1 files changed, 50 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/vlv_sideband.c b/drivers/gpu/drm/i915/display/vlv_sideband.c
new file mode 100644
index 000000000000..e18045f2b89d
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/vlv_sideband.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: MIT
+/* Copyright © 2025 Intel Corporation */
+
+#include <drm/drm_print.h>
+
+#include "intel_display_core.h"
+#include "intel_display_types.h"
+#include "intel_dpio_phy.h"
+#include "vlv_sideband.h"
+
+static enum vlv_iosf_sb_unit vlv_dpio_phy_to_unit(struct intel_display *display,
+						  enum dpio_phy phy)
+{
+	/*
+	 * IOSF_PORT_DPIO: VLV x2 PHY (DP/HDMI B and C), CHV x1 PHY (DP/HDMI D)
+	 * IOSF_PORT_DPIO_2: CHV x2 PHY (DP/HDMI B and C)
+	 */
+	if (display->platform.cherryview)
+		return phy == DPIO_PHY0 ? VLV_IOSF_SB_DPIO_2 : VLV_IOSF_SB_DPIO;
+	else
+		return VLV_IOSF_SB_DPIO;
+}
+
+u32 vlv_dpio_read(struct drm_device *drm, enum dpio_phy phy, int reg)
+{
+	struct intel_display *display = to_intel_display(drm);
+	enum vlv_iosf_sb_unit unit = vlv_dpio_phy_to_unit(display, phy);
+	u32 val;
+
+	val = vlv_iosf_sb_read(drm, unit, reg);
+
+	/*
+	 * FIXME: There might be some registers where all 1's is a valid value,
+	 * so ideally we should check the register offset instead...
+	 */
+	drm_WARN(display->drm, val == 0xffffffff,
+		 "DPIO PHY%d read reg 0x%x == 0x%x\n",
+		 phy, reg, val);
+
+	return val;
+}
+
+void vlv_dpio_write(struct drm_device *drm,
+		    enum dpio_phy phy, int reg, u32 val)
+{
+	struct intel_display *display = to_intel_display(drm);
+	enum vlv_iosf_sb_unit unit = vlv_dpio_phy_to_unit(display, phy);
+
+	vlv_iosf_sb_write(drm, unit, reg, val);
+}