drm/xe/pf: Sanitize VF scratch registers on FLR

[ Upstream commit 13a48a0 ]

Some VF accessible registers (like GuC scratch registers) must be
explicitly reset during the FLR. While this is today done by the GuC
firmware, according to the design, this should be responsibility of
the PF driver, as future platforms may require more registers to be
reset. Likewise GuC, the PF can access VFs registers by adding some
platform specific offset to the original register address.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240902192953.1792-1-michal.wajdeczko@intel.com
Stable-dep-of: 81dccec ("drm/xe/pf: Prepare to stop SR-IOV support prior GT reset")
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: mwajdecz

drivers/gpu/drm/xe/xe_gt_sriov_pf.c

@@ -5,8 +5,10 @@
 
 #include <drm/drm_managed.h>
 
+#include "regs/xe_guc_regs.h"
 #include "regs/xe_regs.h"
 
+#include "xe_gt.h"
 #include "xe_gt_sriov_pf.h"
 #include "xe_gt_sriov_pf_config.h"
 #include "xe_gt_sriov_pf_control.h"
@@ -89,6 +91,56 @@ void xe_gt_sriov_pf_init_hw(struct xe_gt *gt)
 	xe_gt_sriov_pf_service_update(gt);
 }
 
+static u32 pf_get_vf_regs_stride(struct xe_device *xe)
+{
+	return GRAPHICS_VERx100(xe) > 1200 ? 0x400 : 0x1000;
+}
+
+static struct xe_reg xe_reg_vf_to_pf(struct xe_reg vf_reg, unsigned int vfid, u32 stride)
+{
+	struct xe_reg pf_reg = vf_reg;
+
+	pf_reg.vf = 0;
+	pf_reg.addr += stride * vfid;
+
+	return pf_reg;
+}
+
+static void pf_clear_vf_scratch_regs(struct xe_gt *gt, unsigned int vfid)
+{
+	u32 stride = pf_get_vf_regs_stride(gt_to_xe(gt));
+	struct xe_reg scratch;
+	int n, count;
+
+	if (xe_gt_is_media_type(gt)) {
+		count = MED_VF_SW_FLAG_COUNT;
+		for (n = 0; n < count; n++) {
+			scratch = xe_reg_vf_to_pf(MED_VF_SW_FLAG(n), vfid, stride);
+			xe_mmio_write32(gt, scratch, 0);
+		}
+	} else {
+		count = VF_SW_FLAG_COUNT;
+		for (n = 0; n < count; n++) {
+			scratch = xe_reg_vf_to_pf(VF_SW_FLAG(n), vfid, stride);
+			xe_mmio_write32(gt, scratch, 0);
+		}
+	}
+}
+
+/**
+ * xe_gt_sriov_pf_sanitize_hw() - Reset hardware state related to a VF.
+ * @gt: the &xe_gt
+ * @vfid: the VF identifier
+ *
+ * This function can only be called on PF.
+ */
+void xe_gt_sriov_pf_sanitize_hw(struct xe_gt *gt, unsigned int vfid)
+{
+	xe_gt_assert(gt, IS_SRIOV_PF(gt_to_xe(gt)));
+
+	pf_clear_vf_scratch_regs(gt, vfid);
+}
+
 /**
  * xe_gt_sriov_pf_restart - Restart SR-IOV support after a GT reset.
  * @gt: the &xe_gt

drivers/gpu/drm/xe/xe_gt_sriov_pf.h

@@ -11,6 +11,7 @@ struct xe_gt;
 #ifdef CONFIG_PCI_IOV
 int xe_gt_sriov_pf_init_early(struct xe_gt *gt);
 void xe_gt_sriov_pf_init_hw(struct xe_gt *gt);
+void xe_gt_sriov_pf_sanitize_hw(struct xe_gt *gt, unsigned int vfid);
 void xe_gt_sriov_pf_restart(struct xe_gt *gt);
 #else
 static inline int xe_gt_sriov_pf_init_early(struct xe_gt *gt)

drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c

@@ -9,6 +9,7 @@
 
 #include "xe_device.h"
 #include "xe_gt.h"
+#include "xe_gt_sriov_pf.h"
 #include "xe_gt_sriov_pf_config.h"
 #include "xe_gt_sriov_pf_control.h"
 #include "xe_gt_sriov_pf_helpers.h"
@@ -1008,7 +1009,7 @@ static bool pf_exit_vf_flr_reset_mmio(struct xe_gt *gt, unsigned int vfid)
 	if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_MMIO))
 		return false;
 
-	/* XXX: placeholder */
+	xe_gt_sriov_pf_sanitize_hw(gt, vfid);
 
 	pf_enter_vf_flr_send_finish(gt, vfid);
 	return true;