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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
The Greybus core code has been stable for a long time, and has been shipping for many years in millions of phones. With the advent of a recent Google Summer of Code project, and a number of new devices in the works from various companies, it is time to get the core greybus code out of staging as it really is going to be with us for a while. Cc: Johan Hovold <johan@kernel.org> Cc: linux-kernel@vger.kernel.org Cc: greybus-dev@lists.linaro.org Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Alex Elder <elder@kernel.org> Link: https://lore.kernel.org/r/20190825055429.18547-9-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
197 lines
4.4 KiB
C
197 lines
4.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* SVC Greybus "watchdog" driver.
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*
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* Copyright 2016 Google Inc.
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*/
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#include <linux/delay.h>
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#include <linux/suspend.h>
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#include <linux/workqueue.h>
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#include <linux/greybus.h>
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#define SVC_WATCHDOG_PERIOD (2 * HZ)
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struct gb_svc_watchdog {
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struct delayed_work work;
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struct gb_svc *svc;
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bool enabled;
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struct notifier_block pm_notifier;
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};
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static struct delayed_work reset_work;
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static int svc_watchdog_pm_notifier(struct notifier_block *notifier,
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unsigned long pm_event, void *unused)
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{
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struct gb_svc_watchdog *watchdog =
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container_of(notifier, struct gb_svc_watchdog, pm_notifier);
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switch (pm_event) {
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case PM_SUSPEND_PREPARE:
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gb_svc_watchdog_disable(watchdog->svc);
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break;
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case PM_POST_SUSPEND:
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gb_svc_watchdog_enable(watchdog->svc);
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break;
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default:
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break;
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}
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return NOTIFY_DONE;
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}
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static void greybus_reset(struct work_struct *work)
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{
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static char const start_path[] = "/system/bin/start";
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static char *envp[] = {
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"HOME=/",
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"PATH=/sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin",
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NULL,
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};
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static char *argv[] = {
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(char *)start_path,
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"unipro_reset",
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NULL,
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};
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pr_err("svc_watchdog: calling \"%s %s\" to reset greybus network!\n",
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argv[0], argv[1]);
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call_usermodehelper(start_path, argv, envp, UMH_WAIT_EXEC);
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}
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static void do_work(struct work_struct *work)
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{
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struct gb_svc_watchdog *watchdog;
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struct gb_svc *svc;
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int retval;
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watchdog = container_of(work, struct gb_svc_watchdog, work.work);
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svc = watchdog->svc;
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dev_dbg(&svc->dev, "%s: ping.\n", __func__);
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retval = gb_svc_ping(svc);
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if (retval) {
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/*
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* Something went really wrong, let's warn userspace and then
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* pull the plug and reset the whole greybus network.
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* We need to do this outside of this workqueue as we will be
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* tearing down the svc device itself. So queue up
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* yet-another-callback to do that.
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*/
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dev_err(&svc->dev,
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"SVC ping has returned %d, something is wrong!!!\n",
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retval);
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if (svc->action == GB_SVC_WATCHDOG_BITE_PANIC_KERNEL) {
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panic("SVC is not responding\n");
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} else if (svc->action == GB_SVC_WATCHDOG_BITE_RESET_UNIPRO) {
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dev_err(&svc->dev, "Resetting the greybus network, watch out!!!\n");
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INIT_DELAYED_WORK(&reset_work, greybus_reset);
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schedule_delayed_work(&reset_work, HZ / 2);
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/*
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* Disable ourselves, we don't want to trip again unless
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* userspace wants us to.
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*/
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watchdog->enabled = false;
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}
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}
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/* resubmit our work to happen again, if we are still "alive" */
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if (watchdog->enabled)
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schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
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}
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int gb_svc_watchdog_create(struct gb_svc *svc)
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{
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struct gb_svc_watchdog *watchdog;
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int retval;
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if (svc->watchdog)
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return 0;
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watchdog = kmalloc(sizeof(*watchdog), GFP_KERNEL);
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if (!watchdog)
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return -ENOMEM;
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watchdog->enabled = false;
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watchdog->svc = svc;
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INIT_DELAYED_WORK(&watchdog->work, do_work);
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svc->watchdog = watchdog;
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watchdog->pm_notifier.notifier_call = svc_watchdog_pm_notifier;
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retval = register_pm_notifier(&watchdog->pm_notifier);
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if (retval) {
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dev_err(&svc->dev, "error registering pm notifier(%d)\n",
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retval);
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goto svc_watchdog_create_err;
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}
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retval = gb_svc_watchdog_enable(svc);
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if (retval) {
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dev_err(&svc->dev, "error enabling watchdog (%d)\n", retval);
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unregister_pm_notifier(&watchdog->pm_notifier);
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goto svc_watchdog_create_err;
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}
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return retval;
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svc_watchdog_create_err:
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svc->watchdog = NULL;
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kfree(watchdog);
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return retval;
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}
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void gb_svc_watchdog_destroy(struct gb_svc *svc)
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{
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struct gb_svc_watchdog *watchdog = svc->watchdog;
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if (!watchdog)
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return;
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unregister_pm_notifier(&watchdog->pm_notifier);
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gb_svc_watchdog_disable(svc);
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svc->watchdog = NULL;
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kfree(watchdog);
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}
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bool gb_svc_watchdog_enabled(struct gb_svc *svc)
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{
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if (!svc || !svc->watchdog)
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return false;
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return svc->watchdog->enabled;
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}
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int gb_svc_watchdog_enable(struct gb_svc *svc)
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{
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struct gb_svc_watchdog *watchdog;
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if (!svc->watchdog)
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return -ENODEV;
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watchdog = svc->watchdog;
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if (watchdog->enabled)
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return 0;
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watchdog->enabled = true;
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schedule_delayed_work(&watchdog->work, SVC_WATCHDOG_PERIOD);
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return 0;
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}
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int gb_svc_watchdog_disable(struct gb_svc *svc)
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{
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struct gb_svc_watchdog *watchdog;
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if (!svc->watchdog)
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return -ENODEV;
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watchdog = svc->watchdog;
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if (!watchdog->enabled)
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return 0;
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watchdog->enabled = false;
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cancel_delayed_work_sync(&watchdog->work);
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return 0;
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}
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