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 <drm/i915_drm.h>
10
11 #include "i915_drv.h"
12 #include "intel_de.h"
13 #include "intel_vga.h"
14
intel_vga_cntrl_reg(struct drm_i915_private * i915)15 static i915_reg_t intel_vga_cntrl_reg(struct drm_i915_private *i915)
16 {
17 if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
18 return VLV_VGACNTRL;
19 else if (INTEL_GEN(i915) >= 5)
20 return CPU_VGACNTRL;
21 else
22 return VGACNTRL;
23 }
24
25 /* Disable the VGA plane that we never use */
intel_vga_disable(struct drm_i915_private * dev_priv)26 void intel_vga_disable(struct drm_i915_private *dev_priv)
27 {
28 struct pci_dev *pdev = dev_priv->drm.pdev;
29 i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
30 u8 sr1;
31
32 /* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
33 vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
34 outb(SR01, VGA_SR_INDEX);
35 sr1 = inb(VGA_SR_DATA);
36 outb(sr1 | 1 << 5, VGA_SR_DATA);
37 vga_put(pdev, VGA_RSRC_LEGACY_IO);
38 udelay(300);
39
40 intel_de_write(dev_priv, vga_reg, VGA_DISP_DISABLE);
41 intel_de_posting_read(dev_priv, vga_reg);
42 }
43
intel_vga_redisable_power_on(struct drm_i915_private * dev_priv)44 void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv)
45 {
46 i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv);
47
48 if (!(intel_de_read(dev_priv, vga_reg) & VGA_DISP_DISABLE)) {
49 drm_dbg_kms(&dev_priv->drm,
50 "Something enabled VGA plane, disabling it\n");
51 intel_vga_disable(dev_priv);
52 }
53 }
54
intel_vga_redisable(struct drm_i915_private * i915)55 void intel_vga_redisable(struct drm_i915_private *i915)
56 {
57 intel_wakeref_t wakeref;
58
59 /*
60 * This function can be called both from intel_modeset_setup_hw_state or
61 * at a very early point in our resume sequence, where the power well
62 * structures are not yet restored. Since this function is at a very
63 * paranoid "someone might have enabled VGA while we were not looking"
64 * level, just check if the power well is enabled instead of trying to
65 * follow the "don't touch the power well if we don't need it" policy
66 * the rest of the driver uses.
67 */
68 wakeref = intel_display_power_get_if_enabled(i915, POWER_DOMAIN_VGA);
69 if (!wakeref)
70 return;
71
72 intel_vga_redisable_power_on(i915);
73
74 intel_display_power_put(i915, POWER_DOMAIN_VGA, wakeref);
75 }
76
intel_vga_reset_io_mem(struct drm_i915_private * i915)77 void intel_vga_reset_io_mem(struct drm_i915_private *i915)
78 {
79 struct pci_dev *pdev = i915->drm.pdev;
80
81 /*
82 * After we re-enable the power well, if we touch VGA register 0x3d5
83 * we'll get unclaimed register interrupts. This stops after we write
84 * anything to the VGA MSR register. The vgacon module uses this
85 * register all the time, so if we unbind our driver and, as a
86 * consequence, bind vgacon, we'll get stuck in an infinite loop at
87 * console_unlock(). So make here we touch the VGA MSR register, making
88 * sure vgacon can keep working normally without triggering interrupts
89 * and error messages.
90 */
91 vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
92 outb(inb(VGA_MSR_READ), VGA_MSR_WRITE);
93 vga_put(pdev, VGA_RSRC_LEGACY_IO);
94 }
95
96 static int
intel_vga_set_state(struct drm_i915_private * i915,bool enable_decode)97 intel_vga_set_state(struct drm_i915_private *i915, bool enable_decode)
98 {
99 unsigned int reg = INTEL_GEN(i915) >= 6 ? SNB_GMCH_CTRL : INTEL_GMCH_CTRL;
100 u16 gmch_ctrl;
101
102 if (pci_read_config_word(i915->bridge_dev, reg, &gmch_ctrl)) {
103 drm_err(&i915->drm, "failed to read control word\n");
104 return -EIO;
105 }
106
107 if (!!(gmch_ctrl & INTEL_GMCH_VGA_DISABLE) == !enable_decode)
108 return 0;
109
110 if (enable_decode)
111 gmch_ctrl &= ~INTEL_GMCH_VGA_DISABLE;
112 else
113 gmch_ctrl |= INTEL_GMCH_VGA_DISABLE;
114
115 if (pci_write_config_word(i915->bridge_dev, reg, gmch_ctrl)) {
116 drm_err(&i915->drm, "failed to write control word\n");
117 return -EIO;
118 }
119
120 return 0;
121 }
122
123 static unsigned int
intel_vga_set_decode(void * cookie,bool enable_decode)124 intel_vga_set_decode(void *cookie, bool enable_decode)
125 {
126 struct drm_i915_private *i915 = cookie;
127
128 intel_vga_set_state(i915, enable_decode);
129
130 if (enable_decode)
131 return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM |
132 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
133 else
134 return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
135 }
136
intel_vga_register(struct drm_i915_private * i915)137 int intel_vga_register(struct drm_i915_private *i915)
138 {
139 struct pci_dev *pdev = i915->drm.pdev;
140 int ret;
141
142 /*
143 * If we have > 1 VGA cards, then we need to arbitrate access to the
144 * common VGA resources.
145 *
146 * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA),
147 * then we do not take part in VGA arbitration and the
148 * vga_client_register() fails with -ENODEV.
149 */
150 ret = vga_client_register(pdev, i915, NULL, intel_vga_set_decode);
151 if (ret && ret != -ENODEV)
152 return ret;
153
154 return 0;
155 }
156
intel_vga_unregister(struct drm_i915_private * i915)157 void intel_vga_unregister(struct drm_i915_private *i915)
158 {
159 struct pci_dev *pdev = i915->drm.pdev;
160
161 vga_client_register(pdev, NULL, NULL, NULL);
162 }
163