arch/sh/drivers/pci/ops-sh4.c

   1 /*
   2  * Generic SH-4 / SH-4A PCIC operations (SH7751, SH7780).
   3  *
   4  * Copyright (C) 2002 - 2009  Paul Mundt
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License v2. See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10 #include <linux/pci.h>
  11 #include <linux/io.h>
  12 #include <asm/addrspace.h>
  13 #include "pci-sh4.h"
  14
  15 /*
  16  * Direct access to PCI hardware...
  17  */
  18 #define CONFIG_CMD(bus, devfn, where) \
  19         (0x80000000 | (bus->number << 16) | (devfn << 8) | (where & ~3))
  20
  21 static DEFINE_SPINLOCK(sh4_pci_lock);
  22
  23 /*
  24  * Functions for accessing PCI configuration space with type 1 accesses
  25  */
  26 static int sh4_pci_read(struct pci_bus *bus, unsigned int devfn,
  27                            int where, int size, u32 *val)
  28 {
  29         struct pci_channel *chan = bus->sysdata;
  30         unsigned long flags;
  31         u32 data;
  32
  33         /*
  34          * PCIPDR may only be accessed as 32 bit words,
  35          * so we must do byte alignment by hand
  36          */
  37         spin_lock_irqsave(&sh4_pci_lock, flags);
  38         pci_write_reg(chan, CONFIG_CMD(bus, devfn, where), SH4_PCIPAR);
  39         data = pci_read_reg(chan, SH4_PCIPDR);
  40         spin_unlock_irqrestore(&sh4_pci_lock, flags);
  41
  42         switch (size) {
  43         case 1:
  44                 *val = (data >> ((where & 3) << 3)) & 0xff;
  45                 break;
  46         case 2:
  47                 *val = (data >> ((where & 2) << 3)) & 0xffff;
  48                 break;
  49         case 4:
  50                 *val = data;
  51                 break;
  52         default:
  53                 return PCIBIOS_FUNC_NOT_SUPPORTED;
  54         }
  55
  56         return PCIBIOS_SUCCESSFUL;
  57 }
  58
  59 /*
  60  * Since SH4 only does 32bit access we'll have to do a read,
  61  * mask,write operation.
  62  * We'll allow an odd byte offset, though it should be illegal.
  63  */
  64 static int sh4_pci_write(struct pci_bus *bus, unsigned int devfn,
  65                          int where, int size, u32 val)
  66 {
  67         struct pci_channel *chan = bus->sysdata;
  68         unsigned long flags;
  69         int shift;
  70         u32 data;
  71
  72         spin_lock_irqsave(&sh4_pci_lock, flags);
  73         pci_write_reg(chan, CONFIG_CMD(bus, devfn, where), SH4_PCIPAR);
  74         data = pci_read_reg(chan, SH4_PCIPDR);
  75         spin_unlock_irqrestore(&sh4_pci_lock, flags);
  76
  77         switch (size) {
  78         case 1:
  79                 shift = (where & 3) << 3;
  80                 data &= ~(0xff << shift);
  81                 data |= ((val & 0xff) << shift);
  82                 break;
  83         case 2:
  84                 shift = (where & 2) << 3;
  85                 data &= ~(0xffff << shift);
  86                 data |= ((val & 0xffff) << shift);
  87                 break;
  88         case 4:
  89                 data = val;
  90                 break;
  91         default:
  92                 return PCIBIOS_FUNC_NOT_SUPPORTED;
  93         }
  94
  95         pci_write_reg(chan, data, SH4_PCIPDR);
  96
  97         return PCIBIOS_SUCCESSFUL;
  98 }
  99
 100 struct pci_ops sh4_pci_ops = {
 101         .read           = sh4_pci_read,
 102         .write          = sh4_pci_write,
 103 };
 104
 105 int __attribute__((weak)) pci_fixup_pcic(struct pci_channel *chan)
 106 {
 107         /* Nothing to do. */
 108         return 0;
 109 }