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 <benh@kernel.crashing.org> 6 * (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com> 7 * (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org> 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 51struct 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) 69extern void vga_set_legacy_decoding(struct pci_dev *pdev, 70 unsigned int decodes); 71#else 72static inline void vga_set_legacy_decoding(struct pci_dev *pdev, 73 unsigned int decodes) { }; 74#endif 75 76/** 77 * vga_get - acquire & locks VGA resources 78 * 79 * @pdev: pci device of the VGA card or NULL for the system default 80 * @rsrc: bit mask of resources to acquire and lock 81 * @interruptible: blocking should be interruptible by signals ? 82 * 83 * This function acquires VGA resources for the given 84 * card and mark those resources locked. If the resource requested 85 * are "normal" (and not legacy) resources, the arbiter will first check 86 * whether the card is doing legacy decoding for that type of resource. If 87 * yes, the lock is "converted" into a legacy resource lock. 88 * The arbiter will first look for all VGA cards that might conflict 89 * and disable their IOs and/or Memory access, including VGA forwarding 90 * on P2P bridges if necessary, so that the requested resources can 91 * be used. Then, the card is marked as locking these resources and 92 * the IO and/or Memory accesse are enabled on the card (including 93 * VGA forwarding on parent P2P bridges if any). 94 * This function will block if some conflicting card is already locking 95 * one of the required resources (or any resource on a different bus 96 * segment, since P2P bridges don't differenciate VGA memory and IO 97 * afaik). You can indicate whether this blocking should be interruptible 98 * by a signal (for userland interface) or not. 99 * Must not be called at interrupt time or in atomic context. 100 * If the card already owns the resources, the function succeeds. 101 * Nested calls are supported (a per-resource counter is maintained) 102 */ 103 104#if defined(CONFIG_VGA_ARB) 105extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible); 106#else 107static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; } 108#endif 109 110/** 111 * vga_get_interruptible 112 * 113 * Shortcut to vga_get 114 */ 115 116static inline int vga_get_interruptible(struct pci_dev *pdev, 117 unsigned int rsrc) 118{ 119 return vga_get(pdev, rsrc, 1); 120} 121 122/** 123 * vga_get_uninterruptible 124 * 125 * Shortcut to vga_get 126 */ 127 128static inline int vga_get_uninterruptible(struct pci_dev *pdev, 129 unsigned int rsrc) 130{ 131 return vga_get(pdev, rsrc, 0); 132} 133 134/** 135 * vga_tryget - try to acquire & lock legacy VGA resources 136 * 137 * @pdev: pci devivce of VGA card or NULL for system default 138 * @rsrc: bit mask of resources to acquire and lock 139 * 140 * This function performs the same operation as vga_get(), but 141 * will return an error (-EBUSY) instead of blocking if the resources 142 * are already locked by another card. It can be called in any context 143 */ 144 145#if defined(CONFIG_VGA_ARB) 146extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); 147#else 148static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; } 149#endif 150 151/** 152 * vga_put - release lock on legacy VGA resources 153 * 154 * @pdev: pci device of VGA card or NULL for system default 155 * @rsrc: but mask of resource to release 156 * 157 * This function releases resources previously locked by vga_get() 158 * or vga_tryget(). The resources aren't disabled right away, so 159 * that a subsequence vga_get() on the same card will succeed 160 * immediately. Resources have a counter, so locks are only 161 * released if the counter reaches 0. 162 */ 163 164#if defined(CONFIG_VGA_ARB) 165extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); 166#else 167#define vga_put(pdev, rsrc) 168#endif 169 170 171/** 172 * vga_default_device 173 * 174 * This can be defined by the platform. The default implementation 175 * is rather dumb and will probably only work properly on single 176 * vga card setups and/or x86 platforms. 177 * 178 * If your VGA default device is not PCI, you'll have to return 179 * NULL here. In this case, I assume it will not conflict with 180 * any PCI card. If this is not true, I'll have to define two archs 181 * hooks for enabling/disabling the VGA default device if that is 182 * possible. This may be a problem with real _ISA_ VGA cards, in 183 * addition to a PCI one. I don't know at this point how to deal 184 * with that card. Can theirs IOs be disabled at all ? If not, then 185 * I suppose it's a matter of having the proper arch hook telling 186 * us about it, so we basically never allow anybody to succeed a 187 * vga_get()... 188 */ 189 190#ifdef CONFIG_VGA_ARB 191extern struct pci_dev *vga_default_device(void); 192extern void vga_set_default_device(struct pci_dev *pdev); 193#else 194static inline struct pci_dev *vga_default_device(void) { return NULL; }; 195static inline void vga_set_default_device(struct pci_dev *pdev) { }; 196#endif 197 198/** 199 * vga_conflicts 200 * 201 * Architectures should define this if they have several 202 * independent PCI domains that can afford concurrent VGA 203 * decoding 204 */ 205 206#ifndef __ARCH_HAS_VGA_CONFLICT 207static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) 208{ 209 return 1; 210} 211#endif 212 213/** 214 * vga_client_register 215 * 216 * @pdev: pci device of the VGA client 217 * @cookie: client cookie to be used in callbacks 218 * @irq_set_state: irq state change callback 219 * @set_vga_decode: vga decode change callback 220 * 221 * return value: 0 on success, -1 on failure 222 * Register a client with the VGA arbitration logic 223 * 224 * Clients have two callback mechanisms they can use. 225 * irq enable/disable callback - 226 * If a client can't disable its GPUs VGA resources, then we 227 * need to be able to ask it to turn off its irqs when we 228 * turn off its mem and io decoding. 229 * set_vga_decode 230 * If a client can disable its GPU VGA resource, it will 231 * get a callback from this to set the encode/decode state 232 * 233 * Rationale: we cannot disable VGA decode resources unconditionally 234 * some single GPU laptops seem to require ACPI or BIOS access to the 235 * VGA registers to control things like backlights etc. 236 * Hopefully newer multi-GPU laptops do something saner, and desktops 237 * won't have any special ACPI for this. 238 * They driver will get a callback when VGA arbitration is first used 239 * by userspace since we some older X servers have issues. 240 */ 241#if defined(CONFIG_VGA_ARB) 242int vga_client_register(struct pci_dev *pdev, void *cookie, 243 void (*irq_set_state)(void *cookie, bool state), 244 unsigned int (*set_vga_decode)(void *cookie, bool state)); 245#else 246static inline 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{ 250 return 0; 251} 252#endif 253 254#endif /* LINUX_VGA_H */ 255