1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * PCI operations for the Sega Dreamcast 4 * 5 * Copyright (C) 2001, 2002 M. R. Brown 6 * Copyright (C) 2002, 2003 Paul Mundt 7 */ 8 9 #include <linux/sched.h> 10 #include <linux/kernel.h> 11 #include <linux/param.h> 12 #include <linux/interrupt.h> 13 #include <linux/init.h> 14 #include <linux/irq.h> 15 #include <linux/pci.h> 16 #include <linux/module.h> 17 #include <linux/io.h> 18 #include <mach/pci.h> 19 20 /* 21 * The !gapspci_config_access case really shouldn't happen, ever, unless 22 * someone implicitly messes around with the last devfn value.. otherwise we 23 * only support a single device anyways, and if we didn't have a BBA, we 24 * wouldn't make it terribly far through the PCI setup anyways. 25 * 26 * Also, we could very easily support both Type 0 and Type 1 configurations 27 * here, but since it doesn't seem that there is any such implementation in 28 * existence, we don't bother. 29 * 30 * I suppose if someone actually gets around to ripping the chip out of 31 * the BBA and hanging some more devices off of it, then this might be 32 * something to take into consideration. However, due to the cost of the BBA, 33 * and the general lack of activity by DC hardware hackers, this doesn't seem 34 * likely to happen anytime soon. 35 */ 36 static int gapspci_config_access(unsigned char bus, unsigned int devfn) 37 { 38 return (bus == 0) && (devfn == 0); 39 } 40 41 /* 42 * We can also actually read and write in b/w/l sizes! Thankfully this part 43 * was at least done right, and we don't have to do the stupid masking and 44 * shifting that we do on the 7751! Small wonders never cease to amaze. 45 */ 46 static int gapspci_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val) 47 { 48 *val = 0xffffffff; 49 50 if (!gapspci_config_access(bus->number, devfn)) 51 return PCIBIOS_DEVICE_NOT_FOUND; 52 53 switch (size) { 54 case 1: *val = inb(GAPSPCI_BBA_CONFIG+where); break; 55 case 2: *val = inw(GAPSPCI_BBA_CONFIG+where); break; 56 case 4: *val = inl(GAPSPCI_BBA_CONFIG+where); break; 57 } 58 59 return PCIBIOS_SUCCESSFUL; 60 } 61 62 static int gapspci_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val) 63 { 64 if (!gapspci_config_access(bus->number, devfn)) 65 return PCIBIOS_DEVICE_NOT_FOUND; 66 67 switch (size) { 68 case 1: outb(( u8)val, GAPSPCI_BBA_CONFIG+where); break; 69 case 2: outw((u16)val, GAPSPCI_BBA_CONFIG+where); break; 70 case 4: outl((u32)val, GAPSPCI_BBA_CONFIG+where); break; 71 } 72 73 return PCIBIOS_SUCCESSFUL; 74 } 75 76 struct pci_ops gapspci_pci_ops = { 77 .read = gapspci_read, 78 .write = gapspci_write, 79 }; 80