[PATCH v3 18/43] drm/xe/pci: Convert register access to use xe_mmio

[Matt Roper]

Stop using GT pointers for register access.

v2:
 - Clarify comment about manual GSI offset handling.  (Rodrigo)

Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
 drivers/gpu/drm/xe/xe_pci.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
index aa0c29450b4a..5ba4ec229494 100644
--- a/drivers/gpu/drm/xe/xe_pci.c
+++ b/drivers/gpu/drm/xe/xe_pci.c
@@ -473,13 +473,15 @@ enum xe_gmdid_type {
 
 static void read_gmdid(struct xe_device *xe, enum xe_gmdid_type type, u32 *ver, u32 *revid)
 {
-	struct xe_gt *gt = xe_root_mmio_gt(xe);
+	struct xe_mmio *mmio = xe_root_tile_mmio(xe);
 	struct xe_reg gmdid_reg = GMD_ID;
 	u32 val;
 
 	KUNIT_STATIC_STUB_REDIRECT(read_gmdid, xe, type, ver, revid);
 
 	if (IS_SRIOV_VF(xe)) {
+		struct xe_gt *gt = xe_root_mmio_gt(xe);
+
 		/*
 		 * To get the value of the GMDID register, VFs must obtain it
 		 * from the GuC using MMIO communication.
@@ -515,14 +517,17 @@ static void read_gmdid(struct xe_device *xe, enum xe_gmdid_type type, u32 *ver,
 		gt->info.type = XE_GT_TYPE_UNINITIALIZED;
 	} else {
 		/*
-		 * We need to apply the GSI offset explicitly here as at this
-		 * point the xe_gt is not fully uninitialized and only basic
-		 * access to MMIO registers is possible.
+		 * GMD_ID is a GT register, but at this point in the driver
+		 * init we haven't fully initialized the GT yet so we need to
+		 * read the register with the tile's MMIO accessor.  That means
+		 * we need to apply the GSI offset manually since it won't get
+		 * automatically added as it would if we were using a GT mmio
+		 * accessor.
 		 */
 		if (type == GMDID_MEDIA)
 			gmdid_reg.addr += MEDIA_GT_GSI_OFFSET;
 
-		val = xe_mmio_read32(gt, gmdid_reg);
+		val = xe_mmio_read32(mmio, gmdid_reg);
 	}
 
 	*ver = REG_FIELD_GET(GMD_ID_ARCH_MASK, val) * 100 + REG_FIELD_GET(GMD_ID_RELEASE_MASK, val);
-- 
2.45.2