blob: 7baec9fd8756639ddc4876feae1b8f29357ad904 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel MIC Platform Software Stack (MPSS)
*
* Copyright(c) 2015 Intel Corporation.
*
* Intel MIC Coprocessor State Management (COSM) Driver
*/
#include <linux/kthread.h>
#include <linux/sched/signal.h>
#include "cosm_main.h"
/*
* The COSM driver uses SCIF to communicate between the management node and the
* MIC cards. SCIF is used to (a) Send a shutdown command to the card (b)
* receive a shutdown status back from the card upon completion of shutdown and
* (c) receive periodic heartbeat messages from the card used to deduce if the
* card has crashed.
*
* A COSM server consisting of a SCIF listening endpoint waits for incoming
* connections from the card. Upon acceptance of the connection, a separate
* work-item is scheduled to handle SCIF message processing for that card. The
* life-time of this work-item is therefore the time from which the connection
* from a card is accepted to the time at which the connection is closed. A new
* work-item starts each time the card boots and is alive till the card (a)
* shuts down (b) is reset (c) crashes (d) cosm_client driver on the card is
* unloaded.
*
* From the point of view of COSM interactions with SCIF during card
* shutdown, reset and crash are as follows:
*
* Card shutdown
* -------------
* 1. COSM client on the card invokes orderly_poweroff() in response to SHUTDOWN
* message from the host.
* 2. Card driver shutdown callback invokes scif_unregister_device(..) resulting
* in scif_remove(..) getting called on the card
* 3. scif_remove -> scif_stop -> scif_handle_remove_node ->
* scif_peer_unregister_device -> device_unregister for the host peer device
* 4. During device_unregister remove(..) method of cosm_client is invoked which
* closes the COSM SCIF endpoint on the card. This results in a SCIF_DISCNCT
* message being sent to host SCIF. SCIF_DISCNCT message processing on the
* host SCIF sets the host COSM SCIF endpoint state to DISCONNECTED and wakes
* up the host COSM thread blocked in scif_poll(..) resulting in
* scif_poll(..) returning EPOLLHUP.
* 5. On the card, scif_peer_release_dev is next called which results in an
* SCIF_EXIT message being sent to the host and after receiving the
* SCIF_EXIT_ACK from the host the peer device teardown on the card is
* complete.
* 6. As part of the SCIF_EXIT message processing on the host, host sends a
* SCIF_REMOVE_NODE to itself corresponding to the card being removed. This
* starts a similar SCIF peer device teardown sequence on the host
* corresponding to the card being shut down.
*
* Card reset
* ----------
* The case of interest here is when the card has not been previously shut down
* since most of the steps below are skipped in that case:
* 1. cosm_stop(..) invokes hw_ops->stop(..) method of the base PCIe driver
* which unregisters the SCIF HW device resulting in scif_remove(..) being
* called on the host.
* 2. scif_remove(..) calls scif_disconnect_node(..) which results in a
* SCIF_EXIT message being sent to the card.
* 3. The card executes scif_stop() as part of SCIF_EXIT message
* processing. This results in the COSM endpoint on the card being closed and
* the SCIF host peer device on the card getting unregistered similar to
* steps 3, 4 and 5 for the card shutdown case above. scif_poll(..) on the
* host returns EPOLLHUP as a result.
* 4. On the host, card peer device unregister and SCIF HW remove(..) also
* subsequently complete.
*
* Card crash
* ----------
* If a reset is issued after the card has crashed, there is no SCIF_DISCNT
* message from the card which would result in scif_poll(..) returning
* EPOLLHUP. In this case when the host SCIF driver sends a SCIF_REMOVE_NODE
* message to itself resulting in the card SCIF peer device being unregistered,
* this results in a scif_peer_release_dev -> scif_cleanup_scifdev->
* scif_invalidate_ep call sequence which sets the endpoint state to
* DISCONNECTED and results in scif_poll(..) returning EPOLLHUP.
*/
#define COSM_SCIF_BACKLOG 16
#define COSM_HEARTBEAT_CHECK_DELTA_SEC 10
#define COSM_HEARTBEAT_TIMEOUT_SEC \
(COSM_HEARTBEAT_SEND_SEC + COSM_HEARTBEAT_CHECK_DELTA_SEC)
#define COSM_HEARTBEAT_TIMEOUT_MSEC (COSM_HEARTBEAT_TIMEOUT_SEC * MSEC_PER_SEC)
static struct task_struct *server_thread;
static scif_epd_t listen_epd;
/* Publish MIC card's shutdown status to user space MIC daemon */
static void cosm_update_mic_status(struct cosm_device *cdev)
{
if (cdev->shutdown_status_int != MIC_NOP) {
cosm_set_shutdown_status(cdev, cdev->shutdown_status_int);
cdev->shutdown_status_int = MIC_NOP;
}
}
/* Store MIC card's shutdown status internally when it is received */
static void cosm_shutdown_status_int(struct cosm_device *cdev,
enum mic_status shutdown_status)
{
switch (shutdown_status) {
case MIC_HALTED:
case MIC_POWER_OFF:
case MIC_RESTART:
case MIC_CRASHED:
break;
default:
dev_err(&cdev->dev, "%s %d Unexpected shutdown_status %d\n",
__func__, __LINE__, shutdown_status);
return;
};
cdev->shutdown_status_int = shutdown_status;
cdev->heartbeat_watchdog_enable = false;
if (cdev->state != MIC_SHUTTING_DOWN)
cosm_set_state(cdev, MIC_SHUTTING_DOWN);
}
/* Non-blocking recv. Read and process all available messages */
static void cosm_scif_recv(struct cosm_device *cdev)
{
struct cosm_msg msg;
int rc;
while (1) {
rc = scif_recv(cdev->epd, &msg, sizeof(msg), 0);
if (!rc) {
break;
} else if (rc < 0) {
dev_dbg(&cdev->dev, "%s: %d rc %d\n",
__func__, __LINE__, rc);
break;
}
dev_dbg(&cdev->dev, "%s: %d rc %d id 0x%llx\n",
__func__, __LINE__, rc, msg.id);
switch (msg.id) {
case COSM_MSG_SHUTDOWN_STATUS:
cosm_shutdown_status_int(cdev, msg.shutdown_status);
break;
case COSM_MSG_HEARTBEAT:
/* Nothing to do, heartbeat only unblocks scif_poll */
break;
default:
dev_err(&cdev->dev, "%s: %d unknown msg.id %lld\n",
__func__, __LINE__, msg.id);
break;
}
}
}
/* Publish crashed status for this MIC card */
static void cosm_set_crashed(struct cosm_device *cdev)
{
dev_err(&cdev->dev, "node alive timeout\n");
cosm_shutdown_status_int(cdev, MIC_CRASHED);
cosm_update_mic_status(cdev);
}
/* Send host time to the MIC card to sync system time between host and MIC */
static void cosm_send_time(struct cosm_device *cdev)
{
struct cosm_msg msg = { .id = COSM_MSG_SYNC_TIME };
struct timespec64 ts;
int rc;
ktime_get_real_ts64(&ts);
msg.timespec.tv_sec = ts.tv_sec;
msg.timespec.tv_nsec = ts.tv_nsec;
rc = scif_send(cdev->epd, &msg, sizeof(msg), SCIF_SEND_BLOCK);
if (rc < 0)
dev_err(&cdev->dev, "%s %d scif_send failed rc %d\n",
__func__, __LINE__, rc);
}
/*
* Close this cosm_device's endpoint after its peer endpoint on the card has
* been closed. In all cases except MIC card crash EPOLLHUP on the host is
* triggered by the client's endpoint being closed.
*/
static void cosm_scif_close(struct cosm_device *cdev)
{
/*
* Because SHUTDOWN_STATUS message is sent by the MIC cards in the
* reboot notifier when shutdown is still not complete, we notify mpssd
* to reset the card when SCIF endpoint is closed.
*/
cosm_update_mic_status(cdev);
scif_close(cdev->epd);
cdev->epd = NULL;
dev_dbg(&cdev->dev, "%s %d\n", __func__, __LINE__);
}
/*
* Set card state to ONLINE when a new SCIF connection from a MIC card is
* received. Normally the state is BOOTING when the connection comes in, but can
* be ONLINE if cosm_client driver on the card was unloaded and then reloaded.
*/
static int cosm_set_online(struct cosm_device *cdev)
{
int rc = 0;
if (MIC_BOOTING == cdev->state || MIC_ONLINE == cdev->state) {
cdev->heartbeat_watchdog_enable = cdev->sysfs_heartbeat_enable;
cdev->epd = cdev->newepd;
if (cdev->state == MIC_BOOTING)
cosm_set_state(cdev, MIC_ONLINE);
cosm_send_time(cdev);
dev_dbg(&cdev->dev, "%s %d\n", __func__, __LINE__);
} else {
dev_warn(&cdev->dev, "%s %d not going online in state: %s\n",
__func__, __LINE__, cosm_state_string[cdev->state]);
rc = -EINVAL;
}
/* Drop reference acquired by bus_find_device in the server thread */
put_device(&cdev->dev);
return rc;
}
/*
* Work function for handling work for a SCIF connection from a particular MIC
* card. It first sets the card state to ONLINE and then calls scif_poll to
* block on activity such as incoming messages on the SCIF endpoint. When the
* endpoint is closed, the work function exits, completing its life cycle, from
* MIC card boot to card shutdown/reset/crash.
*/
void cosm_scif_work(struct work_struct *work)
{
struct cosm_device *cdev = container_of(work, struct cosm_device,
scif_work);
struct scif_pollepd pollepd;
int rc;
mutex_lock(&cdev->cosm_mutex);
if (cosm_set_online(cdev))
goto exit;
while (1) {
pollepd.epd = cdev->epd;
pollepd.events = EPOLLIN;
/* Drop the mutex before blocking in scif_poll(..) */
mutex_unlock(&cdev->cosm_mutex);
/* poll(..) with timeout on our endpoint */
rc = scif_poll(&pollepd, 1, COSM_HEARTBEAT_TIMEOUT_MSEC);
mutex_lock(&cdev->cosm_mutex);
if (rc < 0) {
dev_err(&cdev->dev, "%s %d scif_poll rc %d\n",
__func__, __LINE__, rc);
continue;
}
/* There is a message from the card */
if (pollepd.revents & EPOLLIN)
cosm_scif_recv(cdev);
/* The peer endpoint is closed or this endpoint disconnected */
if (pollepd.revents & EPOLLHUP) {
cosm_scif_close(cdev);
break;
}
/* Did we timeout from poll? */
if (!rc && cdev->heartbeat_watchdog_enable)
cosm_set_crashed(cdev);
}
exit:
dev_dbg(&cdev->dev, "%s %d exiting\n", __func__, __LINE__);
mutex_unlock(&cdev->cosm_mutex);
}
/*
* COSM SCIF server thread function. Accepts incoming SCIF connections from MIC
* cards, finds the correct cosm_device to associate that connection with and
* schedules individual work items for each MIC card.
*/
static int cosm_scif_server(void *unused)
{
struct cosm_device *cdev;
scif_epd_t newepd;
struct scif_port_id port_id;
int rc;
allow_signal(SIGKILL);
while (!kthread_should_stop()) {
rc = scif_accept(listen_epd, &port_id, &newepd,
SCIF_ACCEPT_SYNC);
if (rc < 0) {
if (-ERESTARTSYS != rc)
pr_err("%s %d rc %d\n", __func__, __LINE__, rc);
continue;
}
/*
* Associate the incoming connection with a particular
* cosm_device, COSM device ID == SCIF node ID - 1
*/
cdev = cosm_find_cdev_by_id(port_id.node - 1);
if (!cdev)
continue;
cdev->newepd = newepd;
schedule_work(&cdev->scif_work);
}
pr_debug("%s %d Server thread stopped\n", __func__, __LINE__);
return 0;
}
static int cosm_scif_listen(void)
{
int rc;
listen_epd = scif_open();
if (!listen_epd) {
pr_err("%s %d scif_open failed\n", __func__, __LINE__);
return -ENOMEM;
}
rc = scif_bind(listen_epd, SCIF_COSM_LISTEN_PORT);
if (rc < 0) {
pr_err("%s %d scif_bind failed rc %d\n",
__func__, __LINE__, rc);
goto err;
}
rc = scif_listen(listen_epd, COSM_SCIF_BACKLOG);
if (rc < 0) {
pr_err("%s %d scif_listen rc %d\n", __func__, __LINE__, rc);
goto err;
}
pr_debug("%s %d listen_epd set up\n", __func__, __LINE__);
return 0;
err:
scif_close(listen_epd);
listen_epd = NULL;
return rc;
}
static void cosm_scif_listen_exit(void)
{
pr_debug("%s %d closing listen_epd\n", __func__, __LINE__);
if (listen_epd) {
scif_close(listen_epd);
listen_epd = NULL;
}
}
/*
* Create a listening SCIF endpoint and a server kthread which accepts incoming
* SCIF connections from MIC cards
*/
int cosm_scif_init(void)
{
int rc = cosm_scif_listen();
if (rc) {
pr_err("%s %d cosm_scif_listen rc %d\n",
__func__, __LINE__, rc);
goto err;
}
server_thread = kthread_run(cosm_scif_server, NULL, "cosm_server");
if (IS_ERR(server_thread)) {
rc = PTR_ERR(server_thread);
pr_err("%s %d kthread_run rc %d\n", __func__, __LINE__, rc);
goto listen_exit;
}
return 0;
listen_exit:
cosm_scif_listen_exit();
err:
return rc;
}
/* Stop the running server thread and close the listening SCIF endpoint */
void cosm_scif_exit(void)
{
int rc;
if (!IS_ERR_OR_NULL(server_thread)) {
rc = send_sig(SIGKILL, server_thread, 0);
if (rc) {
pr_err("%s %d send_sig rc %d\n",
__func__, __LINE__, rc);
return;
}
kthread_stop(server_thread);
}
cosm_scif_listen_exit();
}