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  */
  15 static void quirk_sb1250_pci(struct pci_dev *dev)
  16 {
  17         pci_write_config_byte(dev, 0x40, 0xff);
  18 }
  19 DECLARE_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  */
  31 struct sb1250_bus_dma_limit_exclude {
  32         bool set;
  33         unsigned char start;
  34         unsigned char end;
  35 };
  36
  37 static 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
  64 static 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 }
  70 DECLARE_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  */
  76 static void quirk_sb1250_ht(struct pci_dev *dev)
  77 {
  78         dev->class = PCI_CLASS_BRIDGE_PCI << 8;
  79 }
  80 DECLARE_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  */
  86 static void quirk_sp1011(struct pci_dev *dev)
  87 {
  88         pci_write_config_byte(dev, 0x64, 0xff);
  89 }
  90 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIPACKETS, PCI_DEVICE_ID_SP1011,
  91                         quirk_sp1011);