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 #include <video/vga.h> 35 36 /* Legacy VGA regions */ 37 #define VGA_RSRC_NONE 0x00 38 #define VGA_RSRC_LEGACY_IO 0x01 39 #define VGA_RSRC_LEGACY_MEM 0x02 40 #define VGA_RSRC_LEGACY_MASK (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM) 41 /* Non-legacy access */ 42 #define VGA_RSRC_NORMAL_IO 0x04 43 #define VGA_RSRC_NORMAL_MEM 0x08 44 45 /* Passing that instead of a pci_dev to use the system "default" 46 * device, that is the one used by vgacon. Archs will probably 47 * have to provide their own vga_default_device(); 48 */ 49 #define VGA_DEFAULT_DEVICE (NULL) 50 51 struct pci_dev; 52 53 /* For use by clients */ 54 55 /** 56 * vga_set_legacy_decoding 57 * 58 * @pdev: pci device of the VGA card 59 * @decodes: bit mask of what legacy regions the card decodes 60 * 61 * Indicates to the arbiter if the card decodes legacy VGA IOs, 62 * legacy VGA Memory, both, or none. All cards default to both, 63 * the card driver (fbdev for example) should tell the arbiter 64 * if it has disabled legacy decoding, so the card can be left 65 * out of the arbitration process (and can be safe to take 66 * interrupts at any time. 67 */ 68 #if defined(CONFIG_VGA_ARB) 69 extern void vga_set_legacy_decoding(struct pci_dev *pdev, 70 unsigned int decodes); 71 #else 72 static inline void vga_set_legacy_decoding(struct pci_dev *pdev, 73 unsigned int decodes) 74 { 75 } 76 #endif 77 78 /** 79 * vga_get - acquire & locks VGA resources 80 * 81 * @pdev: pci device of the VGA card or NULL for the system default 82 * @rsrc: bit mask of resources to acquire and lock 83 * @interruptible: blocking should be interruptible by signals ? 84 * 85 * This function acquires VGA resources for the given 86 * card and mark those resources locked. If the resource requested 87 * are "normal" (and not legacy) resources, the arbiter will first check 88 * whether the card is doing legacy decoding for that type of resource. If 89 * yes, the lock is "converted" into a legacy resource lock. 90 * The arbiter will first look for all VGA cards that might conflict 91 * and disable their IOs and/or Memory access, including VGA forwarding 92 * on P2P bridges if necessary, so that the requested resources can 93 * be used. Then, the card is marked as locking these resources and 94 * the IO and/or Memory accesse are enabled on the card (including 95 * VGA forwarding on parent P2P bridges if any). 96 * This function will block if some conflicting card is already locking 97 * one of the required resources (or any resource on a different bus 98 * segment, since P2P bridges don't differenciate VGA memory and IO 99 * afaik). You can indicate whether this blocking should be interruptible 100 * by a signal (for userland interface) or not. 101 * Must not be called at interrupt time or in atomic context. 102 * If the card already owns the resources, the function succeeds. 103 * Nested calls are supported (a per-resource counter is maintained) 104 */ 105 106 #if defined(CONFIG_VGA_ARB) 107 extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible); 108 #else 109 static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; } 110 #endif 111 112 /** 113 * vga_get_interruptible 114 * 115 * Shortcut to vga_get 116 */ 117 118 static inline int vga_get_interruptible(struct pci_dev *pdev, 119 unsigned int rsrc) 120 { 121 return vga_get(pdev, rsrc, 1); 122 } 123 124 /** 125 * vga_get_uninterruptible 126 * 127 * Shortcut to vga_get 128 */ 129 130 static inline int vga_get_uninterruptible(struct pci_dev *pdev, 131 unsigned int rsrc) 132 { 133 return vga_get(pdev, rsrc, 0); 134 } 135 136 /** 137 * vga_tryget - try to acquire & lock legacy VGA resources 138 * 139 * @pdev: pci devivce of VGA card or NULL for system default 140 * @rsrc: bit mask of resources to acquire and lock 141 * 142 * This function performs the same operation as vga_get(), but 143 * will return an error (-EBUSY) instead of blocking if the resources 144 * are already locked by another card. It can be called in any context 145 */ 146 147 #if defined(CONFIG_VGA_ARB) 148 extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); 149 #else 150 static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; } 151 #endif 152 153 /** 154 * vga_put - release lock on legacy VGA resources 155 * 156 * @pdev: pci device of VGA card or NULL for system default 157 * @rsrc: but mask of resource to release 158 * 159 * This function releases resources previously locked by vga_get() 160 * or vga_tryget(). The resources aren't disabled right away, so 161 * that a subsequence vga_get() on the same card will succeed 162 * immediately. Resources have a counter, so locks are only 163 * released if the counter reaches 0. 164 */ 165 166 #if defined(CONFIG_VGA_ARB) 167 extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); 168 #else 169 #define vga_put(pdev, rsrc) 170 #endif 171 172 173 /** 174 * vga_default_device 175 * 176 * This can be defined by the platform. The default implementation 177 * is rather dumb and will probably only work properly on single 178 * vga card setups and/or x86 platforms. 179 * 180 * If your VGA default device is not PCI, you'll have to return 181 * NULL here. In this case, I assume it will not conflict with 182 * any PCI card. If this is not true, I'll have to define two archs 183 * hooks for enabling/disabling the VGA default device if that is 184 * possible. This may be a problem with real _ISA_ VGA cards, in 185 * addition to a PCI one. I don't know at this point how to deal 186 * with that card. Can theirs IOs be disabled at all ? If not, then 187 * I suppose it's a matter of having the proper arch hook telling 188 * us about it, so we basically never allow anybody to succeed a 189 * vga_get()... 190 */ 191 192 #ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE 193 #ifdef CONFIG_VGA_ARB 194 extern struct pci_dev *vga_default_device(void); 195 extern void vga_set_default_device(struct pci_dev *pdev); 196 #else 197 static inline struct pci_dev *vga_default_device(void) { return NULL; }; 198 static inline void vga_set_default_device(struct pci_dev *pdev) { }; 199 #endif 200 #endif 201 202 /** 203 * vga_conflicts 204 * 205 * Architectures should define this if they have several 206 * independent PCI domains that can afford concurrent VGA 207 * decoding 208 */ 209 210 #ifndef __ARCH_HAS_VGA_CONFLICT 211 static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) 212 { 213 return 1; 214 } 215 #endif 216 217 /** 218 * vga_client_register 219 * 220 * @pdev: pci device of the VGA client 221 * @cookie: client cookie to be used in callbacks 222 * @irq_set_state: irq state change callback 223 * @set_vga_decode: vga decode change callback 224 * 225 * return value: 0 on success, -1 on failure 226 * Register a client with the VGA arbitration logic 227 * 228 * Clients have two callback mechanisms they can use. 229 * irq enable/disable callback - 230 * If a client can't disable its GPUs VGA resources, then we 231 * need to be able to ask it to turn off its irqs when we 232 * turn off its mem and io decoding. 233 * set_vga_decode 234 * If a client can disable its GPU VGA resource, it will 235 * get a callback from this to set the encode/decode state 236 * 237 * Rationale: we cannot disable VGA decode resources unconditionally 238 * some single GPU laptops seem to require ACPI or BIOS access to the 239 * VGA registers to control things like backlights etc. 240 * Hopefully newer multi-GPU laptops do something saner, and desktops 241 * won't have any special ACPI for this. 242 * They driver will get a callback when VGA arbitration is first used 243 * by userspace since we some older X servers have issues. 244 */ 245 #if defined(CONFIG_VGA_ARB) 246 int vga_client_register(struct pci_dev *pdev, void *cookie, 247 void (*irq_set_state)(void *cookie, bool state), 248 unsigned int (*set_vga_decode)(void *cookie, bool state)); 249 #else 250 static inline int vga_client_register(struct pci_dev *pdev, void *cookie, 251 void (*irq_set_state)(void *cookie, bool state), 252 unsigned int (*set_vga_decode)(void *cookie, bool state)) 253 { 254 return 0; 255 } 256 #endif 257 258 #endif /* LINUX_VGA_H */ 259