1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2019 Intel Corporation
4 */
5
6#include <linux/pci.h>
7#include <linux/vgaarb.h>
8
9#include <video/vga.h>
10
11#include "soc/intel_gmch.h"
12
13#include "i915_drv.h"
14#include "i915_reg.h"
15#include "intel_de.h"
16#include "intel_vga.h"
17
18static i915_reg_t intel_vga_cntrl_reg(struct drm_i915_private *i915)
19{
20	if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
21		return VLV_VGACNTRL;
22	else if (DISPLAY_VER(i915) >= 5)
23		return CPU_VGACNTRL;
24	else
25		return VGACNTRL;
26}
27
28/* Disable the VGA plane that we never use */
29void intel_vga_disable(struct drm_i915_private *dev_priv)
30{
31	struct pci_dev *pdev = to_pci_dev(dev_priv->drm.dev);
32	i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
33	u8 sr1;
34
35	if (intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)
36		return;
37
38	/* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
39	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
40	outb(0x01, VGA_SEQ_I);
41	sr1 = inb(VGA_SEQ_D);
42	outb(sr1 | VGA_SR01_SCREEN_OFF, VGA_SEQ_D);
43	vga_put(pdev, VGA_RSRC_LEGACY_IO);
44	udelay(300);
45
46	intel_de_write(dev_priv, vga_reg, VGA_DISP_DISABLE);
47	intel_de_posting_read(dev_priv, vga_reg);
48}
49
50void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv)
51{
52	i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
53
54	if (!(intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)) {
55		drm_dbg_kms(&dev_priv->drm,
56			    "Something enabled VGA plane, disabling it\n");
57		intel_vga_disable(dev_priv);
58	}
59}
60
61void intel_vga_redisable(struct drm_i915_private *i915)
62{
63	intel_wakeref_t wakeref;
64
65	/*
66	 * This function can be called both from intel_modeset_setup_hw_state or
67	 * at a very early point in our resume sequence, where the power well
68	 * structures are not yet restored. Since this function is at a very
69	 * paranoid "someone might have enabled VGA while we were not looking"
70	 * level, just check if the power well is enabled instead of trying to
71	 * follow the "don't touch the power well if we don't need it" policy
72	 * the rest of the driver uses.
73	 */
74	wakeref = intel_display_power_get_if_enabled(i915, POWER_DOMAIN_VGA);
75	if (!wakeref)
76		return;
77
78	intel_vga_redisable_power_on(i915);
79
80	intel_display_power_put(i915, POWER_DOMAIN_VGA, wakeref);
81}
82
83void intel_vga_reset_io_mem(struct drm_i915_private *i915)
84{
85	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
86
87	/*
88	 * After we re-enable the power well, if we touch VGA register 0x3d5
89	 * we'll get unclaimed register interrupts. This stops after we write
90	 * anything to the VGA MSR register. The vgacon module uses this
91	 * register all the time, so if we unbind our driver and, as a
92	 * consequence, bind vgacon, we'll get stuck in an infinite loop at
93	 * console_unlock(). So make here we touch the VGA MSR register, making
94	 * sure vgacon can keep working normally without triggering interrupts
95	 * and error messages.
96	 */
97	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
98	outb(inb(VGA_MIS_R), VGA_MIS_W);
99	vga_put(pdev, VGA_RSRC_LEGACY_IO);
100}
101
102static unsigned int
103intel_vga_set_decode(struct pci_dev *pdev, bool enable_decode)
104{
105	struct drm_i915_private *i915 = pdev_to_i915(pdev);
106
107	intel_gmch_vga_set_state(i915, enable_decode);
108
109	if (enable_decode)
110		return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
111		       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
112	else
113		return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
114}
115
116int intel_vga_register(struct drm_i915_private *i915)
117{
118
119	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
120	int ret;
121
122	/*
123	 * If we have > 1 VGA cards, then we need to arbitrate access to the
124	 * common VGA resources.
125	 *
126	 * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA),
127	 * then we do not take part in VGA arbitration and the
128	 * vga_client_register() fails with -ENODEV.
129	 */
130	ret = vga_client_register(pdev, intel_vga_set_decode);
131	if (ret && ret != -ENODEV)
132		return ret;
133
134	return 0;
135}
136
137void intel_vga_unregister(struct drm_i915_private *i915)
138{
139	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
140
141	vga_client_unregister(pdev);
142}
143