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/*
* Copyright (c) 2012 Intel Corporation. All rights reserved.
* Copyright (c) 2006 - 2012 QLogic Corporation. All rights reserved.
* Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/*
* This file is conditionally built on x86_64 only. Otherwise weak symbol
* versions of the functions exported from here are used.
*/
#include <linux/pci.h>
#include <asm/mtrr.h>
#include <asm/processor.h>
#include "qib.h"
/**
* qib_enable_wc - enable write combining for MMIO writes to the device
* @dd: qlogic_ib device
*
* This routine is x86_64-specific; it twiddles the CPU's MTRRs to enable
* write combining.
*/
int qib_enable_wc(struct qib_devdata *dd)
{
int ret = 0;
u64 pioaddr, piolen;
unsigned bits;
const unsigned long addr = pci_resource_start(dd->pcidev, 0);
const size_t len = pci_resource_len(dd->pcidev, 0);
/*
* Set the PIO buffers to be WCCOMB, so we get HT bursts to the
* chip. Linux (possibly the hardware) requires it to be on a power
* of 2 address matching the length (which has to be a power of 2).
* For rev1, that means the base address, for rev2, it will be just
* the PIO buffers themselves.
* For chips with two sets of buffers, the calculations are
* somewhat more complicated; we need to sum, and the piobufbase
* register has both offsets, 2K in low 32 bits, 4K in high 32 bits.
* The buffers are still packed, so a single range covers both.
*/
if (dd->piobcnt2k && dd->piobcnt4k) {
/* 2 sizes for chip */
unsigned long pio2kbase, pio4kbase;
pio2kbase = dd->piobufbase & 0xffffffffUL;
pio4kbase = (dd->piobufbase >> 32) & 0xffffffffUL;
if (pio2kbase < pio4kbase) {
/* all current chips */
pioaddr = addr + pio2kbase;
piolen = pio4kbase - pio2kbase +
dd->piobcnt4k * dd->align4k;
} else {
pioaddr = addr + pio4kbase;
piolen = pio2kbase - pio4kbase +
dd->piobcnt2k * dd->palign;
}
} else { /* single buffer size (2K, currently) */
pioaddr = addr + dd->piobufbase;
piolen = dd->piobcnt2k * dd->palign +
dd->piobcnt4k * dd->align4k;
}
for (bits = 0; !(piolen & (1ULL << bits)); bits++)
; /* do nothing */
if (piolen != (1ULL << bits)) {
piolen >>= bits;
while (piolen >>= 1)
bits++;
piolen = 1ULL << (bits + 1);
}
if (pioaddr & (piolen - 1)) {
u64 atmp = pioaddr & ~(piolen - 1);
if (atmp < addr || (atmp + piolen) > (addr + len)) {
qib_dev_err(dd,
"No way to align address/size (%llx/%llx), no WC mtrr\n",
(unsigned long long) atmp,
(unsigned long long) piolen << 1);
ret = -ENODEV;
} else {
pioaddr = atmp;
piolen <<= 1;
}
}
if (!ret) {
dd->wc_cookie = arch_phys_wc_add(pioaddr, piolen);
if (dd->wc_cookie < 0)
/* use error from routine */
ret = dd->wc_cookie;
}
return ret;
}
/**
* qib_disable_wc - disable write combining for MMIO writes to the device
* @dd: qlogic_ib device
*/
void qib_disable_wc(struct qib_devdata *dd)
{
arch_phys_wc_del(dd->wc_cookie);
}
/**
* qib_unordered_wc - indicate whether write combining is ordered
*
* Because our performance depends on our ability to do write combining mmio
* writes in the most efficient way, we need to know if we are on an Intel
* or AMD x86_64 processor. AMD x86_64 processors flush WC buffers out in
* the order completed, and so no special flushing is required to get
* correct ordering. Intel processors, however, will flush write buffers
* out in "random" orders, and so explicit ordering is needed at times.
*/
int qib_unordered_wc(void)
{
return boot_cpu_data.x86_vendor != X86_VENDOR_AMD;
}
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