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/****************************************************************************
* arch/arm/src/sama5/sam_pmc.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References:
*
* SAMA5D3 Series Data Sheet
*
* 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 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 <stdint.h>
#include <arch/board/board.h>
#include "chip.h"
#include "chip/sam_hsmci.h"
#include "sam_hsmci.h"
#if defined(CONFIG_SAMA5_HSMCI0) || defined(CONFIG_SAMA5_HSMCI1) || \
defined(CONFIG_SAMA5_HSMCI2)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sam_hsmci_clkdiv
*
* Description:
* Multimedia Card Interface clock (MCCK or MCI_CK) is Master Clock (MCK)
* divided by (2*(CLKDIV) + CLOCKODD + 2).
*
* CLKFULLDIV = 2*CLKDIV + CLOCKODD;
* MCI_SPEED = MCK / (CLKFULLDIV + 2)
* CLKFULLDIV = MCK / MCI_SPEED - 2
*
* CLKDIV = CLKFULLDIV >> 1
* CLOCKODD = CLKFULLDIV & 1
*
* Where CLKDIV has a range of 0-255.
*
* NOTE: The primary use of this function is for cases where the clock
* frequencies are not known a priori and so HSMCI clock dividers must
* be determined dynamically. This is the case, for example, when we
* execute out of SDRAM. In that case, the clocking was set up by the
* bootloader that brought us into SDRAM and it is that bootloader that
* has configured the clocking.
*
* Input parameters:
* target - The target SD frequency
*
* Returned Value:
* A bitset containing the CLKDIV and CLKODD bits as needed to configure
* the HSMCI clock output.
*
****************************************************************************/
uint32_t sam_hsmci_clkdiv(uint32_t target)
{
uint32_t clkfulldiv;
uint32_t ret;
/* Get the largest divisor does not exceed the target value */
clkfulldiv = (BOARD_MCK_FREQUENCY + target - 1) / target;
if (clkfulldiv > 2)
{
clkfulldiv -= 2;
}
else
{
clkfulldiv = 0;
}
if (clkfulldiv > 511)
{
clkfulldiv = 511;
}
ret = (clkfulldiv >> 1) << HSMCI_MR_CLKDIV_SHIFT;
if ((clkfulldiv & 1) != 0)
{
ret |= HSMCI_MR_CLKODD;
}
return ret;
}
#endif /* CONFIG_SAMA5_HSMCI0 || CONFIG_SAMA5_HSMCI1 || CONFIG_SAMA5_HSMCI2 */
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