drivers/infiniband/hw/qib/qib_wc_x86_64.c

   1 /*
   2  * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. 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 "qib.h"
  44
  45 /**
  46  * qib_enable_wc - enable write combining for MMIO writes to the device
  47  * @dd: qlogic_ib device
  48  *
  49  * This routine is x86_64-specific; it twiddles the CPU's MTRRs to enable
  50  * write combining.
  51  */
  52 int qib_enable_wc(struct qib_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          * For chips with two sets of buffers, the calculations are
  67          * somewhat more complicated; we need to sum, and the piobufbase
  68          * register has both offsets, 2K in low 32 bits, 4K in high 32 bits.
  69          * The buffers are still packed, so a single range covers both.
  70          */
  71         if (dd->piobcnt2k && dd->piobcnt4k) {
  72                 /* 2 sizes for chip */
  73                 unsigned long pio2kbase, pio4kbase;
  74                 pio2kbase = dd->piobufbase & 0xffffffffUL;
  75                 pio4kbase = (dd->piobufbase >> 32) & 0xffffffffUL;
  76                 if (pio2kbase < pio4kbase) {
  77                         /* all current chips */
  78                         pioaddr = addr + pio2kbase;
  79                         piolen = pio4kbase - pio2kbase +
  80                                 dd->piobcnt4k * dd->align4k;
  81                 } else {
  82                         pioaddr = addr + pio4kbase;
  83                         piolen = pio2kbase - pio4kbase +
  84                                 dd->piobcnt2k * dd->palign;
  85                 }
  86         } else {  /* single buffer size (2K, currently) */
  87                 pioaddr = addr + dd->piobufbase;
  88                 piolen = dd->piobcnt2k * dd->palign +
  89                         dd->piobcnt4k * dd->align4k;
  90         }
  91
  92         for (bits = 0; !(piolen & (1ULL << bits)); bits++)
  93                 /* do nothing */ ;
  94
  95         if (piolen != (1ULL << bits)) {
  96                 piolen >>= bits;
  97                 while (piolen >>= 1)
  98                         bits++;
  99                 piolen = 1ULL << (bits + 1);
 100         }
 101         if (pioaddr & (piolen - 1)) {
 102                 u64 atmp;
 103                 atmp = pioaddr & ~(piolen - 1);
 104                 if (atmp < addr || (atmp + piolen) > (addr + len)) {
 105                         qib_dev_err(dd, "No way to align address/size "
 106                                     "(%llx/%llx), no WC mtrr\n",
 107                                     (unsigned long long) atmp,
 108                                     (unsigned long long) piolen << 1);
 109                         ret = -ENODEV;
 110                 } else {
 111                         pioaddr = atmp;
 112                         piolen <<= 1;
 113                 }
 114         }
 115
 116         if (!ret) {
 117                 int cookie;
 118
 119                 cookie = mtrr_add(pioaddr, piolen, MTRR_TYPE_WRCOMB, 0);
 120                 if (cookie < 0) {
 121                         {
 122                                 qib_devinfo(dd->pcidev,
 123                                          "mtrr_add()  WC for PIO bufs "
 124                                          "failed (%d)\n",
 125                                          cookie);
 126                                 ret = -EINVAL;
 127                         }
 128                 } else {
 129                         dd->wc_cookie = cookie;
 130                         dd->wc_base = (unsigned long) pioaddr;
 131                         dd->wc_len = (unsigned long) piolen;
 132                 }
 133         }
 134
 135         return ret;
 136 }
 137
 138 /**
 139  * qib_disable_wc - disable write combining for MMIO writes to the device
 140  * @dd: qlogic_ib device
 141  */
 142 void qib_disable_wc(struct qib_devdata *dd)
 143 {
 144         if (dd->wc_cookie) {
 145                 int r;
 146
 147                 r = mtrr_del(dd->wc_cookie, dd->wc_base,
 148                              dd->wc_len);
 149                 if (r < 0)
 150                         qib_devinfo(dd->pcidev,
 151                                  "mtrr_del(%lx, %lx, %lx) failed: %d\n",
 152                                  dd->wc_cookie, dd->wc_base,
 153                                  dd->wc_len, r);
 154                 dd->wc_cookie = 0; /* even on failure */
 155         }
 156 }
 157
 158 /**
 159  * qib_unordered_wc - indicate whether write combining is ordered
 160  *
 161  * Because our performance depends on our ability to do write combining mmio
 162  * writes in the most efficient way, we need to know if we are on an Intel
 163  * or AMD x86_64 processor.  AMD x86_64 processors flush WC buffers out in
 164  * the order completed, and so no special flushing is required to get
 165  * correct ordering.  Intel processors, however, will flush write buffers
 166  * out in "random" orders, and so explicit ordering is needed at times.
 167  */
 168 int qib_unordered_wc(void)
 169 {
 170         return boot_cpu_data.x86_vendor != X86_VENDOR_AMD;
 171 }