From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIXrH-0007wZ-0r for barebox@lists.infradead.org; Wed, 16 Sep 2020 13:52:29 +0000 From: Ahmad Fatoum Date: Wed, 16 Sep 2020 15:50:28 +0200 Message-Id: <20200916135035.7089-4-a.fatoum@pengutronix.de> In-Reply-To: <20200916135035.7089-1-a.fatoum@pengutronix.de> References: <20200916135035.7089-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 03/10] power: reset: reboot-mode: port syscon-reboot-mode support To: barebox@lists.infradead.org Cc: Ahmad Fatoum Reboot modes are one-shot information that should be valid for only a single reset. Syscons that survive a warm reset are one way to implement this. This is used by many BootROMs to allow falling into a recovery mode on the next boot. This ports the Linux syscon-reboot-mode support. Signed-off-by: Ahmad Fatoum --- Documentation/user/reboot-mode.rst | 11 +++ drivers/power/reset/Kconfig | 11 +++ drivers/power/reset/Makefile | 1 + drivers/power/reset/syscon-reboot-mode.c | 85 ++++++++++++++++++++++++ 4 files changed, 108 insertions(+) create mode 100644 drivers/power/reset/syscon-reboot-mode.c diff --git a/Documentation/user/reboot-mode.rst b/Documentation/user/reboot-mode.rst index 1908da3ed2d7..9321d928f41a 100644 --- a/Documentation/user/reboot-mode.rst +++ b/Documentation/user/reboot-mode.rst @@ -45,6 +45,17 @@ Reboot mode providers have priorities. The provider with the highest priority has its parameters aliased as ``$global.system.reboot_mode.prev`` and ``$global.system.reboot_mode.next``. +Reset +~~~~~ + +Reboot modes can be stored on a syscon wrapping general purpose registers +that survives warm resets. If the system instead did reset via an external +power management IC, the registers may lose their value. + +If such reboot mode storage is used, users must take care to use the correct +reset provider. In barebox, multiple reset providers may co-exist. They +``reset`` command allows listing and choosing a specific reboot mode. + Disambiguation ~~~~~~~~~~~~~~ diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index 5554fc122d92..f65e1f67fd59 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -3,3 +3,14 @@ config REBOOT_MODE bool + +config SYSCON_REBOOT_MODE + bool "Generic SYSCON regmap reboot mode driver" + depends on OFDEVICE + depends on MFD_SYSCON + select REBOOT_MODE + help + Say y here will enable reboot mode driver. This will + get reboot mode arguments and store it in SYSCON mapped + register, then the bootloader can read it to take different + action according to the mode. diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index 68231f044a52..56feec78cf26 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -1,2 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o +obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o diff --git a/drivers/power/reset/syscon-reboot-mode.c b/drivers/power/reset/syscon-reboot-mode.c new file mode 100644 index 000000000000..5e4aed943d5c --- /dev/null +++ b/drivers/power/reset/syscon-reboot-mode.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd + */ + +#include +#include +#include +#include +#include +#include +#include + +struct syscon_reboot_mode { + struct regmap *map; + struct reboot_mode_driver reboot; + u32 offset; + u32 mask; +}; + +static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot, + unsigned int magic) +{ + struct syscon_reboot_mode *syscon_rbm; + int ret; + + syscon_rbm = container_of(reboot, struct syscon_reboot_mode, reboot); + + ret = regmap_update_bits(syscon_rbm->map, syscon_rbm->offset, + syscon_rbm->mask, magic); + if (ret < 0) + dev_err(reboot->dev, "update reboot mode bits failed\n"); + + return ret; +} + +static int syscon_reboot_mode_probe(struct device_d *dev) +{ + int ret; + struct syscon_reboot_mode *syscon_rbm; + struct device_node *np = dev->device_node; + u32 magic; + + syscon_rbm = xzalloc(sizeof(*syscon_rbm)); + + syscon_rbm->reboot.dev = dev; + syscon_rbm->reboot.write = syscon_reboot_mode_write; + syscon_rbm->mask = 0xffffffff; + + syscon_rbm->map = syscon_node_to_regmap(dev->parent->device_node); + if (IS_ERR(syscon_rbm->map)) + return PTR_ERR(syscon_rbm->map); + + if (of_property_read_u32(np, "offset", &syscon_rbm->offset)) + return -EINVAL; + + of_property_read_u32(np, "mask", &syscon_rbm->mask); + + ret = regmap_read(syscon_rbm->map, syscon_rbm->offset, &magic); + if (ret) { + dev_err(dev, "error reading reboot mode: %s\n", + strerror(-ret)); + return ret; + } + + magic &= syscon_rbm->mask; + + ret = reboot_mode_register(&syscon_rbm->reboot, magic); + if (ret) + dev_err(dev, "can't register reboot mode\n"); + + return ret; +} + +static const struct of_device_id syscon_reboot_mode_of_match[] = { + { .compatible = "syscon-reboot-mode" }, + { /* sentinel */ } +}; + +static struct driver_d syscon_reboot_mode_driver = { + .probe = syscon_reboot_mode_probe, + .name = "syscon-reboot-mode", + .of_compatible = syscon_reboot_mode_of_match, +}; +coredevice_platform_driver(syscon_reboot_mode_driver); -- 2.28.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox