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