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_vga.h" 13 14 static i915_reg_t intel_vga_cntrl_reg(struct drm_i915_private *i915) 15 { 16 if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)) 17 return VLV_VGACNTRL; 18 else if (INTEL_GEN(i915) >= 5) 19 return CPU_VGACNTRL; 20 else 21 return VGACNTRL; 22 } 23 24 /* Disable the VGA plane that we never use */ 25 void intel_vga_disable(struct drm_i915_private *dev_priv) 26 { 27 struct pci_dev *pdev = dev_priv->drm.pdev; 28 i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv); 29 u8 sr1; 30 31 /* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */ 32 vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO); 33 outb(SR01, VGA_SR_INDEX); 34 sr1 = inb(VGA_SR_DATA); 35 outb(sr1 | 1 << 5, VGA_SR_DATA); 36 vga_put(pdev, VGA_RSRC_LEGACY_IO); 37 udelay(300); 38 39 I915_WRITE(vga_reg, VGA_DISP_DISABLE); 40 POSTING_READ(vga_reg); 41 } 42 43 void intel_vga_redisable_power_on(struct drm_i915_private *dev_priv) 44 { 45 i915_reg_t vga_reg = intel_vga_cntrl_reg(dev_priv); 46 47 if (!(I915_READ(vga_reg) & VGA_DISP_DISABLE)) { 48 DRM_DEBUG_KMS("Something enabled VGA plane, disabling it\n"); 49 intel_vga_disable(dev_priv); 50 } 51 } 52 53 void intel_vga_redisable(struct drm_i915_private *i915) 54 { 55 intel_wakeref_t wakeref; 56 57 /* 58 * This function can be called both from intel_modeset_setup_hw_state or 59 * at a very early point in our resume sequence, where the power well 60 * structures are not yet restored. Since this function is at a very 61 * paranoid "someone might have enabled VGA while we were not looking" 62 * level, just check if the power well is enabled instead of trying to 63 * follow the "don't touch the power well if we don't need it" policy 64 * the rest of the driver uses. 65 */ 66 wakeref = intel_display_power_get_if_enabled(i915, POWER_DOMAIN_VGA); 67 if (!wakeref) 68 return; 69 70 intel_vga_redisable_power_on(i915); 71 72 intel_display_power_put(i915, POWER_DOMAIN_VGA, wakeref); 73 } 74 75 void intel_vga_reset_io_mem(struct drm_i915_private *i915) 76 { 77 struct pci_dev *pdev = i915->drm.pdev; 78 79 /* 80 * After we re-enable the power well, if we touch VGA register 0x3d5 81 * we'll get unclaimed register interrupts. This stops after we write 82 * anything to the VGA MSR register. The vgacon module uses this 83 * register all the time, so if we unbind our driver and, as a 84 * consequence, bind vgacon, we'll get stuck in an infinite loop at 85 * console_unlock(). So make here we touch the VGA MSR register, making 86 * sure vgacon can keep working normally without triggering interrupts 87 * and error messages. 88 */ 89 vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO); 90 outb(inb(VGA_MSR_READ), VGA_MSR_WRITE); 91 vga_put(pdev, VGA_RSRC_LEGACY_IO); 92 } 93 94 static int 95 intel_vga_set_state(struct drm_i915_private *i915, bool enable_decode) 96 { 97 unsigned int reg = INTEL_GEN(i915) >= 6 ? SNB_GMCH_CTRL : INTEL_GMCH_CTRL; 98 u16 gmch_ctrl; 99 100 if (pci_read_config_word(i915->bridge_dev, reg, &gmch_ctrl)) { 101 DRM_ERROR("failed to read control word\n"); 102 return -EIO; 103 } 104 105 if (!!(gmch_ctrl & INTEL_GMCH_VGA_DISABLE) == !enable_decode) 106 return 0; 107 108 if (enable_decode) 109 gmch_ctrl &= ~INTEL_GMCH_VGA_DISABLE; 110 else 111 gmch_ctrl |= INTEL_GMCH_VGA_DISABLE; 112 113 if (pci_write_config_word(i915->bridge_dev, reg, gmch_ctrl)) { 114 DRM_ERROR("failed to write control word\n"); 115 return -EIO; 116 } 117 118 return 0; 119 } 120 121 static unsigned int 122 intel_vga_set_decode(void *cookie, bool enable_decode) 123 { 124 struct drm_i915_private *i915 = cookie; 125 126 intel_vga_set_state(i915, enable_decode); 127 128 if (enable_decode) 129 return VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM | 130 VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 131 else 132 return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; 133 } 134 135 int intel_vga_register(struct drm_i915_private *i915) 136 { 137 struct pci_dev *pdev = i915->drm.pdev; 138 int ret; 139 140 /* 141 * If we have > 1 VGA cards, then we need to arbitrate access to the 142 * common VGA resources. 143 * 144 * If we are a secondary display controller (!PCI_DISPLAY_CLASS_VGA), 145 * then we do not take part in VGA arbitration and the 146 * vga_client_register() fails with -ENODEV. 147 */ 148 ret = vga_client_register(pdev, i915, NULL, intel_vga_set_decode); 149 if (ret && ret != -ENODEV) 150 return ret; 151 152 return 0; 153 } 154 155 void intel_vga_unregister(struct drm_i915_private *i915) 156 { 157 struct pci_dev *pdev = i915->drm.pdev; 158 159 vga_client_register(pdev, NULL, NULL, NULL); 160 } 161