drm/i915/pxp: Add ARB session creation and cleanup

Add MTL's function for ARB session creation using PXP firmware
version 4.3 ABI structure format.

While relooking at the ARB session creation flow in intel_pxp_start,
let's address missing UAPI documentation. Without actually changing
backward compatible behavior, update i915's drm-uapi comments
that describe the possible error values when creating a context
with I915_CONTEXT_PARAM_PROTECTED_CONTENT:
   Since the first merge of PXP support on ADL, i915 returns -ENXIO
   if a dependency such as firmware or component driver was yet to
   be loaded or returns -EIO if the creation attempt failed when
   requested by the PXP firmware (specific firmware error responses
   are reported in dmesg).

Add MTL's function for ARB session invalidation but this
reuses PXP firmware version 4.2 ABI structure format.

For both cases, in the back-end gsccs functions for sending messages
to the firmware inspect the GSC-CS-Mem-Header's pending-bit which
means the GSC firmware is busy and we should retry.

Given the last hw requirement, lets also update functions in
front-end layer that wait for session creation or teardown
completion to use new worst case timeout periods.

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230511231738.1077674-6-alan.previn.teres.alexis@intel.com

1 files changed, 15 insertions, 0 deletions

diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index dba7c5a5b25e..0aa3190e7654 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -2096,6 +2096,21 @@ struct drm_i915_gem_context_param {
  *
  * -ENODEV: feature not available
  * -EPERM: trying to mark a recoverable or not bannable context as protected
+ * -ENXIO: A dependency such as a component driver or firmware is not yet
+ *         loaded so user space may need to attempt again. Depending on the
+ *         device, this error may be reported if protected context creation is
+ *         attempted very early after kernel start because the internal timeout
+ *         waiting for such dependencies is not guaranteed to be larger than
+ *         required (numbers differ depending on system and kernel config):
+ *            - ADL/RPL: dependencies may take up to 3 seconds from kernel start
+ *                       while context creation internal timeout is 250 milisecs
+ *            - MTL: dependencies may take up to 8 seconds from kernel start
+ *                   while context creation internal timeout is 250 milisecs
+ *         NOTE: such dependencies happen once, so a subsequent call to create a
+ *         protected context after a prior successful call will not experience
+ *         such timeouts and will not return -ENXIO (unless the driver is reloaded,
+ *         or, depending on the device, resumes from a suspended state).
+ * -EIO: The firmware did not succeed in creating the protected context.
  */
 #define I915_CONTEXT_PARAM_PROTECTED_CONTENT    0xd
 /* Must be kept compact -- no holes and well documented */