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 #include <video/vga.h> 11 12 #include "i915_drv.h" 13 #include "intel_de.h" 14 #include "intel_vga.h" 15 16 static 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 */ 27 void 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 48 void 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 59 void 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 81 void 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 } 99 100 static int 101 intel_vga_set_state(struct drm_i915_private *i915, bool enable_decode) 102 { 103 unsigned int reg = DISPLAY_VER(i915) >= 6 ? SNB_GMCH_CTRL : INTEL_GMCH_CTRL; 104 u16 gmch_ctrl; 105 106 if (pci_read_config_word(i915->bridge_dev, reg, &gmch_ctrl)) { 107 drm_err(&i915->drm, "failed to read control word\n"); 108 return -EIO; 109 } 110 111 if (!!(gmch_ctrl & INTEL_GMCH_VGA_DISABLE) == !enable_decode) 112 return 0; 113 114 if (enable_decode) 115 gmch_ctrl &= ~INTEL_GMCH_VGA_DISABLE; 116 else 117 gmch_ctrl |= INTEL_GMCH_VGA_DISABLE; 118 119 if (pci_write_config_word(i915->bridge_dev, reg, gmch_ctrl)) { 120 drm_err(&i915->drm, "failed to write control word\n"); 121 return -EIO; 122 } 123 124 return 0; 125 } 126 127 static unsigned int 128 intel_vga_set_decode(struct pci_dev *pdev, bool enable_decode) 129 { 130 struct drm_i915_private *i915 = pdev_to_i915(pdev); 131 132 intel_vga_set_state(i915, enable_decode); 133 134 if (enable_decode) 135 return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | 136 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 137 else 138 return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 139 } 140 141 int intel_vga_register(struct drm_i915_private *i915) 142 { 143 144 struct pci_dev *pdev = to_pci_dev(i915->drm.dev); 145 int ret; 146 147 /* 148 * If we have > 1 VGA cards, then we need to arbitrate access to the 149 * common VGA resources. 150 * 151 * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA), 152 * then we do not take part in VGA arbitration and the 153 * vga_client_register() fails with -ENODEV. 154 */ 155 ret = vga_client_register(pdev, intel_vga_set_decode); 156 if (ret && ret != -ENODEV) 157 return ret; 158 159 return 0; 160 } 161 162 void intel_vga_unregister(struct drm_i915_private *i915) 163 { 164 struct pci_dev *pdev = to_pci_dev(i915->drm.dev); 165 166 vga_client_unregister(pdev); 167 } 168