nuttx/arch/arm/src/armv7-m/arch_clean_dcache.c
2017-06-28 13:16:48 -06:00

150 lines
5.0 KiB
C

/****************************************************************************
* arch/arm/src/armv7-m/arch_clean_dcache.c
*
* Copyright (C) 2015 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Some logic in this header file derives from the ARM CMSIS core_cm7.h
* header file which has a compatible 3-clause BSD license:
*
* Copyright (c) 2009 - 2014 ARM LIMITED. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name ARM, NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include "cache.h"
#if defined(CONFIG_ARMV7M_DCACHE) && !defined(CONFIG_ARMV7M_DCACHE_WRITETHROUGH)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: arch_clean_dcache
*
* Description:
* Clean the data cache within the specified region by flushing the
* contents of the data cache to memory.
*
* Input Parameters:
* start - virtual start address of region
* end - virtual end address of region + 1
*
* Returned Value:
* None
*
* Assumptions:
* This operation is not atomic. This function assumes that the caller
* has exclusive access to the address range so that no harm is done if
* the operation is pre-empted.
*
****************************************************************************/
void arch_clean_dcache(uintptr_t start, uintptr_t end)
{
uint32_t ccsidr;
uint32_t smask;
uint32_t sshift;
uint32_t ways;
uint32_t wshift;
uint32_t ssize;
uint32_t set;
uint32_t sw;
/* Get the characteristics of the D-Cache */
ccsidr = getreg32(NVIC_CCSIDR);
smask = CCSIDR_SETS(ccsidr); /* (Number of sets) - 1 */
sshift = CCSIDR_LSSHIFT(ccsidr) + 4; /* log2(cache-line-size-in-bytes) */
ways = CCSIDR_WAYS(ccsidr); /* (Number of ways) - 1 */
/* Calculate the bit offset for the way field in the DCCSW register by
* counting the number of leading zeroes. For example:
*
* Number of Value of ways Field
* Ways 'ways' Offset
* 2 1 31
* 4 3 30
* 8 7 29
* ...
*/
wshift = arm_clz(ways) & 0x1f;
/* Clean the D-Cache over the range of addresses */
ssize = (1 << sshift);
start &= ~(ssize - 1);
ARM_DSB();
do
{
int32_t tmpways = ways;
/* Isolate the cache line associated with this address. For example
* if the cache line size is 32 bytes and the cache size is 16KB, then
*
* sshift = 5 : Offset to the beginning of the set field
* smask = 0x007f : Mask of the set field
*/
set = ((uint32_t)start >> sshift) & smask;
/* Clean and invalidate each way for this cacheline */
do
{
sw = ((tmpways << wshift) | (set << sshift));
putreg32(sw, NVIC_DCCSW);
}
while (tmpways--);
/* Increment the address by the size of one cache line. */
start += ssize;
}
while (start < end);
ARM_DSB();
ARM_ISB();
}
#endif /* CONFIG_ARMV7M_DCACHE && !CONFIG_ARMV7M_DCACHE_WRITETHROUGH */