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Subject[RFC 4/4] firewire: add mem1394
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While the previous patches were purely infrastructure, this patch
actually adds the code using it: mem1394.

There are some open questions on a few things, maybe someone can help
out there.

diff --git a/drivers/ieee1394/Kconfig b/drivers/ieee1394/Kconfig
index 39142e2..cd7b28c 100644
--- a/drivers/ieee1394/Kconfig
+++ b/drivers/ieee1394/Kconfig
@@ -169,4 +169,21 @@ config IEEE1394_RAWIO
To compile this driver as a module, say M here: the
module will be called raw1394.

+config IEEE1394_MEMDEV
+ tristate "IEEE1394 memory device support"
+ depends on IEEE1394 && EXPERIMENTAL
+ help
+ Say Y here if you want support for the ieee1394 memory device.
+ This is useful for debugging systems attached via firewire
+ since it usually allows you to read from and write to their memory,
+ depending on the controller and machine setup.
+
+ It differs from raw access (which allows the same usage) in that
+ it provides devices nodes (usually called /dev/fwmem-<guid>) that can
+ be read and written with any tool, as opposed to specialised tools
+ required for raw1394.
+
+ To compile this driver as a module, say M here: the
+ module will be called mem1394.
+
endmenu
diff --git a/drivers/ieee1394/Makefile b/drivers/ieee1394/Makefile
index 180bf82..7da4e21 100644
--- a/drivers/ieee1394/Makefile
+++ b/drivers/ieee1394/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_IEEE1394_RAWIO) += raw1394.
obj-$(CONFIG_IEEE1394_SBP2) += sbp2.o
obj-$(CONFIG_IEEE1394_DV1394) += dv1394.o
obj-$(CONFIG_IEEE1394_ETH1394) += eth1394.o
+obj-$(CONFIG_IEEE1394_MEMDEV) += mem1394.o

quiet_cmd_oui2c = OUI2C $@
cmd_oui2c = $(CONFIG_SHELL) $(src)/oui2c.sh < $< > $@
diff --git a/drivers/ieee1394/mem1394.c b/drivers/ieee1394/mem1394.c
new file mode 100644
index 0000000..e9d44a2
--- /dev/null
+++ b/drivers/ieee1394/mem1394.c
@@ -0,0 +1,277 @@
+/*
+ * IEEE 1394 for Linux
+ *
+ * Copyright (C) 2006 Johannes Berg <johannes@sipsolutions.net>
+ *
+ * This code is licensed under the GPL v2. See the file COPYING in the root
+ * directory of the kernel sources for details.
+ *
+ * This module provides a character device for each node attached
+ * to the bus and allows direct memory access on them.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/cdev.h>
+
+#include "ieee1394.h"
+#include "ieee1394_core.h"
+#include "ieee1394_transactions.h"
+#include "mem1394.h"
+#include "nodemgr.h"
+#include "highlevel.h"
+
+static int mem1394_mmap(struct file * file, struct vm_area_struct * vma)
+{
+ return -ENOSYS;
+}
+
+static int mem1394_open(struct inode *inode, struct file *file)
+{
+ struct mem1394_file_info *fi;
+
+ fi = kzalloc(sizeof(*fi), GFP_KERNEL);
+ if (!fi)
+ return -ENOMEM;
+ file->private_data = fi;
+ fi->memdev = container_of(inode->i_cdev, struct mem1394_dev, cdev);
+ return 0;
+}
+
+/* This function essentially clones hpsb_read. Might be better
+ * to create a new hpsb_read_user function instead... */
+static int mem1394_read(struct file *file, char __user * buffer,
+ size_t count, loff_t *offset)
+{
+ struct mem1394_file_info *fi = (struct mem1394_file_info*)file->private_data;
+ /* lower levels only support count as a multiple of 4 */
+ size_t submitcount = (count + (4-1)) & ~(4-1);
+ int retval = 0;
+ struct hpsb_packet *packet;
+
+ /* this is a bit icky. I think I'll want to create a
+ * "struct hpsb_node_class_interface" that you register
+ * with nodemgr.c instead of registering the "struct class_interface"
+ * directly. It would wrap around the "struct class_interface"
+ * and handle things like this.
+ *
+ * This means it would call the node_class_interface's
+ * - "add" method whenever the device is fully there, and an
+ * - "update" method when it survived a bus reset, and the
+ * - "remove" method when it went away, also taking care of
+ * debouncing, which the mem1394 interface currently doesn't handle.
+ *
+ * But I need advice on this. It'll probably works this way
+ * but most likely not once this interface stuff gets more
+ * use; I can imagine using it for scanners instead of raw1394
+ * so that the kernel can validate that a user can only
+ * access a certain scanner and not all 1394 devices on the bus.
+ * In other words some 'raw1394intf' instead of 'raw1394' which
+ * creates one character device per ieee1394 node for finer
+ * grained access control.
+ * That would definitely want to have debouncing etc.
+ *
+ * However, I don't fully understand the states node_entries go
+ * through yet, so I'm not sure this should even be here!
+ * Maybe it should be in open? But then the device could go
+ * into limbo when it is already opened...
+ *
+ * Similarly, what happens if a node is suspended?
+ */
+ if (fi->memdev->ne->in_limbo)
+ return -ENODEV;
+
+ if (count == 0)
+ return 0;
+
+ /* I wonder if it is possible to do DMA directly to the userspace buffer... */
+ packet = hpsb_make_readpacket(fi->memdev->ne->host, fi->memdev->ne->nodeid, *offset, submitcount);
+ if (!packet)
+ return -ENOENT;
+
+ packet->generation = fi->memdev->ne->generation;
+ retval = hpsb_send_packet_and_wait(packet);
+ if (retval < 0)
+ goto out_free;
+
+ retval = hpsb_packet_success(packet);
+
+ if (retval == 0) {
+ if (submitcount == 4) {
+ if (copy_to_user(buffer, &packet->header[3], count))
+ retval = -EFAULT;
+ } else {
+ if (copy_to_user(buffer, packet->data, count))
+ retval = -EFAULT;
+ }
+ }
+
+ if (retval == 0) {
+ retval = count;
+ *offset += count;
+ }
+
+ out_free:
+ hpsb_free_tlabel(packet);
+ hpsb_free_packet(packet);
+
+ return retval;
+}
+
+static int mem1394_release(struct inode *inode, struct file *file)
+{
+ struct mem1394_file_info *fi = (struct mem1394_file_info*)file->private_data;
+
+ kfree(fi);
+
+ return 0;
+}
+
+static struct class *mem1394_sysfs_class;
+
+static struct file_operations mem1394_fops = {
+ .owner = THIS_MODULE,
+ .mmap = mem1394_mmap,
+ .open = mem1394_open,
+ .read = mem1394_read,
+ .release = mem1394_release,
+};
+
+static atomic_t mem1394_dev_ctr;
+
+static struct mem1394_dev * alloc_mem1394_dev(struct device *dev)
+{
+ struct mem1394_dev *result;
+ struct node_entry *ne = container_of(dev, struct node_entry, device);
+ int ret;
+ struct class_device * mem1394_class_member;
+
+ result = kzalloc(sizeof(*result), GFP_KERNEL);
+ if (!result)
+ return NULL;
+
+ cdev_init(&result->cdev, &mem1394_fops);
+ result->cdev.owner = THIS_MODULE;
+ result->ne = ne;
+
+ ret = hpsb_cdev_add(&result->cdev);
+ if (ret) {
+ printk(KERN_ERR "mem1394: failed to register character device!\n");
+ goto out_free;
+ }
+
+ atomic_inc(&mem1394_dev_ctr);
+ mem1394_class_member = class_device_create(mem1394_sysfs_class, NULL, result->cdev.dev,
+ dev, "fwmem-%d", atomic_read(&mem1394_dev_ctr));
+ if (IS_ERR(mem1394_class_member)) {
+ printk(KERN_WARNING "mem1394: class_device_create failed\n");
+ } else {
+ class_set_devdata(mem1394_class_member, result);
+ }
+ dev->driver_data = result;
+
+ return result;
+ out_free:
+ kfree(result);
+ return NULL;
+}
+
+static DEFINE_SPINLOCK(dev_list_lock);
+static LIST_HEAD(dev_list);
+
+static int mem1394_add(struct class_device *cl_dev, struct class_interface *cl_intf)
+{
+ struct mem1394_dev *memdev;
+
+ if (!cl_dev) {
+ printk("cl_dev not assigned\n");
+ return -ENOENT;
+ }
+ if (!cl_dev->dev) {
+ printk("cl_dev->dev not assigned\n");
+ return -ENONET;
+ }
+
+ memdev = alloc_mem1394_dev(cl_dev->dev);
+ if (!memdev)
+ return -ENOMEM;
+
+ spin_lock(&dev_list_lock);
+ list_add_tail(&memdev->list, &dev_list);
+ spin_unlock(&dev_list_lock);
+
+ /* need we do anything else? */
+ return 0;
+}
+
+static void mem1394_del(struct mem1394_dev *memdev)
+{
+ class_device_destroy(mem1394_sysfs_class, memdev->cdev.dev);
+
+ /* kill off everything that might be in progress */
+ /* TODO */
+
+ /* remove character device */
+ hpsb_cdev_del(&memdev->cdev);
+ kfree(memdev);
+}
+
+static void mem1394_remove(struct class_device *cl_dev, struct class_interface *cl_intf)
+{
+ struct mem1394_dev *memdev, *tmp, *found = NULL;
+
+ /* find our memdev corresponding to the class device */
+ spin_lock(&dev_list_lock);
+ list_for_each_entry_safe(memdev, tmp, &dev_list, list) {
+ if (cl_dev->dev == memdev->dev) {
+ list_del(&memdev->list);
+ found = memdev;
+ break;
+ }
+ }
+ spin_unlock(&dev_list_lock);
+ if (!found)
+ return;
+
+ mem1394_del(found);
+}
+
+static struct class_interface mem1394_interface = {
+ .add = mem1394_add,
+ .remove = mem1394_remove,
+};
+
+static int __init init_mem1394(void)
+{
+ int ret;
+
+ spin_lock_init(&dev_list_lock);
+
+ mem1394_sysfs_class = class_create(THIS_MODULE, "mem1394");
+ if (IS_ERR(mem1394_sysfs_class)) {
+ return PTR_ERR(mem1394_sysfs_class);
+ }
+
+ ret = hpsb_register_node_interface(&mem1394_interface);
+ return ret;
+}
+
+static void __exit cleanup_mem1394(void)
+{
+ struct mem1394_dev *memdev, *tmp;
+
+ hpsb_unregister_node_interface(&mem1394_interface);
+ list_for_each_entry_safe(memdev, tmp, &dev_list, list) {
+ list_del(&memdev->list);
+ mem1394_del(memdev);
+ }
+ class_destroy(mem1394_sysfs_class);
+}
+
+module_init(init_mem1394);
+module_exit(cleanup_mem1394);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
diff --git a/drivers/ieee1394/mem1394.h b/drivers/ieee1394/mem1394.h
new file mode 100644
index 0000000..e7cc8ab
--- /dev/null
+++ b/drivers/ieee1394/mem1394.h
@@ -0,0 +1,20 @@
+#ifndef IEEE1394_MEM1394_H
+#define IEEE1394_MEM1394_H
+
+#include <asm/types.h>
+#include <linux/cdev.h>
+#include <linux/list.h>
+#include "nodemgr.h"
+
+struct mem1394_dev {
+ struct device *dev;
+ struct node_entry *ne;
+ struct cdev cdev;
+ struct list_head list;
+};
+
+struct mem1394_file_info {
+ struct mem1394_dev *memdev;
+};
+
+#endif /* IEEE1394_MEM1394_H */

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