arch/mips/pci/fixup-sb1250.c

   1 /*
   2  *      Copyright (C) 2004, 2006  MIPS Technologies, Inc.  All rights reserved.
   3  *          Author:     Maciej W. Rozycki <macro@mips.com>
   4  *      Copyright (C) 2018  Maciej W. Rozycki
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/dma-mapping.h>
  13 #include <linux/pci.h>
  14
  15 /*
  16  * Set the BCM1250, etc. PCI host bridge's TRDY timeout
  17  * to the finite max.
  18  */
  19 static void quirk_sb1250_pci(struct pci_dev *dev)
  20 {
  21         pci_write_config_byte(dev, 0x40, 0xff);
  22 }
  23 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,
  24                         quirk_sb1250_pci);
  25
  26 /*
  27  * The BCM1250, etc. PCI host bridge does not support DAC on its 32-bit
  28  * bus, so we set the bus's DMA mask accordingly.  However the HT link
  29  * down the artificial PCI-HT bridge supports 40-bit addressing and the
  30  * SP1011 HT-PCI bridge downstream supports both DAC and a 64-bit bus
  31  * width, so we record the PCI-HT bridge's secondary and subordinate bus
  32  * numbers and do not set the mask for devices present in the inclusive
  33  * range of those.
  34  */
  35 struct sb1250_bus_dma_mask_exclude {
  36         bool set;
  37         unsigned char start;
  38         unsigned char end;
  39 };
  40
  41 static int sb1250_bus_dma_mask(struct pci_dev *dev, void *data)
  42 {
  43         struct sb1250_bus_dma_mask_exclude *exclude = data;
  44         bool exclude_this;
  45         bool ht_bridge;
  46
  47         exclude_this = exclude->set && (dev->bus->number >= exclude->start &&
  48                                         dev->bus->number <= exclude->end);
  49         ht_bridge = !exclude->set && (dev->vendor == PCI_VENDOR_ID_SIBYTE &&
  50                                       dev->device == PCI_DEVICE_ID_BCM1250_HT);
  51
  52         if (exclude_this) {
  53                 dev_dbg(&dev->dev, "not disabling DAC for device");
  54         } else if (ht_bridge) {
  55                 exclude->start = dev->subordinate->number;
  56                 exclude->end = pci_bus_max_busnr(dev->subordinate);
  57                 exclude->set = true;
  58                 dev_dbg(&dev->dev, "not disabling DAC for [bus %02x-%02x]",
  59                         exclude->start, exclude->end);
  60         } else {
  61                 dev_dbg(&dev->dev, "disabling DAC for device");
  62                 dev->dev.bus_dma_mask = DMA_BIT_MASK(32);
  63         }
  64
  65         return 0;
  66 }
  67
  68 static void quirk_sb1250_pci_dac(struct pci_dev *dev)
  69 {
  70         struct sb1250_bus_dma_mask_exclude exclude = { .set = false };
  71
  72         pci_walk_bus(dev->bus, sb1250_bus_dma_mask, &exclude);
  73 }
  74 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,
  75                         quirk_sb1250_pci_dac);
  76
  77 /*
  78  * The BCM1250, etc. PCI/HT bridge reports as a host bridge.
  79  */
  80 static void quirk_sb1250_ht(struct pci_dev *dev)
  81 {
  82         dev->class = PCI_CLASS_BRIDGE_PCI << 8;
  83 }
  84 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_HT,
  85                         quirk_sb1250_ht);
  86
  87 /*
  88  * Set the SP1011 HT/PCI bridge's TRDY timeout to the finite max.
  89  */
  90 static void quirk_sp1011(struct pci_dev *dev)
  91 {
  92         pci_write_config_byte(dev, 0x64, 0xff);
  93 }
  94 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIPACKETS, PCI_DEVICE_ID_SP1011,
  95                         quirk_sp1011);