drm/i915/guc: Check the locking status of GuC WOPCM registers

GuC WOPCM registers are write-once registers. Current driver code accesses
these registers without checking the accessibility to these registers which
will lead to unpredictable driver behaviors if these registers were touch
by other components (such as faulty BIOS code).

This patch moves the GuC WOPCM registers updating code into intel_wopcm.c
and adds check before and after the update to GuC WOPCM registers so that
we can make sure the driver is in a known state after writing to these
write-once registers.

v6:
 - Made sure module reloading won't bug the kernel while doing
   locking status checking

v7:
 - Fixed patch format issues

v8:
 - Fixed coding style issue on register lock bit macro definition (Sagar)

v9:
 - Avoided to use redundant !! to cast uint to bool (Chris)
 - Return error code instead of GEM_BUG_ON for locked with invalid register
   values case (Sagar)
 - Updated guc_wopcm_hw_init to use guc_wopcm as first parameter (Michal)
 - Added code to set and validate the HuC_LOADING_AGENT_GUC bit in GuC
   WOPCM offset register based on the presence of HuC firmware (Michal)
 - Use bit fields instead of macros for GuC WOPCM flags (Michal)

v10:
 - Refined variable names, removed redundant comments (Joonas)
 - Introduced lockable_reg to handle the write once register write and
   propagate the write error to caller (Joonas)
 - Used lockable_reg abstraction to avoid locking bit check on generic
   i915_reg_t (Michal)
 - Added log message for error paths (Michal)
 - Removed hw_updated flag and only relies on real hardware status

v11:
 - Replaced lockable_reg with simplified function (Michal)
 - Used new macros for locking bits of WOPCM size/offset registers instead
   of using BIT(0) directly (Michal)
 - use intel_wopcm_init_hw() called from intel_gem_init_hw() to do GuC
   WOPCM register setup instead of calling from intel_uc_init_hw() (Michal)

v12:
 - Updated function kernel-doc to align with code changes (Michal)
 - Updated code to use wopcm pointer directly (Michal)

v13:
 - Updated the ordering of s-o-b/cc/r-b tags (Sagar)

BSpec: 10875, 10833

Signed-off-by: Jackie Li <yaodong.li@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com> (v11)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v12)
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1520987574-19351-5-git-send-email-yaodong.li@intel.com

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_guc_reg.h b/drivers/gpu/drm/i915/intel_guc_reg.h
index 01963d085ed6..d86084742a4a 100644
--- a/drivers/gpu/drm/i915/intel_guc_reg.h
+++ b/drivers/gpu/drm/i915/intel_guc_reg.h
@@ -66,15 +66,18 @@
 #define   UOS_MOVE			  (1<<4)
 #define   START_DMA			  (1<<0)
 #define DMA_GUC_WOPCM_OFFSET		_MMIO(0xc340)
+#define   GUC_WOPCM_OFFSET_VALID	  (1<<0)
 #define   HUC_LOADING_AGENT_VCR		  (0<<1)
 #define   HUC_LOADING_AGENT_GUC		  (1<<1)
 #define   GUC_WOPCM_OFFSET_SHIFT	14
+#define   GUC_WOPCM_OFFSET_MASK		  (0x3ffff << GUC_WOPCM_OFFSET_SHIFT)
 #define GUC_MAX_IDLE_COUNT		_MMIO(0xC3E4)
 
 #define HUC_STATUS2             _MMIO(0xD3B0)
 #define   HUC_FW_VERIFIED       (1<<7)
 
 #define GUC_WOPCM_SIZE			_MMIO(0xc050)
+#define   GUC_WOPCM_SIZE_LOCKED		  (1<<0)
 #define   GUC_WOPCM_SIZE_SHIFT		12
 #define   GUC_WOPCM_SIZE_MASK		  (0xfffff << GUC_WOPCM_SIZE_SHIFT)