337 lines
8.1 KiB
C
337 lines
8.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* Driver for watchdog aspect of for Zodiac Inflight Innovations RAVE
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* Supervisory Processor(SP) MCU
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*
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* Copyright (C) 2017 Zodiac Inflight Innovation
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*
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*/
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#include <linux/delay.h>
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#include <linux/kernel.h>
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#include <linux/mfd/rave-sp.h>
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#include <linux/module.h>
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#include <linux/nvmem-consumer.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/reboot.h>
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#include <linux/slab.h>
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#include <linux/watchdog.h>
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enum {
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RAVE_SP_RESET_BYTE = 1,
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RAVE_SP_RESET_REASON_NORMAL = 0,
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RAVE_SP_RESET_DELAY_MS = 500,
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};
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/**
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* struct rave_sp_wdt_variant - RAVE SP watchdog variant
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*
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* @max_timeout: Largest possible watchdog timeout setting
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* @min_timeout: Smallest possible watchdog timeout setting
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*
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* @configure: Function to send configuration command
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* @restart: Function to send "restart" command
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*/
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struct rave_sp_wdt_variant {
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unsigned int max_timeout;
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unsigned int min_timeout;
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int (*configure)(struct watchdog_device *, bool);
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int (*restart)(struct watchdog_device *);
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};
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/**
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* struct rave_sp_wdt - RAVE SP watchdog
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*
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* @wdd: Underlying watchdog device
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* @sp: Pointer to parent RAVE SP device
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* @variant: Device specific variant information
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* @reboot_notifier: Reboot notifier implementing machine reset
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*/
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struct rave_sp_wdt {
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struct watchdog_device wdd;
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struct rave_sp *sp;
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const struct rave_sp_wdt_variant *variant;
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struct notifier_block reboot_notifier;
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};
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static struct rave_sp_wdt *to_rave_sp_wdt(struct watchdog_device *wdd)
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{
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return container_of(wdd, struct rave_sp_wdt, wdd);
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}
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static int rave_sp_wdt_exec(struct watchdog_device *wdd, void *data,
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size_t data_size)
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{
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return rave_sp_exec(to_rave_sp_wdt(wdd)->sp,
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data, data_size, NULL, 0);
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}
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static int rave_sp_wdt_legacy_configure(struct watchdog_device *wdd, bool on)
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{
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u8 cmd[] = {
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[0] = RAVE_SP_CMD_SW_WDT,
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[1] = 0,
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[2] = 0,
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[3] = on,
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[4] = on ? wdd->timeout : 0,
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};
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return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
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}
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static int rave_sp_wdt_rdu_configure(struct watchdog_device *wdd, bool on)
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{
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u8 cmd[] = {
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[0] = RAVE_SP_CMD_SW_WDT,
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[1] = 0,
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[2] = on,
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[3] = (u8)wdd->timeout,
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[4] = (u8)(wdd->timeout >> 8),
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};
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return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
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}
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/**
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* rave_sp_wdt_configure - Configure watchdog device
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*
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* @wdd: Device to configure
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* @on: Desired state of the watchdog timer (ON/OFF)
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*
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* This function configures two aspects of the watchdog timer:
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*
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* - Wheither it is ON or OFF
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* - Its timeout duration
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*
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* with first aspect specified via function argument and second via
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* the value of 'wdd->timeout'.
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*/
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static int rave_sp_wdt_configure(struct watchdog_device *wdd, bool on)
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{
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return to_rave_sp_wdt(wdd)->variant->configure(wdd, on);
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}
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static int rave_sp_wdt_legacy_restart(struct watchdog_device *wdd)
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{
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u8 cmd[] = {
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[0] = RAVE_SP_CMD_RESET,
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[1] = 0,
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[2] = RAVE_SP_RESET_BYTE
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};
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return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
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}
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static int rave_sp_wdt_rdu_restart(struct watchdog_device *wdd)
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{
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u8 cmd[] = {
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[0] = RAVE_SP_CMD_RESET,
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[1] = 0,
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[2] = RAVE_SP_RESET_BYTE,
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[3] = RAVE_SP_RESET_REASON_NORMAL
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};
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return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
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}
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static int rave_sp_wdt_reboot_notifier(struct notifier_block *nb,
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unsigned long action, void *data)
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{
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/*
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* Restart handler is called in atomic context which means we
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* can't communicate to SP via UART. Luckily for use SP will
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* wait 500ms before actually resetting us, so we ask it to do
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* so here and let the rest of the system go on wrapping
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* things up.
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*/
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if (action == SYS_DOWN || action == SYS_HALT) {
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struct rave_sp_wdt *sp_wd =
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container_of(nb, struct rave_sp_wdt, reboot_notifier);
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const int ret = sp_wd->variant->restart(&sp_wd->wdd);
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if (ret < 0)
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dev_err(sp_wd->wdd.parent,
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"Failed to issue restart command (%d)", ret);
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return NOTIFY_OK;
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}
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return NOTIFY_DONE;
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}
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static int rave_sp_wdt_restart(struct watchdog_device *wdd,
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unsigned long action, void *data)
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{
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/*
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* The actual work was done by reboot notifier above. SP
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* firmware waits 500 ms before issuing reset, so let's hang
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* here for twice that delay and hopefuly we'd never reach
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* the return statement.
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*/
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mdelay(2 * RAVE_SP_RESET_DELAY_MS);
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return -EIO;
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}
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static int rave_sp_wdt_start(struct watchdog_device *wdd)
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{
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int ret;
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ret = rave_sp_wdt_configure(wdd, true);
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if (!ret)
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set_bit(WDOG_HW_RUNNING, &wdd->status);
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return ret;
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}
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static int rave_sp_wdt_stop(struct watchdog_device *wdd)
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{
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return rave_sp_wdt_configure(wdd, false);
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}
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static int rave_sp_wdt_set_timeout(struct watchdog_device *wdd,
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unsigned int timeout)
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{
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wdd->timeout = timeout;
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return rave_sp_wdt_configure(wdd, watchdog_active(wdd));
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}
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static int rave_sp_wdt_ping(struct watchdog_device *wdd)
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{
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u8 cmd[] = {
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[0] = RAVE_SP_CMD_PET_WDT,
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[1] = 0,
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};
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return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));
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}
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static const struct watchdog_info rave_sp_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.identity = "RAVE SP Watchdog",
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};
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static const struct watchdog_ops rave_sp_wdt_ops = {
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.owner = THIS_MODULE,
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.start = rave_sp_wdt_start,
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.stop = rave_sp_wdt_stop,
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.ping = rave_sp_wdt_ping,
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.set_timeout = rave_sp_wdt_set_timeout,
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.restart = rave_sp_wdt_restart,
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};
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static const struct rave_sp_wdt_variant rave_sp_wdt_legacy = {
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.max_timeout = 255,
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.min_timeout = 1,
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.configure = rave_sp_wdt_legacy_configure,
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.restart = rave_sp_wdt_legacy_restart,
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};
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static const struct rave_sp_wdt_variant rave_sp_wdt_rdu = {
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.max_timeout = 180,
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.min_timeout = 60,
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.configure = rave_sp_wdt_rdu_configure,
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.restart = rave_sp_wdt_rdu_restart,
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};
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static const struct of_device_id rave_sp_wdt_of_match[] = {
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{
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.compatible = "zii,rave-sp-watchdog-legacy",
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.data = &rave_sp_wdt_legacy,
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},
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{
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.compatible = "zii,rave-sp-watchdog",
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.data = &rave_sp_wdt_rdu,
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},
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{ /* sentinel */ }
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};
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static int rave_sp_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct watchdog_device *wdd;
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struct rave_sp_wdt *sp_wd;
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struct nvmem_cell *cell;
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__le16 timeout = 0;
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int ret;
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sp_wd = devm_kzalloc(dev, sizeof(*sp_wd), GFP_KERNEL);
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if (!sp_wd)
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return -ENOMEM;
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sp_wd->variant = of_device_get_match_data(dev);
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sp_wd->sp = dev_get_drvdata(dev->parent);
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wdd = &sp_wd->wdd;
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wdd->parent = dev;
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wdd->info = &rave_sp_wdt_info;
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wdd->ops = &rave_sp_wdt_ops;
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wdd->min_timeout = sp_wd->variant->min_timeout;
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wdd->max_timeout = sp_wd->variant->max_timeout;
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wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
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wdd->timeout = 60;
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cell = nvmem_cell_get(dev, "wdt-timeout");
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if (!IS_ERR(cell)) {
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size_t len;
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void *value = nvmem_cell_read(cell, &len);
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if (!IS_ERR(value)) {
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memcpy(&timeout, value, min(len, sizeof(timeout)));
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kfree(value);
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}
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nvmem_cell_put(cell);
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}
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watchdog_init_timeout(wdd, le16_to_cpu(timeout), dev);
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watchdog_set_restart_priority(wdd, 255);
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watchdog_stop_on_unregister(wdd);
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sp_wd->reboot_notifier.notifier_call = rave_sp_wdt_reboot_notifier;
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ret = devm_register_reboot_notifier(dev, &sp_wd->reboot_notifier);
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if (ret) {
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dev_err(dev, "Failed to register reboot notifier\n");
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return ret;
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}
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/*
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* We don't know if watchdog is running now. To be sure, let's
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* start it and depend on watchdog core to ping it
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*/
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wdd->max_hw_heartbeat_ms = wdd->max_timeout * 1000;
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ret = rave_sp_wdt_start(wdd);
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if (ret) {
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dev_err(dev, "Watchdog didn't start\n");
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return ret;
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}
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ret = devm_watchdog_register_device(dev, wdd);
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if (ret) {
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rave_sp_wdt_stop(wdd);
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return ret;
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}
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return 0;
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}
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static struct platform_driver rave_sp_wdt_driver = {
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.probe = rave_sp_wdt_probe,
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.driver = {
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.name = KBUILD_MODNAME,
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.of_match_table = rave_sp_wdt_of_match,
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},
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};
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module_platform_driver(rave_sp_wdt_driver);
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MODULE_DEVICE_TABLE(of, rave_sp_wdt_of_match);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
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MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
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MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
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MODULE_DESCRIPTION("RAVE SP Watchdog driver");
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MODULE_ALIAS("platform:rave-sp-watchdog");
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