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5270 | serge | 1 | /* |
2 | * The VGA aribiter manages VGA space routing and VGA resource decode to |
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3 | * allow multiple VGA devices to be used in a system in a safe way. |
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4 | * |
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5 | * (C) Copyright 2005 Benjamin Herrenschmidt |
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6 | * (C) Copyright 2007 Paulo R. Zanoni |
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7 | * (C) Copyright 2007, 2009 Tiago Vignatti |
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8 | * |
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9 | * Permission is hereby granted, free of charge, to any person obtaining a |
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10 | * copy of this software and associated documentation files (the "Software"), |
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11 | * to deal in the Software without restriction, including without limitation |
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12 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
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13 | * and/or sell copies of the Software, and to permit persons to whom the |
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14 | * Software is furnished to do so, subject to the following conditions: |
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15 | * |
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16 | * The above copyright notice and this permission notice (including the next |
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17 | * paragraph) shall be included in all copies or substantial portions of the |
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18 | * Software. |
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19 | * |
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20 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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21 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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22 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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23 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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24 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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25 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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26 | * DEALINGS |
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27 | * IN THE SOFTWARE. |
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28 | * |
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29 | */ |
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30 | |||
31 | #ifndef LINUX_VGA_H |
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32 | #define LINUX_VGA_H |
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33 | |||
34 | //#include |
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35 | |||
36 | /* Legacy VGA regions */ |
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37 | #define VGA_RSRC_NONE 0x00 |
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38 | #define VGA_RSRC_LEGACY_IO 0x01 |
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39 | #define VGA_RSRC_LEGACY_MEM 0x02 |
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40 | #define VGA_RSRC_LEGACY_MASK (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM) |
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41 | /* Non-legacy access */ |
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42 | #define VGA_RSRC_NORMAL_IO 0x04 |
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43 | #define VGA_RSRC_NORMAL_MEM 0x08 |
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44 | |||
45 | /* Passing that instead of a pci_dev to use the system "default" |
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46 | * device, that is the one used by vgacon. Archs will probably |
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47 | * have to provide their own vga_default_device(); |
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48 | */ |
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49 | #define VGA_DEFAULT_DEVICE (NULL) |
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50 | |||
51 | struct pci_dev; |
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52 | |||
53 | /* For use by clients */ |
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54 | |||
55 | /** |
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56 | * vga_set_legacy_decoding |
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57 | * |
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58 | * @pdev: pci device of the VGA card |
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59 | * @decodes: bit mask of what legacy regions the card decodes |
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60 | * |
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61 | * Indicates to the arbiter if the card decodes legacy VGA IOs, |
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62 | * legacy VGA Memory, both, or none. All cards default to both, |
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63 | * the card driver (fbdev for example) should tell the arbiter |
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64 | * if it has disabled legacy decoding, so the card can be left |
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65 | * out of the arbitration process (and can be safe to take |
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66 | * interrupts at any time. |
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67 | */ |
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68 | extern void vga_set_legacy_decoding(struct pci_dev *pdev, |
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69 | unsigned int decodes); |
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70 | |||
71 | /** |
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72 | * vga_get - acquire & locks VGA resources |
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73 | * |
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74 | * @pdev: pci device of the VGA card or NULL for the system default |
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75 | * @rsrc: bit mask of resources to acquire and lock |
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76 | * @interruptible: blocking should be interruptible by signals ? |
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77 | * |
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78 | * This function acquires VGA resources for the given |
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79 | * card and mark those resources locked. If the resource requested |
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80 | * are "normal" (and not legacy) resources, the arbiter will first check |
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81 | * whether the card is doing legacy decoding for that type of resource. If |
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82 | * yes, the lock is "converted" into a legacy resource lock. |
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83 | * The arbiter will first look for all VGA cards that might conflict |
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84 | * and disable their IOs and/or Memory access, including VGA forwarding |
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85 | * on P2P bridges if necessary, so that the requested resources can |
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86 | * be used. Then, the card is marked as locking these resources and |
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87 | * the IO and/or Memory accesse are enabled on the card (including |
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88 | * VGA forwarding on parent P2P bridges if any). |
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89 | * This function will block if some conflicting card is already locking |
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90 | * one of the required resources (or any resource on a different bus |
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91 | * segment, since P2P bridges don't differenciate VGA memory and IO |
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92 | * afaik). You can indicate whether this blocking should be interruptible |
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93 | * by a signal (for userland interface) or not. |
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94 | * Must not be called at interrupt time or in atomic context. |
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95 | * If the card already owns the resources, the function succeeds. |
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96 | * Nested calls are supported (a per-resource counter is maintained) |
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97 | */ |
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98 | |||
99 | #if defined(CONFIG_VGA_ARB) |
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100 | extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible); |
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101 | #else |
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102 | static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; } |
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103 | #endif |
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104 | |||
105 | /** |
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106 | * vga_get_interruptible |
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107 | * |
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108 | * Shortcut to vga_get |
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109 | */ |
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110 | |||
111 | static inline int vga_get_interruptible(struct pci_dev *pdev, |
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112 | unsigned int rsrc) |
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113 | { |
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114 | return vga_get(pdev, rsrc, 1); |
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115 | } |
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116 | |||
117 | /** |
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118 | * vga_get_uninterruptible |
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119 | * |
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120 | * Shortcut to vga_get |
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121 | */ |
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122 | |||
123 | static inline int vga_get_uninterruptible(struct pci_dev *pdev, |
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124 | unsigned int rsrc) |
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125 | { |
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126 | return vga_get(pdev, rsrc, 0); |
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127 | } |
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128 | |||
129 | /** |
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130 | * vga_tryget - try to acquire & lock legacy VGA resources |
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131 | * |
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132 | * @pdev: pci devivce of VGA card or NULL for system default |
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133 | * @rsrc: bit mask of resources to acquire and lock |
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134 | * |
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135 | * This function performs the same operation as vga_get(), but |
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136 | * will return an error (-EBUSY) instead of blocking if the resources |
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137 | * are already locked by another card. It can be called in any context |
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138 | */ |
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139 | |||
140 | #if defined(CONFIG_VGA_ARB) |
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141 | extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); |
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142 | #else |
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143 | static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; } |
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144 | #endif |
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145 | |||
146 | /** |
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147 | * vga_put - release lock on legacy VGA resources |
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148 | * |
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149 | * @pdev: pci device of VGA card or NULL for system default |
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150 | * @rsrc: but mask of resource to release |
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151 | * |
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152 | * This function releases resources previously locked by vga_get() |
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153 | * or vga_tryget(). The resources aren't disabled right away, so |
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154 | * that a subsequence vga_get() on the same card will succeed |
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155 | * immediately. Resources have a counter, so locks are only |
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156 | * released if the counter reaches 0. |
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157 | */ |
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158 | |||
159 | #if defined(CONFIG_VGA_ARB) |
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160 | extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); |
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161 | #else |
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162 | #define vga_put(pdev, rsrc) |
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163 | #endif |
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164 | |||
165 | |||
166 | /** |
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167 | * vga_default_device |
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168 | * |
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169 | * This can be defined by the platform. The default implementation |
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170 | * is rather dumb and will probably only work properly on single |
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171 | * vga card setups and/or x86 platforms. |
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172 | * |
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173 | * If your VGA default device is not PCI, you'll have to return |
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174 | * NULL here. In this case, I assume it will not conflict with |
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175 | * any PCI card. If this is not true, I'll have to define two archs |
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176 | * hooks for enabling/disabling the VGA default device if that is |
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177 | * possible. This may be a problem with real _ISA_ VGA cards, in |
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178 | * addition to a PCI one. I don't know at this point how to deal |
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179 | * with that card. Can theirs IOs be disabled at all ? If not, then |
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180 | * I suppose it's a matter of having the proper arch hook telling |
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181 | * us about it, so we basically never allow anybody to succeed a |
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182 | * vga_get()... |
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183 | */ |
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184 | |||
185 | #ifdef CONFIG_VGA_ARB |
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186 | extern struct pci_dev *vga_default_device(void); |
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187 | extern void vga_set_default_device(struct pci_dev *pdev); |
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188 | #else |
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189 | static inline struct pci_dev *vga_default_device(void) { return NULL; }; |
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190 | static inline void vga_set_default_device(struct pci_dev *pdev) { }; |
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191 | #endif |
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192 | |||
193 | /** |
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194 | * vga_conflicts |
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195 | * |
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196 | * Architectures should define this if they have several |
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197 | * independent PCI domains that can afford concurrent VGA |
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198 | * decoding |
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199 | */ |
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200 | |||
201 | #ifndef __ARCH_HAS_VGA_CONFLICT |
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202 | static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) |
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203 | { |
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204 | return 1; |
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205 | } |
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206 | #endif |
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207 | |||
208 | /** |
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209 | * vga_client_register |
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210 | * |
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211 | * @pdev: pci device of the VGA client |
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212 | * @cookie: client cookie to be used in callbacks |
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213 | * @irq_set_state: irq state change callback |
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214 | * @set_vga_decode: vga decode change callback |
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215 | * |
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216 | * return value: 0 on success, -1 on failure |
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217 | * Register a client with the VGA arbitration logic |
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218 | * |
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219 | * Clients have two callback mechanisms they can use. |
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220 | * irq enable/disable callback - |
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221 | * If a client can't disable its GPUs VGA resources, then we |
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222 | * need to be able to ask it to turn off its irqs when we |
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223 | * turn off its mem and io decoding. |
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224 | * set_vga_decode |
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225 | * If a client can disable its GPU VGA resource, it will |
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226 | * get a callback from this to set the encode/decode state |
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227 | * |
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228 | * Rationale: we cannot disable VGA decode resources unconditionally |
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229 | * some single GPU laptops seem to require ACPI or BIOS access to the |
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230 | * VGA registers to control things like backlights etc. |
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231 | * Hopefully newer multi-GPU laptops do something saner, and desktops |
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232 | * won't have any special ACPI for this. |
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233 | * They driver will get a callback when VGA arbitration is first used |
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234 | * by userspace since we some older X servers have issues. |
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235 | */ |
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236 | #if defined(CONFIG_VGA_ARB) |
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237 | int vga_client_register(struct pci_dev *pdev, void *cookie, |
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238 | void (*irq_set_state)(void *cookie, bool state), |
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239 | unsigned int (*set_vga_decode)(void *cookie, bool state)); |
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240 | #else |
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241 | static inline int vga_client_register(struct pci_dev *pdev, void *cookie, |
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242 | void (*irq_set_state)(void *cookie, bool state), |
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243 | unsigned int (*set_vga_decode)(void *cookie, bool state)) |
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244 | { |
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245 | return 0; |
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246 | } |
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247 | #endif |
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248 | |||
249 | #endif /* LINUX_VGA_H */ |