misc/ibmasm/command.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002
0003 /*
0004  * IBM ASM Service Processor Device Driver
0005  *
0006  * Copyright (C) IBM Corporation, 2004
0007  *
0008  * Author: Max Asböck <amax@us.ibm.com>
0009  */
0010
0011 #include <linux/sched.h>
0012 #include <linux/slab.h>
0013 #include "ibmasm.h"
0014 #include "lowlevel.h"
0015
0016 static void exec_next_command(struct service_processor *sp);
0017
0018 static atomic_t command_count = ATOMIC_INIT(0);
0019
0020 struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
0021 {
0022     struct command *cmd;
0023
0024     if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
0025         return NULL;
0026
0027     cmd = kzalloc(sizeof(struct command), GFP_KERNEL);
0028     if (cmd == NULL)
0029         return NULL;
0030
0031
0032     cmd->buffer = kzalloc(buffer_size, GFP_KERNEL);
0033     if (cmd->buffer == NULL) {
0034         kfree(cmd);
0035         return NULL;
0036     }
0037     cmd->buffer_size = buffer_size;
0038
0039     kref_init(&cmd->kref);
0040     cmd->lock = &sp->lock;
0041
0042     cmd->status = IBMASM_CMD_PENDING;
0043     init_waitqueue_head(&cmd->wait);
0044     INIT_LIST_HEAD(&cmd->queue_node);
0045
0046     atomic_inc(&command_count);
0047     dbg("command count: %d\n", atomic_read(&command_count));
0048
0049     return cmd;
0050 }
0051
0052 void ibmasm_free_command(struct kref *kref)
0053 {
0054     struct command *cmd = to_command(kref);
0055
0056     list_del(&cmd->queue_node);
0057     atomic_dec(&command_count);
0058     dbg("command count: %d\n", atomic_read(&command_count));
0059     kfree(cmd->buffer);
0060     kfree(cmd);
0061 }
0062
0063 static void enqueue_command(struct service_processor *sp, struct command *cmd)
0064 {
0065     list_add_tail(&cmd->queue_node, &sp->command_queue);
0066 }
0067
0068 static struct command *dequeue_command(struct service_processor *sp)
0069 {
0070     struct command *cmd;
0071     struct list_head *next;
0072
0073     if (list_empty(&sp->command_queue))
0074         return NULL;
0075
0076     next = sp->command_queue.next;
0077     list_del_init(next);
0078     cmd = list_entry(next, struct command, queue_node);
0079
0080     return cmd;
0081 }
0082
0083 static inline void do_exec_command(struct service_processor *sp)
0084 {
0085     char tsbuf[32];
0086
0087     dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
0088
0089     if (ibmasm_send_i2o_message(sp)) {
0090         sp->current_command->status = IBMASM_CMD_FAILED;
0091         wake_up(&sp->current_command->wait);
0092         command_put(sp->current_command);
0093         exec_next_command(sp);
0094     }
0095 }
0096
0097 /*
0098  * exec_command
0099  * send a command to a service processor
0100  * Commands are executed sequentially. One command (sp->current_command)
0101  * is sent to the service processor. Once the interrupt handler gets a
0102  * message of type command_response, the message is copied into
0103  * the current commands buffer,
0104  */
0105 void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
0106 {
0107     unsigned long flags;
0108     char tsbuf[32];
0109
0110     dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
0111
0112     spin_lock_irqsave(&sp->lock, flags);
0113
0114     if (!sp->current_command) {
0115         sp->current_command = cmd;
0116         command_get(sp->current_command);
0117         spin_unlock_irqrestore(&sp->lock, flags);
0118         do_exec_command(sp);
0119     } else {
0120         enqueue_command(sp, cmd);
0121         spin_unlock_irqrestore(&sp->lock, flags);
0122     }
0123 }
0124
0125 static void exec_next_command(struct service_processor *sp)
0126 {
0127     unsigned long flags;
0128     char tsbuf[32];
0129
0130     dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
0131
0132     spin_lock_irqsave(&sp->lock, flags);
0133     sp->current_command = dequeue_command(sp);
0134     if (sp->current_command) {
0135         command_get(sp->current_command);
0136         spin_unlock_irqrestore(&sp->lock, flags);
0137         do_exec_command(sp);
0138     } else {
0139         spin_unlock_irqrestore(&sp->lock, flags);
0140     }
0141 }
0142
0143 /*
0144  * Sleep until a command has failed or a response has been received
0145  * and the command status been updated by the interrupt handler.
0146  * (see receive_response).
0147  */
0148 void ibmasm_wait_for_response(struct command *cmd, int timeout)
0149 {
0150     wait_event_interruptible_timeout(cmd->wait,
0151                 cmd->status == IBMASM_CMD_COMPLETE ||
0152                 cmd->status == IBMASM_CMD_FAILED,
0153                 timeout * HZ);
0154 }
0155
0156 /*
0157  * receive_command_response
0158  * called by the interrupt handler when a dot command of type command_response
0159  * was received.
0160  */
0161 void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
0162 {
0163     struct command *cmd = sp->current_command;
0164
0165     if (!sp->current_command)
0166         return;
0167
0168     memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
0169     cmd->status = IBMASM_CMD_COMPLETE;
0170     wake_up(&sp->current_command->wait);
0171     command_put(sp->current_command);
0172     exec_next_command(sp);
0173 }