[PATCH] I2O: second code cleanup of sparse warnings and unneeded syncronization

[mirror_ubuntu-artful-kernel.git] / drivers / message / i2o / exec-osm.c

/*
 *      Executive OSM
 *
 *      Copyright (C) 1999-2002 Red Hat Software
 *
 *      Written by Alan Cox, Building Number Three Ltd
 *
 *      This program is free software; you can redistribute it and/or modify it
 *      under the terms of the GNU General Public License as published by the
 *      Free Software Foundation; either version 2 of the License, or (at your
 *      option) any later version.
 *
 *      A lot of the I2O message side code from this is taken from the Red
 *      Creek RCPCI45 adapter driver by Red Creek Communications
 *
 *      Fixes/additions:
 *              Philipp Rumpf
 *              Juha Sievänen <Juha.Sievanen@cs.Helsinki.FI>
 *              Auvo Häkkinen <Auvo.Hakkinen@cs.Helsinki.FI>
 *              Deepak Saxena <deepak@plexity.net>
 *              Boji T Kannanthanam <boji.t.kannanthanam@intel.com>
 *              Alan Cox <alan@redhat.com>:
 *                      Ported to Linux 2.5.
 *              Markus Lidel <Markus.Lidel@shadowconnect.com>:
 *                      Minor fixes for 2.6.
 *              Markus Lidel <Markus.Lidel@shadowconnect.com>:
 *                      Support for sysfs included.
 */

#include <linux/module.h>
#include <linux/i2o.h>
#include <linux/delay.h>
#include "core.h"

#define OSM_NAME "exec-osm"

struct i2o_driver i2o_exec_driver;

static int i2o_exec_lct_notify(struct i2o_controller *c, u32 change_ind);

/* global wait list for POST WAIT */
static LIST_HEAD(i2o_exec_wait_list);

/* Wait struct needed for POST WAIT */
struct i2o_exec_wait {
        wait_queue_head_t *wq;  /* Pointer to Wait queue */
        struct i2o_dma dma;     /* DMA buffers to free on failure */
        u32 tcntxt;             /* transaction context from reply */
        int complete;           /* 1 if reply received otherwise 0 */
        u32 m;                  /* message id */
        struct i2o_message *msg;        /* pointer to the reply message */
        struct list_head list;  /* node in global wait list */
};

/* Exec OSM class handling definition */
static struct i2o_class_id i2o_exec_class_id[] = {
        {I2O_CLASS_EXECUTIVE},
        {I2O_CLASS_END}
};

/**
 *      i2o_exec_wait_alloc - Allocate a i2o_exec_wait struct an initialize it
 *
 *      Allocate the i2o_exec_wait struct and initialize the wait.
 *
 *      Returns i2o_exec_wait pointer on success or negative error code on
 *      failure.
 */
static struct i2o_exec_wait *i2o_exec_wait_alloc(void)
{
        struct i2o_exec_wait *wait;

        wait = kmalloc(sizeof(*wait), GFP_KERNEL);
        if (!wait)
                return ERR_PTR(-ENOMEM);

        memset(wait, 0, sizeof(*wait));

        INIT_LIST_HEAD(&wait->list);

        return wait;
};

/**
 *      i2o_exec_wait_free - Free a i2o_exec_wait struct
 *      @i2o_exec_wait: I2O wait data which should be cleaned up
 */
static void i2o_exec_wait_free(struct i2o_exec_wait *wait)
{
        kfree(wait);
};

/**
 *      i2o_msg_post_wait_mem - Post and wait a message with DMA buffers
 *      @c: controller
 *      @m: message to post
 *      @timeout: time in seconds to wait
 *      @dma: i2o_dma struct of the DMA buffer to free on failure
 *
 *      This API allows an OSM to post a message and then be told whether or
 *      not the system received a successful reply. If the message times out
 *      then the value '-ETIMEDOUT' is returned. This is a special case. In
 *      this situation the message may (should) complete at an indefinite time
 *      in the future. When it completes it will use the memory buffer
 *      attached to the request. If -ETIMEDOUT is returned then the memory
 *      buffer must not be freed. Instead the event completion will free them
 *      for you. In all other cases the buffer are your problem.
 *
 *      Returns 0 on success, negative error code on timeout or positive error
 *      code from reply.
 */
int i2o_msg_post_wait_mem(struct i2o_controller *c, u32 m, unsigned long
                          timeout, struct i2o_dma *dma)
{
        DECLARE_WAIT_QUEUE_HEAD(wq);
        struct i2o_exec_wait *wait;
        static u32 tcntxt = 0x80000000;
        struct i2o_message __iomem *msg = i2o_msg_in_to_virt(c, m);
        int rc = 0;

        wait = i2o_exec_wait_alloc();
        if (!wait)
                return -ENOMEM;

        if (tcntxt == 0xffffffff)
                tcntxt = 0x80000000;

        if (dma)
                wait->dma = *dma;

        /*
         * Fill in the message initiator context and transaction context.
         * We will only use transaction contexts >= 0x80000000 for POST WAIT,
         * so we could find a POST WAIT reply easier in the reply handler.
         */
        writel(i2o_exec_driver.context, &msg->u.s.icntxt);
        wait->tcntxt = tcntxt++;
        writel(wait->tcntxt, &msg->u.s.tcntxt);

        /*
         * Post the message to the controller. At some point later it will
         * return. If we time out before it returns then complete will be zero.
         */
        i2o_msg_post(c, m);

        if (!wait->complete) {
                wait->wq = &wq;
                /*
                 * we add elements add the head, because if a entry in the list
                 * will never be removed, we have to iterate over it every time
                 */
                list_add(&wait->list, &i2o_exec_wait_list);

                wait_event_interruptible_timeout(wq, wait->complete,
                        timeout * HZ);

                wait->wq = NULL;
        }

        barrier();

        if (wait->complete) {
                rc = le32_to_cpu(wait->msg->body[0]) >> 24;
                i2o_flush_reply(c, wait->m);
                i2o_exec_wait_free(wait);
        } else {
                /*
                 * We cannot remove it now. This is important. When it does
                 * terminate (which it must do if the controller has not
                 * died...) then it will otherwise scribble on stuff.
                 *
                 * FIXME: try abort message
                 */
                if (dma)
                        dma->virt = NULL;

                rc = -ETIMEDOUT;
        }

        return rc;
};

/**
 *      i2o_msg_post_wait_complete - Reply to a i2o_msg_post request from IOP
 *      @c: I2O controller which answers
 *      @m: message id
 *      @msg: pointer to the I2O reply message
 *      @context: transaction context of request
 *
 *      This function is called in interrupt context only. If the reply reached
 *      before the timeout, the i2o_exec_wait struct is filled with the message
 *      and the task will be waked up. The task is now responsible for returning
 *      the message m back to the controller! If the message reaches us after
 *      the timeout clean up the i2o_exec_wait struct (including allocated
 *      DMA buffer).
 *
 *      Return 0 on success and if the message m should not be given back to the
 *      I2O controller, or >0 on success and if the message should be given back
 *      afterwords. Returns negative error code on failure. In this case the
 *      message must also be given back to the controller.
 */
static int i2o_msg_post_wait_complete(struct i2o_controller *c, u32 m,
                                      struct i2o_message *msg, u32 context)
{
        struct i2o_exec_wait *wait, *tmp;
        unsigned long flags;
        static spinlock_t lock = SPIN_LOCK_UNLOCKED;
        int rc = 1;

        /*
         * We need to search through the i2o_exec_wait_list to see if the given
         * message is still outstanding. If not, it means that the IOP took
         * longer to respond to the message than we had allowed and timer has
         * already expired. Not much we can do about that except log it for
         * debug purposes, increase timeout, and recompile.
         */
        spin_lock_irqsave(&lock, flags);
        list_for_each_entry_safe(wait, tmp, &i2o_exec_wait_list, list) {
                if (wait->tcntxt == context) {
                        list_del(&wait->list);

                        spin_unlock_irqrestore(&lock, flags);

                        wait->m = m;
                        wait->msg = msg;
                        wait->complete = 1;

                        barrier();

                        if (wait->wq) {
                                wake_up_interruptible(wait->wq);
                                rc = 0;
                        } else {
                                struct device *dev;

                                dev = &c->pdev->dev;

                                pr_debug("%s: timedout reply received!\n",
                                         c->name);
                                i2o_dma_free(dev, &wait->dma);
                                i2o_exec_wait_free(wait);
                                rc = -1;
                        }

                        return rc;
                }
        }

        spin_unlock_irqrestore(&lock, flags);

        osm_warn("%s: Bogus reply in POST WAIT (tr-context: %08x)!\n", c->name,
                 context);

        return -1;
};

/**
 *      i2o_exec_show_vendor_id - Displays Vendor ID of controller
 *      @d: device of which the Vendor ID should be displayed
 *      @buf: buffer into which the Vendor ID should be printed
 *
 *      Returns number of bytes printed into buffer.
 */
static ssize_t i2o_exec_show_vendor_id(struct device *d, char *buf)
{
        struct i2o_device *dev = to_i2o_device(d);
        u16 id;

        if (i2o_parm_field_get(dev, 0x0000, 0, &id, 2)) {
                sprintf(buf, "0x%04x", id);
                return strlen(buf) + 1;
        }

        return 0;
};

/**
 *      i2o_exec_show_product_id - Displays Product ID of controller
 *      @d: device of which the Product ID should be displayed
 *      @buf: buffer into which the Product ID should be printed
 *
 *      Returns number of bytes printed into buffer.
 */
static ssize_t i2o_exec_show_product_id(struct device *d, char *buf)
{
        struct i2o_device *dev = to_i2o_device(d);
        u16 id;

        if (i2o_parm_field_get(dev, 0x0000, 1, &id, 2)) {
                sprintf(buf, "0x%04x", id);
                return strlen(buf) + 1;
        }

        return 0;
};

/* Exec-OSM device attributes */
static DEVICE_ATTR(vendor_id, S_IRUGO, i2o_exec_show_vendor_id, NULL);
static DEVICE_ATTR(product_id, S_IRUGO, i2o_exec_show_product_id, NULL);

/**
 *      i2o_exec_probe - Called if a new I2O device (executive class) appears
 *      @dev: I2O device which should be probed
 *
 *      Registers event notification for every event from Executive device. The
 *      return is always 0, because we want all devices of class Executive.
 *
 *      Returns 0 on success.
 */
static int i2o_exec_probe(struct device *dev)
{
        struct i2o_device *i2o_dev = to_i2o_device(dev);
        struct i2o_controller *c = i2o_dev->iop;

        i2o_event_register(i2o_dev, &i2o_exec_driver, 0, 0xffffffff);

        c->exec = i2o_dev;

        i2o_exec_lct_notify(c, c->lct->change_ind + 1);

        device_create_file(dev, &dev_attr_vendor_id);
        device_create_file(dev, &dev_attr_product_id);

        return 0;
};

/**
 *      i2o_exec_remove - Called on I2O device removal
 *      @dev: I2O device which was removed
 *
 *      Unregisters event notification from Executive I2O device.
 *
 *      Returns 0 on success.
 */
static int i2o_exec_remove(struct device *dev)
{
        device_remove_file(dev, &dev_attr_product_id);
        device_remove_file(dev, &dev_attr_vendor_id);

        i2o_event_register(to_i2o_device(dev), &i2o_exec_driver, 0, 0);

        return 0;
};

/**
 *      i2o_exec_lct_modified - Called on LCT NOTIFY reply
 *      @c: I2O controller on which the LCT has modified
 *
 *      This function handles asynchronus LCT NOTIFY replies. It parses the
 *      new LCT and if the buffer for the LCT was to small sends a LCT NOTIFY
 *      again, otherwise send LCT NOTIFY to get informed on next LCT change.
 */
static void i2o_exec_lct_modified(struct i2o_controller *c)
{
        u32 change_ind = 0;

        if (i2o_device_parse_lct(c) != -EAGAIN)
                change_ind = c->lct->change_ind + 1;

        i2o_exec_lct_notify(c, change_ind);
};

/**
 *      i2o_exec_reply -  I2O Executive reply handler
 *      @c: I2O controller from which the reply comes
 *      @m: message id
 *      @msg: pointer to the I2O reply message
 *
 *      This function is always called from interrupt context. If a POST WAIT
 *      reply was received, pass it to the complete function. If a LCT NOTIFY
 *      reply was received, a new event is created to handle the update.
 *
 *      Returns 0 on success and if the reply should not be flushed or > 0
 *      on success and if the reply should be flushed. Returns negative error
 *      code on failure and if the reply should be flushed.
 */
static int i2o_exec_reply(struct i2o_controller *c, u32 m,
                          struct i2o_message *msg)
{
        u32 context;

        if (le32_to_cpu(msg->u.head[0]) & MSG_FAIL) {
                /*
                 * If Fail bit is set we must take the transaction context of
                 * the preserved message to find the right request again.
                 */
                struct i2o_message __iomem *pmsg;
                u32 pm;

                pm = le32_to_cpu(msg->body[3]);

                pmsg = i2o_msg_in_to_virt(c, pm);

                i2o_report_status(KERN_INFO, "i2o_core", msg);

                context = readl(&pmsg->u.s.tcntxt);

                /* Release the preserved msg */
                i2o_msg_nop(c, pm);
        } else
                context = le32_to_cpu(msg->u.s.tcntxt);

        if (context & 0x80000000)
                return i2o_msg_post_wait_complete(c, m, msg, context);

        if ((le32_to_cpu(msg->u.head[1]) >> 24) == I2O_CMD_LCT_NOTIFY) {
                struct work_struct *work;

                pr_debug("%s: LCT notify received\n", c->name);

                work = kmalloc(sizeof(*work), GFP_ATOMIC);
                if (!work)
                        return -ENOMEM;

                INIT_WORK(work, (void (*)(void *))i2o_exec_lct_modified, c);
                queue_work(i2o_exec_driver.event_queue, work);
                return 1;
        }

        /*
         * If this happens, we want to dump the message to the syslog so
         * it can be sent back to the card manufacturer by the end user
         * to aid in debugging.
         *
         */
        printk(KERN_WARNING "%s: Unsolicited message reply sent to core!"
               "Message dumped to syslog\n", c->name);
        i2o_dump_message(msg);

        return -EFAULT;
}

/**
 *      i2o_exec_event - Event handling function
 *      @evt: Event which occurs
 *
 *      Handles events send by the Executive device. At the moment does not do
 *      anything useful.
 */
static void i2o_exec_event(struct i2o_event *evt)
{
        if (likely(evt->i2o_dev))
                osm_debug("Event received from device: %d\n",
                          evt->i2o_dev->lct_data.tid);
        kfree(evt);
};

/**
 *      i2o_exec_lct_get - Get the IOP's Logical Configuration Table
 *      @c: I2O controller from which the LCT should be fetched
 *
 *      Send a LCT NOTIFY request to the controller, and wait
 *      I2O_TIMEOUT_LCT_GET seconds until arrival of response. If the LCT is
 *      to large, retry it.
 *
 *      Returns 0 on success or negative error code on failure.
 */
int i2o_exec_lct_get(struct i2o_controller *c)
{
        struct i2o_message __iomem *msg;
        u32 m;
        int i = 0;
        int rc = -EAGAIN;

        for (i = 1; i <= I2O_LCT_GET_TRIES; i++) {
                m = i2o_msg_get_wait(c, &msg, I2O_TIMEOUT_MESSAGE_GET);
                if (m == I2O_QUEUE_EMPTY)
                        return -ETIMEDOUT;

                writel(EIGHT_WORD_MSG_SIZE | SGL_OFFSET_6, &msg->u.head[0]);
                writel(I2O_CMD_LCT_NOTIFY << 24 | HOST_TID << 12 | ADAPTER_TID,
                       &msg->u.head[1]);
                writel(0xffffffff, &msg->body[0]);
                writel(0x00000000, &msg->body[1]);
                writel(0xd0000000 | c->dlct.len, &msg->body[2]);
                writel(c->dlct.phys, &msg->body[3]);

                rc = i2o_msg_post_wait(c, m, I2O_TIMEOUT_LCT_GET);
                if (rc < 0)
                        break;

                rc = i2o_device_parse_lct(c);
                if (rc != -EAGAIN)
                        break;
        }

        return rc;
}

/**
 *      i2o_exec_lct_notify - Send a asynchronus LCT NOTIFY request
 *      @c: I2O controller to which the request should be send
 *      @change_ind: change indicator
 *
 *      This function sends a LCT NOTIFY request to the I2O controller with
 *      the change indicator change_ind. If the change_ind == 0 the controller
 *      replies immediately after the request. If change_ind > 0 the reply is
 *      send after change indicator of the LCT is > change_ind.
 */
static int i2o_exec_lct_notify(struct i2o_controller *c, u32 change_ind)
{
        i2o_status_block *sb = c->status_block.virt;
        struct device *dev;
        struct i2o_message __iomem *msg;
        u32 m;

        dev = &c->pdev->dev;

        if (i2o_dma_realloc(dev, &c->dlct, sb->expected_lct_size, GFP_KERNEL))
                return -ENOMEM;

        m = i2o_msg_get_wait(c, &msg, I2O_TIMEOUT_MESSAGE_GET);
        if (m == I2O_QUEUE_EMPTY)
                return -ETIMEDOUT;

        writel(EIGHT_WORD_MSG_SIZE | SGL_OFFSET_6, &msg->u.head[0]);
        writel(I2O_CMD_LCT_NOTIFY << 24 | HOST_TID << 12 | ADAPTER_TID,
               &msg->u.head[1]);
        writel(i2o_exec_driver.context, &msg->u.s.icntxt);
        writel(0, &msg->u.s.tcntxt);    /* FIXME */
        writel(0xffffffff, &msg->body[0]);
        writel(change_ind, &msg->body[1]);
        writel(0xd0000000 | c->dlct.len, &msg->body[2]);
        writel(c->dlct.phys, &msg->body[3]);

        i2o_msg_post(c, m);

        return 0;
};

/* Exec OSM driver struct */
struct i2o_driver i2o_exec_driver = {
        .name = OSM_NAME,
        .reply = i2o_exec_reply,
        .event = i2o_exec_event,
        .classes = i2o_exec_class_id,
        .driver = {
                   .probe = i2o_exec_probe,
                   .remove = i2o_exec_remove,
                   },
};

/**
 *      i2o_exec_init - Registers the Exec OSM
 *
 *      Registers the Exec OSM in the I2O core.
 *
 *      Returns 0 on success or negative error code on failure.
 */
int __init i2o_exec_init(void)
{
        return i2o_driver_register(&i2o_exec_driver);
};

/**
 *      i2o_exec_exit - Removes the Exec OSM
 *
 *      Unregisters the Exec OSM from the I2O core.
 */
void __exit i2o_exec_exit(void)
{
        i2o_driver_unregister(&i2o_exec_driver);
};

EXPORT_SYMBOL(i2o_msg_post_wait_mem);
EXPORT_SYMBOL(i2o_exec_lct_get);