reset_assert,
+ .deassert = at91_reset_deassert,
+ .status = at91_reset_dev_status,
+};
+
+static int at91_reset_of_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ struct at91_reset *reset = to_at91_reset(rcdev);
+
+ if (!reset->data->n_device_reset ||
+ (reset_spec->args[0] < reset->data->device_reset_min_id ||
+ reset_spec->args[0] > reset->data->device_reset_max_id))
+ return -EINVAL;
+
+ return reset_spec->args[0];
+}
+
+static int at91_rcdev_init(struct at91_reset *reset,
+ struct platform_device *pdev)
+{
+ if (!reset->data->n_device_reset)
+ return 0;
+
+ reset->dev_base = devm_of_iomap(&pdev->dev, pdev->dev.of_node, 1,
+ NULL);
+ if (IS_ERR(reset->dev_base))
+ return -ENODEV;
+
+ spin_lock_init(&reset->lock);
+ reset->rcdev.ops = &at91_reset_ops;
+ reset->rcdev.owner = THIS_MODULE;
+ reset->rcdev.of_node = pdev->dev.of_node;
+ reset->rcdev.nr_resets = reset->data->n_device_reset;
+ reset->rcdev.of_reset_n_cells = 1;
+ reset->rcdev.of_xlate = at91_reset_of_xlate;
+
+ return devm_reset_controller_register(&pdev->dev, &reset->rcdev);
+}
+
+static int __init at91_reset_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+ struct at91_reset *reset;
+ struct device_node *np;
+ int ret, idx = 0;
+
+ reset = devm_kzalloc(&pdev->dev, sizeof(*reset), GFP_KERNEL);
+ if (!reset)
+ return -ENOMEM;
+
+ reset->rstc_base = devm_of_iomap(&pdev->dev, pdev->dev.of_node, 0, NULL);
+ if (IS_ERR(reset->rstc_base)) {
+ dev_err(&pdev->dev, "Could not map reset controller address\n");
+ return -ENODEV;
+ }
+
+ 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_and_match(np, at91_ramc_of_match, &match) {
+ reset->ramc_lpr = (u32)match->data;
+ reset->ramc_base[idx] = devm_of_iomap(&pdev->dev, np, 0, NULL);
+ if (IS_ERR(reset->ramc_base[idx])) {
+ dev_err(&pdev->dev, "Could not map ram controller address\n");
+ of_node_put(np);
+ return -ENODEV;
+ }
+ idx++;
+ }
+ }
+
+ reset->data = device_get_match_data(&pdev->dev);
+ if (!reset->data)
+ return -ENODEV;
+
+ reset->nb.notifier_call = at91_reset;
+ reset->nb.priority = 192;
+
+ reset->sclk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(reset->sclk))
+ return PTR_ERR(reset->sclk);
+
+ ret = clk_prepare_enable(reset->sclk);
+ if (ret) {
+ dev_err(&pdev->dev, "Could not enable slow clock\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, reset);
+
+ ret = at91_rcdev_init(reset, pdev);
+ if (ret)
+ goto disable_clk;
+
+ if (of_device_is_compatible(pdev->dev.of_node, "microchip,sam9x60-rstc")) {
+ u32 val = readl(reset->rstc_base + AT91_RSTC_MR);
+
+ writel(AT91_RSTC_KEY | AT91_RSTC_URSTASYNC | val,
+ reset->rstc_base + AT91_RSTC_MR);
+ }
+
+ ret = register_restart_handler(&reset->nb);
+ if (ret)
+ goto disable_clk;
+
+ at91_reset_status(pdev, reset->rstc_base);
+
+ return 0;
+
+disable_clk:
+ clk_disable_unprepare(reset->sclk);
+ return ret;
+}
+
+static int __exit at91_reset_remove(struct platform_device *pdev)
+{
+ struct at91_reset *reset = platform_get_drvdata(pdev);
+
+ unregister_restart_handler(&reset->nb);
+ clk_disable_unprepare(reset->sclk);
+
+ return 0;
+}
+
+static struct platform_driver at91_reset_driver = {
+ .remove = __exit_p(at91_reset_remove),
+ .driver = {
+ .name = "at91-reset",
+ .of_match_table = at91_reset_of_match,
+ },
+};
+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");