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/arch/mips/pci/fixup-sb1250.c

http://github.com/mirrors/linux
C | 91 lines | 55 code | 11 blank | 25 comment | 8 complexity | 8fca0841b3695a409522a169861c62eb MD5 | raw file
 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 *	Copyright (C) 2004, 2006  MIPS Technologies, Inc.  All rights reserved.
 4 *	    Author:	Maciej W. Rozycki <macro@mips.com>
 5 *	Copyright (C) 2018  Maciej W. Rozycki
 6 */
 7
 8#include <linux/dma-mapping.h>
 9#include <linux/pci.h>
10
11/*
12 * Set the BCM1250, etc. PCI host bridge's TRDY timeout
13 * to the finite max.
14 */
15static void quirk_sb1250_pci(struct pci_dev *dev)
16{
17	pci_write_config_byte(dev, 0x40, 0xff);
18}
19DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,
20			quirk_sb1250_pci);
21
22/*
23 * The BCM1250, etc. PCI host bridge does not support DAC on its 32-bit
24 * bus, so we set the bus's DMA limit accordingly.  However the HT link
25 * down the artificial PCI-HT bridge supports 40-bit addressing and the
26 * SP1011 HT-PCI bridge downstream supports both DAC and a 64-bit bus
27 * width, so we record the PCI-HT bridge's secondary and subordinate bus
28 * numbers and do not set the limit for devices present in the inclusive
29 * range of those.
30 */
31struct sb1250_bus_dma_limit_exclude {
32	bool set;
33	unsigned char start;
34	unsigned char end;
35};
36
37static int sb1250_bus_dma_limit(struct pci_dev *dev, void *data)
38{
39	struct sb1250_bus_dma_limit_exclude *exclude = data;
40	bool exclude_this;
41	bool ht_bridge;
42
43	exclude_this = exclude->set && (dev->bus->number >= exclude->start &&
44					dev->bus->number <= exclude->end);
45	ht_bridge = !exclude->set && (dev->vendor == PCI_VENDOR_ID_SIBYTE &&
46				      dev->device == PCI_DEVICE_ID_BCM1250_HT);
47
48	if (exclude_this) {
49		dev_dbg(&dev->dev, "not disabling DAC for device");
50	} else if (ht_bridge) {
51		exclude->start = dev->subordinate->number;
52		exclude->end = pci_bus_max_busnr(dev->subordinate);
53		exclude->set = true;
54		dev_dbg(&dev->dev, "not disabling DAC for [bus %02x-%02x]",
55			exclude->start, exclude->end);
56	} else {
57		dev_dbg(&dev->dev, "disabling DAC for device");
58		dev->dev.bus_dma_limit = DMA_BIT_MASK(32);
59	}
60
61	return 0;
62}
63
64static void quirk_sb1250_pci_dac(struct pci_dev *dev)
65{
66	struct sb1250_bus_dma_limit_exclude exclude = { .set = false };
67
68	pci_walk_bus(dev->bus, sb1250_bus_dma_limit, &exclude);
69}
70DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,
71			quirk_sb1250_pci_dac);
72
73/*
74 * The BCM1250, etc. PCI/HT bridge reports as a host bridge.
75 */
76static void quirk_sb1250_ht(struct pci_dev *dev)
77{
78	dev->class = PCI_CLASS_BRIDGE_PCI << 8;
79}
80DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_HT,
81			quirk_sb1250_ht);
82
83/*
84 * Set the SP1011 HT/PCI bridge's TRDY timeout to the finite max.
85 */
86static void quirk_sp1011(struct pci_dev *dev)
87{
88	pci_write_config_byte(dev, 0x64, 0xff);
89}
90DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIPACKETS, PCI_DEVICE_ID_SP1011,
91			quirk_sp1011);