// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2012-2019, Intel Corporation. All rights reserved.
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* Intel Management Engine Interface (Intel MEI) Linux driver
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*/
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#include <linux/export.h>
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#include <linux/sched.h>
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#include <linux/wait.h>
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#include <linux/delay.h>
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#include <linux/mei.h>
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#include "mei_dev.h"
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#include "hbm.h"
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#include "client.h"
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const char *mei_dev_state_str(int state)
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{
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#define MEI_DEV_STATE(state) case MEI_DEV_##state: return #state
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switch (state) {
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MEI_DEV_STATE(INITIALIZING);
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MEI_DEV_STATE(INIT_CLIENTS);
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MEI_DEV_STATE(ENABLED);
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MEI_DEV_STATE(RESETTING);
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MEI_DEV_STATE(DISABLED);
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MEI_DEV_STATE(POWER_DOWN);
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MEI_DEV_STATE(POWER_UP);
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default:
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return "unknown";
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}
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#undef MEI_DEV_STATE
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}
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const char *mei_pg_state_str(enum mei_pg_state state)
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{
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#define MEI_PG_STATE(state) case MEI_PG_##state: return #state
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switch (state) {
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MEI_PG_STATE(OFF);
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MEI_PG_STATE(ON);
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default:
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return "unknown";
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}
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#undef MEI_PG_STATE
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}
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/**
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* mei_fw_status2str - convert fw status registers to printable string
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*
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* @fw_status: firmware status
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* @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
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* @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
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*
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* Return: number of bytes written or -EINVAL if buffer is to small
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*/
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ssize_t mei_fw_status2str(struct mei_fw_status *fw_status,
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char *buf, size_t len)
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{
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ssize_t cnt = 0;
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int i;
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buf[0] = '\0';
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if (len < MEI_FW_STATUS_STR_SZ)
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return -EINVAL;
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for (i = 0; i < fw_status->count; i++)
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cnt += scnprintf(buf + cnt, len - cnt, "%08X ",
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fw_status->status[i]);
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/* drop last space */
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buf[cnt] = '\0';
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return cnt;
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}
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EXPORT_SYMBOL_GPL(mei_fw_status2str);
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/**
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* mei_cancel_work - Cancel mei background jobs
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*
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* @dev: the device structure
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*/
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void mei_cancel_work(struct mei_device *dev)
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{
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cancel_work_sync(&dev->reset_work);
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cancel_work_sync(&dev->bus_rescan_work);
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cancel_delayed_work_sync(&dev->timer_work);
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}
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EXPORT_SYMBOL_GPL(mei_cancel_work);
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/**
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* mei_reset - resets host and fw.
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*
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* @dev: the device structure
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*
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* Return: 0 on success or < 0 if the reset hasn't succeeded
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*/
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int mei_reset(struct mei_device *dev)
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{
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enum mei_dev_state state = dev->dev_state;
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bool interrupts_enabled;
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int ret;
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if (state != MEI_DEV_INITIALIZING &&
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state != MEI_DEV_DISABLED &&
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state != MEI_DEV_POWER_DOWN &&
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state != MEI_DEV_POWER_UP) {
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char fw_sts_str[MEI_FW_STATUS_STR_SZ];
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mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
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dev_warn(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
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mei_dev_state_str(state), fw_sts_str);
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}
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mei_clear_interrupts(dev);
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/* we're already in reset, cancel the init timer
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* if the reset was called due the hbm protocol error
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* we need to call it before hw start
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* so the hbm watchdog won't kick in
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*/
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mei_hbm_idle(dev);
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/* enter reset flow */
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interrupts_enabled = state != MEI_DEV_POWER_DOWN;
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mei_set_devstate(dev, MEI_DEV_RESETTING);
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dev->reset_count++;
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if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
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dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
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mei_set_devstate(dev, MEI_DEV_DISABLED);
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return -ENODEV;
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}
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ret = mei_hw_reset(dev, interrupts_enabled);
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/* fall through and remove the sw state even if hw reset has failed */
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/* no need to clean up software state in case of power up */
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if (state != MEI_DEV_INITIALIZING && state != MEI_DEV_POWER_UP)
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mei_cl_all_disconnect(dev);
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mei_hbm_reset(dev);
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memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));
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if (ret) {
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dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
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return ret;
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}
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if (state == MEI_DEV_POWER_DOWN) {
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dev_dbg(dev->dev, "powering down: end of reset\n");
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mei_set_devstate(dev, MEI_DEV_DISABLED);
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return 0;
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}
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ret = mei_hw_start(dev);
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if (ret) {
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dev_err(dev->dev, "hw_start failed ret = %d\n", ret);
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return ret;
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}
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dev_dbg(dev->dev, "link is established start sending messages.\n");
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mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
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ret = mei_hbm_start_req(dev);
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if (ret) {
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dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
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mei_set_devstate(dev, MEI_DEV_RESETTING);
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return ret;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(mei_reset);
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/**
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* mei_start - initializes host and fw to start work.
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*
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* @dev: the device structure
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*
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* Return: 0 on success, <0 on failure.
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*/
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int mei_start(struct mei_device *dev)
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{
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int ret;
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mutex_lock(&dev->device_lock);
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/* acknowledge interrupt and stop interrupts */
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mei_clear_interrupts(dev);
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ret = mei_hw_config(dev);
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if (ret)
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goto err;
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dev_dbg(dev->dev, "reset in start the mei device.\n");
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dev->reset_count = 0;
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do {
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mei_set_devstate(dev, MEI_DEV_INITIALIZING);
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ret = mei_reset(dev);
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if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
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dev_err(dev->dev, "reset failed ret = %d", ret);
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goto err;
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}
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} while (ret);
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if (mei_hbm_start_wait(dev)) {
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dev_err(dev->dev, "HBM haven't started");
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goto err;
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}
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if (!mei_host_is_ready(dev)) {
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dev_err(dev->dev, "host is not ready.\n");
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goto err;
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}
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if (!mei_hw_is_ready(dev)) {
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dev_err(dev->dev, "ME is not ready.\n");
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goto err;
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}
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if (!mei_hbm_version_is_supported(dev)) {
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dev_dbg(dev->dev, "MEI start failed.\n");
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goto err;
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}
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dev_dbg(dev->dev, "link layer has been established.\n");
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mutex_unlock(&dev->device_lock);
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return 0;
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err:
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dev_err(dev->dev, "link layer initialization failed.\n");
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mei_set_devstate(dev, MEI_DEV_DISABLED);
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mutex_unlock(&dev->device_lock);
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return -ENODEV;
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}
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EXPORT_SYMBOL_GPL(mei_start);
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/**
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* mei_restart - restart device after suspend
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*
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* @dev: the device structure
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*
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* Return: 0 on success or -ENODEV if the restart hasn't succeeded
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*/
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int mei_restart(struct mei_device *dev)
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{
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int err;
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mutex_lock(&dev->device_lock);
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mei_set_devstate(dev, MEI_DEV_POWER_UP);
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dev->reset_count = 0;
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err = mei_reset(dev);
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mutex_unlock(&dev->device_lock);
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if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
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dev_err(dev->dev, "device disabled = %d\n", err);
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return -ENODEV;
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}
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/* try to start again */
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if (err)
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schedule_work(&dev->reset_work);
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return 0;
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}
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EXPORT_SYMBOL_GPL(mei_restart);
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static void mei_reset_work(struct work_struct *work)
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{
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struct mei_device *dev =
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container_of(work, struct mei_device, reset_work);
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int ret;
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mei_clear_interrupts(dev);
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mei_synchronize_irq(dev);
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mutex_lock(&dev->device_lock);
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ret = mei_reset(dev);
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mutex_unlock(&dev->device_lock);
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if (dev->dev_state == MEI_DEV_DISABLED) {
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dev_err(dev->dev, "device disabled = %d\n", ret);
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return;
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}
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/* retry reset in case of failure */
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if (ret)
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schedule_work(&dev->reset_work);
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}
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void mei_stop(struct mei_device *dev)
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{
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dev_dbg(dev->dev, "stopping the device.\n");
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mutex_lock(&dev->device_lock);
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mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
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mutex_unlock(&dev->device_lock);
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mei_cl_bus_remove_devices(dev);
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mei_cancel_work(dev);
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mei_clear_interrupts(dev);
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mei_synchronize_irq(dev);
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mutex_lock(&dev->device_lock);
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mei_reset(dev);
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/* move device to disabled state unconditionally */
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mei_set_devstate(dev, MEI_DEV_DISABLED);
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mutex_unlock(&dev->device_lock);
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}
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EXPORT_SYMBOL_GPL(mei_stop);
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/**
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* mei_write_is_idle - check if the write queues are idle
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*
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* @dev: the device structure
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*
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* Return: true of there is no pending write
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*/
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bool mei_write_is_idle(struct mei_device *dev)
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{
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bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
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list_empty(&dev->ctrl_wr_list) &&
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list_empty(&dev->write_list) &&
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list_empty(&dev->write_waiting_list));
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dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
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idle,
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mei_dev_state_str(dev->dev_state),
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list_empty(&dev->ctrl_wr_list),
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list_empty(&dev->write_list),
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list_empty(&dev->write_waiting_list));
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return idle;
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}
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EXPORT_SYMBOL_GPL(mei_write_is_idle);
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/**
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* mei_device_init -- initialize mei_device structure
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*
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* @dev: the mei device
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* @device: the device structure
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* @hw_ops: hw operations
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*/
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void mei_device_init(struct mei_device *dev,
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struct device *device,
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const struct mei_hw_ops *hw_ops)
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{
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/* setup our list array */
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INIT_LIST_HEAD(&dev->file_list);
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INIT_LIST_HEAD(&dev->device_list);
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INIT_LIST_HEAD(&dev->me_clients);
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mutex_init(&dev->device_lock);
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init_rwsem(&dev->me_clients_rwsem);
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mutex_init(&dev->cl_bus_lock);
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init_waitqueue_head(&dev->wait_hw_ready);
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init_waitqueue_head(&dev->wait_pg);
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init_waitqueue_head(&dev->wait_hbm_start);
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dev->dev_state = MEI_DEV_INITIALIZING;
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dev->reset_count = 0;
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INIT_LIST_HEAD(&dev->write_list);
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INIT_LIST_HEAD(&dev->write_waiting_list);
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INIT_LIST_HEAD(&dev->ctrl_wr_list);
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INIT_LIST_HEAD(&dev->ctrl_rd_list);
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dev->tx_queue_limit = MEI_TX_QUEUE_LIMIT_DEFAULT;
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INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
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INIT_WORK(&dev->reset_work, mei_reset_work);
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INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);
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bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
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dev->open_handle_count = 0;
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/*
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* Reserving the first client ID
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* 0: Reserved for MEI Bus Message communications
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*/
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bitmap_set(dev->host_clients_map, 0, 1);
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dev->pg_event = MEI_PG_EVENT_IDLE;
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dev->ops = hw_ops;
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dev->dev = device;
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}
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EXPORT_SYMBOL_GPL(mei_device_init);
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