arch/mips/pci/ops-sni.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * SNI specific PCI support for RM200/RM300.
   7  *
   8  * Copyright (C) 1997 - 2000, 2003 Ralf Baechle <ralf@linux-mips.org>
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/pci.h>
  12 #include <linux/types.h>
  13 #include <asm/sni.h>
  14
  15 /*
  16  * It seems that on the RM200 only lower 3 bits of the 5 bit PCI device
  17  * address are decoded.  We therefore manually have to reject attempts at
  18  * reading outside this range.  Being on the paranoid side we only do this
  19  * test for bus 0 and hope forwarding and decoding work properly for any
  20  * subordinated busses.
  21  *
  22  * ASIC PCI only supports type 1 config cycles.
  23  */
  24 static int set_config_address(unsigned int busno, unsigned int devfn, int reg)
  25 {
  26         if ((devfn > 255) || (reg > 255))
  27                 return PCIBIOS_BAD_REGISTER_NUMBER;
  28
  29         if (busno == 0 && devfn >= PCI_DEVFN(8, 0))
  30                 return PCIBIOS_DEVICE_NOT_FOUND;
  31
  32         *(volatile u32 *)PCIMT_CONFIG_ADDRESS =
  33                  ((busno    & 0xff) << 16) |
  34                  ((devfn    & 0xff) <<  8) |
  35                   (reg      & 0xfc);
  36
  37         return PCIBIOS_SUCCESSFUL;
  38 }
  39
  40 static int pcimt_read(struct pci_bus *bus, unsigned int devfn, int reg,
  41                       int size, u32 * val)
  42 {
  43         int res;
  44
  45         if ((res = set_config_address(bus->number, devfn, reg)))
  46                 return res;
  47
  48         switch (size) {
  49         case 1:
  50                 *val = *(volatile  u8 *) (PCIMT_CONFIG_DATA + (reg & 3));
  51                 break;
  52         case 2:
  53                 *val = *(volatile u16 *) (PCIMT_CONFIG_DATA + (reg & 2));
  54                 break;
  55         case 4:
  56                 *val = *(volatile u32 *) PCIMT_CONFIG_DATA;
  57                 break;
  58         }
  59
  60         return 0;
  61 }
  62
  63 static int pcimt_write(struct pci_bus *bus, unsigned int devfn, int reg,
  64                        int size, u32 val)
  65 {
  66         int res;
  67
  68         if ((res = set_config_address(bus->number, devfn, reg)))
  69                 return res;
  70
  71         switch (size) {
  72         case 1:
  73                 *(volatile  u8 *) (PCIMT_CONFIG_DATA + (reg & 3)) = val;
  74                 break;
  75         case 2:
  76                 *(volatile u16 *) (PCIMT_CONFIG_DATA + (reg & 2)) = val;
  77                 break;
  78         case 4:
  79                 *(volatile u32 *) PCIMT_CONFIG_DATA = val;
  80                 break;
  81         }
  82
  83         return 0;
  84 }
  85
  86 struct pci_ops sni_pci_ops = {
  87         .read = pcimt_read,
  88         .write = pcimt_write,
  89 };