From 07b7ddd9b7f17a567e3ac2b33a4dffcb2a4524e0 Mon Sep 17 00:00:00 2001 From: Jesse Barnes Date: Wed, 3 Aug 2011 11:28:44 -0700 Subject: [PATCH] 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: Jesse Barnes Signed-off-by: Keith Packard --- drivers/gpu/drm/i915/i915_debugfs.c | 99 +++++++++++++++++++++++++++++ drivers/gpu/drm/i915/i915_reg.h | 8 +++ 2 files changed, 107 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 5bf7bf57c64..a8ab6263e0d 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -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 */ diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 56cae72a520..d1331f771e2 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -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) -- 2.46.0