1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/kernel.h> 3 #include <linux/pci.h> 4 #include <asm/pci-direct.h> 5 #include <asm/io.h> 6 #include <asm/pci_x86.h> 7 8 /* Direct PCI access. This is used for PCI accesses in early boot before 9 the PCI subsystem works. */ 10 11 u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset) 12 { 13 u32 v; 14 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8); 15 v = inl(0xcfc); 16 return v; 17 } 18 19 u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset) 20 { 21 u8 v; 22 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8); 23 v = inb(0xcfc + (offset&3)); 24 return v; 25 } 26 27 u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset) 28 { 29 u16 v; 30 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8); 31 v = inw(0xcfc + (offset&2)); 32 return v; 33 } 34 35 void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset, 36 u32 val) 37 { 38 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8); 39 outl(val, 0xcfc); 40 } 41 42 void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val) 43 { 44 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8); 45 outb(val, 0xcfc + (offset&3)); 46 } 47 48 void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val) 49 { 50 outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8); 51 outw(val, 0xcfc + (offset&2)); 52 } 53 54 int early_pci_allowed(void) 55 { 56 return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) == 57 PCI_PROBE_CONF1; 58 } 59 60