arch/mips/pci/ops-gt64xxx_pci0.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 1999, 2000, 2004  MIPS Technologies, Inc.
   4  *      All rights reserved.
   5  *      Authors: Carsten Langgaard <carstenl@mips.com>
   6  *               Maciej W. Rozycki <macro@mips.com>
   7  */
   8 #include <linux/types.h>
   9 #include <linux/pci.h>
  10 #include <linux/kernel.h>
  11
  12 #include <asm/gt64120.h>
  13
  14 #define PCI_ACCESS_READ  0
  15 #define PCI_ACCESS_WRITE 1
  16
  17 /*
  18  *  PCI configuration cycle AD bus definition
  19  */
  20 /* Type 0 */
  21 #define PCI_CFG_TYPE0_REG_SHF           0
  22 #define PCI_CFG_TYPE0_FUNC_SHF          8
  23
  24 /* Type 1 */
  25 #define PCI_CFG_TYPE1_REG_SHF           0
  26 #define PCI_CFG_TYPE1_FUNC_SHF          8
  27 #define PCI_CFG_TYPE1_DEV_SHF           11
  28 #define PCI_CFG_TYPE1_BUS_SHF           16
  29
  30 static int gt64xxx_pci0_pcibios_config_access(unsigned char access_type,
  31                 struct pci_bus *bus, unsigned int devfn, int where, u32 * data)
  32 {
  33         unsigned char busnum = bus->number;
  34         u32 intr;
  35
  36         if ((busnum == 0) && (devfn >= PCI_DEVFN(31, 0)))
  37                 return -1;      /* Because of a bug in the galileo (for slot 31). */
  38
  39         /* Clear cause register bits */
  40         GT_WRITE(GT_INTRCAUSE_OFS, ~(GT_INTRCAUSE_MASABORT0_BIT |
  41                                      GT_INTRCAUSE_TARABORT0_BIT));
  42
  43         /* Setup address */
  44         GT_WRITE(GT_PCI0_CFGADDR_OFS,
  45                  (busnum << GT_PCI0_CFGADDR_BUSNUM_SHF) |
  46                  (devfn << GT_PCI0_CFGADDR_FUNCTNUM_SHF) |
  47                  ((where / 4) << GT_PCI0_CFGADDR_REGNUM_SHF) |
  48                  GT_PCI0_CFGADDR_CONFIGEN_BIT);
  49
  50         if (access_type == PCI_ACCESS_WRITE) {
  51                 if (busnum == 0 && PCI_SLOT(devfn) == 0) {
  52                         /*
  53                          * The Galileo system controller is acting
  54                          * differently than other devices.
  55                          */
  56                         GT_WRITE(GT_PCI0_CFGDATA_OFS, *data);
  57                 } else
  58                         __GT_WRITE(GT_PCI0_CFGDATA_OFS, *data);
  59         } else {
  60                 if (busnum == 0 && PCI_SLOT(devfn) == 0) {
  61                         /*
  62                          * The Galileo system controller is acting
  63                          * differently than other devices.
  64                          */
  65                         *data = GT_READ(GT_PCI0_CFGDATA_OFS);
  66                 } else
  67                         *data = __GT_READ(GT_PCI0_CFGDATA_OFS);
  68         }
  69
  70         /* Check for master or target abort */
  71         intr = GT_READ(GT_INTRCAUSE_OFS);
  72
  73         if (intr & (GT_INTRCAUSE_MASABORT0_BIT | GT_INTRCAUSE_TARABORT0_BIT)) {
  74                 /* Error occurred */
  75
  76                 /* Clear bits */
  77                 GT_WRITE(GT_INTRCAUSE_OFS, ~(GT_INTRCAUSE_MASABORT0_BIT |
  78                                              GT_INTRCAUSE_TARABORT0_BIT));
  79
  80                 return -1;
  81         }
  82
  83         return 0;
  84 }
  85
  86
  87 /*
  88  * We can't address 8 and 16 bit words directly.  Instead we have to
  89  * read/write a 32bit word and mask/modify the data we actually want.
  90  */
  91 static int gt64xxx_pci0_pcibios_read(struct pci_bus *bus, unsigned int devfn,
  92                 int where, int size, u32 * val)
  93 {
  94         u32 data = 0;
  95
  96         if (gt64xxx_pci0_pcibios_config_access(PCI_ACCESS_READ, bus, devfn,
  97                                                where, &data))
  98                 return PCIBIOS_DEVICE_NOT_FOUND;
  99
 100         if (size == 1)
 101                 *val = (data >> ((where & 3) << 3)) & 0xff;
 102         else if (size == 2)
 103                 *val = (data >> ((where & 3) << 3)) & 0xffff;
 104         else
 105                 *val = data;
 106
 107         return PCIBIOS_SUCCESSFUL;
 108 }
 109
 110 static int gt64xxx_pci0_pcibios_write(struct pci_bus *bus, unsigned int devfn,
 111                 int where, int size, u32 val)
 112 {
 113         u32 data = 0;
 114
 115         if (size == 4)
 116                 data = val;
 117         else {
 118                 if (gt64xxx_pci0_pcibios_config_access(PCI_ACCESS_READ, bus,
 119                                                        devfn, where, &data))
 120                         return PCIBIOS_DEVICE_NOT_FOUND;
 121
 122                 if (size == 1)
 123                         data = (data & ~(0xff << ((where & 3) << 3))) |
 124                                 (val << ((where & 3) << 3));
 125                 else if (size == 2)
 126                         data = (data & ~(0xffff << ((where & 3) << 3))) |
 127                                 (val << ((where & 3) << 3));
 128         }
 129
 130         if (gt64xxx_pci0_pcibios_config_access(PCI_ACCESS_WRITE, bus, devfn,
 131                                                where, &data))
 132                 return PCIBIOS_DEVICE_NOT_FOUND;
 133
 134         return PCIBIOS_SUCCESSFUL;
 135 }
 136
 137 struct pci_ops gt64xxx_pci0_ops = {
 138         .read   = gt64xxx_pci0_pcibios_read,
 139         .write  = gt64xxx_pci0_pcibios_write
 140 };