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

   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);
  92