intel: Export pooled EU and min no. of eus in a pool.

Update kernel interface with new I915_GETPARAM ioctl entries for
pooled EU and min no. of eus in a pool. Add a wrapping function
for each parameter. Userspace drivers need these values when decide
the thread count. This kernel enabled pooled eu by default for BXT
and for fused down 2x6 parts it is advised to turn it off.

But there is another HW issue in these parts (fused
down 2x6 parts) before C0 that requires Pooled EU to be enabled as a
workaround. In this case the pool configuration changes depending upon
which subslice is disabled and the no. of eus in a pool is different,
So userspace need to know min no. of eus in a pool.

V2: use return value as the query results.
    ret < 0 when error, ret = 0 when not support, and ret > 0 indicate
    query results.(Chris)
V3: Correct V2 errors.

Signed-off-by: Yang Rong <rong.r.yang@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

include/drm/i915_drm.h

@@ -357,6 +357,8 @@ typedef struct drm_i915_irq_wait {
 #define I915_PARAM_HAS_GPU_RESET	 35
 #define I915_PARAM_HAS_RESOURCE_STREAMER 36
 #define I915_PARAM_HAS_EXEC_SOFTPIN	 37
+#define I915_PARAM_HAS_POOLED_EU         38
+#define I915_PARAM_MIN_EU_IN_POOL        39
 
 typedef struct drm_i915_getparam {
 	__s32 param;

intel/intel_bufmgr.h

@@ -273,6 +273,9 @@ int drm_intel_get_reset_stats(drm_intel_context *ctx,
 int drm_intel_get_subslice_total(int fd, unsigned int *subslice_total);
 int drm_intel_get_eu_total(int fd, unsigned int *eu_total);
 
+int drm_intel_get_pooled_eu(int fd);
+int drm_intel_get_min_eu_in_pool(int fd);
+
 /** @{ Compatibility defines to keep old code building despite the symbol rename
  * from dri_* to drm_intel_*
  */

intel/intel_bufmgr_gem.c

@@ -3237,6 +3237,36 @@ drm_intel_get_eu_total(int fd, unsigned int *eu_total)
 	return 0;
 }
 
+int
+drm_intel_get_pooled_eu(int fd)
+{
+	drm_i915_getparam_t gp;
+	int ret = -1;
+
+	memclear(gp);
+	gp.param = I915_PARAM_HAS_POOLED_EU;
+	gp.value = &ret;
+	if (drmIoctl(fd, DRM_IOCTL_I915_GETPARAM, &gp))
+		return -errno;
+
+	return ret;
+}
+
+int
+drm_intel_get_min_eu_in_pool(int fd)
+{
+	drm_i915_getparam_t gp;
+	int ret = -1;
+
+	memclear(gp);
+	gp.param = I915_PARAM_MIN_EU_IN_POOL;
+	gp.value = &ret;
+	if (drmIoctl(fd, DRM_IOCTL_I915_GETPARAM, &gp))
+		return -errno;
+
+	return ret;
+}
+
 /**
  * Annotate the given bo for use in aub dumping.
  *