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336 lines
8.1 KiB
336 lines
8.1 KiB
// 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 <[email protected]>"); |
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MODULE_AUTHOR("Nikita Yushchenko <[email protected]>"); |
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MODULE_AUTHOR("Andrey Smirnov <[email protected]>"); |
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MODULE_DESCRIPTION("RAVE SP Watchdog driver"); |
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MODULE_ALIAS("platform:rave-sp-watchdog");
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