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[178.255.168.113]) by smtp.googlemail.com with ESMTPSA id c65sm37382975wma.44.2019.07.22.12.53.27 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 22 Jul 2019 12:53:28 -0700 (PDT) From: Evgeny Kolesnikov Cc: Evgeny Kolesnikov , Sebastian Reichel , Rob Herring , Mark Rutland , Jason Cooper , Andrew Lunn , Gregory Clement , Sebastian Hesselbarth , linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 4/5] power/reset: Add a restart driver for UART-based PM MCUs Date: Mon, 22 Jul 2019 21:53:04 +0200 Message-Id: X-Mailer: git-send-email 2.21.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: unlisted-recipients:; (no To-header on input) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org This adds the restart driver for power managing micro controller units that are connected to a board via the UART interface. Signed-off-by: Evgeny Kolesnikov --- drivers/power/reset/Kconfig | 7 + drivers/power/reset/Makefile | 1 + drivers/power/reset/uart-restart.c | 204 +++++++++++++++++++++++++++++ 3 files changed, 212 insertions(+) create mode 100644 drivers/power/reset/uart-restart.c diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index 02fdf45e3988..4b187af1fba6 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -223,6 +223,13 @@ config POWER_RESET_UART_POWEROFF Power off support for boards with UART-based PM MCU such as WD My Cloud NAS, QNAP Turbo NAS, Synology devices. +config POWER_RESET_UART + tristate "UART-based PM MCU restart driver" + depends on OF_GPIO + help + Reboot support for boards with UART-based PM MCU + such as WD My Cloud NAS, QNAP Turbo NAS, Synology devices. + config POWER_RESET_ZX tristate "ZTE SoCs reset driver" depends on ARCH_ZX || COMPILE_TEST diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index efe8f25f463d..fa8a936d7a1a 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o obj-$(CONFIG_POWER_RESET_SYSCON_POWEROFF) += syscon-poweroff.o obj-$(CONFIG_POWER_RESET_RMOBILE) += rmobile-reset.o obj-$(CONFIG_POWER_RESET_UART_POWEROFF) += uart-poweroff.o +obj-$(CONFIG_POWER_RESET_UART) += uart-restart.o obj-$(CONFIG_POWER_RESET_ZX) += zx-reboot.o obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o diff --git a/drivers/power/reset/uart-restart.c b/drivers/power/reset/uart-restart.c new file mode 100644 index 000000000000..be4dcbbb826e --- /dev/null +++ b/drivers/power/reset/uart-restart.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Restart for boards with UART-based PM MCUs + * such as WD My Cloud NAS, QNAP Turbo NAS, Synology devices. + * + * Copyright (C) 2019 Evgeny Kolesnikov + * + * Based on the code from: + * + * Copyright (C) 2016 Martin Mueller + * Copyright (C) 2012 Andrew Lunn + * Copyright (C) 2009 Martin Michlmayr + * Copyright (C) 2008 Byron Bradley + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#ifdef CONFIG_ARM +#include +#endif + +#define UART_REG(b, x) (b + ((UART_##x) << 2)) + + +struct uart_restart { + struct notifier_block restart_handler; + const u8 *cmd; + int cmd_len; + void __iomem *base; + unsigned int divisor; + u32 byte_delay_ms; + u32 timeout_ms; + void *pm_restart_org; +}; + +static int uart_restart_notify(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + struct uart_restart *uart_restart = + container_of(this, struct uart_restart, restart_handler); + int i; + + /* Hijack UART and reset into sane state */ + writel(0x83, UART_REG(uart_restart->base, LCR)); + writel(uart_restart->divisor & 0xFF, UART_REG(uart_restart->base, DLL)); + writel((uart_restart->divisor >> 8) & 0xFF, UART_REG(uart_restart->base, DLM)); + writel(0x03, UART_REG(uart_restart->base, LCR)); + writel(0x00, UART_REG(uart_restart->base, IER)); + writel(0x00, UART_REG(uart_restart->base, FCR)); + writel(0x00, UART_REG(uart_restart->base, MCR)); + + /* Send the command */ + for (i = 0; i < uart_restart->cmd_len; i++) { + writel(uart_restart->cmd[i], UART_REG(uart_restart->base, TX)); + mdelay(uart_restart->byte_delay_ms); + } + mdelay(uart_restart->timeout_ms); + WARN_ON(1); + + return NOTIFY_DONE; +} + +static int uart_restart_probe(struct platform_device *pdev) +{ + struct uart_restart *uart_restart; + struct resource *res; + void __iomem *base; + struct clk *clk; + u32 baud; + bool override; + int err; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "Missing resource\n"); + return -EINVAL; + } + + base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + if (!base) { + dev_err(&pdev->dev, "Unable to map resource\n"); + return -EINVAL; + } + + /* We need to know tclk in order to calculate the UART divisor */ + clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(clk)) { + dev_err(&pdev->dev, "Clk missing\n"); + return PTR_ERR(clk); + } + + uart_restart = devm_kzalloc(&pdev->dev, sizeof(*uart_restart), + GFP_KERNEL); + if (!uart_restart) + return -ENOMEM; + + uart_restart->cmd = of_get_property(pdev->dev.of_node, "cmd", + &uart_restart->cmd_len); + if (uart_restart->cmd == NULL || uart_restart->cmd_len < 1) { + dev_err(&pdev->dev, "Cmd is missing or empty\n"); + return -EINVAL; + } + + of_property_read_u32(pdev->dev.of_node, "baud", &baud); + if (baud < 75 || baud > 460800) { + dev_err(&pdev->dev, "Baud rate is missing or invalid\n"); + return -EINVAL; + } + + uart_restart->restart_handler.notifier_call = uart_restart_notify; + uart_restart->restart_handler.priority = 129; + uart_restart->base = base; + uart_restart->divisor = + ((clk_get_rate(clk) + (8 * baud)) / (16 * baud)); + uart_restart->byte_delay_ms = 5; + uart_restart->timeout_ms = 1000; + of_property_read_u32(pdev->dev.of_node, "byte-delay", + &uart_restart->byte_delay_ms); + of_property_read_u32(pdev->dev.of_node, "timeout", + &uart_restart->timeout_ms); + + override = of_property_read_bool(pdev->dev.of_node, "override"); + + if (override) + uart_restart->restart_handler.priority = 192; + + platform_set_drvdata(pdev, uart_restart); + +#ifdef CONFIG_ARM + char symname[KSYM_NAME_LEN]; + + if (arm_pm_restart && !override) { + lookup_symbol_name((ulong)arm_pm_restart, symname); + dev_err(&pdev->dev, + "The arm_pm_restart is already claimed by %s (%p) and override is false", + symname, arm_pm_restart); + return -EBUSY; + } +#endif + + err = register_restart_handler(&uart_restart->restart_handler); + if (err) { + dev_err(&pdev->dev, + "Unable to register restart handler: %d\n", err); + return -ENODEV; + } + +#ifdef CONFIG_ARM + if (arm_pm_restart && override) { + uart_restart->pm_restart_org = arm_pm_restart; + arm_pm_restart = NULL; + } +#endif + + return 0; +} + +static int uart_restart_remove(struct platform_device *pdev) +{ + struct uart_restart *uart_restart = platform_get_drvdata(pdev); + int err; + + err = unregister_restart_handler(&uart_restart->restart_handler); + if (err) { + dev_err(&pdev->dev, + "Unable to unregister restart handler, %d\n", err); + return -ENODEV; + } + +#ifdef CONFIG_ARM + if (arm_pm_restart == NULL && uart_restart->pm_restart_org != NULL) + arm_pm_restart = uart_restart->pm_restart_org; +#endif + + return 0; +} + +static const struct of_device_id of_uart_restart_match[] = { + { .compatible = "uart-restart", }, + {}, +}; + +static struct platform_driver uart_restart_driver = { + .probe = uart_restart_probe, + .remove = uart_restart_remove, + .driver = { + .name = "uart_restart", + .of_match_table = of_uart_restart_match, + }, +}; +module_platform_driver(uart_restart_driver); + +MODULE_AUTHOR("Evgeny Kolesnikov "); +MODULE_DESCRIPTION("UART-based PM MCU restart driver"); +MODULE_LICENSE("GPL v2"); -- 2.21.0