1 /* 2 * vgaarb.c 3 * 4 * (C) Copyright 2005 Benjamin Herrenschmidt <[email protected]> 5 * (C) Copyright 2007 Paulo R. Zanoni <[email protected]> 6 * (C) Copyright 2007, 2009 Tiago Vignatti <[email protected]> 7 */ 8 9 #ifndef LINUX_VGA_H 10 11 #include <asm/vga.h> 12 13 /* Legacy VGA regions */ 14 #define VGA_RSRC_NONE 0x00 15 #define VGA_RSRC_LEGACY_IO 0x01 16 #define VGA_RSRC_LEGACY_MEM 0x02 17 #define VGA_RSRC_LEGACY_MASK (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM) 18 /* Non-legacy access */ 19 #define VGA_RSRC_NORMAL_IO 0x04 20 #define VGA_RSRC_NORMAL_MEM 0x08 21 22 /* Passing that instead of a pci_dev to use the system "default" 23 * device, that is the one used by vgacon. Archs will probably 24 * have to provide their own vga_default_device(); 25 */ 26 #define VGA_DEFAULT_DEVICE (NULL) 27 28 /* For use by clients */ 29 30 /** 31 * vga_set_legacy_decoding 32 * 33 * @pdev: pci device of the VGA card 34 * @decodes: bit mask of what legacy regions the card decodes 35 * 36 * Indicates to the arbiter if the card decodes legacy VGA IOs, 37 * legacy VGA Memory, both, or none. All cards default to both, 38 * the card driver (fbdev for example) should tell the arbiter 39 * if it has disabled legacy decoding, so the card can be left 40 * out of the arbitration process (and can be safe to take 41 * interrupts at any time. 42 */ 43 extern void vga_set_legacy_decoding(struct pci_dev *pdev, 44 unsigned int decodes); 45 46 /** 47 * vga_get - acquire & locks VGA resources 48 * 49 * @pdev: pci device of the VGA card or NULL for the system default 50 * @rsrc: bit mask of resources to acquire and lock 51 * @interruptible: blocking should be interruptible by signals ? 52 * 53 * This function acquires VGA resources for the given 54 * card and mark those resources locked. If the resource requested 55 * are "normal" (and not legacy) resources, the arbiter will first check 56 * wether the card is doing legacy decoding for that type of resource. If 57 * yes, the lock is "converted" into a legacy resource lock. 58 * The arbiter will first look for all VGA cards that might conflict 59 * and disable their IOs and/or Memory access, inlcuding VGA forwarding 60 * on P2P bridges if necessary, so that the requested resources can 61 * be used. Then, the card is marked as locking these resources and 62 * the IO and/or Memory accesse are enabled on the card (including 63 * VGA forwarding on parent P2P bridges if any). 64 * This function will block if some conflicting card is already locking 65 * one of the required resources (or any resource on a different bus 66 * segment, since P2P bridges don't differenciate VGA memory and IO 67 * afaik). You can indicate wether this blocking should be interruptible 68 * by a signal (for userland interface) or not. 69 * Must not be called at interrupt time or in atomic context. 70 * If the card already owns the resources, the function succeeds. 71 * Nested calls are supported (a per-resource counter is maintained) 72 */ 73 74 extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, 75 int interruptible); 76 77 /** 78 * vga_get_interruptible 79 * 80 * Shortcut to vga_get 81 */ 82 83 static inline int vga_get_interruptible(struct pci_dev *pdev, 84 unsigned int rsrc) 85 { 86 return vga_get(pdev, rsrc, 1); 87 } 88 89 /** 90 * vga_get_uninterruptible 91 * 92 * Shortcut to vga_get 93 */ 94 95 static inline int vga_get_uninterruptible(struct pci_dev *pdev, 96 unsigned int rsrc) 97 { 98 return vga_get(pdev, rsrc, 0); 99 } 100 101 /** 102 * vga_tryget - try to acquire & lock legacy VGA resources 103 * 104 * @pdev: pci devivce of VGA card or NULL for system default 105 * @rsrc: bit mask of resources to acquire and lock 106 * 107 * This function performs the same operation as vga_get(), but 108 * will return an error (-EBUSY) instead of blocking if the resources 109 * are already locked by another card. It can be called in any context 110 */ 111 112 extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); 113 114 /** 115 * vga_put - release lock on legacy VGA resources 116 * 117 * @pdev: pci device of VGA card or NULL for system default 118 * @rsrc: but mask of resource to release 119 * 120 * This function releases resources previously locked by vga_get() 121 * or vga_tryget(). The resources aren't disabled right away, so 122 * that a subsequence vga_get() on the same card will succeed 123 * immediately. Resources have a counter, so locks are only 124 * released if the counter reaches 0. 125 */ 126 127 extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); 128 129 130 /** 131 * vga_default_device 132 * 133 * This can be defined by the platform. The default implementation 134 * is rather dumb and will probably only work properly on single 135 * vga card setups and/or x86 platforms. 136 * 137 * If your VGA default device is not PCI, you'll have to return 138 * NULL here. In this case, I assume it will not conflict with 139 * any PCI card. If this is not true, I'll have to define two archs 140 * hooks for enabling/disabling the VGA default device if that is 141 * possible. This may be a problem with real _ISA_ VGA cards, in 142 * addition to a PCI one. I don't know at this point how to deal 143 * with that card. Can theirs IOs be disabled at all ? If not, then 144 * I suppose it's a matter of having the proper arch hook telling 145 * us about it, so we basically never allow anybody to succeed a 146 * vga_get()... 147 */ 148 149 #ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE 150 extern struct pci_dev *vga_default_device(void); 151 #endif 152 153 /** 154 * vga_conflicts 155 * 156 * Architectures should define this if they have several 157 * independant PCI domains that can afford concurrent VGA 158 * decoding 159 */ 160 161 #ifndef __ARCH_HAS_VGA_CONFLICT 162 static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) 163 { 164 return 1; 165 } 166 #endif 167 168 /** 169 * vga_client_register 170 * 171 * @pdev: pci device of the VGA client 172 * @cookie: client cookie to be used in callbacks 173 * @irq_set_state: irq state change callback 174 * @set_vga_decode: vga decode change callback 175 * 176 * return value: 0 on success, -1 on failure 177 * Register a client with the VGA arbitration logic 178 * 179 * Clients have two callback mechanisms they can use. 180 * irq enable/disable callback - 181 * If a client can't disable its GPUs VGA resources, then we 182 * need to be able to ask it to turn off its irqs when we 183 * turn off its mem and io decoding. 184 * set_vga_decode 185 * If a client can disable its GPU VGA resource, it will 186 * get a callback from this to set the encode/decode state 187 * 188 * Rationale: we cannot disable VGA decode resources unconditionally 189 * some single GPU laptops seem to require ACPI or BIOS access to the 190 * VGA registers to control things like backlights etc. 191 * Hopefully newer multi-GPU laptops do something saner, and desktops 192 * won't have any special ACPI for this. 193 * They driver will get a callback when VGA arbitration is first used 194 * by userspace since we some older X servers have issues. 195 */ 196 int vga_client_register(struct pci_dev *pdev, void *cookie, 197 void (*irq_set_state)(void *cookie, bool state), 198 unsigned int (*set_vga_decode)(void *cookie, bool state)); 199 200 #endif /* LINUX_VGA_H */ 201