On 30.03.2016 11:20, Andy Yan wrote: > This driver parses the reboot commands like "reboot bootloader" > and "reboot recovery" to get a boot mode described in the > device tree , then call the write interfae to store the boot > mode in some place like special register or sram, which can > be read by the bootloader after system reboot, then the bootloader > can take different action according to the mode stored. > > This is commonly used on Android based devices, in order to > reboot the device into fastboot or recovery mode. > > Reviewed-by: Matthias Brugger <matthias.bgg@xxxxxxxxx> > Reviewed-by: Moritz Fischer <moritz.fischer@xxxxxxxxx> > Tested-by: John Stultz <john.stultz@xxxxxxxxxx> > Acked-by: John Stultz <john.stultz@xxxxxxxxxx> > Signed-off-by: Andy Yan <andy.yan@xxxxxxxxxxxxxx> > > --- > > Changes in v7: > - address some suggestions from Krzysztof, make syscon-reboot-mode driver data self-contained. > Thanks for changes, few comments below. (...) > diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c > new file mode 100644 > index 0000000..ae6f931 > --- /dev/null > +++ b/drivers/power/reset/reboot-mode.c > @@ -0,0 +1,115 @@ > +/* > + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + */ > + > +#include <linux/device.h> > +#include <linux/init.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/reboot.h> > +#include "reboot-mode.h" > + > +#define PREFIX "mode-" > + > +struct mode_info { > + const char *mode; > + unsigned int magic; > + struct list_head list; > +}; > + > +struct reboot_mode_driver { > + struct device *dev; > + struct list_head head; > + int (*write)(struct device *dev, int magic); > + struct notifier_block reboot_notifier; > +}; > + > +static int get_reboot_mode_magic(struct reboot_mode_driver *reboot, > + const char *cmd) > +{ > + const char *normal = "normal"; > + int magic = 0; > + struct mode_info *info; > + > + if (!cmd) > + cmd = normal; > + > + list_for_each_entry(info, &reboot->head, list) { > + if (!strcmp(info->mode, cmd)) { > + magic = info->magic; > + break; > + } > + } > + > + return magic; > +} > + > +static int reboot_mode_notify(struct notifier_block *this, > + unsigned long mode, void *cmd) > +{ > + struct reboot_mode_driver *reboot; > + int magic; > + > + reboot = container_of(this, struct reboot_mode_driver, reboot_notifier); > + magic = get_reboot_mode_magic(reboot, cmd); > + if (magic) > + reboot->write(reboot->dev, magic); > + > + return NOTIFY_DONE; > +} > + > +int reboot_mode_register(struct device *dev, int (*write)(struct device *, int)) > +{ > + struct reboot_mode_driver *reboot; > + struct mode_info *info; > + struct property *prop; > + struct device_node *np; > + size_t len = strlen(PREFIX); > + int ret; > + > + reboot = devm_kzalloc(dev, sizeof(*reboot), GFP_KERNEL); > + if (!reboot) > + return -ENOMEM; > + > + reboot->dev = dev; > + reboot->write = write; > + INIT_LIST_HEAD(&reboot->head); > + > + np = of_node_get(dev->of_node); > + for_each_property_of_node(np, prop) { > + if (len > strlen(prop->name) || strncmp(prop->name, PREFIX, len)) > + continue; > + > + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL); > + if (!info) Clean up needed: of_node_put() and kfree_const() for items stored on the list from previous iterations. > + return -ENOMEM; > + > + info->mode = kstrdup_const(prop->name + len, GFP_KERNEL); > + if (of_property_read_u32(np, prop->name, &info->magic)) { > + dev_err(dev, "reboot mode %s without magic number\n", > + info->mode); > + devm_kfree(dev, info); > + continue; > + } > + list_add_tail(&info->list, &reboot->head); > + } > + of_node_put(np); If you of_node_put() here, there is no sense in getting it before. I mentioned of_node_get() only because I am not sure about life-cycle of nodes in case of DT overlays and you are storing the pointer to string from DT. The doubts I have are concerning only the case of freeing nodes from overlay. I don't know if of_node_get() is needed but of_node_get()+of_node_put() seems useless. > + > + reboot->reboot_notifier.notifier_call = reboot_mode_notify; > + ret = register_reboot_notifier(&reboot->reboot_notifier); > + if (ret) > + dev_err(dev, "can't register reboot notifier\n"); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(reboot_mode_register); > + > +MODULE_AUTHOR("Andy Yan <andy.yan@xxxxxxxxxxxxxx"); > +MODULE_DESCRIPTION("System reboot mode driver"); > +MODULE_LICENSE("GPL v2"); > diff --git a/drivers/power/reset/reboot-mode.h b/drivers/power/reset/reboot-mode.h > new file mode 100644 > index 0000000..c861129 > --- /dev/null > +++ b/drivers/power/reset/reboot-mode.h > @@ -0,0 +1,6 @@ > +#ifndef __REBOOT_MODE_H__ > +#define __REBOOT_MODE_H__ > + > +int reboot_mode_register(struct device *dev, int (*write)(struct device *, int)); > + > +#endif > diff --git a/drivers/power/reset/syscon-reboot-mode.c b/drivers/power/reset/syscon-reboot-mode.c > new file mode 100644 > index 0000000..f1b8072 > --- /dev/null > +++ b/drivers/power/reset/syscon-reboot-mode.c > @@ -0,0 +1,86 @@ > +/* > + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + */ > + > +#include <linux/init.h> > +#include <linux/module.h> > +#include <linux/kernel.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > +#include <linux/reboot.h> > +#include <linux/regmap.h> > +#include <linux/mfd/syscon.h> > +#include "reboot-mode.h" > + > +struct syscon_reboot_mode { > + struct device *dev; 'dev' looks unused (only set). > + struct regmap *map; > + u32 offset; > + u32 mask; > +}; > + > +static int syscon_reboot_mode_write(struct device *dev, int magic) > +{ > + struct syscon_reboot_mode *syscon_rbm = dev_get_drvdata(dev); > + int ret; > + > + ret = regmap_update_bits(syscon_rbm->map, syscon_rbm->offset, > + syscon_rbm->mask, magic); > + if (ret < 0) > + dev_err(dev, "update reboot mode bits failed\n"); > + > + return ret; > +} > + > +static int syscon_reboot_mode_probe(struct platform_device *pdev) > +{ > + int ret; > + struct syscon_reboot_mode *syscon_rbm; > + > + syscon_rbm = devm_kzalloc(&pdev->dev, sizeof(*syscon_rbm), GFP_KERNEL); > + if (!syscon_rbm) > + return -ENOMEM; > + > + syscon_rbm->dev = &pdev->dev; > + syscon_rbm->mask = 0xffffffff; > + > + syscon_rbm->map = syscon_node_to_regmap(pdev->dev.parent->of_node); > + if (IS_ERR(syscon_rbm->map)) > + return PTR_ERR(syscon_rbm->map); > + > + if (of_property_read_u32(pdev->dev.of_node, "offset", &syscon_rbm->offset)) > + return -EINVAL; > + > + of_property_read_u32(pdev->dev.of_node, "mask", &syscon_rbm->mask); > + > + dev_set_drvdata(&pdev->dev, syscon_rbm); > + > + ret = reboot_mode_register(&pdev->dev, syscon_reboot_mode_write); > + if (ret) > + dev_err(&pdev->dev, "can't register reboot mode\n"); > + > + return ret; > +} > + > +static const struct of_device_id syscon_reboot_mode_of_match[] = { > + { .compatible = "syscon-reboot-mode" }, > + {} > +}; > + > +static struct platform_driver syscon_reboot_mode_driver = { > + .probe = syscon_reboot_mode_probe, Cleanup needed. What will happen after device unbind? Memory will be released (devm-*()) but reboot notifier won't thus leading to OOPS on reboot. Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html