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/*
* arch/sh/mm/tlb-urb.c
*
* TLB entry wiring helpers for URB-equipped parts.
*
* Copyright (C) 2010 Matt Fleming
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/mm.h>
#include <linux/io.h>
#include <asm/tlb.h>
#include <asm/mmu_context.h>
/*
* Load the entry for 'addr' into the TLB and wire the entry.
*/
void tlb_wire_entry(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
{
unsigned long status, flags;
int urb;
local_irq_save(flags);
status = __raw_readl(MMUCR);
urb = (status & MMUCR_URB) >> MMUCR_URB_SHIFT;
status &= ~MMUCR_URC;
/*
* Make sure we're not trying to wire the last TLB entry slot.
*/
BUG_ON(!--urb);
urb = urb % MMUCR_URB_NENTRIES;
/*
* Insert this entry into the highest non-wired TLB slot (via
* the URC field).
*/
status |= (urb << MMUCR_URC_SHIFT);
__raw_writel(status, MMUCR);
ctrl_barrier();
/* Load the entry into the TLB */
__update_tlb(vma, addr, pte);
/* ... and wire it up. */
status = __raw_readl(MMUCR);
status &= ~MMUCR_URB;
status |= (urb << MMUCR_URB_SHIFT);
__raw_writel(status, MMUCR);
ctrl_barrier();
local_irq_restore(flags);
}
/*
* Unwire the last wired TLB entry.
*
* It should also be noted that it is not possible to wire and unwire
* TLB entries in an arbitrary order. If you wire TLB entry N, followed
* by entry N+1, you must unwire entry N+1 first, then entry N. In this
* respect, it works like a stack or LIFO queue.
*/
void tlb_unwire_entry(void)
{
unsigned long status, flags;
int urb;
local_irq_save(flags);
status = __raw_readl(MMUCR);
urb = (status & MMUCR_URB) >> MMUCR_URB_SHIFT;
status &= ~MMUCR_URB;
/*
* Make sure we're not trying to unwire a TLB entry when none
* have been wired.
*/
BUG_ON(urb++ == MMUCR_URB_NENTRIES);
urb = urb % MMUCR_URB_NENTRIES;
status |= (urb << MMUCR_URB_SHIFT);
__raw_writel(status, MMUCR);
ctrl_barrier();
local_irq_restore(flags);
}
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