drivers/infiniband/hw/ipath/ipath_wc_x86_64.c

   1 /*
   2  * Copyright (c) 2006 QLogic, Inc. All rights reserved.
   3  * Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33
  34 /*
  35  * This file is conditionally built on x86_64 only.  Otherwise weak symbol
  36  * versions of the functions exported from here are used.
  37  */
  38
  39 #include <linux/pci.h>
  40 #include <asm/mtrr.h>
  41 #include <asm/processor.h>
  42
  43 #include "ipath_kernel.h"
  44
  45 /**
  46  * ipath_enable_wc - enable write combining for MMIO writes to the device
  47  * @dd: infinipath device
  48  *
  49  * This routine is x86_64-specific; it twiddles the CPU's MTRRs to enable
  50  * write combining.
  51  */
  52 int ipath_enable_wc(struct ipath_devdata *dd)
  53 {
  54         int ret = 0;
  55         u64 pioaddr, piolen;
  56         unsigned bits;
  57         const unsigned long addr = pci_resource_start(dd->pcidev, 0);
  58         const size_t len = pci_resource_len(dd->pcidev, 0);
  59
  60         /*
  61          * Set the PIO buffers to be WCCOMB, so we get HT bursts to the
  62          * chip.  Linux (possibly the hardware) requires it to be on a power
  63          * of 2 address matching the length (which has to be a power of 2).
  64          * For rev1, that means the base address, for rev2, it will be just
  65          * the PIO buffers themselves.
  66          */
  67         pioaddr = addr + dd->ipath_piobufbase;
  68         piolen = (dd->ipath_piobcnt2k +
  69                   dd->ipath_piobcnt4k) *
  70                 ALIGN(dd->ipath_piobcnt2k +
  71                       dd->ipath_piobcnt4k, dd->ipath_palign);
  72
  73         for (bits = 0; !(piolen & (1ULL << bits)); bits++)
  74                 /* do nothing */ ;
  75
  76         if (piolen != (1ULL << bits)) {
  77                 piolen >>= bits;
  78                 while (piolen >>= 1)
  79                         bits++;
  80                 piolen = 1ULL << (bits + 1);
  81         }
  82         if (pioaddr & (piolen - 1)) {
  83                 u64 atmp;
  84                 ipath_dbg("pioaddr %llx not on right boundary for size "
  85                           "%llx, fixing\n",
  86                           (unsigned long long) pioaddr,
  87                           (unsigned long long) piolen);
  88                 atmp = pioaddr & ~(piolen - 1);
  89                 if (atmp < addr || (atmp + piolen) > (addr + len)) {
  90                         ipath_dev_err(dd, "No way to align address/size "
  91                                       "(%llx/%llx), no WC mtrr\n",
  92                                       (unsigned long long) atmp,
  93                                       (unsigned long long) piolen << 1);
  94                         ret = -ENODEV;
  95                 } else {
  96                         ipath_dbg("changing WC base from %llx to %llx, "
  97                                   "len from %llx to %llx\n",
  98                                   (unsigned long long) pioaddr,
  99                                   (unsigned long long) atmp,
 100                                   (unsigned long long) piolen,
 101                                   (unsigned long long) piolen << 1);
 102                         pioaddr = atmp;
 103                         piolen <<= 1;
 104                 }
 105         }
 106
 107         if (!ret) {
 108                 int cookie;
 109                 ipath_cdbg(VERBOSE, "Setting mtrr for chip to WC "
 110                            "(addr %llx, len=0x%llx)\n",
 111                            (unsigned long long) pioaddr,
 112                            (unsigned long long) piolen);
 113                 cookie = mtrr_add(pioaddr, piolen, MTRR_TYPE_WRCOMB, 0);
 114                 if (cookie < 0) {
 115                         {
 116                                 dev_info(&dd->pcidev->dev,
 117                                          "mtrr_add()  WC for PIO bufs "
 118                                          "failed (%d)\n",
 119                                          cookie);
 120                                 ret = -EINVAL;
 121                         }
 122                 } else {
 123                         ipath_cdbg(VERBOSE, "Set mtrr for chip to WC, "
 124                                    "cookie is %d\n", cookie);
 125                         dd->ipath_wc_cookie = cookie;
 126                         dd->ipath_wc_base = (unsigned long) pioaddr;
 127                         dd->ipath_wc_len = (unsigned long) piolen;
 128                 }
 129         }
 130
 131         return ret;
 132 }
 133
 134 /**
 135  * ipath_disable_wc - disable write combining for MMIO writes to the device
 136  * @dd: infinipath device
 137  */
 138 void ipath_disable_wc(struct ipath_devdata *dd)
 139 {
 140         if (dd->ipath_wc_cookie) {
 141                 int r;
 142                 ipath_cdbg(VERBOSE, "undoing WCCOMB on pio buffers\n");
 143                 r = mtrr_del(dd->ipath_wc_cookie, dd->ipath_wc_base,
 144                              dd->ipath_wc_len);
 145                 if (r < 0)
 146                         dev_info(&dd->pcidev->dev,
 147                                  "mtrr_del(%lx, %lx, %lx) failed: %d\n",
 148                                  dd->ipath_wc_cookie, dd->ipath_wc_base,
 149                                  dd->ipath_wc_len, r);
 150                 dd->ipath_wc_cookie = 0; /* even on failure */
 151         }
 152 }
 153
 154 /**
 155  * ipath_unordered_wc - indicate whether write combining is ordered
 156  *
 157  * Because our performance depends on our ability to do write combining mmio
 158  * writes in the most efficient way, we need to know if we are on an Intel
 159  * or AMD x86_64 processor.  AMD x86_64 processors flush WC buffers out in
 160  * the order completed, and so no special flushing is required to get
 161  * correct ordering.  Intel processors, however, will flush write buffers
 162  * out in "random" orders, and so explicit ordering is needed at times.
 163  */
 164 int ipath_unordered_wc(void)
 165 {
 166         return boot_cpu_data.x86_vendor != X86_VENDOR_AMD;
 167 }