xref: /linux/drivers/gpu/drm/i915/display/vlv_sideband.c (revision 8d2b0853add1d7534dc0794e3c8e0b9e8c4ec640)
1 // SPDX-License-Identifier: MIT
2 /* Copyright © 2025 Intel Corporation */
3 
4 #include <drm/drm_print.h>
5 
6 #include "intel_display_core.h"
7 #include "intel_display_types.h"
8 #include "intel_dpio_phy.h"
9 #include "vlv_sideband.h"
10 
11 static enum vlv_iosf_sb_unit vlv_dpio_phy_to_unit(struct intel_display *display,
12 						  enum dpio_phy phy)
13 {
14 	/*
15 	 * IOSF_PORT_DPIO: VLV x2 PHY (DP/HDMI B and C), CHV x1 PHY (DP/HDMI D)
16 	 * IOSF_PORT_DPIO_2: CHV x2 PHY (DP/HDMI B and C)
17 	 */
18 	if (display->platform.cherryview)
19 		return phy == DPIO_PHY0 ? VLV_IOSF_SB_DPIO_2 : VLV_IOSF_SB_DPIO;
20 	else
21 		return VLV_IOSF_SB_DPIO;
22 }
23 
24 u32 vlv_dpio_read(struct drm_device *drm, enum dpio_phy phy, int reg)
25 {
26 	struct intel_display *display = to_intel_display(drm);
27 	enum vlv_iosf_sb_unit unit = vlv_dpio_phy_to_unit(display, phy);
28 	u32 val;
29 
30 	val = vlv_iosf_sb_read(drm, unit, reg);
31 
32 	/*
33 	 * FIXME: There might be some registers where all 1's is a valid value,
34 	 * so ideally we should check the register offset instead...
35 	 */
36 	drm_WARN(display->drm, val == 0xffffffff,
37 		 "DPIO PHY%d read reg 0x%x == 0x%x\n",
38 		 phy, reg, val);
39 
40 	return val;
41 }
42 
43 void vlv_dpio_write(struct drm_device *drm,
44 		    enum dpio_phy phy, int reg, u32 val)
45 {
46 	struct intel_display *display = to_intel_display(drm);
47 	enum vlv_iosf_sb_unit unit = vlv_dpio_phy_to_unit(display, phy);
48 
49 	vlv_iosf_sb_write(drm, unit, reg, val);
50 }
51