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drm/i915: allow cache sharing policy control

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Expose the SNB+ cache sharing policy register in debugfs.  The new file,
i915_cache_sharing, has 4 values, 0-3, with 0 being "max uncore
resources" and 3 being the minimum.  Exposing this control should make
benchmarking easier and help us choose a good default.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
This commit is contained in:
Jesse Barnes 2011-08-03 11:28:44 -07:00 committed by Keith Packard
parent c0864cb39c
commit 07b7ddd9b7
2 changed files with 107 additions and 0 deletions
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99
drivers/gpu/drm/i915/i915_debugfs.c
View file

@ -1408,6 +1408,85 @@ static const struct file_operations i915_max_freq_fops = {
.llseek = default_llseek,
};
static int
i915_cache_sharing_open(struct inode *inode,
struct file *filp)
{
filp->private_data = inode->i_private;
return 0;
}
static ssize_t
i915_cache_sharing_read(struct file *filp,
char __user *ubuf,
size_t max,
loff_t *ppos)
{
struct drm_device *dev = filp->private_data;
drm_i915_private_t *dev_priv = dev->dev_private;
char buf[80];
u32 snpcr;
int len;
mutex_lock(&dev_priv->dev->struct_mutex);
snpcr = I915_READ(GEN6_MBCUNIT_SNPCR);
mutex_unlock(&dev_priv->dev->struct_mutex);
len = snprintf(buf, sizeof (buf),
"%d\n", (snpcr & GEN6_MBC_SNPCR_MASK) >>
GEN6_MBC_SNPCR_SHIFT);
if (len > sizeof (buf))
len = sizeof (buf);
return simple_read_from_buffer(ubuf, max, ppos, buf, len);
}
static ssize_t
i915_cache_sharing_write(struct file *filp,
const char __user *ubuf,
size_t cnt,
loff_t *ppos)
{
struct drm_device *dev = filp->private_data;
struct drm_i915_private *dev_priv = dev->dev_private;
char buf[20];
u32 snpcr;
int val = 1;
if (cnt > 0) {
if (cnt > sizeof (buf) - 1)
return -EINVAL;
if (copy_from_user(buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
val = simple_strtoul(buf, NULL, 0);
}
if (val < 0 || val > 3)
return -EINVAL;
DRM_DEBUG_DRIVER("Manually setting uncore sharing to %d\n", val);
/* Update the cache sharing policy here as well */
snpcr = I915_READ(GEN6_MBCUNIT_SNPCR);
snpcr &= ~GEN6_MBC_SNPCR_MASK;
snpcr |= (val << GEN6_MBC_SNPCR_SHIFT);
I915_WRITE(GEN6_MBCUNIT_SNPCR, snpcr);
return cnt;
}
static const struct file_operations i915_cache_sharing_fops = {
.owner = THIS_MODULE,
.open = i915_cache_sharing_open,
.read = i915_cache_sharing_read,
.write = i915_cache_sharing_write,
.llseek = default_llseek,
};
/* As the drm_debugfs_init() routines are called before dev->dev_private is
* allocated we need to hook into the minor for release. */
static int
@ -1522,6 +1601,21 @@ static int i915_max_freq_create(struct dentry *root, struct drm_minor *minor)
return drm_add_fake_info_node(minor, ent, &i915_max_freq_fops);
}
static int i915_cache_sharing_create(struct dentry *root, struct drm_minor *minor)
{
struct drm_device *dev = minor->dev;
struct dentry *ent;
ent = debugfs_create_file("i915_cache_sharing",
S_IRUGO | S_IWUSR,
root, dev,
&i915_cache_sharing_fops);
if (IS_ERR(ent))
return PTR_ERR(ent);
return drm_add_fake_info_node(minor, ent, &i915_cache_sharing_fops);
}
static struct drm_info_list i915_debugfs_list[] = {
{"i915_capabilities", i915_capabilities, 0},
{"i915_gem_objects", i915_gem_object_info, 0},
@ -1576,6 +1670,9 @@ int i915_debugfs_init(struct drm_minor *minor)
if (ret)
return ret;
ret = i915_max_freq_create(minor->debugfs_root, minor);
if (ret)
return ret;
ret = i915_cache_sharing_create(minor->debugfs_root, minor);
if (ret)
return ret;
@ -1594,6 +1691,8 @@ void i915_debugfs_cleanup(struct drm_minor *minor)
1, minor);
drm_debugfs_remove_files((struct drm_info_list *) &i915_max_freq_fops,
1, minor);
drm_debugfs_remove_files((struct drm_info_list *) &i915_cache_sharing_fops,
1, minor);
}
#endif /* CONFIG_DEBUG_FS */

8
drivers/gpu/drm/i915/i915_reg.h
View file

@ -78,6 +78,14 @@
#define GRDOM_RENDER (1<<2)
#define GRDOM_MEDIA (3<<2)
#define GEN6_MBCUNIT_SNPCR 0x900c /* for LLC config */
#define GEN6_MBC_SNPCR_SHIFT 21
#define GEN6_MBC_SNPCR_MASK (3<<21)
#define GEN6_MBC_SNPCR_MAX (0<<21)
#define GEN6_MBC_SNPCR_MED (1<<21)
#define GEN6_MBC_SNPCR_LOW (2<<21)
#define GEN6_MBC_SNPCR_MIN (3<<21) /* only 1/16th of the cache is shared */
#define GEN6_GDRST 0x941c
#define GEN6_GRDOM_FULL (1 << 0)
#define GEN6_GRDOM_RENDER (1 << 1)