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