intel_vga.c revision 1.6 
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 = dev_priv->drm.pdev;
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#ifdef __linux__
41	outb(0x01, VGA_SEQ_I);
42	sr1 = inb(VGA_SEQ_D);
43	outb(sr1 | VGA_SR01_SCREEN_OFF, VGA_SEQ_D);
44#else
45	outb(VGA_SEQ_I, 0x01);
46	sr1 = inb(VGA_SEQ_D);
47	outb(VGA_SEQ_D, sr1 | VGA_SR01_SCREEN_OFF);
48#endif
49	vga_put(pdev, VGA_RSRC_LEGACY_IO);
50	udelay(300);
51
52	intel_de_write(dev_priv, vga_reg, VGA_DISP_DISABLE);
53	intel_de_posting_read(dev_priv, vga_reg);
54}
55
56void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv)
57{
58	i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
59
60	if (!(intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)) {
61		drm_dbg_kms(&dev_priv->drm,
62			    "Something enabled VGA plane, disabling it\n");
63		intel_vga_disable(dev_priv);
64	}
65}
66
67void intel_vga_redisable(struct drm_i915_private *i915)
68{
69	intel_wakeref_t wakeref;
70
71	/*
72	 * This function can be called both from intel_modeset_setup_hw_state or
73	 * at a very early point in our resume sequence, where the power well
74	 * structures are not yet restored. Since this function is at a very
75	 * paranoid "someone might have enabled VGA while we were not looking"
76	 * level, just check if the power well is enabled instead of trying to
77	 * follow the "don't touch the power well if we don't need it" policy
78	 * the rest of the driver uses.
79	 */
80	wakeref = intel_display_power_get_if_enabled(i915, POWER_DOMAIN_VGA);
81	if (!wakeref)
82		return;
83
84	intel_vga_redisable_power_on(i915);
85
86	intel_display_power_put(i915, POWER_DOMAIN_VGA, wakeref);
87}
88
89void intel_vga_reset_io_mem(struct drm_i915_private *i915)
90{
91	struct pci_dev *pdev = i915->drm.pdev;
92
93	/*
94	 * After we re-enable the power well, if we touch VGA register 0x3d5
95	 * we'll get unclaimed register interrupts. This stops after we write
96	 * anything to the VGA MSR register. The vgacon module uses this
97	 * register all the time, so if we unbind our driver and, as a
98	 * consequence, bind vgacon, we'll get stuck in an infinite loop at
99	 * console_unlock(). So make here we touch the VGA MSR register, making
100	 * sure vgacon can keep working normally without triggering interrupts
101	 * and error messages.
102	 */
103	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
104#ifdef __linux__
105	outb(inb(VGA_MIS_R), VGA_MIS_W);
106#else
107	outb(VGA_MIS_W, inb(VGA_MIS_R));
108#endif
109	vga_put(pdev, VGA_RSRC_LEGACY_IO);
110}
111
112static unsigned int
113intel_vga_set_decode(struct pci_dev *pdev, bool enable_decode)
114{
115	STUB();
116	return 0;
117#ifdef notyet
118	struct drm_i915_private *i915 = pdev_to_i915(pdev);
119
120	intel_gmch_vga_set_state(i915, enable_decode);
121
122	if (enable_decode)
123		return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
124		       VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
125	else
126		return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
127#endif
128}
129
130int intel_vga_register(struct drm_i915_private *i915)
131{
132
133	struct pci_dev *pdev = i915->drm.pdev;
134	int ret;
135
136	/*
137	 * If we have > 1 VGA cards, then we need to arbitrate access to the
138	 * common VGA resources.
139	 *
140	 * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA),
141	 * then we do not take part in VGA arbitration and the
142	 * vga_client_register() fails with -ENODEV.
143	 */
144	ret = vga_client_register(pdev, intel_vga_set_decode);
145	if (ret && ret != -ENODEV)
146		return ret;
147
148	return 0;
149}
150
151void intel_vga_unregister(struct drm_i915_private *i915)
152{
153	struct pci_dev *pdev = i915->drm.pdev;
154
155	vga_client_unregister(pdev);
156}
157