[PATCH 4/4] drm/i915: l3 parity sysfs interface

Ben Widawsky
2012-05-25T23:58:25Z

Dumb binary interfaces which allow root-only updates of the cache
remapping registers. As mentioned in a previous patch, software using
this interface needs to know about HW limits, and other programming
considerations as the kernel interface does no checking for these things
on the root-only interface.

v1: Drop extra posting reads (Chris)
Return negative values in the sysfs interfaces on errors (Chris)

v2: Return -EINVAL for offset % 4 (Jesse)
Move schizo userspace check out (Jesse)
Cleaner sysfs item initializers (Daniel)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
drivers/gpu/drm/i915/i915_sysfs.c | 121 ++++++++++++++++++++++++++++++++++++-
1 file changed, 119 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 79f8344..c201327 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -29,6 +29,7 @@
#include <linux/module.h>
#include <linux/stat.h>
#include <linux/sysfs.h>
+#include "intel_drv.h"
#include "i915_drv.h"

static u32 calc_residency(struct drm_device *dev, const u32 reg)
@@ -92,20 +93,136 @@ static struct attribute_group rc6_attr_group = {
.attrs = rc6_attrs
};

+static int l3_access_valid(struct drm_device *dev, loff_t offset)
+{
+ if (!IS_IVYBRIDGE(dev))
+ return -EPERM;
+
+ if (offset % 4 != 0)
+ return -EINVAL;
+
+ if (offset >= GEN7_L3LOG_SIZE)
+ return -ENXIO;
+
+ return 0;
+}
+
+static ssize_t
+i915_l3_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf,
+ loff_t offset, size_t count)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct drm_minor *dminor = container_of(dev, struct drm_minor, kdev);
+ struct drm_device *drm_dev = dminor->dev;
+ struct drm_i915_private *dev_priv = drm_dev->dev_private;
+ uint32_t misccpctl;
+ int i, ret;
+
+ ret = l3_access_valid(drm_dev, offset);
+ if (ret)
+ return ret;
+
+ ret = i915_mutex_lock_interruptible(drm_dev);
+ if (ret)
+ return ret;
+
+ misccpctl = I915_READ(GEN7_MISCCPCTL);
+ I915_WRITE(GEN7_MISCCPCTL, misccpctl & ~GEN7_DOP_CLOCK_GATE_ENABLE);
+
+ for (i = offset; count >= 4 && i < GEN7_L3LOG_SIZE; i += 4, count -= 4)
+ *((uint32_t *)(&buf[i])) = I915_READ(GEN7_L3LOG_BASE + i);
+
+ I915_WRITE(GEN7_MISCCPCTL, misccpctl);
+
+ mutex_unlock(&drm_dev->struct_mutex);
+
+ return i - offset;
+}
+
+static ssize_t
+i915_l3_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr, char *buf,
+ loff_t offset, size_t count)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct drm_minor *dminor = container_of(dev, struct drm_minor, kdev);
+ struct drm_device *drm_dev = dminor->dev;
+ struct drm_i915_private *dev_priv = drm_dev->dev_private;
+ u32 *temp = NULL; /* Just here to make handling failures easy */
+ int ret;
+
+ ret = l3_access_valid(drm_dev, offset);
+ if (ret)
+ return ret;
+
+ ret = i915_mutex_lock_interruptible(drm_dev);
+ if (ret)
+ return ret;
+
+ if (!dev_priv->mm.l3_remap_info) {
+ temp = kzalloc(GEN7_L3LOG_SIZE, GFP_KERNEL);
+ if (!temp) {
+ mutex_unlock(&drm_dev->struct_mutex);
+ return -ENOMEM;
+ }
+ }
+
+ ret = i915_gpu_idle(drm_dev);
+ if (ret) {
+ kfree(temp);
+ mutex_unlock(&drm_dev->struct_mutex);
+ return ret;
+ }
+
+ /* TODO: Ideally we really want a GPU reset here to make sure errors
+ * aren't propagated. Since I cannot find a stable way to reset the GPU
+ * at this point it is left as a TODO.
+ */
+ if (temp)
+ dev_priv->mm.l3_remap_info = temp;
+
+ memcpy(dev_priv->mm.l3_remap_info + (offset/4),
+ buf + (offset/4),
+ count);
+
+ i915_gem_l3_remap(drm_dev);
+
+ mutex_unlock(&drm_dev->struct_mutex);
+
+ return count;
+}
+
+static struct bin_attribute dpf_attrs = {
+ .attr = {.name = "l3_parity", .mode = (S_IRUSR | S_IWUSR)},
+ .size = GEN7_L3LOG_SIZE,
+ .read = i915_l3_read,
+ .write = i915_l3_write,
+ .mmap = NULL
+};
+
void i915_setup_sysfs(struct drm_device *dev)
{
int ret;

- /* ILK doesn't have any residency information */
+ /* ILK and below don't yet have relevant sysfs files */
if (INTEL_INFO(dev)->gen < 6)
return;

ret = sysfs_merge_group(&dev->primary->kdev.kobj, &rc6_attr_group);
if (ret)
- DRM_ERROR("sysfs setup failed\n");
+ DRM_ERROR("RC6 residency sysfs setup failed\n");
+
+ if (!IS_IVYBRIDGE(dev))
+ return;
+
+ ret = device_create_bin_file(&dev->primary->kdev, &dpf_attrs);
+ if (ret)
+ DRM_ERROR("l3 parity sysfs setup failed\n");
}

void i915_teardown_sysfs(struct drm_device *dev)
{
+ device_remove_bin_file(&dev->primary->kdev, &dpf_attrs);
sysfs_unmerge_group(&dev->primary->kdev.kobj, &rc6_attr_group);
}
--
1.7.10.2