1// SPDX-License-Identifier: MIT
2/*
3 * Copyright �� 2019 Intel Corporation
4 */
5
6#include <linux/vgaarb.h>
7
8#include <video/vga.h>
9#include "soc/intel_gmch.h"
10
11#include "i915_drv.h"
12#include "i915_reg.h"
13#include "intel_de.h"
14#include "intel_vga.h"
15
16static i915_reg_t intel_vga_cntrl_reg(struct drm_i915_private *i915)
17{
18	if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
19		return VLV_VGACNTRL;
20	else if (DISPLAY_VER(i915) >= 5)
21		return CPU_VGACNTRL;
22	else
23		return VGACNTRL;
24}
25
26/* Disable the VGA plane that we never use */
27void intel_vga_disable(struct drm_i915_private *dev_priv)
28{
29	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
30	i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
31	u8 sr1;
32
33	if (intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)
34		return;
35
36	/* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
37	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
38	outb(0x01, VGA_SEQ_I);
39	sr1 = inb(VGA_SEQ_D);
40	outb(sr1 | VGA_SR01_SCREEN_OFF, VGA_SEQ_D);
41	vga_put(pdev, VGA_RSRC_LEGACY_IO);
42	udelay(300);
43
44	intel_de_write(dev_priv, vga_reg, VGA_DISP_DISABLE);
45	intel_de_posting_read(dev_priv, vga_reg);
46}
47
48void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv)
49{
50	i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
51
52	if (!(intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)) {
53		drm_dbg_kms(&dev_priv->drm,
54			    "Something enabled VGA plane, disabling it\n");
55		intel_vga_disable(dev_priv);
56	}
57}
58
59void intel_vga_redisable(struct drm_i915_private *i915)
60{
61	intel_wakeref_t wakeref;
62
63	/*
64	 * This function can be called both from intel_modeset_setup_hw_state or
65	 * at a very early point in our resume sequence, where the power well
66	 * structures are not yet restored. Since this function is at a very
67	 * paranoid "someone might have enabled VGA while we were not looking"
68	 * level, just check if the power well is enabled instead of trying to
69	 * follow the "don't touch the power well if we don't need it" policy
70	 * the rest of the driver uses.
71	 */
72	wakeref = intel_display_power_get_if_enabled(i915, POWER_DOMAIN_VGA);
73	if (!wakeref)
74		return;
75
76	intel_vga_redisable_power_on(i915);
77
78	intel_display_power_put(i915, POWER_DOMAIN_VGA, wakeref);
79}
80
81void intel_vga_reset_io_mem(struct drm_i915_private *i915)
82{
83	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
84
85	/*
86	 * After we re-enable the power well, if we touch VGA register 0x3d5
87	 * we'll get unclaimed register interrupts. This stops after we write
88	 * anything to the VGA MSR register. The vgacon module uses this
89	 * register all the time, so if we unbind our driver and, as a
90	 * consequence, bind vgacon, we'll get stuck in an infinite loop at
91	 * console_unlock(). So make here we touch the VGA MSR register, making
92	 * sure vgacon can keep working normally without triggering interrupts
93	 * and error messages.
94	 */
95	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
96	outb(inb(VGA_MIS_R), VGA_MIS_W);
97	vga_put(pdev, VGA_RSRC_LEGACY_IO);
98}
99
100int intel_vga_register(struct drm_i915_private *i915)
101{
102
103	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
104	int ret;
105
106	/*
107	 * If we have > 1 VGA cards, then we need to arbitrate access to the
108	 * common VGA resources.
109	 *
110	 * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA),
111	 * then we do not take part in VGA arbitration and the
112	 * vga_client_register() fails with -ENODEV.
113	 */
114	ret = vga_client_register(pdev, intel_gmch_vga_set_decode);
115	if (ret && ret != -ENODEV)
116		return ret;
117
118	return 0;
119}
120
121void intel_vga_unregister(struct drm_i915_private *i915)
122{
123	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
124
125	vga_client_unregister(pdev);
126}
127