linux/drivers/gpu/drm/ttm/ttm_bo_vm.c
Jerome Glisse 82c5da6bf8 drm/ttm: ttm_fault callback to allow driver to handle bo placement V6
On fault the driver is given the opportunity to perform any operation
it sees fit in order to place the buffer into a CPU visible area of
memory. This patch doesn't break TTM users, nouveau, vmwgfx and radeon
should keep working properly. Future patch will take advantage of this
infrastructure and remove the old path from TTM once driver are
converted.

V2 return VM_FAULT_NOPAGE if callback return -EBUSY or -ERESTARTSYS
V3 balance io_mem_reserve and io_mem_free call, fault_reserve_notify
   is responsible to perform any necessary task for mapping to succeed
V4 minor cleanup, atomic_t -> bool as member is protected by reserve
   mecanism from concurent access
V5 the callback is now responsible for iomapping the bo and providing
   a virtual address this simplify TTM and will allow to get rid of
   TTM_MEMTYPE_FLAG_NEEDS_IOREMAP
V6 use the bus addr data to decide to ioremap or this isn't needed
   but we don't necesarily need to ioremap in the callback but still
   allow driver to use static mapping

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-04-20 14:12:05 +10:00

453 lines
11 KiB
C

/**************************************************************************
*
* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/*
* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
*/
#include <ttm/ttm_module.h>
#include <ttm/ttm_bo_driver.h>
#include <ttm/ttm_placement.h>
#include <linux/mm.h>
#include <linux/rbtree.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#define TTM_BO_VM_NUM_PREFAULT 16
static struct ttm_buffer_object *ttm_bo_vm_lookup_rb(struct ttm_bo_device *bdev,
unsigned long page_start,
unsigned long num_pages)
{
struct rb_node *cur = bdev->addr_space_rb.rb_node;
unsigned long cur_offset;
struct ttm_buffer_object *bo;
struct ttm_buffer_object *best_bo = NULL;
while (likely(cur != NULL)) {
bo = rb_entry(cur, struct ttm_buffer_object, vm_rb);
cur_offset = bo->vm_node->start;
if (page_start >= cur_offset) {
cur = cur->rb_right;
best_bo = bo;
if (page_start == cur_offset)
break;
} else
cur = cur->rb_left;
}
if (unlikely(best_bo == NULL))
return NULL;
if (unlikely((best_bo->vm_node->start + best_bo->num_pages) <
(page_start + num_pages)))
return NULL;
return best_bo;
}
static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
vma->vm_private_data;
struct ttm_bo_device *bdev = bo->bdev;
unsigned long page_offset;
unsigned long page_last;
unsigned long pfn;
struct ttm_tt *ttm = NULL;
struct page *page;
int ret;
int i;
unsigned long address = (unsigned long)vmf->virtual_address;
int retval = VM_FAULT_NOPAGE;
/*
* Work around locking order reversal in fault / nopfn
* between mmap_sem and bo_reserve: Perform a trylock operation
* for reserve, and if it fails, retry the fault after scheduling.
*/
ret = ttm_bo_reserve(bo, true, true, false, 0);
if (unlikely(ret != 0)) {
if (ret == -EBUSY)
set_need_resched();
return VM_FAULT_NOPAGE;
}
if (bdev->driver->fault_reserve_notify) {
ret = bdev->driver->fault_reserve_notify(bo);
switch (ret) {
case 0:
break;
case -EBUSY:
set_need_resched();
case -ERESTARTSYS:
retval = VM_FAULT_NOPAGE;
goto out_unlock;
default:
retval = VM_FAULT_SIGBUS;
goto out_unlock;
}
}
/*
* Wait for buffer data in transit, due to a pipelined
* move.
*/
spin_lock(&bo->lock);
if (test_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags)) {
ret = ttm_bo_wait(bo, false, true, false);
spin_unlock(&bo->lock);
if (unlikely(ret != 0)) {
retval = (ret != -ERESTARTSYS) ?
VM_FAULT_SIGBUS : VM_FAULT_NOPAGE;
goto out_unlock;
}
} else
spin_unlock(&bo->lock);
ret = ttm_mem_io_reserve(bdev, &bo->mem);
if (ret) {
retval = VM_FAULT_SIGBUS;
goto out_unlock;
}
page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
bo->vm_node->start - vma->vm_pgoff;
page_last = ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) +
bo->vm_node->start - vma->vm_pgoff;
if (unlikely(page_offset >= bo->num_pages)) {
retval = VM_FAULT_SIGBUS;
goto out_unlock;
}
/*
* Strictly, we're not allowed to modify vma->vm_page_prot here,
* since the mmap_sem is only held in read mode. However, we
* modify only the caching bits of vma->vm_page_prot and
* consider those bits protected by
* the bo->mutex, as we should be the only writers.
* There shouldn't really be any readers of these bits except
* within vm_insert_mixed()? fork?
*
* TODO: Add a list of vmas to the bo, and change the
* vma->vm_page_prot when the object changes caching policy, with
* the correct locks held.
*/
if (bo->mem.bus.is_iomem) {
vma->vm_page_prot = ttm_io_prot(bo->mem.placement,
vma->vm_page_prot);
} else {
ttm = bo->ttm;
vma->vm_page_prot = (bo->mem.placement & TTM_PL_FLAG_CACHED) ?
vm_get_page_prot(vma->vm_flags) :
ttm_io_prot(bo->mem.placement, vma->vm_page_prot);
}
/*
* Speculatively prefault a number of pages. Only error on
* first page.
*/
for (i = 0; i < TTM_BO_VM_NUM_PREFAULT; ++i) {
if (bo->mem.bus.is_iomem)
pfn = ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT) + page_offset;
else {
page = ttm_tt_get_page(ttm, page_offset);
if (unlikely(!page && i == 0)) {
retval = VM_FAULT_OOM;
goto out_unlock;
} else if (unlikely(!page)) {
break;
}
pfn = page_to_pfn(page);
}
ret = vm_insert_mixed(vma, address, pfn);
/*
* Somebody beat us to this PTE or prefaulting to
* an already populated PTE, or prefaulting error.
*/
if (unlikely((ret == -EBUSY) || (ret != 0 && i > 0)))
break;
else if (unlikely(ret != 0)) {
retval =
(ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
goto out_unlock;
}
address += PAGE_SIZE;
if (unlikely(++page_offset >= page_last))
break;
}
out_unlock:
ttm_bo_unreserve(bo);
return retval;
}
static void ttm_bo_vm_open(struct vm_area_struct *vma)
{
struct ttm_buffer_object *bo =
(struct ttm_buffer_object *)vma->vm_private_data;
(void)ttm_bo_reference(bo);
}
static void ttm_bo_vm_close(struct vm_area_struct *vma)
{
struct ttm_buffer_object *bo = (struct ttm_buffer_object *)vma->vm_private_data;
ttm_bo_unref(&bo);
vma->vm_private_data = NULL;
}
static const struct vm_operations_struct ttm_bo_vm_ops = {
.fault = ttm_bo_vm_fault,
.open = ttm_bo_vm_open,
.close = ttm_bo_vm_close
};
int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
struct ttm_bo_device *bdev)
{
struct ttm_bo_driver *driver;
struct ttm_buffer_object *bo;
int ret;
read_lock(&bdev->vm_lock);
bo = ttm_bo_vm_lookup_rb(bdev, vma->vm_pgoff,
(vma->vm_end - vma->vm_start) >> PAGE_SHIFT);
if (likely(bo != NULL))
ttm_bo_reference(bo);
read_unlock(&bdev->vm_lock);
if (unlikely(bo == NULL)) {
printk(KERN_ERR TTM_PFX
"Could not find buffer object to map.\n");
return -EINVAL;
}
driver = bo->bdev->driver;
if (unlikely(!driver->verify_access)) {
ret = -EPERM;
goto out_unref;
}
ret = driver->verify_access(bo, filp);
if (unlikely(ret != 0))
goto out_unref;
vma->vm_ops = &ttm_bo_vm_ops;
/*
* Note: We're transferring the bo reference to
* vma->vm_private_data here.
*/
vma->vm_private_data = bo;
vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
return 0;
out_unref:
ttm_bo_unref(&bo);
return ret;
}
EXPORT_SYMBOL(ttm_bo_mmap);
int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
{
if (vma->vm_pgoff != 0)
return -EACCES;
vma->vm_ops = &ttm_bo_vm_ops;
vma->vm_private_data = ttm_bo_reference(bo);
vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
return 0;
}
EXPORT_SYMBOL(ttm_fbdev_mmap);
ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
const char __user *wbuf, char __user *rbuf, size_t count,
loff_t *f_pos, bool write)
{
struct ttm_buffer_object *bo;
struct ttm_bo_driver *driver;
struct ttm_bo_kmap_obj map;
unsigned long dev_offset = (*f_pos >> PAGE_SHIFT);
unsigned long kmap_offset;
unsigned long kmap_end;
unsigned long kmap_num;
size_t io_size;
unsigned int page_offset;
char *virtual;
int ret;
bool no_wait = false;
bool dummy;
read_lock(&bdev->vm_lock);
bo = ttm_bo_vm_lookup_rb(bdev, dev_offset, 1);
if (likely(bo != NULL))
ttm_bo_reference(bo);
read_unlock(&bdev->vm_lock);
if (unlikely(bo == NULL))
return -EFAULT;
driver = bo->bdev->driver;
if (unlikely(!driver->verify_access)) {
ret = -EPERM;
goto out_unref;
}
ret = driver->verify_access(bo, filp);
if (unlikely(ret != 0))
goto out_unref;
kmap_offset = dev_offset - bo->vm_node->start;
if (unlikely(kmap_offset >= bo->num_pages)) {
ret = -EFBIG;
goto out_unref;
}
page_offset = *f_pos & ~PAGE_MASK;
io_size = bo->num_pages - kmap_offset;
io_size = (io_size << PAGE_SHIFT) - page_offset;
if (count < io_size)
io_size = count;
kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
kmap_num = kmap_end - kmap_offset + 1;
ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
switch (ret) {
case 0:
break;
case -EBUSY:
ret = -EAGAIN;
goto out_unref;
default:
goto out_unref;
}
ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
if (unlikely(ret != 0)) {
ttm_bo_unreserve(bo);
goto out_unref;
}
virtual = ttm_kmap_obj_virtual(&map, &dummy);
virtual += page_offset;
if (write)
ret = copy_from_user(virtual, wbuf, io_size);
else
ret = copy_to_user(rbuf, virtual, io_size);
ttm_bo_kunmap(&map);
ttm_bo_unreserve(bo);
ttm_bo_unref(&bo);
if (unlikely(ret != 0))
return -EFBIG;
*f_pos += io_size;
return io_size;
out_unref:
ttm_bo_unref(&bo);
return ret;
}
ssize_t ttm_bo_fbdev_io(struct ttm_buffer_object *bo, const char __user *wbuf,
char __user *rbuf, size_t count, loff_t *f_pos,
bool write)
{
struct ttm_bo_kmap_obj map;
unsigned long kmap_offset;
unsigned long kmap_end;
unsigned long kmap_num;
size_t io_size;
unsigned int page_offset;
char *virtual;
int ret;
bool no_wait = false;
bool dummy;
kmap_offset = (*f_pos >> PAGE_SHIFT);
if (unlikely(kmap_offset >= bo->num_pages))
return -EFBIG;
page_offset = *f_pos & ~PAGE_MASK;
io_size = bo->num_pages - kmap_offset;
io_size = (io_size << PAGE_SHIFT) - page_offset;
if (count < io_size)
io_size = count;
kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
kmap_num = kmap_end - kmap_offset + 1;
ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
switch (ret) {
case 0:
break;
case -EBUSY:
return -EAGAIN;
default:
return ret;
}
ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
if (unlikely(ret != 0)) {
ttm_bo_unreserve(bo);
return ret;
}
virtual = ttm_kmap_obj_virtual(&map, &dummy);
virtual += page_offset;
if (write)
ret = copy_from_user(virtual, wbuf, io_size);
else
ret = copy_to_user(rbuf, virtual, io_size);
ttm_bo_kunmap(&map);
ttm_bo_unreserve(bo);
ttm_bo_unref(&bo);
if (unlikely(ret != 0))
return ret;
*f_pos += io_size;
return io_size;
}