On 2007.04.10 11:12:17 +0000, Andi Kleen wrote:
> > > On Mon, Apr 09, 2007 at 02:55:57PM -0700, Ashok Raj wrote:
> > > > Most GFX drivers don't call standard PCI DMA APIs to allocate DMA
> > > > buffer,
> > > > Such drivers will be broken with IOMMU enabled. To workaround this
> > > > issue,
> > > > we added two options.
> > >
> > > All drm drivers do it. If the usual out of tree crap vendors are too
> > > stupid for their own sake it's their fault.
> > >
> > > So NACK to this patch.
> >
> > That's my feeling as well, everything we care about should be using
> > the proper APIs or else what is the point of them...
>
> They can't. There is no proper API to do IOMMU mappings from user space.
> And that is how Xorg on x86 works.
>
> I had some hackish patches to enable mapping on
> /sys/bus/pci/.../coherent_mem, but
> you need ioctls to pass out the translated address and it wasn't
> exactly pretty. Still also not sure that's the right way.
>
For agpgart based gfx driver, we need to enable dma mapping on agpgart module,
which would work in the IOMMU case. I attach my current patches to do this.
Dave, how do you think about it?
diff --git a/drivers/char/agp/agp.h b/drivers/char/agp/agp.h
index 552815d..0d3312d 100644
--- a/drivers/char/agp/agp.h
+++ b/drivers/char/agp/agp.h
@@ -115,6 +115,9 @@ struct agp_bridge_driver {
void *(*agp_alloc_page)(struct agp_bridge_data *);
void (*agp_destroy_page)(void *);
int (*agp_type_to_mask_type) (struct agp_bridge_data *, int);
+ int (*agp_map_dma_pages)(struct agp_bridge_data *, struct agp_memory*);
+ void (*agp_unmap_dma_pages)(struct agp_bridge_data *,
+ struct agp_memory *);
};
struct agp_bridge_data {
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index f902d71..03a001a 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -112,22 +112,34 @@ void agp_alloc_page_array(size_t size, s
mem->memory = NULL;
mem->vmalloc_flag = 0;
- if (size <= 2*PAGE_SIZE)
+ if (size <= 2*PAGE_SIZE) {
mem->memory = kmalloc(size, GFP_KERNEL | __GFP_NORETRY);
+ mem->dma_memory = kmalloc(size, GFP_KERNEL | __GFP_NORETRY);
+ }
if (mem->memory == NULL) {
mem->memory = vmalloc(size);
- mem->vmalloc_flag = 1;
+ mem->vmalloc_flag = AGP_MEMORY_VMALLOC;
+ }
+ if (mem->dma_memory == NULL) {
+ mem->dma_memory = vmalloc(size);
+ /* XXX this is a little overdo */
+ mem->vmalloc_flag |= AGP_DMA_MEMORY_VMALLOC;
}
}
EXPORT_SYMBOL(agp_alloc_page_array);
void agp_free_page_array(struct agp_memory *mem)
{
- if (mem->vmalloc_flag) {
+ if (mem->vmalloc_flag & AGP_MEMORY_VMALLOC) {
vfree(mem->memory);
} else {
kfree(mem->memory);
}
+ if (mem->vmalloc_flag & AGP_DMA_MEMORY_VMALLOC) {
+ vfree(mem->dma_memory);
+ } else {
+ kfree(mem->dma_memory);
+ }
}
EXPORT_SYMBOL(agp_free_page_array);
@@ -155,6 +167,15 @@ static struct agp_memory *agp_create_use
kfree(new);
return NULL;
}
+ if (new->dma_memory == NULL) {
+ agp_free_key(new->key);
+ if (new->vmalloc_flag)
+ vfree(new->memory);
+ else
+ kfree(new->memory);
+ kfree(new);
+ return NULL;
+ }
new->num_scratch_pages = 0;
return new;
}
@@ -181,6 +202,15 @@ struct agp_memory *agp_create_memory(int
kfree(new);
return NULL;
}
+ if (new->dma_memory == NULL) {
+ agp_free_key(new->key);
+ if (new->vmalloc_flag)
+ vfree(new->memory);
+ else
+ kfree(new->memory);
+ kfree(new);
+ return NULL;
+ }
new->num_scratch_pages = scratch_pages;
new->type = AGP_NORMAL_MEMORY;
return new;
@@ -433,6 +463,13 @@ int agp_bind_memory(struct agp_memory *c
curr->bridge->driver->cache_flush();
curr->is_flushed = TRUE;
}
+
+ if (curr->bridge->driver->agp_map_dma_pages) {
+ if (!curr->bridge->driver->agp_map_dma_pages(curr->bridge,
curr))
+ return -EINVAL;
+ curr->is_dma_mapped = 1;
+ }
+
ret_val = curr->bridge->driver->insert_memory(curr, pg_start,
curr->type);
if (ret_val != 0)
@@ -470,6 +507,10 @@ int agp_unbind_memory(struct agp_memory
if (ret_val != 0)
return ret_val;
+ if (curr->bridge->driver->agp_unmap_dma_pages)
+ curr->bridge->driver->agp_unmap_dma_pages(curr->bridge, curr);
+ curr->is_dma_mapped = 0;
+
curr->is_bound = FALSE;
curr->pg_start = 0;
return 0;
@@ -1094,8 +1135,13 @@ int agp_generic_insert_memory(struct agp
}
for (i = 0, j = pg_start; i < mem->page_count; i++, j++) {
- writel(bridge->driver->mask_memory(bridge, mem->memory[i],
mask_type),
- bridge->gatt_table+j);
+ if (mem->is_dma_mapped)
+ writel(bridge->driver->mask_memory(bridge,
+ mem->dma_memory[i], mask_type),
+ bridge->gatt_table+j);
+ else
+ writel(bridge->driver->mask_memory(bridge,
mem->memory[i], mask_type),
+ bridge->gatt_table+j);
}
readl(bridge->gatt_table+j-1); /* PCI Posting. */
@@ -1356,3 +1406,41 @@ const struct aper_size_info_16 agp3_gene
};
EXPORT_SYMBOL(agp3_generic_sizes);
+int agp_generic_map_dma_pages(struct agp_bridge_data *bridge, struct
agp_memory *mem)
+{
+ struct pci_dev *dev;
+ int i;
+
+ if (!bridge || !mem)
+ return 0;
+ dev = bridge->dev;
+ for (i = 0; i < mem->page_count; i++ ) {
+ mem->dma_memory[i] = pci_map_single(dev,
+ gart_to_virt(mem->memory[i]), PAGE_SIZE,
+ PCI_DMA_BIDIRECTIONAL);
+ if (pci_dma_mapping_error(mem->dma_memory[i])) {
+ int j;
+ for (j = 0; j < i; j++) {
+ pci_unmap_single(dev, mem->dma_memory[j],
+ PAGE_SIZE,
+ PCI_DMA_BIDIRECTIONAL);
+ }
+ return 0;
+ }
+ }
+ return 1;
+}
+
+void agp_generic_unmap_dma_pages(struct agp_bridge_data *bridge, struct
agp_memory *mem)
+{
+ struct pci_dev *dev;
+ int i;
+ if (!bridge || !mem)
+ return;
+ dev = bridge->dev;
+ for (i = 0; i < mem->page_count; i++ )
+ pci_unmap_single(dev, mem->dma_memory[i], PAGE_SIZE,
+ PCI_DMA_BIDIRECTIONAL);
+}
+EXPORT_SYMBOL(agp_generic_map_dma_pages);
+EXPORT_SYMBOL(agp_generic_unmap_dma_pages);
diff --git a/include/linux/agp_backend.h b/include/linux/agp_backend.h
index abc521c..abd2ca6 100644
--- a/include/linux/agp_backend.h
+++ b/include/linux/agp_backend.h
@@ -79,6 +79,8 @@ struct agp_memory {
struct agp_memory *prev;
struct agp_bridge_data *bridge;
unsigned long *memory;
+ dma_addr_t *dma_memory;
+ u8 is_dma_mapped;
size_t page_count;
int key;
int num_scratch_pages;
@@ -90,6 +92,9 @@ struct agp_memory {
u8 vmalloc_flag;
};
+#define AGP_MEMORY_VMALLOC 1
+#define AGP_DMA_MEMORY_VMALLOC 2
+
#define AGP_NORMAL_MEMORY 0
#define AGP_USER_TYPES (1 << 16)
