drivers/misc/ibmasm/command.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 /*
   4  * IBM ASM Service Processor Device Driver
   5  *
   6  * Copyright (C) IBM Corporation, 2004
   7  *
   8  * Author: Max Asböck <amax@us.ibm.com>
   9  */
  10
  11 #include <linux/sched.h>
  12 #include <linux/slab.h>
  13 #include "ibmasm.h"
  14 #include "lowlevel.h"
  15
  16 static void exec_next_command(struct service_processor *sp);
  17
  18 static atomic_t command_count = ATOMIC_INIT(0);
  19
  20 struct command *ibmasm_new_command(struct service_processor *sp, size_t buffer_size)
  21 {
  22         struct command *cmd;
  23
  24         if (buffer_size > IBMASM_CMD_MAX_BUFFER_SIZE)
  25                 return NULL;
  26
  27         cmd = kzalloc(sizeof(struct command), GFP_KERNEL);
  28         if (cmd == NULL)
  29                 return NULL;
  30
  31
  32         cmd->buffer = kzalloc(buffer_size, GFP_KERNEL);
  33         if (cmd->buffer == NULL) {
  34                 kfree(cmd);
  35                 return NULL;
  36         }
  37         cmd->buffer_size = buffer_size;
  38
  39         kref_init(&cmd->kref);
  40         cmd->lock = &sp->lock;
  41
  42         cmd->status = IBMASM_CMD_PENDING;
  43         init_waitqueue_head(&cmd->wait);
  44         INIT_LIST_HEAD(&cmd->queue_node);
  45
  46         atomic_inc(&command_count);
  47         dbg("command count: %d\n", atomic_read(&command_count));
  48
  49         return cmd;
  50 }
  51
  52 void ibmasm_free_command(struct kref *kref)
  53 {
  54         struct command *cmd = to_command(kref);
  55
  56         list_del(&cmd->queue_node);
  57         atomic_dec(&command_count);
  58         dbg("command count: %d\n", atomic_read(&command_count));
  59         kfree(cmd->buffer);
  60         kfree(cmd);
  61 }
  62
  63 static void enqueue_command(struct service_processor *sp, struct command *cmd)
  64 {
  65         list_add_tail(&cmd->queue_node, &sp->command_queue);
  66 }
  67
  68 static struct command *dequeue_command(struct service_processor *sp)
  69 {
  70         struct command *cmd;
  71         struct list_head *next;
  72
  73         if (list_empty(&sp->command_queue))
  74                 return NULL;
  75
  76         next = sp->command_queue.next;
  77         list_del_init(next);
  78         cmd = list_entry(next, struct command, queue_node);
  79
  80         return cmd;
  81 }
  82
  83 static inline void do_exec_command(struct service_processor *sp)
  84 {
  85         char tsbuf[32];
  86
  87         dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
  88
  89         if (ibmasm_send_i2o_message(sp)) {
  90                 sp->current_command->status = IBMASM_CMD_FAILED;
  91                 wake_up(&sp->current_command->wait);
  92                 command_put(sp->current_command);
  93                 exec_next_command(sp);
  94         }
  95 }
  96
  97 /**
  98  * exec_command
  99  * send a command to a service processor
 100  * Commands are executed sequentially. One command (sp->current_command)
 101  * is sent to the service processor. Once the interrupt handler gets a
 102  * message of type command_response, the message is copied into
 103  * the current commands buffer,
 104  */
 105 void ibmasm_exec_command(struct service_processor *sp, struct command *cmd)
 106 {
 107         unsigned long flags;
 108         char tsbuf[32];
 109
 110         dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
 111
 112         spin_lock_irqsave(&sp->lock, flags);
 113
 114         if (!sp->current_command) {
 115                 sp->current_command = cmd;
 116                 command_get(sp->current_command);
 117                 spin_unlock_irqrestore(&sp->lock, flags);
 118                 do_exec_command(sp);
 119         } else {
 120                 enqueue_command(sp, cmd);
 121                 spin_unlock_irqrestore(&sp->lock, flags);
 122         }
 123 }
 124
 125 static void exec_next_command(struct service_processor *sp)
 126 {
 127         unsigned long flags;
 128         char tsbuf[32];
 129
 130         dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
 131
 132         spin_lock_irqsave(&sp->lock, flags);
 133         sp->current_command = dequeue_command(sp);
 134         if (sp->current_command) {
 135                 command_get(sp->current_command);
 136                 spin_unlock_irqrestore(&sp->lock, flags);
 137                 do_exec_command(sp);
 138         } else {
 139                 spin_unlock_irqrestore(&sp->lock, flags);
 140         }
 141 }
 142
 143 /**
 144  * Sleep until a command has failed or a response has been received
 145  * and the command status been updated by the interrupt handler.
 146  * (see receive_response).
 147  */
 148 void ibmasm_wait_for_response(struct command *cmd, int timeout)
 149 {
 150         wait_event_interruptible_timeout(cmd->wait,
 151                                 cmd->status == IBMASM_CMD_COMPLETE ||
 152                                 cmd->status == IBMASM_CMD_FAILED,
 153                                 timeout * HZ);
 154 }
 155
 156 /**
 157  * receive_command_response
 158  * called by the interrupt handler when a dot command of type command_response
 159  * was received.
 160  */
 161 void ibmasm_receive_command_response(struct service_processor *sp, void *response, size_t size)
 162 {
 163         struct command *cmd = sp->current_command;
 164
 165         if (!sp->current_command)
 166                 return;
 167
 168         memcpy_fromio(cmd->buffer, response, min(size, cmd->buffer_size));
 169         cmd->status = IBMASM_CMD_COMPLETE;
 170         wake_up(&sp->current_command->wait);
 171         command_put(sp->current_command);
 172         exec_next_command(sp);
 173 }