drivers/parisc/ccio-rm-dma.c

   1 /*
   2  * ccio-rm-dma.c:
   3  *      DMA management routines for first generation cache-coherent machines.
   4  *      "Real Mode" operation refers to U2/Uturn chip operation. The chip
   5  *      can perform coherency checks w/o using the I/O MMU. That's all we
   6  *      need until support for more than 4GB phys mem is needed.
   7  *
   8  *      This is the trivial case - basically what x86 does.
   9  *
  10  *      Drawbacks of using Real Mode are:
  11  *      o outbound DMA is slower since one isn't using the prefetching
  12  *        U2 can do for outbound DMA.
  13  *      o Ability to do scatter/gather in HW is also lost.
  14  *      o only known to work with PCX-W processor. (eg C360)
  15  *        (PCX-U/U+ are not coherent with U2 in real mode.)
  16  *
  17  *
  18  * This program is free software; you can redistribute it and/or modify
  19  * it under the terms of the GNU General Public License as published by
  20  * the Free Software Foundation; either version 2 of the License, or
  21  * (at your option) any later version.
  22  *
  23  *
  24  * Original version/author:
  25  *      CVSROOT=:pserver:anonymous@198.186.203.37:/cvsroot/linux-parisc
  26  *      cvs -z3 co linux/arch/parisc/kernel/dma-rm.c
  27  *
  28  *      (C) Copyright 2000 Philipp Rumpf <prumpf@tux.org>
  29  *
  30  *
  31  * Adopted for The Puffin Group's parisc-linux port by Grant Grundler.
  32  *      (C) Copyright 2000 Grant Grundler <grundler@puffin.external.hp.com>
  33  *
  34  */
  35
  36 #include <linux/types.h>
  37 #include <linux/init.h>
  38 #include <linux/mm.h>
  39 #include <linux/string.h>
  40 #include <linux/pci.h>
  41 #include <linux/gfp.h>
  42
  43 #include <asm/uaccess.h>
  44
  45 #include <asm/io.h>
  46 #include <asm/hardware.h>
  47 #include <asm/page.h>
  48
  49 /* Only chose "ccio" since that's what HP-UX calls it....
  50 ** Make it easier for folks to migrate from one to the other :^)
  51 */
  52 #define MODULE_NAME "ccio"
  53
  54 #define U2_IOA_RUNWAY 0x580
  55 #define U2_BC_GSC     0x501
  56 #define UTURN_IOA_RUNWAY 0x581
  57 #define UTURN_BC_GSC     0x502
  58
  59 #define IS_U2(id) ( \
  60     (((id)->hw_type == HPHW_IOA) && ((id)->hversion == U2_IOA_RUNWAY)) || \
  61     (((id)->hw_type == HPHW_BCPORT) && ((id)->hversion == U2_BC_GSC))  \
  62 )
  63
  64 #define IS_UTURN(id) ( \
  65     (((id)->hw_type == HPHW_IOA) && ((id)->hversion == UTURN_IOA_RUNWAY)) || \
  66     (((id)->hw_type == HPHW_BCPORT) && ((id)->hversion == UTURN_BC_GSC))  \
  67 )
  68
  69 static int ccio_dma_supported( struct pci_dev *dev, u64 mask)
  70 {
  71         if (dev == NULL) {
  72                 printk(KERN_ERR MODULE_NAME ": EISA/ISA/et al not supported\n");
  73                 BUG();
  74                 return(0);
  75         }
  76
  77         /* only support 32-bit devices (ie PCI/GSC) */
  78         return((int) (mask >= 0xffffffffUL));
  79 }
  80
  81
  82 static void *ccio_alloc_consistent(struct pci_dev *dev, size_t size,
  83                                  dma_addr_t *handle)
  84 {
  85         void *ret;
  86
  87         ret = (void *)__get_free_pages(GFP_ATOMIC, get_order(size));
  88
  89         if (ret != NULL) {
  90                 memset(ret, 0, size);
  91                 *handle = virt_to_phys(ret);
  92         }
  93         return ret;
  94 }
  95
  96 static void ccio_free_consistent(struct pci_dev *dev, size_t size,
  97                                void *vaddr, dma_addr_t handle)
  98 {
  99         free_pages((unsigned long)vaddr, get_order(size));
 100 }
 101
 102 static dma_addr_t ccio_map_single(struct pci_dev *dev, void *ptr, size_t size,
 103                           int direction)
 104 {
 105         return virt_to_phys(ptr);
 106 }
 107
 108 static void ccio_unmap_single(struct pci_dev *dev, dma_addr_t dma_addr,
 109                             size_t size, int direction)
 110 {
 111         /* Nothing to do */
 112 }
 113
 114
 115 static int ccio_map_sg(struct pci_dev *dev, struct scatterlist *sglist, int nents, int direction)
 116 {
 117         int tmp = nents;
 118
 119         /* KISS: map each buffer separately. */
 120         while (nents) {
 121                 sg_dma_address(sglist) = ccio_map_single(dev, sglist->address, sglist->length, direction);
 122                 sg_dma_len(sglist) = sglist->length;
 123                 nents--;
 124                 sglist++;
 125         }
 126
 127         return tmp;
 128 }
 129
 130
 131 static void ccio_unmap_sg(struct pci_dev *dev, struct scatterlist *sglist, int nents, int direction)
 132 {
 133 #if 0
 134         while (nents) {
 135                 ccio_unmap_single(dev, sg_dma_address(sglist), sg_dma_len(sglist), direction);
 136                 nents--;
 137                 sglist++;
 138         }
 139         return;
 140 #else
 141         /* Do nothing (copied from current ccio_unmap_single()  :^) */
 142 #endif
 143 }
 144
 145
 146 static struct pci_dma_ops ccio_ops = {
 147         ccio_dma_supported,
 148         ccio_alloc_consistent,
 149         ccio_free_consistent,
 150         ccio_map_single,
 151         ccio_unmap_single,
 152         ccio_map_sg,
 153         ccio_unmap_sg,
 154         NULL,                   /* dma_sync_single_for_cpu : NOP for U2 */
 155         NULL,                   /* dma_sync_single_for_device : NOP for U2 */
 156         NULL,                   /* dma_sync_sg_for_cpu     : ditto */
 157         NULL,                   /* dma_sync_sg_for_device     : ditto */
 158 };
 159
 160
 161 /*
 162 ** Determine if u2 should claim this chip (return 0) or not (return 1).
 163 ** If so, initialize the chip and tell other partners in crime they
 164 ** have work to do.
 165 */
 166 static int
 167 ccio_probe(struct parisc_device *dev)
 168 {
 169         printk(KERN_INFO "%s found %s at 0x%lx\n", MODULE_NAME,
 170                         dev->id.hversion == U2_BC_GSC ? "U2" : "UTurn",
 171                         dev->hpa.start);
 172
 173 /*
 174 ** FIXME - should check U2 registers to verify it's really running
 175 ** in "Real Mode".
 176 */
 177
 178 #if 0
 179 /* will need this for "Virtual Mode" operation */
 180         ccio_hw_init(ccio_dev);
 181         ccio_common_init(ccio_dev);
 182 #endif
 183         hppa_dma_ops = &ccio_ops;
 184         return 0;
 185 }
 186
 187 static struct parisc_device_id ccio_tbl[] = {
 188         { HPHW_BCPORT, HVERSION_REV_ANY_ID, U2_BC_GSC, 0xc },
 189         { HPHW_BCPORT, HVERSION_REV_ANY_ID, UTURN_BC_GSC, 0xc },
 190         { 0, }
 191 };
 192
 193 static struct parisc_driver ccio_driver = {
 194         .name =         "U2/Uturn",
 195         .id_table =     ccio_tbl,
 196         .probe =        ccio_probe,
 197 };
 198
 199 void __init ccio_init(void)
 200 {
 201         register_parisc_driver(&ccio_driver);
 202 }