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path: root/drivers/gpu/drm/i915/gt/uc/intel_huc.c
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Diffstat (limited to 'drivers/gpu/drm/i915/gt/uc/intel_huc.c')
-rw-r--r--drivers/gpu/drm/i915/gt/uc/intel_huc.c35
1 files changed, 31 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.c b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
index 33608a114d4e..8be515c8d0f0 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_huc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
@@ -9,6 +9,34 @@
#include "intel_huc.h"
#include "i915_drv.h"
+/**
+ * DOC: HuC
+ *
+ * The HuC is a dedicated microcontroller for usage in media HEVC (High
+ * Efficiency Video Coding) operations. Userspace can directly use the firmware
+ * capabilities by adding HuC specific commands to batch buffers.
+ *
+ * The kernel driver is only responsible for loading the HuC firmware and
+ * triggering its security authentication, which is performed by the GuC. For
+ * The GuC to correctly perform the authentication, the HuC binary must be
+ * loaded before the GuC one. Loading the HuC is optional; however, not using
+ * the HuC might negatively impact power usage and/or performance of media
+ * workloads, depending on the use-cases.
+ *
+ * See https://github.com/intel/media-driver for the latest details on HuC
+ * functionality.
+ */
+
+/**
+ * DOC: HuC Memory Management
+ *
+ * Similarly to the GuC, the HuC can't do any memory allocations on its own,
+ * with the difference being that the allocations for HuC usage are handled by
+ * the userspace driver instead of the kernel one. The HuC accesses the memory
+ * via the PPGTT belonging to the context loaded on the VCS executing the
+ * HuC-specific commands.
+ */
+
void intel_huc_init_early(struct intel_huc *huc)
{
struct drm_i915_private *i915 = huc_to_gt(huc)->i915;
@@ -118,10 +146,9 @@ void intel_huc_fini(struct intel_huc *huc)
*
* Called after HuC and GuC firmware loading during intel_uc_init_hw().
*
- * This function pins HuC firmware image object into GGTT.
- * Then it invokes GuC action to authenticate passing the offset to RSA
- * signature through intel_guc_auth_huc(). It then waits for 50ms for
- * firmware verification ACK and unpins the object.
+ * This function invokes the GuC action to authenticate the HuC firmware,
+ * passing the offset of the RSA signature to intel_guc_auth_huc(). It then
+ * waits for up to 50ms for firmware verification ACK.
*/
int intel_huc_auth(struct intel_huc *huc)
{