Quelle  command.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later

/*
 * IBM ASM Service Processor Device Driver
 *
 * Copyright (C) IBM Corporation, 2004
 *
 * Author: Max Asböck <amax@us.ibm.com>
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include "ibmasm.h"
#include "lowlevel.h"

static void exec_next_command(struct service_processor *sp);

static atomic_t command_count = ATOMIC_INIT(0);

struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
{
 struct command *cmd;

 if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
  return NULL;

 cmd = kzalloc(sizeof(struct command), GFP_KERNEL);
 if (cmd == NULL)
  return NULL;


 cmd->buffer = kzalloc(buffer_size, GFP_KERNEL);
 if (cmd->buffer == NULL) {
  kfree(cmd);
  return NULL;
 }
 cmd->buffer_size = buffer_size;

 kref_init(&cmd->kref);
 cmd->lock = &sp->lock;

 cmd->status = IBMASM_CMD_PENDING;
 init_waitqueue_head(&cmd->wait);
 INIT_LIST_HEAD(&cmd->queue_node);

 atomic_inc(&command_count);
 dbg("command count: %d\n", atomic_read(&command_count));

 return cmd;
}

void ibmasm_free_command(struct kref *kref)
{
 struct command *cmd = to_command(kref);

 list_del(&cmd->queue_node);
 atomic_dec(&command_count);
 dbg("command count: %d\n", atomic_read(&command_count));
 kfree(cmd->buffer);
 kfree(cmd);
}

static void enqueue_command(struct service_processor *sp, struct command *cmd)
{
 list_add_tail(&cmd->queue_node, &sp->command_queue);
}

static struct command *dequeue_command(struct service_processor *sp)
{
 struct command *cmd;
 struct list_head *next;

 if (list_empty(&sp->command_queue))
  return NULL;

 next = sp->command_queue.next;
 list_del_init(next);
 cmd = list_entry(next, struct command, queue_node);

 return cmd;
}

static inline void do_exec_command(struct service_processor *sp)
{
 char tsbuf[32];

 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));

 if (ibmasm_send_i2o_message(sp)) {
  sp->current_command->status = IBMASM_CMD_FAILED;
  wake_up(&sp->current_command->wait);
  command_put(sp->current_command);
  exec_next_command(sp);
 }
}

/*
 * exec_command
 * send a command to a service processor
 * Commands are executed sequentially. One command (sp->current_command)
 * is sent to the service processor. Once the interrupt handler gets a
 * message of type command_response, the message is copied into
 * the current commands buffer,
 */
void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
{
 unsigned long flags;
 char tsbuf[32];

 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));

 spin_lock_irqsave(&sp->lock, flags);

 if (!sp->current_command) {
  sp->current_command = cmd;
  command_get(sp->current_command);
  spin_unlock_irqrestore(&sp->lock, flags);
  do_exec_command(sp);
 } else {
  enqueue_command(sp, cmd);
  spin_unlock_irqrestore(&sp->lock, flags);
 }
}

static void exec_next_command(struct service_processor *sp)
{
 unsigned long flags;
 char tsbuf[32];

 dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));

 spin_lock_irqsave(&sp->lock, flags);
 sp->current_command = dequeue_command(sp);
 if (sp->current_command) {
  command_get(sp->current_command);
  spin_unlock_irqrestore(&sp->lock, flags);
  do_exec_command(sp);
 } else {
  spin_unlock_irqrestore(&sp->lock, flags);
 }
}

/*
 * Sleep until a command has failed or a response has been received
 * and the command status been updated by the interrupt handler.
 * (see receive_response).
 */
void ibmasm_wait_for_response(struct command *cmd, int timeout)
{
 wait_event_interruptible_timeout(cmd->wait,
    cmd->status == IBMASM_CMD_COMPLETE ||
    cmd->status == IBMASM_CMD_FAILED,
    timeout * HZ);
}

/*
 * receive_command_response
 * called by the interrupt handler when a dot command of type command_response
 * was received.
 */
void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
{
 struct command *cmd = sp->current_command;

 if (!sp->current_command)
  return;

 memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
 cmd->status = IBMASM_CMD_COMPLETE;
 wake_up(&sp->current_command->wait);
 command_put(sp->current_command);
 exec_next_command(sp);
}