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ibmebus.c

/*
 * IBM PowerPC IBM eBus Infrastructure Support.
 *
 * Copyright (c) 2005 IBM Corporation
 *  Joachim Fenkes <fenkes@de.ibm.com>
 *  Heiko J Schick <schickhj@de.ibm.com>
 *
 * All rights reserved.
 *
 * This source code is distributed under a dual license of GPL v2.0 and OpenIB
 * BSD.
 *
 * OpenIB BSD License
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials
 * provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/init.h>
#include <linux/console.h>
#include <linux/kobject.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <asm/ibmebus.h>
#include <asm/abs_addr.h>

static struct device ibmebus_bus_device = { /* fake "parent" device */
      .bus_id = "ibmebus",
};

struct bus_type ibmebus_bus_type;

/* These devices will automatically be added to the bus during init */
static struct of_device_id __initdata ibmebus_matches[] = {
      { .compatible = "IBM,lhca" },
      { .compatible = "IBM,lhea" },
      {},
};

static void *ibmebus_alloc_coherent(struct device *dev,
                            size_t size,
                            dma_addr_t *dma_handle,
                            gfp_t flag)
{
      void *mem;

      mem = kmalloc(size, flag);
      *dma_handle = (dma_addr_t)mem;

      return mem;
}

static void ibmebus_free_coherent(struct device *dev,
                          size_t size, void *vaddr,
                          dma_addr_t dma_handle)
{
      kfree(vaddr);
}

static dma_addr_t ibmebus_map_page(struct device *dev,
                           struct page *page,
                           unsigned long offset,
                           size_t size,
                           enum dma_data_direction direction,
                           struct dma_attrs *attrs)
{
      return (dma_addr_t)(page_address(page) + offset);
}

static void ibmebus_unmap_page(struct device *dev,
                         dma_addr_t dma_addr,
                         size_t size,
                         enum dma_data_direction direction,
                         struct dma_attrs *attrs)
{
      return;
}

static int ibmebus_map_sg(struct device *dev,
                    struct scatterlist *sgl,
                    int nents, enum dma_data_direction direction,
                    struct dma_attrs *attrs)
{
      struct scatterlist *sg;
      int i;

      for_each_sg(sgl, sg, nents, i) {
            sg->dma_address = (dma_addr_t) sg_virt(sg);
            sg->dma_length = sg->length;
      }

      return nents;
}

static void ibmebus_unmap_sg(struct device *dev,
                       struct scatterlist *sg,
                       int nents, enum dma_data_direction direction,
                       struct dma_attrs *attrs)
{
      return;
}

static int ibmebus_dma_supported(struct device *dev, u64 mask)
{
      return 1;
}

static struct dma_mapping_ops ibmebus_dma_ops = {
      .alloc_coherent = ibmebus_alloc_coherent,
      .free_coherent  = ibmebus_free_coherent,
      .map_sg         = ibmebus_map_sg,
      .unmap_sg       = ibmebus_unmap_sg,
      .dma_supported  = ibmebus_dma_supported,
      .map_page       = ibmebus_map_page,
      .unmap_page     = ibmebus_unmap_page,
};

static int ibmebus_match_path(struct device *dev, void *data)
{
      struct device_node *dn = to_of_device(dev)->node;
      return (dn->full_name &&
            (strcasecmp((char *)data, dn->full_name) == 0));
}

static int ibmebus_match_node(struct device *dev, void *data)
{
      return to_of_device(dev)->node == data;
}

static int ibmebus_create_device(struct device_node *dn)
{
      struct of_device *dev;
      int ret;

      dev = of_device_alloc(dn, NULL, &ibmebus_bus_device);
      if (!dev)
            return -ENOMEM;

      dev->dev.bus = &ibmebus_bus_type;
      dev->dev.archdata.dma_ops = &ibmebus_dma_ops;

      ret = of_device_register(dev);
      if (ret) {
            of_device_free(dev);
            return ret;
      }

      return 0;
}

static int ibmebus_create_devices(const struct of_device_id *matches)
{
      struct device_node *root, *child;
      int ret = 0;

      root = of_find_node_by_path("/");

      for_each_child_of_node(root, child) {
            if (!of_match_node(matches, child))
                  continue;

            if (bus_find_device(&ibmebus_bus_type, NULL, child,
                            ibmebus_match_node))
                  continue;

            ret = ibmebus_create_device(child);
            if (ret) {
                  printk(KERN_ERR "%s: failed to create device (%i)",
                         __func__, ret);
                  of_node_put(child);
                  break;
            }
      }

      of_node_put(root);
      return ret;
}

int ibmebus_register_driver(struct of_platform_driver *drv)
{
      /* If the driver uses devices that ibmebus doesn't know, add them */
      ibmebus_create_devices(drv->match_table);

      return of_register_driver(drv, &ibmebus_bus_type);
}
EXPORT_SYMBOL(ibmebus_register_driver);

void ibmebus_unregister_driver(struct of_platform_driver *drv)
{
      of_unregister_driver(drv);
}
EXPORT_SYMBOL(ibmebus_unregister_driver);

int ibmebus_request_irq(u32 ist, irq_handler_t handler,
                  unsigned long irq_flags, const char *devname,
                  void *dev_id)
{
      unsigned int irq = irq_create_mapping(NULL, ist);

      if (irq == NO_IRQ)
            return -EINVAL;

      return request_irq(irq, handler, irq_flags, devname, dev_id);
}
EXPORT_SYMBOL(ibmebus_request_irq);

void ibmebus_free_irq(u32 ist, void *dev_id)
{
      unsigned int irq = irq_find_mapping(NULL, ist);

      free_irq(irq, dev_id);
}
EXPORT_SYMBOL(ibmebus_free_irq);

static char *ibmebus_chomp(const char *in, size_t count)
{
      char *out = kmalloc(count + 1, GFP_KERNEL);

      if (!out)
            return NULL;

      memcpy(out, in, count);
      out[count] = '\0';
      if (out[count - 1] == '\n')
            out[count - 1] = '\0';

      return out;
}

static ssize_t ibmebus_store_probe(struct bus_type *bus,
                           const char *buf, size_t count)
{
      struct device_node *dn = NULL;
      char *path;
      ssize_t rc = 0;

      path = ibmebus_chomp(buf, count);
      if (!path)
            return -ENOMEM;

      if (bus_find_device(&ibmebus_bus_type, NULL, path,
                      ibmebus_match_path)) {
            printk(KERN_WARNING "%s: %s has already been probed\n",
                   __func__, path);
            rc = -EEXIST;
            goto out;
      }

      if ((dn = of_find_node_by_path(path))) {
            rc = ibmebus_create_device(dn);
            of_node_put(dn);
      } else {
            printk(KERN_WARNING "%s: no such device node: %s\n",
                   __func__, path);
            rc = -ENODEV;
      }

out:
      kfree(path);
      if (rc)
            return rc;
      return count;
}

static ssize_t ibmebus_store_remove(struct bus_type *bus,
                            const char *buf, size_t count)
{
      struct device *dev;
      char *path;

      path = ibmebus_chomp(buf, count);
      if (!path)
            return -ENOMEM;

      if ((dev = bus_find_device(&ibmebus_bus_type, NULL, path,
                           ibmebus_match_path))) {
            of_device_unregister(to_of_device(dev));

            kfree(path);
            return count;
      } else {
            printk(KERN_WARNING "%s: %s not on the bus\n",
                   __func__, path);

            kfree(path);
            return -ENODEV;
      }
}

static struct bus_attribute ibmebus_bus_attrs[] = {
      __ATTR(probe, S_IWUSR, NULL, ibmebus_store_probe),
      __ATTR(remove, S_IWUSR, NULL, ibmebus_store_remove),
      __ATTR_NULL
};

struct bus_type ibmebus_bus_type = {
      .uevent    = of_device_uevent,
      .bus_attrs = ibmebus_bus_attrs
};
EXPORT_SYMBOL(ibmebus_bus_type);

static int __init ibmebus_bus_init(void)
{
      int err;

      printk(KERN_INFO "IBM eBus Device Driver\n");

      err = of_bus_type_init(&ibmebus_bus_type, "ibmebus");
      if (err) {
            printk(KERN_ERR "%s: failed to register IBM eBus.\n",
                   __func__);
            return err;
      }

      err = device_register(&ibmebus_bus_device);
      if (err) {
            printk(KERN_WARNING "%s: device_register returned %i\n",
                   __func__, err);
            bus_unregister(&ibmebus_bus_type);

            return err;
      }

      err = ibmebus_create_devices(ibmebus_matches);
      if (err) {
            device_unregister(&ibmebus_bus_device);
            bus_unregister(&ibmebus_bus_type);
            return err;
      }

      return 0;
}
postcore_initcall(ibmebus_bus_init);

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