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 */ 68extern void vga_set_legacy_decoding(struct pci_dev *pdev, 69 unsigned int decodes); 70 71/** 72 * vga_get - acquire & locks VGA resources 73 * 74 * @pdev: pci device of the VGA card or NULL for the system default 75 * @rsrc: bit mask of resources to acquire and lock 76 * @interruptible: blocking should be interruptible by signals ? 77 * 78 * This function acquires VGA resources for the given 79 * card and mark those resources locked. If the resource requested 80 * are "normal" (and not legacy) resources, the arbiter will first check 81 * whether the card is doing legacy decoding for that type of resource. If 82 * yes, the lock is "converted" into a legacy resource lock. 83 * The arbiter will first look for all VGA cards that might conflict 84 * and disable their IOs and/or Memory access, including VGA forwarding 85 * on P2P bridges if necessary, so that the requested resources can 86 * be used. Then, the card is marked as locking these resources and 87 * the IO and/or Memory accesse are enabled on the card (including 88 * VGA forwarding on parent P2P bridges if any). 89 * This function will block if some conflicting card is already locking 90 * one of the required resources (or any resource on a different bus 91 * segment, since P2P bridges don't differenciate VGA memory and IO 92 * afaik). You can indicate whether this blocking should be interruptible 93 * by a signal (for userland interface) or not. 94 * Must not be called at interrupt time or in atomic context. 95 * If the card already owns the resources, the function succeeds. 96 * Nested calls are supported (a per-resource counter is maintained) 97 */ 98 99#if defined(CONFIG_VGA_ARB) 100extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible); 101#else 102static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; } 103#endif 104 105/** 106 * vga_get_interruptible 107 * 108 * Shortcut to vga_get 109 */ 110 111static inline int vga_get_interruptible(struct pci_dev *pdev, 112 unsigned int rsrc) 113{ 114 return vga_get(pdev, rsrc, 1); 115} 116 117/** 118 * vga_get_uninterruptible 119 * 120 * Shortcut to vga_get 121 */ 122 123static inline int vga_get_uninterruptible(struct pci_dev *pdev, 124 unsigned int rsrc) 125{ 126 return vga_get(pdev, rsrc, 0); 127} 128 129/** 130 * vga_tryget - try to acquire & lock legacy VGA resources 131 * 132 * @pdev: pci devivce of VGA card or NULL for system default 133 * @rsrc: bit mask of resources to acquire and lock 134 * 135 * This function performs the same operation as vga_get(), but 136 * will return an error (-EBUSY) instead of blocking if the resources 137 * are already locked by another card. It can be called in any context 138 */ 139 140#if defined(CONFIG_VGA_ARB) 141extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); 142#else 143static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; } 144#endif 145 146/** 147 * vga_put - release lock on legacy VGA resources 148 * 149 * @pdev: pci device of VGA card or NULL for system default 150 * @rsrc: but mask of resource to release 151 * 152 * This function releases resources previously locked by vga_get() 153 * or vga_tryget(). The resources aren't disabled right away, so 154 * that a subsequence vga_get() on the same card will succeed 155 * immediately. Resources have a counter, so locks are only 156 * released if the counter reaches 0. 157 */ 158 159#if defined(CONFIG_VGA_ARB) 160extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); 161#else 162#define vga_put(pdev, rsrc) 163#endif 164 165 166/** 167 * vga_default_device 168 * 169 * This can be defined by the platform. The default implementation 170 * is rather dumb and will probably only work properly on single 171 * vga card setups and/or x86 platforms. 172 * 173 * If your VGA default device is not PCI, you'll have to return 174 * NULL here. In this case, I assume it will not conflict with 175 * any PCI card. If this is not true, I'll have to define two archs 176 * hooks for enabling/disabling the VGA default device if that is 177 * possible. This may be a problem with real _ISA_ VGA cards, in 178 * addition to a PCI one. I don't know at this point how to deal 179 * with that card. Can theirs IOs be disabled at all ? If not, then 180 * I suppose it's a matter of having the proper arch hook telling 181 * us about it, so we basically never allow anybody to succeed a 182 * vga_get()... 183 */ 184 185#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE 186#ifdef CONFIG_VGA_ARB 187extern struct pci_dev *vga_default_device(void); 188extern void vga_set_default_device(struct pci_dev *pdev); 189#else 190static inline struct pci_dev *vga_default_device(void) { return NULL; }; 191static inline void vga_set_default_device(struct pci_dev *pdev) { }; 192#endif 193#endif 194 195/** 196 * vga_conflicts 197 * 198 * Architectures should define this if they have several 199 * independent PCI domains that can afford concurrent VGA 200 * decoding 201 */ 202 203#ifndef __ARCH_HAS_VGA_CONFLICT 204static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) 205{ 206 return 1; 207} 208#endif 209 210/** 211 * vga_client_register 212 * 213 * @pdev: pci device of the VGA client 214 * @cookie: client cookie to be used in callbacks 215 * @irq_set_state: irq state change callback 216 * @set_vga_decode: vga decode change callback 217 * 218 * return value: 0 on success, -1 on failure 219 * Register a client with the VGA arbitration logic 220 * 221 * Clients have two callback mechanisms they can use. 222 * irq enable/disable callback - 223 * If a client can't disable its GPUs VGA resources, then we 224 * need to be able to ask it to turn off its irqs when we 225 * turn off its mem and io decoding. 226 * set_vga_decode 227 * If a client can disable its GPU VGA resource, it will 228 * get a callback from this to set the encode/decode state 229 * 230 * Rationale: we cannot disable VGA decode resources unconditionally 231 * some single GPU laptops seem to require ACPI or BIOS access to the 232 * VGA registers to control things like backlights etc. 233 * Hopefully newer multi-GPU laptops do something saner, and desktops 234 * won't have any special ACPI for this. 235 * They driver will get a callback when VGA arbitration is first used 236 * by userspace since we some older X servers have issues. 237 */ 238#if defined(CONFIG_VGA_ARB) 239int vga_client_register(struct pci_dev *pdev, void *cookie, 240 void (*irq_set_state)(void *cookie, bool state), 241 unsigned int (*set_vga_decode)(void *cookie, bool state)); 242#else 243static inline int vga_client_register(struct pci_dev *pdev, void *cookie, 244 void (*irq_set_state)(void *cookie, bool state), 245 unsigned int (*set_vga_decode)(void *cookie, bool state)) 246{ 247 return 0; 248} 249#endif 250 251#endif /* LINUX_VGA_H */ 252