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/**********************************************************************
*
* Copyright (C) Imagination Technologies Ltd. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful but, except
* as otherwise stated in writing, without any warranty; without even the
* implied warranty of merchantability or fitness for a particular purpose.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
* The full GNU General Public License is included in this distribution in
* the file called "COPYING".
*
* Contact Information:
* Imagination Technologies Ltd. <gpl-support@imgtec.com>
* Home Park Estate, Kings Langley, Herts, WD4 8LZ, UK
*
******************************************************************************/
#include <linux/version.h>
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,38))
#ifndef AUTOCONF_INCLUDED
#include <linux/config.h>
#endif
#endif
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include "img_defs.h"
#include "pvr_debug.h"
#include "mutils.h"
#if defined(SUPPORT_LINUX_X86_PAT)
#define PAT_LINUX_X86_WC 1
#define PAT_X86_ENTRY_BITS 8
#define PAT_X86_BIT_PWT 1U
#define PAT_X86_BIT_PCD 2U
#define PAT_X86_BIT_PAT 4U
#define PAT_X86_BIT_MASK (PAT_X86_BIT_PAT | PAT_X86_BIT_PCD | PAT_X86_BIT_PWT)
static IMG_BOOL g_write_combining_available = IMG_FALSE;
#define PROT_TO_PAT_INDEX(v, B) ((v & _PAGE_ ## B) ? PAT_X86_BIT_ ## B : 0)
static inline IMG_UINT
pvr_pat_index(pgprotval_t prot_val)
{
IMG_UINT ret = 0;
pgprotval_t val = prot_val & _PAGE_CACHE_MASK;
ret |= PROT_TO_PAT_INDEX(val, PAT);
ret |= PROT_TO_PAT_INDEX(val, PCD);
ret |= PROT_TO_PAT_INDEX(val, PWT);
return ret;
}
static inline IMG_UINT
pvr_pat_entry(u64 pat, IMG_UINT index)
{
return (IMG_UINT)(pat >> (index * PAT_X86_ENTRY_BITS)) & PAT_X86_BIT_MASK;
}
static IMG_VOID
PVRLinuxX86PATProbe(IMG_VOID)
{
if (cpu_has_pat)
{
u64 pat;
IMG_UINT pat_index;
IMG_UINT pat_entry;
PVR_TRACE(("%s: PAT available", __FUNCTION__));
rdmsrl(MSR_IA32_CR_PAT, pat);
PVR_TRACE(("%s: Top 32 bits of PAT: 0x%.8x", __FUNCTION__, (IMG_UINT)(pat >> 32)));
PVR_TRACE(("%s: Bottom 32 bits of PAT: 0x%.8x", __FUNCTION__, (IMG_UINT)(pat)));
pat_index = pvr_pat_index(_PAGE_CACHE_WC);
PVR_TRACE(("%s: PAT index for write combining: %u", __FUNCTION__, pat_index));
pat_entry = pvr_pat_entry(pat, pat_index);
PVR_TRACE(("%s: PAT entry for write combining: 0x%.2x (should be 0x%.2x)", __FUNCTION__, pat_entry, PAT_LINUX_X86_WC));
#if defined(SUPPORT_LINUX_X86_WRITECOMBINE)
g_write_combining_available = (IMG_BOOL)(pat_entry == PAT_LINUX_X86_WC);
#endif
}
#if defined(DEBUG)
#if defined(SUPPORT_LINUX_X86_WRITECOMBINE)
if (g_write_combining_available)
{
PVR_TRACE(("%s: Write combining available via PAT", __FUNCTION__));
}
else
{
PVR_TRACE(("%s: Write combining not available", __FUNCTION__));
}
#else
PVR_TRACE(("%s: Write combining disabled in driver build", __FUNCTION__));
#endif
#endif
}
pgprot_t
pvr_pgprot_writecombine(pgprot_t prot)
{
return (g_write_combining_available) ?
__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_MASK) | _PAGE_CACHE_WC) : pgprot_noncached(prot);
}
#endif
IMG_VOID
PVRLinuxMUtilsInit(IMG_VOID)
{
#if defined(SUPPORT_LINUX_X86_PAT)
PVRLinuxX86PATProbe();
#endif
}
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