Re: [RFC][AGPGART] Allow multiple backends to be initialized

Re: [RFC][AGPGART] Allow multiple backends to be initialized

[Christoph Hellwig]

Last time I checked Dave Jones (davej@codemonkey.org.uk) was agpgart
maintainer, not Rusty or me.  So please resend to Dave and the
linux-kernel list so other people (like me can comment).

Comments on the patch format:  Please don't send output of bk export
over multiple changesets - while you can use that to generate the
patch please strip the bk checkin comments and write a single patch
description that explains your overall changes, aka what you did
and if it's not obvious why.

If you patch does multiple things at once split it into one patch per
problem or feature.


> -struct agp_bridge_data agp_bridge_dummy = { .type = NOT_SUPPORTED };
> -struct agp_bridge_data *agp_bridge = &agp_bridge_dummy;
> +struct agp_bridge_data *agp_bridge = NULL;

there's no need to initialize global variables to NULL - the C standard
guarantees that gets done implicitly - and letting the compile do that
decreases the size of the kernel image.

> -/* XXX Kludge alert: agpgart isn't ready for multiple bridges yet */
>  struct agp_bridge_data *agp_alloc_bridge(void)
>  {
> -	return agp_bridge;
> +	struct  agp_bridge_data *bridge = kmalloc(sizeof(struct agp_bridge_data), 
> GFP_KERNEL);
> +	if(!agp_count) agp_bridge = bridge;
> +	return bridge;
>  }

Some style problems here - never create lines longer than 80
charactersm, and follow Documentation/CodingStyle indentation (or just
look at the other agpgart code).

Also you should check the kmalloc return value;

It should look like:

struct agp_bridge_data *agp_alloc_bridge(void)
{
	struct agp_bridge_data *bridge;

	bridge = kmalloc(sizeof(*bridge), GFP_KERNEL);
	if (!bridge)
		return NULL;

	/* cludge for the transition to passing the agp_bridge around */
	if (!agp_count)
		agp_bridge = bridge;

	return bridge;
}

Also where do you free the kmalloced bridges again?

> +	if(!agp_count) {

	if (!agp_count) {

> +	if(!agp_count) {

Dito.

>  	memset(info, 0, sizeof(struct agp_kern_info));
> -	if (!agp_bridge || agp_bridge->type == NOT_SUPPORTED ||
> -	    !agp_bridge->version) {
> +	if ((agp_bridge == NULL) || (agp_bridge->type == NOT_SUPPORTED)) {

Why do you drop the version check here?

[RFC][AGPGART]Allow multiple backends to be initialized

[Mike Werner]

This is a patch which extends the agpgart backend API to address
multiple bridges and allows them to be initialized.
I have corresponding patches for drm and some video drivers which use agpgart
so that they will continue to work with the default agp_bridge.
I can send those changes as 2 separate patches later.
The purpose is only for the api changes to generic code.

# This is a BitKeeper generated diff -Nru style patch.
#
#   Allow multiple agpgart backends to be initialized and addressed.
#   The semantics of agp_backend_acquire has been extended to allow
#   addressing the default agp bridge or a specific bridge described
#   by a struct agp_bridge_data.
# 

diff -Nru a/drivers/char/agp/agp.h b/drivers/char/agp/agp.h
--- a/drivers/char/agp/agp.h	2004-12-06 17:14:39 -08:00
+++ b/drivers/char/agp/agp.h	2004-12-06 17:14:39 -08:00
@@ -1,5 +1,6 @@
 /*
  * AGPGART
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2004 Dave Jones
  * Copyright (C) 1999 Jeff Hartmann
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -118,6 +119,7 @@
 struct agp_bridge_data {
 	struct agp_version *version;
 	struct agp_bridge_driver *driver;
+	struct list_head list;
 	struct vm_operations_struct *vm_ops;
 	void *previous_size;
 	void *current_size;
diff -Nru a/drivers/char/agp/backend.c b/drivers/char/agp/backend.c
--- a/drivers/char/agp/backend.c	2004-12-06 17:14:39 -08:00
+++ b/drivers/char/agp/backend.c	2004-12-06 17:14:39 -08:00
@@ -1,5 +1,6 @@
 /*
  * AGPGART driver backend routines.
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2003 Dave Jones.
  * Copyright (C) 1999 Jeff Hartmann.
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -42,7 +43,7 @@
  * fix some real stupidity. It's only by chance we can bump
  * past 0.99 at all due to some boolean logic error. */
 #define AGPGART_VERSION_MAJOR 0
-#define AGPGART_VERSION_MINOR 100
+#define AGPGART_VERSION_MINOR 101
 static struct agp_version agp_current_version =
 {
 	.major = AGPGART_VERSION_MAJOR,
@@ -51,24 +52,53 @@
 
 static int agp_count=0;
 
-struct agp_bridge_data agp_bridge_dummy = { .type = NOT_SUPPORTED };
-struct agp_bridge_data *agp_bridge = &agp_bridge_dummy;
+agp_bridge_data_p agp_bridge;
+LIST_HEAD(agp_bridges);
 EXPORT_SYMBOL(agp_bridge);
-
+EXPORT_SYMBOL(agp_bridges);
 
 /**
- *	agp_backend_acquire  -  attempt to acquire the agp backend.
+ *	agp_backend_acquire  -  attempt to acquire an agp backend.
  *
+ *	
+ *	returns -ENODEV if no valid defaults,
  *	returns -EBUSY if agp is in use,
  *	returns 0 if the caller owns the agp backend
  */
-int agp_backend_acquire(void)
+int agp_backend_acquire(struct pci_dev *pdev, agp_bridge_data_p 
*acquired_bridge)
 {
-	if (agp_bridge->type == NOT_SUPPORTED)
-		return -EINVAL;
-	if (atomic_read(&agp_bridge->agp_in_use))
+	agp_bridge_data_p bridge;
+
+	if (!pdev) {
+		if (!agp_bridge)
+			return -ENODEV;
+		bridge = agp_bridge;
+	} else {
+        	list_for_each_entry(bridge, &agp_bridges, list) {
+			int match=0;
+			switch(pdev->class) {
+				/* Standard bridges have a valid pci_dev */
+				case PCI_CLASS_BRIDGE_HOST:
+					if (bridge->dev==pdev)
+						match=1;
+					break;
+				/* Non-standard bridges can use a devices pci_dev */
+				default:
+                			if (bridge->dev->bus==pdev->bus)
+						match=1;
+					break;
+			}
+                        if (match)
+				break;
+        	}
+	}
+
+	if (atomic_read(&bridge->agp_in_use))
 		return -EBUSY;
-	atomic_inc(&agp_bridge->agp_in_use);
+	atomic_inc(&bridge->agp_in_use);
+	if (acquired_bridge)
+		*acquired_bridge = bridge;
+	DBG("pdev = 0x%lx, acquired bridge = 0x%lx\n", (unsigned long)pdev, 
(unsigned long)bridge);
 	return 0;
 }
 EXPORT_SYMBOL(agp_backend_acquire);
@@ -82,10 +112,11 @@
  *
  *	(Ensure that all memory it bound is unbound.)
  */
-void agp_backend_release(void)
+void agp_backend_release(agp_bridge_data_p bridge)
 {
-	if (agp_bridge->type != NOT_SUPPORTED)
-		atomic_dec(&agp_bridge->agp_in_use);
+
+	if (bridge)
+		atomic_dec(&bridge->agp_in_use);
 }
 EXPORT_SYMBOL(agp_backend_release);
 
@@ -102,7 +133,7 @@
 	{4096, 3932}
 };
 
-static int agp_find_max(void)
+int agp_find_max(void)
 {
 	long memory, index, result;
 
@@ -121,13 +152,13 @@
 	     (maxes_table[index].agp - maxes_table[index - 1].agp)) /
 	   (maxes_table[index].mem - maxes_table[index - 1].mem);
 
-	printk(KERN_INFO PFX "Maximum main memory to use for agp memory: %ldM\n", 
result);
+	if(!agp_count) printk(KERN_INFO PFX "Maximum main memory to use for agp 
memory: %ldM\n", result);
 	result = result << (20 - PAGE_SHIFT);
 	return result;
 }
 
 
-static int agp_backend_initialize(struct agp_bridge_data *bridge)
+static int agp_backend_initialize(agp_bridge_data_p bridge)
 {
 	int size_value, rc, got_gatt=0, got_keylist=0;
 
@@ -178,8 +209,8 @@
 		goto err_out;
 	}
 
-	printk(KERN_INFO PFX "AGP aperture is %dM @ 0x%lx\n",
-	       size_value, bridge->gart_bus_addr);
+	printk(KERN_INFO PFX "agp_bridge = 0x%lx: AGP aperture is %dM @ 0x%lx\n",
+	       (unsigned long)bridge, size_value, bridge->gart_bus_addr);
 
 	return 0;
 
@@ -197,7 +228,7 @@
 }
 
 /* cannot be __exit b/c as it could be called from __init code */
-static void agp_backend_cleanup(struct agp_bridge_data *bridge)
+static void agp_backend_cleanup(agp_bridge_data_p bridge)
 {
 	if (bridge->driver->cleanup)
 		bridge->driver->cleanup();
@@ -225,21 +256,34 @@
 	&agp_copy_info
 };
 
-/* XXX Kludge alert: agpgart isn't ready for multiple bridges yet */
-struct agp_bridge_data *agp_alloc_bridge(void)
+agp_bridge_data_p agp_alloc_bridge(void)
 {
-	return agp_bridge;
+	agp_bridge_data_p bridge = kmalloc(sizeof(*bridge), GFP_KERNEL);
+
+	if (!bridge)
+		return NULL;
+
+	/* Kludge for the transition to passing the agp_bridge around */
+	if (!agp_count)
+		agp_bridge = bridge;
+
+	return bridge;
 }
 EXPORT_SYMBOL(agp_alloc_bridge);
 
 
-void agp_put_bridge(struct agp_bridge_data *bridge)
+void agp_put_bridge(agp_bridge_data_p bridge)
 {
+        kfree(bridge);
+
+        /* Kludge for the transition to passing the agp_bridge around */
+        if (!agp_count)
+                agp_bridge = NULL;
 }
 EXPORT_SYMBOL(agp_put_bridge);
 
 
-int agp_add_bridge(struct agp_bridge_data *bridge)
+int agp_add_bridge(agp_bridge_data_p bridge)
 {
 	int error;
 
@@ -251,56 +295,53 @@
 		return -EINVAL;
 	}
 
-	if (agp_count) {
-		printk (KERN_INFO PFX
-		       "Only one agpgart device currently supported.\n");
-		return -ENODEV;
-	}
-
 	/* Grab reference on the chipset driver. */
 	if (!try_module_get(bridge->driver->owner)) {
 		printk (KERN_INFO PFX "Couldn't lock chipset driver.\n");
 		return -EINVAL;
 	}
 
-	bridge->type = SUPPORTED;
-
-	error = agp_backend_initialize(agp_bridge);
+	error = agp_backend_initialize(bridge);
 	if (error) {
 		printk (KERN_INFO PFX "agp_backend_initialize() failed.\n");
 		goto err_out;
 	}
 
-	error = agp_frontend_initialize();
-	if (error) {
-		printk (KERN_INFO PFX "agp_frontend_initialize() failed.\n");
-		goto frontend_err;
-	}
+	if (!agp_count) {
+		error = agp_frontend_initialize();
+		if (error) {
+			printk (KERN_INFO PFX "agp_frontend_initialize() failed.\n");
+			goto frontend_err;
+		}
 
-	/* FIXME: What to do with this? */
-	inter_module_register("drm_agp", THIS_MODULE, &drm_agp);
+		/* FIXME: What to do with this? */
+		inter_module_register("drm_agp", THIS_MODULE, &drm_agp);
+	}
 
 	agp_count++;
+	list_add(&bridge->list, &agp_bridges);
 	return 0;
 
 frontend_err:
-	agp_backend_cleanup(agp_bridge);
+	agp_backend_cleanup(bridge);
 err_out:
-	bridge->type = NOT_SUPPORTED;
 	module_put(bridge->driver->owner);
+	agp_put_bridge(bridge);
 	return error;
 }
 EXPORT_SYMBOL_GPL(agp_add_bridge);
 
 
-void agp_remove_bridge(struct agp_bridge_data *bridge)
+void agp_remove_bridge(agp_bridge_data_p bridge)
 {
-	bridge->type = NOT_SUPPORTED;
-	agp_frontend_cleanup();
 	agp_backend_cleanup(bridge);
-	inter_module_unregister("drm_agp");
 	agp_count--;
+	if(!agp_count) {
+		agp_frontend_cleanup();
+		inter_module_unregister("drm_agp");
+	}
 	module_put(bridge->driver->owner);
+	list_del(&bridge->list);
 }
 EXPORT_SYMBOL_GPL(agp_remove_bridge);
 
diff -Nru a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c
--- a/drivers/char/agp/frontend.c	2004-12-06 17:14:39 -08:00
+++ b/drivers/char/agp/frontend.c	2004-12-06 17:14:39 -08:00
@@ -1,5 +1,6 @@
 /*
  * AGPGART driver frontend
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2003 Dave Jones
  * Copyright (C) 1999 Jeff Hartmann
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -292,14 +293,14 @@
 static void agp_free_memory_wrap(struct agp_memory *memory)
 {
 	agp_remove_from_pool(memory);
-	agp_free_memory(memory);
+	agp_free_memory(agp_bridge, memory);
 }
 
 static struct agp_memory *agp_allocate_memory_wrap(size_t pg_count, u32 type)
 {
 	struct agp_memory *memory;
 
-	memory = agp_allocate_memory(pg_count, type);
+	memory = agp_allocate_memory(agp_bridge, pg_count, type);
 	if (memory == NULL)
 		return NULL;
 
@@ -420,7 +421,7 @@
 	if (agp_fe.current_controller == controller) {
 		agp_fe.current_controller = NULL;
 		agp_fe.backend_acquired = FALSE;
-		agp_backend_release();
+		agp_backend_release(agp_bridge);
 	}
 	kfree(controller);
 	return 0;
@@ -468,7 +469,7 @@
 
 	agp_fe.current_controller = NULL;
 	agp_fe.used_by_controller = FALSE;
-	agp_backend_release();
+	agp_backend_release(agp_bridge);
 }
 
 /* 
@@ -605,7 +606,7 @@
 	if (!(test_bit(AGP_FF_IS_VALID, &priv->access_flags)))
 		goto out_eperm;
 
-	agp_copy_info(&kerninfo);
+	agp_copy_info(agp_bridge, &kerninfo);
 	size = vma->vm_end - vma->vm_start;
 	current_size = kerninfo.aper_size;
 	current_size = current_size * 0x100000;
@@ -757,7 +758,7 @@
 	struct agp_info userinfo;
 	struct agp_kern_info kerninfo;
 
-	agp_copy_info(&kerninfo);
+	agp_copy_info(agp_bridge, &kerninfo);
 
 	userinfo.version.major = kerninfo.version.major;
 	userinfo.version.minor = kerninfo.version.minor;
@@ -788,7 +789,7 @@
 	if (agp_fe.current_controller != NULL)
 		return -EBUSY;
 
-	ret = agp_backend_acquire();
+	ret = agp_backend_acquire(NULL, NULL);
 	if (ret == 0)
 		agp_fe.backend_acquired = TRUE;
 	else
@@ -803,7 +804,7 @@
 
 		if (controller == NULL) {
 			agp_fe.backend_acquired = FALSE;
-			agp_backend_release();
+			agp_backend_release(agp_bridge);
 			return -ENOMEM;
 		}
 		agp_insert_controller(controller);
@@ -830,7 +831,7 @@
 	if (copy_from_user(&mode, arg, sizeof(struct agp_setup)))
 		return -EFAULT;
 
-	agp_enable(mode.agp_mode);
+	agp_enable(agp_bridge, mode.agp_mode);
 	return 0;
 }
 
@@ -961,7 +962,7 @@
 	if (memory == NULL)
 		return -EINVAL;
 
-	return agp_bind_memory(memory, bind_info.pg_start);
+	return agp_bind_memory(agp_bridge, memory, bind_info.pg_start);
 }
 
 static int agpioc_unbind_wrap(struct agp_file_private *priv, void __user 
*arg)
@@ -978,7 +979,7 @@
 	if (memory == NULL)
 		return -EINVAL;
 
-	return agp_unbind_memory(memory);
+	return agp_unbind_memory(agp_bridge, memory);
 }
 
 static int agp_ioctl(struct inode *inode, struct file *file,
diff -Nru a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
--- a/drivers/char/agp/generic.c	2004-12-06 17:14:39 -08:00
+++ b/drivers/char/agp/generic.c	2004-12-06 17:14:39 -08:00
@@ -1,5 +1,6 @@
 /*
  * AGPGART driver.
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2004 Dave Jones.
  * Copyright (C) 1999 Jeff Hartmann.
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -112,23 +113,23 @@
  *	It is the only function that can be called when the backend is not owned
  *	by the caller.  (So it can free memory on client death.)
  */
-void agp_free_memory(struct agp_memory *curr)
+void agp_free_memory(agp_bridge_data_p bridge, struct agp_memory *curr)
 {
 	size_t i;
 
-	if ((agp_bridge->type == NOT_SUPPORTED) || (curr == NULL))
+	if ((bridge == NULL) || (curr == NULL))
 		return;
 
 	if (curr->is_bound == TRUE)
-		agp_unbind_memory(curr);
+		agp_unbind_memory(bridge, curr);
 
 	if (curr->type != 0) {
-		agp_bridge->driver->free_by_type(curr);
+		bridge->driver->free_by_type(curr);
 		return;
 	}
 	if (curr->page_count != 0) {
 		for (i = 0; i < curr->page_count; i++) {
-			agp_bridge->driver->agp_destroy_page(phys_to_virt(curr->memory[i]));
+			bridge->driver->agp_destroy_page(phys_to_virt(curr->memory[i]));
 		}
 	}
 	agp_free_key(curr->key);
@@ -150,20 +151,20 @@
  *
  *	It returns NULL whenever memory is unavailable.
  */
-struct agp_memory *agp_allocate_memory(size_t page_count, u32 type)
+struct agp_memory *agp_allocate_memory(agp_bridge_data_p bridge, size_t 
page_count, u32 type)
 {
 	int scratch_pages;
 	struct agp_memory *new;
 	size_t i;
 
-	if (agp_bridge->type == NOT_SUPPORTED)
+	if (!bridge)
 		return NULL;
 
-	if ((atomic_read(&agp_bridge->current_memory_agp) + page_count) > 
agp_bridge->max_memory_agp)
+	if ((atomic_read(&bridge->current_memory_agp) + page_count) > 
bridge->max_memory_agp)
 		return NULL;
 
 	if (type != 0) {
-		new = agp_bridge->driver->alloc_by_type(page_count, type);
+		new = bridge->driver->alloc_by_type(page_count, type);
 		return new;
 	}
 
@@ -175,14 +176,14 @@
 		return NULL;
 
 	for (i = 0; i < page_count; i++) {
-		void *addr = agp_bridge->driver->agp_alloc_page();
+		void *addr = bridge->driver->agp_alloc_page();
 
 		if (addr == NULL) {
-			agp_free_memory(new);
+			agp_free_memory(bridge, new);
 			return NULL;
 		}
 		new->memory[i] =
-			agp_bridge->driver->mask_memory(virt_to_phys(addr), type);
+			bridge->driver->mask_memory(virt_to_phys(addr), type);
 		new->page_count++;
 	}
 
@@ -196,14 +197,14 @@
 /* End - Generic routines for handling agp_memory structures */
 
 
-static int agp_return_size(void)
+static int agp_return_size(agp_bridge_data_p bridge)
 {
 	int current_size;
 	void *temp;
 
-	temp = agp_bridge->current_size;
+	temp = bridge->current_size;
 
-	switch (agp_bridge->driver->size_type) {
+	switch (bridge->driver->size_type) {
 	case U8_APER_SIZE:
 		current_size = A_SIZE_8(temp)->size;
 		break;
@@ -275,26 +276,25 @@
  *	This function copies information about the agp bridge device and the state 
of
  *	the agp backend into an agp_kern_info pointer.
  */
-int agp_copy_info(struct agp_kern_info *info)
+int agp_copy_info(agp_bridge_data_p bridge, struct agp_kern_info *info)
 {
 	memset(info, 0, sizeof(struct agp_kern_info));
-	if (!agp_bridge || agp_bridge->type == NOT_SUPPORTED ||
-	    !agp_bridge->version) {
+	if (!bridge) {
 		info->chipset = NOT_SUPPORTED;
 		return -EIO;
 	}
 
-	info->version.major = agp_bridge->version->major;
-	info->version.minor = agp_bridge->version->minor;
-	info->chipset = agp_bridge->type;
-	info->device = agp_bridge->dev;
-	info->mode = agp_bridge->mode;
-	info->aper_base = agp_bridge->gart_bus_addr;
-	info->aper_size = agp_return_size();
-	info->max_memory = agp_bridge->max_memory_agp;
-	info->current_memory = atomic_read(&agp_bridge->current_memory_agp);
-	info->cant_use_aperture = agp_bridge->driver->cant_use_aperture;
-	info->vm_ops = agp_bridge->vm_ops;
+	info->version.major = bridge->version->major;
+	info->version.minor = bridge->version->minor;
+	info->chipset = SUPPORTED;
+	info->device = bridge->dev;
+	info->mode = bridge->mode;
+	info->aper_base = bridge->gart_bus_addr;
+	info->aper_size = agp_return_size(bridge);
+	info->max_memory = bridge->max_memory_agp;
+	info->current_memory = atomic_read(&bridge->current_memory_agp);
+	info->cant_use_aperture = bridge->driver->cant_use_aperture;
+	info->vm_ops = bridge->vm_ops;
 	info->page_mask = ~0UL;
 	return 0;
 }
@@ -319,11 +319,11 @@
  *	It returns -EINVAL if the pointer == NULL.
  *	It returns -EBUSY if the area of the table requested is already in use.
  */
-int agp_bind_memory(struct agp_memory *curr, off_t pg_start)
+int agp_bind_memory(agp_bridge_data_p bridge, struct agp_memory *curr, off_t 
pg_start)
 {
 	int ret_val;
 
-	if ((agp_bridge->type == NOT_SUPPORTED) || (curr == NULL))
+	if ((bridge == NULL) || (curr == NULL))
 		return -EINVAL;
 
 	if (curr->is_bound == TRUE) {
@@ -331,10 +331,10 @@
 		return -EINVAL;
 	}
 	if (curr->is_flushed == FALSE) {
-		agp_bridge->driver->cache_flush();
+		bridge->driver->cache_flush();
 		curr->is_flushed = TRUE;
 	}
-	ret_val = agp_bridge->driver->insert_memory(curr, pg_start, curr->type);
+	ret_val = bridge->driver->insert_memory(curr, pg_start, curr->type);
 
 	if (ret_val != 0)
 		return ret_val;
@@ -354,11 +354,11 @@
  * It returns -EINVAL if this piece of agp_memory is not currently bound to
  * the graphics aperture translation table or if the agp_memory pointer == 
NULL
  */
-int agp_unbind_memory(struct agp_memory *curr)
+int agp_unbind_memory(agp_bridge_data_p bridge, struct agp_memory *curr)
 {
 	int ret_val;
 
-	if ((agp_bridge->type == NOT_SUPPORTED) || (curr == NULL))
+	if ((bridge == NULL) || (curr == NULL))
 		return -EINVAL;
 
 	if (curr->is_bound != TRUE) {
@@ -366,7 +366,7 @@
 		return -EINVAL;
 	}
 
-	ret_val = agp_bridge->driver->remove_memory(curr, curr->pg_start, 
curr->type);
+	ret_val = bridge->driver->remove_memory(curr, curr->pg_start, curr->type);
 
 	if (ret_val != 0)
 		return ret_val;
@@ -949,11 +949,11 @@
  *
  * @mode:	agp mode register value to configure with.
  */
-void agp_enable(u32 mode)
+void agp_enable(agp_bridge_data_p bridge, u32 mode)
 {
-	if (agp_bridge->type == NOT_SUPPORTED)
+	if (!bridge)
 		return;
-	agp_bridge->driver->agp_enable(mode);
+	bridge->driver->agp_enable(mode);
 }
 EXPORT_SYMBOL(agp_enable);
 
diff -Nru a/include/linux/agp_backend.h b/include/linux/agp_backend.h
--- a/include/linux/agp_backend.h	2004-12-06 17:14:39 -08:00
+++ b/include/linux/agp_backend.h	2004-12-06 17:14:39 -08:00
@@ -1,6 +1,7 @@
 /*
  * AGPGART backend specific includes. Not for userspace consumption.
  *
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2003 Dave Jones
  * Copyright (C) 1999 Jeff Hartmann
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -87,14 +88,18 @@
 
 #define AGP_NORMAL_MEMORY 0
 
-extern void agp_free_memory(struct agp_memory *);
-extern struct agp_memory *agp_allocate_memory(size_t, u32);
-extern int agp_copy_info(struct agp_kern_info *);
-extern int agp_bind_memory(struct agp_memory *, off_t);
-extern int agp_unbind_memory(struct agp_memory *);
-extern void agp_enable(u32);
-extern int agp_backend_acquire(void);
-extern void agp_backend_release(void);
+typedef struct agp_bridge_data *agp_bridge_data_p;
+extern agp_bridge_data_p agp_bridge;
+extern struct list_head agp_bridges;
+
+extern void agp_free_memory(agp_bridge_data_p, struct agp_memory *);
+extern struct agp_memory *agp_allocate_memory(agp_bridge_data_p, size_t, 
u32);
+extern int agp_copy_info(agp_bridge_data_p, struct agp_kern_info *);
+extern int agp_bind_memory(agp_bridge_data_p, struct agp_memory *, off_t);
+extern int agp_unbind_memory(agp_bridge_data_p, struct agp_memory *);
+extern void agp_enable(agp_bridge_data_p, u32);
+extern int agp_backend_acquire(struct pci_dev *, agp_bridge_data_p *);
+extern void agp_backend_release(agp_bridge_data_p);
 
 /*
  * Interface between drm and agp code.  When agp initializes, it makes
@@ -102,14 +107,14 @@
  * use it.  Keith Owens <kaos@ocs.com.au> 28 Oct 2000.
  */
 typedef struct {
-	void			(*free_memory)(struct agp_memory *);
-	struct agp_memory *	(*allocate_memory)(size_t, u32);
-	int			(*bind_memory)(struct agp_memory *, off_t);
-	int			(*unbind_memory)(struct agp_memory *);
-	void			(*enable)(u32);
-	int			(*acquire)(void);
-	void			(*release)(void);
-	int			(*copy_info)(struct agp_kern_info *);
+	void			(*free_memory)(agp_bridge_data_p, struct agp_memory *);
+	struct agp_memory *	(*allocate_memory)(agp_bridge_data_p, size_t, u32);
+	int			(*bind_memory)(agp_bridge_data_p, struct agp_memory *, off_t);
+	int			(*unbind_memory)(agp_bridge_data_p, struct agp_memory *);
+	void			(*enable)(agp_bridge_data_p, u32);
+	int			(*acquire)(struct pci_dev *, agp_bridge_data_p *);
+	void			(*release)(agp_bridge_data_p);
+	int			(*copy_info)(agp_bridge_data_p, struct agp_kern_info *);
 } drm_agp_t;
 
 extern const drm_agp_t *drm_agp_p;

Re: [RFC][AGPGART]Allow multiple backends to be initialized

[Christoph Hellwig]

> -struct agp_bridge_data agp_bridge_dummy = { .type = NOT_SUPPORTED };
> -struct agp_bridge_data *agp_bridge = &agp_bridge_dummy;
> +agp_bridge_data_p agp_bridge;

Please don't intoroduce new new typedefs, especially not for pointer
types.

> +LIST_HEAD(agp_bridges);
>  EXPORT_SYMBOL(agp_bridge);
> -
> +EXPORT_SYMBOL(agp_bridges);

> -int agp_backend_acquire(void)
> +int agp_backend_acquire(struct pci_dev *pdev, agp_bridge_data_p 
> *acquired_bridge)
>  {
> -	if (agp_bridge->type == NOT_SUPPORTED)
> -		return -EINVAL;
> -	if (atomic_read(&agp_bridge->agp_in_use))
> +	agp_bridge_data_p bridge;
> +
> +	if (!pdev) {
> +		if (!agp_bridge)
> +			return -ENODEV;
> +		bridge = agp_bridge;
> +	} else {
> +        	list_for_each_entry(bridge, &agp_bridges, list) {
> +			int match=0;
> +			switch(pdev->class) {
> +				/* Standard bridges have a valid pci_dev */
> +				case PCI_CLASS_BRIDGE_HOST:
> +					if (bridge->dev==pdev)
> +						match=1;
> +					break;
> +				/* Non-standard bridges can use a devices pci_dev */
> +				default:
> +                			if (bridge->dev->bus==pdev->bus)
> +						match=1;
> +					break;
> +			}
> +                        if (match)
> +				break;
> +        	}
> +	}

Wrong interface.  Please pass in the pci_dev of the grpahics cards and
add a new method for lowlevel drivers to find the bridge.  For the normal
bridges (aka everything but the hp, alpha and your new driver) you'd do
a generic helper that just walks down the parent pointers until it finds
a class.

Also I'd suggest returning the found bridges as return value of the
function.

> -	printk(KERN_INFO PFX "AGP aperture is %dM @ 0x%lx\n",
> -	       size_value, bridge->gart_bus_addr);
> +	printk(KERN_INFO PFX "agp_bridge = 0x%lx: AGP aperture is %dM @ 0x%lx\n",
> +	       (unsigned long)bridge, size_value, bridge->gart_bus_addr);

pointers should be printed using %p, but this isn't a place where you should
print it at all.

Re: [RFC][AGPGART]Allow multiple backends to be initialized

[Mike Werner]

On Tuesday 07 December 2004 01:02, Christoph Hellwig wrote:

> Wrong interface.  Please pass in the pci_dev of the grpahics cards and
> add a new method for lowlevel drivers to find the bridge.  For the normal
> bridges (aka everything but the hp, alpha and your new driver) you'd do
> a generic helper that just walks down the parent pointers until it finds
> a class.
>

In order to do this they way you want I need to know how this helper function
finds the bridge of interest. Just searching for the class doesn't cut it, we 
need a match criterion for the multi-bridge case. 

Re: [RFC][AGPGART]Allow multiple backends to be initialized

[Mike Werner]

On Tuesday 07 December 2004 01:02, Christoph Hellwig wrote:

> Wrong interface.  Please pass in the pci_dev of the grpahics cards and
> add a new method for lowlevel drivers to find the bridge.  For the normal
> bridges (aka everything but the hp, alpha and your new driver) you'd do
> a generic helper that just walks down the parent pointers until it finds
> a class.
I see what you mean now for the x86 class systems.
Thanks. I'll clean it up.

Re: [RFC][AGPGART]Allow multiple backends to be initialized

[Mike Werner]

On Tuesday 07 December 2004 01:02, Christoph Hellwig wrote:
> Wrong interface.  Please pass in the pci_dev of the grpahics cards and
> add a new method for lowlevel drivers to find the bridge.  For the normal
> bridges (aka everything but the hp, alpha and your new driver) you'd do
> a generic helper that just walks down the parent pointers until it finds
> a class.
> 
how do you want to handle the frontend driver?

> Also I'd suggest returning the found bridges as return value of the
> function.
> 
How should the caller distinguish between
a real error and the bridge in use by another client?

Re: [RFC][AGPGART]Allow multiple backends to be initialized

[Mike Werner]

Here is a modified patch which is much simpler.
Please comment for further improvements.
# This is a BitKeeper generated diff -Nru style patch.
#
#   Allow multiple agpgart backends to be initialized and addressed.
# 
diff -Nru a/drivers/char/agp/agp.h b/drivers/char/agp/agp.h
--- a/drivers/char/agp/agp.h	2004-12-09 20:46:37 -08:00
+++ b/drivers/char/agp/agp.h	2004-12-09 20:46:37 -08:00
@@ -1,5 +1,6 @@
 /*
  * AGPGART
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2004 Dave Jones
  * Copyright (C) 1999 Jeff Hartmann
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -139,6 +140,7 @@
 	int capndx;
 	char major_version;
 	char minor_version;
+	struct list_head list;
 };
 
 #define OUTREG64(mmap, addr, val)	__raw_writeq((val), (mmap)+(addr))
@@ -271,6 +273,7 @@
 void global_cache_flush(void);
 void get_agp_version(struct agp_bridge_data *bridge);
 unsigned long agp_generic_mask_memory(unsigned long addr, int type);
+struct agp_bridge_data *agp_generic_find_bridge(struct pci_dev *pdev);
 
 /* generic routines for agp>=3 */
 int agp3_generic_fetch_size(void);
diff -Nru a/drivers/char/agp/backend.c b/drivers/char/agp/backend.c
--- a/drivers/char/agp/backend.c	2004-12-09 20:46:37 -08:00
+++ b/drivers/char/agp/backend.c	2004-12-09 20:46:37 -08:00
@@ -1,5 +1,6 @@
 /*
  * AGPGART driver backend routines.
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2003 Dave Jones.
  * Copyright (C) 1999 Jeff Hartmann.
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -42,34 +43,36 @@
  * fix some real stupidity. It's only by chance we can bump
  * past 0.99 at all due to some boolean logic error. */
 #define AGPGART_VERSION_MAJOR 0
-#define AGPGART_VERSION_MINOR 100
+#define AGPGART_VERSION_MINOR 101
 static struct agp_version agp_current_version =
 {
 	.major = AGPGART_VERSION_MAJOR,
 	.minor = AGPGART_VERSION_MINOR,
 };
 
-static int agp_count=0;
-
-struct agp_bridge_data agp_bridge_dummy = { .type = NOT_SUPPORTED };
-struct agp_bridge_data *agp_bridge = &agp_bridge_dummy;
+struct agp_bridge_data *agp_bridge;
+LIST_HEAD(agp_bridges);
+struct agp_bridge_data *(*agp_find_bridge)(struct pci_dev *) = &agp_generic_find_bridge;
 EXPORT_SYMBOL(agp_bridge);
-
+EXPORT_SYMBOL(agp_bridges);
 
 /**
- *	agp_backend_acquire  -  attempt to acquire the agp backend.
+ *	agp_backend_acquire  -  attempt to acquire an agp backend.
  *
- *	returns -EBUSY if agp is in use,
- *	returns 0 if the caller owns the agp backend
  */
-int agp_backend_acquire(void)
+struct agp_bridge_data *agp_backend_acquire(struct pci_dev *pdev)
 {
-	if (agp_bridge->type == NOT_SUPPORTED)
-		return -EINVAL;
-	if (atomic_read(&agp_bridge->agp_in_use))
-		return -EBUSY;
-	atomic_inc(&agp_bridge->agp_in_use);
-	return 0;
+	struct agp_bridge_data *bridge;
+
+	bridge = agp_find_bridge(pdev);
+
+	if (!bridge)
+		return NULL;
+	
+	if (atomic_read(&bridge->agp_in_use))
+		return NULL;
+	atomic_inc(&bridge->agp_in_use);
+	return bridge;
 }
 EXPORT_SYMBOL(agp_backend_acquire);
 
@@ -82,10 +85,11 @@
  *
  *	(Ensure that all memory it bound is unbound.)
  */
-void agp_backend_release(void)
+void agp_backend_release(struct agp_bridge_data *bridge)
 {
-	if (agp_bridge->type != NOT_SUPPORTED)
-		atomic_dec(&agp_bridge->agp_in_use);
+
+	if (bridge)
+		atomic_dec(&bridge->agp_in_use);
 }
 EXPORT_SYMBOL(agp_backend_release);
 
@@ -121,7 +125,6 @@
 	     (maxes_table[index].agp - maxes_table[index - 1].agp)) /
 	   (maxes_table[index].mem - maxes_table[index - 1].mem);
 
-	printk(KERN_INFO PFX "Maximum main memory to use for agp memory: %ldM\n", result);
 	result = result << (20 - PAGE_SHIFT);
 	return result;
 }
@@ -178,9 +181,6 @@
 		goto err_out;
 	}
 
-	printk(KERN_INFO PFX "AGP aperture is %dM @ 0x%lx\n",
-	       size_value, bridge->gart_bus_addr);
-
 	return 0;
 
 err_out:
@@ -225,16 +225,31 @@
 	&agp_copy_info
 };
 
-/* XXX Kludge alert: agpgart isn't ready for multiple bridges yet */
+/* When we remove the global variable agp_bridge from all drivers
+ * then agp_alloc_bridge and agp_generic_find_bridge need to be updated
+ */
+
 struct agp_bridge_data *agp_alloc_bridge(void)
 {
-	return agp_bridge;
+	struct agp_bridge_data *bridge = kmalloc(sizeof(*bridge), GFP_KERNEL);
+
+	if (!bridge)
+		return NULL;
+
+	if (list_empty(&agp_bridges))
+		agp_bridge = bridge;
+
+	return bridge;
 }
 EXPORT_SYMBOL(agp_alloc_bridge);
 
 
 void agp_put_bridge(struct agp_bridge_data *bridge)
 {
+        kfree(bridge);
+
+        if (list_empty(&agp_bridges))
+                agp_bridge = NULL;
 }
 EXPORT_SYMBOL(agp_put_bridge);
 
@@ -251,43 +266,41 @@
 		return -EINVAL;
 	}
 
-	if (agp_count) {
-		printk (KERN_INFO PFX
-		       "Only one agpgart device currently supported.\n");
-		return -ENODEV;
-	}
-
 	/* Grab reference on the chipset driver. */
 	if (!try_module_get(bridge->driver->owner)) {
 		printk (KERN_INFO PFX "Couldn't lock chipset driver.\n");
 		return -EINVAL;
 	}
 
-	bridge->type = SUPPORTED;
-
-	error = agp_backend_initialize(agp_bridge);
+	error = agp_backend_initialize(bridge);
 	if (error) {
 		printk (KERN_INFO PFX "agp_backend_initialize() failed.\n");
 		goto err_out;
 	}
 
-	error = agp_frontend_initialize();
-	if (error) {
-		printk (KERN_INFO PFX "agp_frontend_initialize() failed.\n");
-		goto frontend_err;
-	}
+	if (list_empty(&agp_bridges)) {
+		error = agp_frontend_initialize();
+		if (error) {
+			printk (KERN_INFO PFX "agp_frontend_initialize() failed.\n");
+			goto frontend_err;
+		}
+
+		/* FIXME: What to do with this? */
+		inter_module_register("drm_agp", THIS_MODULE, &drm_agp);
+
+		printk(KERN_INFO PFX "AGP aperture is %dM @ 0x%lx\n",
+			bridge->driver->fetch_size(), bridge->gart_bus_addr);
 
-	/* FIXME: What to do with this? */
-	inter_module_register("drm_agp", THIS_MODULE, &drm_agp);
+	}
 
-	agp_count++;
+	list_add(&bridge->list, &agp_bridges);
 	return 0;
 
 frontend_err:
-	agp_backend_cleanup(agp_bridge);
+	agp_backend_cleanup(bridge);
 err_out:
-	bridge->type = NOT_SUPPORTED;
 	module_put(bridge->driver->owner);
+	agp_put_bridge(bridge);
 	return error;
 }
 EXPORT_SYMBOL_GPL(agp_add_bridge);
@@ -295,11 +308,12 @@
 
 void agp_remove_bridge(struct agp_bridge_data *bridge)
 {
-	bridge->type = NOT_SUPPORTED;
-	agp_frontend_cleanup();
 	agp_backend_cleanup(bridge);
-	inter_module_unregister("drm_agp");
-	agp_count--;
+	list_del(&bridge->list);
+	if (list_empty(&agp_bridges)) {
+		agp_frontend_cleanup();
+		inter_module_unregister("drm_agp");
+	}
 	module_put(bridge->driver->owner);
 }
 EXPORT_SYMBOL_GPL(agp_remove_bridge);
diff -Nru a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c
--- a/drivers/char/agp/frontend.c	2004-12-09 20:46:37 -08:00
+++ b/drivers/char/agp/frontend.c	2004-12-09 20:46:37 -08:00
@@ -1,5 +1,6 @@
 /*
  * AGPGART driver frontend
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2003 Dave Jones
  * Copyright (C) 1999 Jeff Hartmann
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -292,14 +293,14 @@
 static void agp_free_memory_wrap(struct agp_memory *memory)
 {
 	agp_remove_from_pool(memory);
-	agp_free_memory(memory);
+	agp_free_memory(agp_bridge, memory);
 }
 
 static struct agp_memory *agp_allocate_memory_wrap(size_t pg_count, u32 type)
 {
 	struct agp_memory *memory;
 
-	memory = agp_allocate_memory(pg_count, type);
+	memory = agp_allocate_memory(agp_bridge, pg_count, type);
 	if (memory == NULL)
 		return NULL;
 
@@ -420,7 +421,7 @@
 	if (agp_fe.current_controller == controller) {
 		agp_fe.current_controller = NULL;
 		agp_fe.backend_acquired = FALSE;
-		agp_backend_release();
+		agp_backend_release(agp_bridge);
 	}
 	kfree(controller);
 	return 0;
@@ -468,7 +469,7 @@
 
 	agp_fe.current_controller = NULL;
 	agp_fe.used_by_controller = FALSE;
-	agp_backend_release();
+	agp_backend_release(agp_bridge);
 }
 
 /* 
@@ -605,7 +606,7 @@
 	if (!(test_bit(AGP_FF_IS_VALID, &priv->access_flags)))
 		goto out_eperm;
 
-	agp_copy_info(&kerninfo);
+	agp_copy_info(agp_bridge, &kerninfo);
 	size = vma->vm_end - vma->vm_start;
 	current_size = kerninfo.aper_size;
 	current_size = current_size * 0x100000;
@@ -757,7 +758,7 @@
 	struct agp_info userinfo;
 	struct agp_kern_info kerninfo;
 
-	agp_copy_info(&kerninfo);
+	agp_copy_info(agp_bridge, &kerninfo);
 
 	userinfo.version.major = kerninfo.version.major;
 	userinfo.version.minor = kerninfo.version.minor;
@@ -777,7 +778,6 @@
 
 static int agpioc_acquire_wrap(struct agp_file_private *priv)
 {
-	int ret;
 	struct agp_controller *controller;
 
 	DBG("");
@@ -788,11 +788,15 @@
 	if (agp_fe.current_controller != NULL)
 		return -EBUSY;
 
-	ret = agp_backend_acquire();
-	if (ret == 0)
-		agp_fe.backend_acquired = TRUE;
-	else
-		return ret;
+	if(!agp_bridge)
+		return -ENODEV;
+
+        if (atomic_read(&agp_bridge->agp_in_use))
+                return -EBUSY;
+
+	atomic_inc(&agp_bridge->agp_in_use);
+
+	agp_fe.backend_acquired = TRUE;
 
 	controller = agp_find_controller_by_pid(priv->my_pid);
 
@@ -803,7 +807,7 @@
 
 		if (controller == NULL) {
 			agp_fe.backend_acquired = FALSE;
-			agp_backend_release();
+			agp_backend_release(agp_bridge);
 			return -ENOMEM;
 		}
 		agp_insert_controller(controller);
@@ -830,7 +834,7 @@
 	if (copy_from_user(&mode, arg, sizeof(struct agp_setup)))
 		return -EFAULT;
 
-	agp_enable(mode.agp_mode);
+	agp_enable(agp_bridge, mode.agp_mode);
 	return 0;
 }
 
@@ -961,7 +965,7 @@
 	if (memory == NULL)
 		return -EINVAL;
 
-	return agp_bind_memory(memory, bind_info.pg_start);
+	return agp_bind_memory(agp_bridge, memory, bind_info.pg_start);
 }
 
 static int agpioc_unbind_wrap(struct agp_file_private *priv, void __user *arg)
@@ -978,7 +982,7 @@
 	if (memory == NULL)
 		return -EINVAL;
 
-	return agp_unbind_memory(memory);
+	return agp_unbind_memory(agp_bridge, memory);
 }
 
 static int agp_ioctl(struct inode *inode, struct file *file,
diff -Nru a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
--- a/drivers/char/agp/generic.c	2004-12-09 20:46:37 -08:00
+++ b/drivers/char/agp/generic.c	2004-12-09 20:46:37 -08:00
@@ -1,5 +1,6 @@
 /*
  * AGPGART driver.
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2004 Dave Jones.
  * Copyright (C) 1999 Jeff Hartmann.
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -112,23 +113,23 @@
  *	It is the only function that can be called when the backend is not owned
  *	by the caller.  (So it can free memory on client death.)
  */
-void agp_free_memory(struct agp_memory *curr)
+void agp_free_memory(struct agp_bridge_data *bridge, struct agp_memory *curr)
 {
 	size_t i;
 
-	if ((agp_bridge->type == NOT_SUPPORTED) || (curr == NULL))
+	if ((bridge == NULL) || (curr == NULL))
 		return;
 
 	if (curr->is_bound == TRUE)
-		agp_unbind_memory(curr);
+		agp_unbind_memory(bridge, curr);
 
 	if (curr->type != 0) {
-		agp_bridge->driver->free_by_type(curr);
+		bridge->driver->free_by_type(curr);
 		return;
 	}
 	if (curr->page_count != 0) {
 		for (i = 0; i < curr->page_count; i++) {
-			agp_bridge->driver->agp_destroy_page(phys_to_virt(curr->memory[i]));
+			bridge->driver->agp_destroy_page(phys_to_virt(curr->memory[i]));
 		}
 	}
 	agp_free_key(curr->key);
@@ -150,20 +151,20 @@
  *
  *	It returns NULL whenever memory is unavailable.
  */
-struct agp_memory *agp_allocate_memory(size_t page_count, u32 type)
+struct agp_memory *agp_allocate_memory(struct agp_bridge_data *bridge, size_t page_count, u32 type)
 {
 	int scratch_pages;
 	struct agp_memory *new;
 	size_t i;
 
-	if (agp_bridge->type == NOT_SUPPORTED)
+	if (!bridge)
 		return NULL;
 
-	if ((atomic_read(&agp_bridge->current_memory_agp) + page_count) > agp_bridge->max_memory_agp)
+	if ((atomic_read(&bridge->current_memory_agp) + page_count) > bridge->max_memory_agp)
 		return NULL;
 
 	if (type != 0) {
-		new = agp_bridge->driver->alloc_by_type(page_count, type);
+		new = bridge->driver->alloc_by_type(page_count, type);
 		return new;
 	}
 
@@ -175,14 +176,14 @@
 		return NULL;
 
 	for (i = 0; i < page_count; i++) {
-		void *addr = agp_bridge->driver->agp_alloc_page();
+		void *addr = bridge->driver->agp_alloc_page();
 
 		if (addr == NULL) {
-			agp_free_memory(new);
+			agp_free_memory(bridge, new);
 			return NULL;
 		}
 		new->memory[i] =
-			agp_bridge->driver->mask_memory(virt_to_phys(addr), type);
+			bridge->driver->mask_memory(virt_to_phys(addr), type);
 		new->page_count++;
 	}
 
@@ -196,14 +197,14 @@
 /* End - Generic routines for handling agp_memory structures */
 
 
-static int agp_return_size(void)
+static int agp_return_size(struct agp_bridge_data *bridge)
 {
 	int current_size;
 	void *temp;
 
-	temp = agp_bridge->current_size;
+	temp = bridge->current_size;
 
-	switch (agp_bridge->driver->size_type) {
+	switch (bridge->driver->size_type) {
 	case U8_APER_SIZE:
 		current_size = A_SIZE_8(temp)->size;
 		break;
@@ -275,26 +276,25 @@
  *	This function copies information about the agp bridge device and the state of
  *	the agp backend into an agp_kern_info pointer.
  */
-int agp_copy_info(struct agp_kern_info *info)
+int agp_copy_info(struct agp_bridge_data *bridge, struct agp_kern_info *info)
 {
 	memset(info, 0, sizeof(struct agp_kern_info));
-	if (!agp_bridge || agp_bridge->type == NOT_SUPPORTED ||
-	    !agp_bridge->version) {
+	if (!bridge) {
 		info->chipset = NOT_SUPPORTED;
 		return -EIO;
 	}
 
-	info->version.major = agp_bridge->version->major;
-	info->version.minor = agp_bridge->version->minor;
-	info->chipset = agp_bridge->type;
-	info->device = agp_bridge->dev;
-	info->mode = agp_bridge->mode;
-	info->aper_base = agp_bridge->gart_bus_addr;
-	info->aper_size = agp_return_size();
-	info->max_memory = agp_bridge->max_memory_agp;
-	info->current_memory = atomic_read(&agp_bridge->current_memory_agp);
-	info->cant_use_aperture = agp_bridge->driver->cant_use_aperture;
-	info->vm_ops = agp_bridge->vm_ops;
+	info->version.major = bridge->version->major;
+	info->version.minor = bridge->version->minor;
+	info->chipset = SUPPORTED;
+	info->device = bridge->dev;
+	info->mode = bridge->mode;
+	info->aper_base = bridge->gart_bus_addr;
+	info->aper_size = agp_return_size(bridge);
+	info->max_memory = bridge->max_memory_agp;
+	info->current_memory = atomic_read(&bridge->current_memory_agp);
+	info->cant_use_aperture = bridge->driver->cant_use_aperture;
+	info->vm_ops = bridge->vm_ops;
 	info->page_mask = ~0UL;
 	return 0;
 }
@@ -319,11 +319,11 @@
  *	It returns -EINVAL if the pointer == NULL.
  *	It returns -EBUSY if the area of the table requested is already in use.
  */
-int agp_bind_memory(struct agp_memory *curr, off_t pg_start)
+int agp_bind_memory(struct agp_bridge_data *bridge, struct agp_memory *curr, off_t pg_start)
 {
 	int ret_val;
 
-	if ((agp_bridge->type == NOT_SUPPORTED) || (curr == NULL))
+	if ((bridge == NULL) || (curr == NULL))
 		return -EINVAL;
 
 	if (curr->is_bound == TRUE) {
@@ -331,10 +331,10 @@
 		return -EINVAL;
 	}
 	if (curr->is_flushed == FALSE) {
-		agp_bridge->driver->cache_flush();
+		bridge->driver->cache_flush();
 		curr->is_flushed = TRUE;
 	}
-	ret_val = agp_bridge->driver->insert_memory(curr, pg_start, curr->type);
+	ret_val = bridge->driver->insert_memory(curr, pg_start, curr->type);
 
 	if (ret_val != 0)
 		return ret_val;
@@ -354,11 +354,11 @@
  * It returns -EINVAL if this piece of agp_memory is not currently bound to
  * the graphics aperture translation table or if the agp_memory pointer == NULL
  */
-int agp_unbind_memory(struct agp_memory *curr)
+int agp_unbind_memory(struct agp_bridge_data *bridge, struct agp_memory *curr)
 {
 	int ret_val;
 
-	if ((agp_bridge->type == NOT_SUPPORTED) || (curr == NULL))
+	if ((bridge == NULL) || (curr == NULL))
 		return -EINVAL;
 
 	if (curr->is_bound != TRUE) {
@@ -366,7 +366,7 @@
 		return -EINVAL;
 	}
 
-	ret_val = agp_bridge->driver->remove_memory(curr, curr->pg_start, curr->type);
+	ret_val = bridge->driver->remove_memory(curr, curr->pg_start, curr->type);
 
 	if (ret_val != 0)
 		return ret_val;
@@ -949,14 +949,25 @@
  *
  * @mode:	agp mode register value to configure with.
  */
-void agp_enable(u32 mode)
+void agp_enable(struct agp_bridge_data *bridge, u32 mode)
 {
-	if (agp_bridge->type == NOT_SUPPORTED)
+	if (!bridge)
 		return;
-	agp_bridge->driver->agp_enable(mode);
+	bridge->driver->agp_enable(mode);
 }
 EXPORT_SYMBOL(agp_enable);
 
+/* When we remove the global variable agp_bridge from all drivers 
+ * then agp_alloc_bridge and agp_generic_find_bridge need to be updated
+ */
+
+struct agp_bridge_data *agp_generic_find_bridge(struct pci_dev *pdev)
+{
+	if (list_empty(&agp_bridges))
+		return NULL;
+
+	return agp_bridge;
+}
 
 #ifdef CONFIG_SMP
 static void ipi_handler(void *null)
diff -Nru a/include/linux/agp_backend.h b/include/linux/agp_backend.h
--- a/include/linux/agp_backend.h	2004-12-09 20:46:37 -08:00
+++ b/include/linux/agp_backend.h	2004-12-09 20:46:37 -08:00
@@ -1,6 +1,7 @@
 /*
  * AGPGART backend specific includes. Not for userspace consumption.
  *
+ * Copyright (C) 2004 Silicon Graphics, Inc.
  * Copyright (C) 2002-2003 Dave Jones
  * Copyright (C) 1999 Jeff Hartmann
  * Copyright (C) 1999 Precision Insight, Inc.
@@ -87,14 +88,17 @@
 
 #define AGP_NORMAL_MEMORY 0
 
-extern void agp_free_memory(struct agp_memory *);
-extern struct agp_memory *agp_allocate_memory(size_t, u32);
-extern int agp_copy_info(struct agp_kern_info *);
-extern int agp_bind_memory(struct agp_memory *, off_t);
-extern int agp_unbind_memory(struct agp_memory *);
-extern void agp_enable(u32);
-extern int agp_backend_acquire(void);
-extern void agp_backend_release(void);
+extern struct agp_bridge_data *agp_bridge;
+extern struct list_head agp_bridges;
+
+extern void agp_free_memory(struct agp_bridge_data *, struct agp_memory *);
+extern struct agp_memory *agp_allocate_memory(struct agp_bridge_data *, size_t, u32);
+extern int agp_copy_info(struct agp_bridge_data *, struct agp_kern_info *);
+extern int agp_bind_memory(struct agp_bridge_data *, struct agp_memory *, off_t);
+extern int agp_unbind_memory(struct agp_bridge_data *, struct agp_memory *);
+extern void agp_enable(struct agp_bridge_data *, u32);
+extern struct agp_bridge_data *agp_backend_acquire(struct pci_dev *);
+extern void agp_backend_release(struct agp_bridge_data *);
 
 /*
  * Interface between drm and agp code.  When agp initializes, it makes
@@ -102,14 +106,14 @@
  * use it.  Keith Owens <kaos@ocs.com.au> 28 Oct 2000.
  */
 typedef struct {
-	void			(*free_memory)(struct agp_memory *);
-	struct agp_memory *	(*allocate_memory)(size_t, u32);
-	int			(*bind_memory)(struct agp_memory *, off_t);
-	int			(*unbind_memory)(struct agp_memory *);
-	void			(*enable)(u32);
-	int			(*acquire)(void);
-	void			(*release)(void);
-	int			(*copy_info)(struct agp_kern_info *);
+	void			(*free_memory)(struct agp_bridge_data *, struct agp_memory *);
+	struct agp_memory *	(*allocate_memory)(struct agp_bridge_data *, size_t, u32);
+	int			(*bind_memory)(struct agp_bridge_data *, struct agp_memory *, off_t);
+	int			(*unbind_memory)(struct agp_bridge_data *, struct agp_memory *);
+	void			(*enable)(struct agp_bridge_data *, u32);
+	struct agp_bridge_data *(*acquire)(struct pci_dev *);
+	void			(*release)(struct agp_bridge_data *);
+	int			(*copy_info)(struct agp_bridge_data *, struct agp_kern_info *);
 } drm_agp_t;
 
 extern const drm_agp_t *drm_agp_p;