85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/pci.h>
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#include <asm/pci-direct.h>
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#include <asm/io.h>
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#include <asm/pci_x86.h>
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/* Direct PCI access. This is used for PCI accesses in early boot before
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the PCI subsystem works. */
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u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset)
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{
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u32 v;
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outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
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v = inl(0xcfc);
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return v;
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}
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u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset)
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{
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u8 v;
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outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
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v = inb(0xcfc + (offset&3));
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return v;
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}
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u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset)
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{
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u16 v;
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outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
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v = inw(0xcfc + (offset&2));
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return v;
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}
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void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
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u32 val)
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{
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outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
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outl(val, 0xcfc);
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}
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void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val)
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{
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outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
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outb(val, 0xcfc + (offset&3));
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}
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void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val)
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{
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outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
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outw(val, 0xcfc + (offset&2));
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}
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u32 pci_early_find_cap(int bus, int slot, int func, int cap)
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{
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int bytes;
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u8 pos;
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if (!(read_pci_config_16(bus, slot, func, PCI_STATUS) &
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PCI_STATUS_CAP_LIST))
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return 0;
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pos = read_pci_config_byte(bus, slot, func, PCI_CAPABILITY_LIST);
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for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
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u8 id;
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pos &= ~3;
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id = read_pci_config_byte(bus, slot, func, pos+PCI_CAP_LIST_ID);
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if (id == 0xff)
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break;
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if (id == cap)
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return pos;
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pos = read_pci_config_byte(bus, slot, func,
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pos+PCI_CAP_LIST_NEXT);
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}
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return 0;
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}
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int early_pci_allowed(void)
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{
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return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
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PCI_PROBE_CONF1;
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}
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