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