Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 07b7ddd9 authored by Jesse Barnes's avatar Jesse Barnes Committed by Keith Packard
Browse files

drm/i915: allow cache sharing policy control 



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: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarKeith Packard <keithp@keithp.com>
parent c0864cb3

drivers/gpu/drm/i915/i915_debugfs.c

+99 −0
Original line number Diff line number Diff line
@@ -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 */

drivers/gpu/drm/i915/i915_reg.h

+8 −0
Original line number Diff line number Diff line
@@ -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)