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 10#ifndef LINUX_VGA_H 11 12#include <asm/vga.h> 13 14/* Legacy VGA regions */ 15#define VGA_RSRC_NONE 0x00 16#define VGA_RSRC_LEGACY_IO 0x01 17#define VGA_RSRC_LEGACY_MEM 0x02 18#define VGA_RSRC_LEGACY_MASK (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM) 19/* Non-legacy access */ 20#define VGA_RSRC_NORMAL_IO 0x04 21#define VGA_RSRC_NORMAL_MEM 0x08 22 23/* Passing that instead of a pci_dev to use the system "default" 24 * device, that is the one used by vgacon. Archs will probably 25 * have to provide their own vga_default_device(); 26 */ 27#define VGA_DEFAULT_DEVICE (NULL) 28 29/* For use by clients */ 30 31/** 32 * vga_set_legacy_decoding 33 * 34 * @pdev: pci device of the VGA card 35 * @decodes: bit mask of what legacy regions the card decodes 36 * 37 * Indicates to the arbiter if the card decodes legacy VGA IOs, 38 * legacy VGA Memory, both, or none. All cards default to both, 39 * the card driver (fbdev for example) should tell the arbiter 40 * if it has disabled legacy decoding, so the card can be left 41 * out of the arbitration process (and can be safe to take 42 * interrupts at any time. 43 */ 44extern void vga_set_legacy_decoding(struct pci_dev *pdev, 45 unsigned int decodes); 46 47/** 48 * vga_get - acquire & locks VGA resources 49 * 50 * @pdev: pci device of the VGA card or NULL for the system default 51 * @rsrc: bit mask of resources to acquire and lock 52 * @interruptible: blocking should be interruptible by signals ? 53 * 54 * This function acquires VGA resources for the given 55 * card and mark those resources locked. If the resource requested 56 * are "normal" (and not legacy) resources, the arbiter will first check 57 * wether the card is doing legacy decoding for that type of resource. If 58 * yes, the lock is "converted" into a legacy resource lock. 59 * The arbiter will first look for all VGA cards that might conflict 60 * and disable their IOs and/or Memory access, inlcuding VGA forwarding 61 * on P2P bridges if necessary, so that the requested resources can 62 * be used. Then, the card is marked as locking these resources and 63 * the IO and/or Memory accesse are enabled on the card (including 64 * VGA forwarding on parent P2P bridges if any). 65 * This function will block if some conflicting card is already locking 66 * one of the required resources (or any resource on a different bus 67 * segment, since P2P bridges don't differenciate VGA memory and IO 68 * afaik). You can indicate wether this blocking should be interruptible 69 * by a signal (for userland interface) or not. 70 * Must not be called at interrupt time or in atomic context. 71 * If the card already owns the resources, the function succeeds. 72 * Nested calls are supported (a per-resource counter is maintained) 73 */ 74 75extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, 76 int interruptible); 77 78/** 79 * vga_get_interruptible 80 * 81 * Shortcut to vga_get 82 */ 83 84static inline int vga_get_interruptible(struct pci_dev *pdev, 85 unsigned int rsrc) 86{ 87 return vga_get(pdev, rsrc, 1); 88} 89 90/** 91 * vga_get_uninterruptible 92 * 93 * Shortcut to vga_get 94 */ 95 96static inline int vga_get_uninterruptible(struct pci_dev *pdev, 97 unsigned int rsrc) 98{ 99 return vga_get(pdev, rsrc, 0); 100} 101 102/** 103 * vga_tryget - try to acquire & lock legacy VGA resources 104 * 105 * @pdev: pci devivce of VGA card or NULL for system default 106 * @rsrc: bit mask of resources to acquire and lock 107 * 108 * This function performs the same operation as vga_get(), but 109 * will return an error (-EBUSY) instead of blocking if the resources 110 * are already locked by another card. It can be called in any context 111 */ 112 113extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc); 114 115/** 116 * vga_put - release lock on legacy VGA resources 117 * 118 * @pdev: pci device of VGA card or NULL for system default 119 * @rsrc: but mask of resource to release 120 * 121 * This function releases resources previously locked by vga_get() 122 * or vga_tryget(). The resources aren't disabled right away, so 123 * that a subsequence vga_get() on the same card will succeed 124 * immediately. Resources have a counter, so locks are only 125 * released if the counter reaches 0. 126 */ 127 128extern void vga_put(struct pci_dev *pdev, unsigned int rsrc); 129 130 131/** 132 * vga_default_device 133 * 134 * This can be defined by the platform. The default implementation 135 * is rather dumb and will probably only work properly on single 136 * vga card setups and/or x86 platforms. 137 * 138 * If your VGA default device is not PCI, you'll have to return 139 * NULL here. In this case, I assume it will not conflict with 140 * any PCI card. If this is not true, I'll have to define two archs 141 * hooks for enabling/disabling the VGA default device if that is 142 * possible. This may be a problem with real _ISA_ VGA cards, in 143 * addition to a PCI one. I don't know at this point how to deal 144 * with that card. Can theirs IOs be disabled at all ? If not, then 145 * I suppose it's a matter of having the proper arch hook telling 146 * us about it, so we basically never allow anybody to succeed a 147 * vga_get()... 148 */ 149 150#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE 151extern struct pci_dev *vga_default_device(void); 152#endif 153 154/** 155 * vga_conflicts 156 * 157 * Architectures should define this if they have several 158 * independant PCI domains that can afford concurrent VGA 159 * decoding 160 */ 161 162#ifndef __ARCH_HAS_VGA_CONFLICT 163static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) 164{ 165 return 1; 166} 167#endif 168 169/** 170 * vga_client_register 171 * 172 * @pdev: pci device of the VGA client 173 * @cookie: client cookie to be used in callbacks 174 * @irq_set_state: irq state change callback 175 * @set_vga_decode: vga decode change callback 176 * 177 * return value: 0 on success, -1 on failure 178 * Register a client with the VGA arbitration logic 179 * 180 * Clients have two callback mechanisms they can use. 181 * irq enable/disable callback - 182 * If a client can't disable its GPUs VGA resources, then we 183 * need to be able to ask it to turn off its irqs when we 184 * turn off its mem and io decoding. 185 * set_vga_decode 186 * If a client can disable its GPU VGA resource, it will 187 * get a callback from this to set the encode/decode state 188 * 189 * Rationale: we cannot disable VGA decode resources unconditionally 190 * some single GPU laptops seem to require ACPI or BIOS access to the 191 * VGA registers to control things like backlights etc. 192 * Hopefully newer multi-GPU laptops do something saner, and desktops 193 * won't have any special ACPI for this. 194 * They driver will get a callback when VGA arbitration is first used 195 * by userspace since we some older X servers have issues. 196 */ 197#if defined(CONFIG_VGA_ARB) 198int vga_client_register(struct pci_dev *pdev, void *cookie, 199 void (*irq_set_state)(void *cookie, bool state), 200 unsigned int (*set_vga_decode)(void *cookie, bool state)); 201#else 202static inline int vga_client_register(struct pci_dev *pdev, void *cookie, 203 void (*irq_set_state)(void *cookie, bool state), 204 unsigned int (*set_vga_decode)(void *cookie, bool state)) 205{ 206 return 0; 207} 208#endif 209 210#endif /* LINUX_VGA_H */ 211