[PATCH 5/6] drm/radeon: add VRAM debugfs access

[Alex Deucher]

On Thu, Dec 12, 2013 at 8:35 AM, Christian König
<deathsimple at vodafone.de> wrote:
> Am 12.12.2013 14:31, schrieb Alex Deucher:
>
>> On Thu, Dec 12, 2013 at 3:42 AM, Christian König
>> <deathsimple at vodafone.de> wrote:
>>>
>>> From: Christian König <christian.koenig at amd.com>
>>>
>>> Not very fast, but makes it possible to access even the
>>> normally inaccessible parts of VRAM from userspace.
>>>
>>> Signed-off-by: Christian König <christian.koenig at amd.com>
>>> ---
>>>   drivers/gpu/drm/radeon/radeon.h     |  4 +++
>>>   drivers/gpu/drm/radeon/radeon_ttm.c | 72
>>> ++++++++++++++++++++++++++++++++++++-
>>>   2 files changed, 75 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/radeon/radeon.h
>>> b/drivers/gpu/drm/radeon/radeon.h
>>> index b1f990d..49f210c1 100644
>>> --- a/drivers/gpu/drm/radeon/radeon.h
>>> +++ b/drivers/gpu/drm/radeon/radeon.h
>>> @@ -413,6 +413,10 @@ struct radeon_mman {
>>>          struct ttm_bo_device            bdev;
>>>          bool                            mem_global_referenced;
>>>          bool                            initialized;
>>> +
>>> +#if defined(CONFIG_DEBUG_FS)
>>> +       struct dentry                   *vram;
>>> +#endif
>>>   };
>>>
>>>   /* bo virtual address in a specific vm */
>>> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c
>>> b/drivers/gpu/drm/radeon/radeon_ttm.c
>>> index a2d6c4f..f5e8eed 100644
>>> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
>>> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
>>> @@ -39,12 +39,14 @@
>>>   #include <linux/seq_file.h>
>>>   #include <linux/slab.h>
>>>   #include <linux/swiotlb.h>
>>> +#include <linux/debugfs.h>
>>>   #include "radeon_reg.h"
>>>   #include "radeon.h"
>>>
>>>   #define DRM_FILE_PAGE_OFFSET (0x100000000ULL >> PAGE_SHIFT)
>>>
>>>   static int radeon_ttm_debugfs_init(struct radeon_device *rdev);
>>> +static void radeon_ttm_debugfs_fini(struct radeon_device *rdev);
>>>
>>>   static struct radeon_device *radeon_get_rdev(struct ttm_bo_device
>>> *bdev)
>>>   {
>>> @@ -753,6 +755,7 @@ void radeon_ttm_fini(struct radeon_device *rdev)
>>>
>>>          if (!rdev->mman.initialized)
>>>                  return;
>>> +       radeon_ttm_debugfs_fini(rdev);
>>>          if (rdev->stollen_vga_memory) {
>>>                  r = radeon_bo_reserve(rdev->stollen_vga_memory, false);
>>>                  if (r == 0) {
>>> @@ -862,12 +865,70 @@ static struct drm_info_list
>>> radeon_ttm_debugfs_list[] = {
>>>   #endif
>>>   };
>>>
>>> +static int radeon_ttm_mem_open(struct inode *inode, struct file *filep)
>>> +{
>>> +       filep->private_data = inode->i_private;
>>> +       return 0;
>>> +}
>>> +
>>> +static ssize_t radeon_ttm_vram_read(struct file *f, char __user *buf,
>>> +                                   size_t size, loff_t *pos)
>>> +{
>>> +       struct radeon_device *rdev = f->private_data;
>>> +       ssize_t result = 0;
>>> +       int r;
>>> +
>>> +       if (size & 0x3 || *pos & 0x3)
>>> +               return -EINVAL;
>>> +
>>> +       while (size) {
>>> +               unsigned long flags;
>>> +               uint32_t value;
>>> +
>>> +               if (*pos >= rdev->mc.mc_vram_size || *pos >= 0x7FFFFFFF)
>>> +                       return result;
>>> +
>>> +               spin_lock_irqsave(&rdev->mmio_idx_lock, flags);
>>> +               WREG32(RADEON_MM_INDEX, ((uint32_t)*pos) | 0x80000000);
>>
>> Starting with evergreen dGPUs, there is also an MM_INDEX_HI register
>> at 0x18 for accessing addresses over 30 bits.
>
>
> I know, but I wanted to keep that as simple and stupid as possible. I mean
> this code should work from r100 till CIK and except for HAINAN do we really
> have cards with more than 2GB or ram?

Most Hawaii boards are shipping with 4GB and a number of workstation
cards have large amounts of memory.

Alex

>
> And I'm not even sure if radeon_ttm is the right place for this.
>
> Christian.
>
>
>>
>> Alex
>>
>>
>>> +               value = RREG32(RADEON_MM_DATA);
>>> +               spin_unlock_irqrestore(&rdev->mmio_idx_lock, flags);
>>> +
>>> +               r = put_user(value, (uint32_t *)buf);
>>> +               if (r)
>>> +                       return r;
>>> +
>>> +               result += 4;
>>> +               buf += 4;
>>> +               *pos += 4;
>>> +               size -= 4;
>>> +       }
>>> +
>>> +       return result;
>>> +}
>>> +
>>> +static const struct file_operations radeon_ttm_vram_fops = {
>>> +       .owner = THIS_MODULE,
>>> +       .open = radeon_ttm_mem_open,
>>> +       .read = radeon_ttm_vram_read,
>>> +};
>>> +
>>>   #endif
>>>
>>>   static int radeon_ttm_debugfs_init(struct radeon_device *rdev)
>>>   {
>>>   #if defined(CONFIG_DEBUG_FS)
>>> -       unsigned count = ARRAY_SIZE(radeon_ttm_debugfs_list);
>>> +       unsigned count;
>>> +
>>> +       struct drm_minor *minor = rdev->ddev->primary;
>>> +       struct dentry *ent, *root = minor->debugfs_root;
>>> +
>>> +       ent = debugfs_create_file("radeon_vram", S_IFREG | S_IRUGO, root,
>>> +                                 rdev, &radeon_ttm_vram_fops);
>>> +       if (IS_ERR(ent))
>>> +               return PTR_ERR(ent);
>>> +       rdev->mman.vram = ent;
>>> +
>>> +       count = ARRAY_SIZE(radeon_ttm_debugfs_list);
>>>
>>>   #ifdef CONFIG_SWIOTLB
>>>          if (!swiotlb_nr_tbl())
>>> @@ -880,3 +941,12 @@ static int radeon_ttm_debugfs_init(struct
>>> radeon_device *rdev)
>>>          return 0;
>>>   #endif
>>>   }
>>> +
>>> +static void radeon_ttm_debugfs_fini(struct radeon_device *rdev)
>>> +{
>>> +#if defined(CONFIG_DEBUG_FS)
>>> +
>>> +       debugfs_remove(rdev->mman.vram);
>>> +       rdev->mman.vram = NULL;
>>> +#endif
>>> +}
>>> --
>>> 1.8.1.2
>>>
>>> _______________________________________________
>>> dri-devel mailing list
>>> dri-devel at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
>