u-boot/cpu/lh7a40x/speed.c
wdenk f832d8a143 * Patch by Paul Ruhland, 10 Jun 2004:
fix support for Logic SDK-LH7A404 board and clean up the
  LH7A404 register macros.

* Patch by Matthew McClintock, 10 Jun 2004:
  Modify code to select correct serial clock on Sandpoint8245
2004-06-10 21:55:33 +00:00

84 lines
2.3 KiB
C

/*
* (C) Copyright 2001-2004
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* (C) Copyright 2002
* David Mueller, ELSOFT AG, d.mueller@elsoft.ch
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but 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., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <lh7a40x.h>
/* ------------------------------------------------------------------------- */
/* NOTE: This describes the proper use of this file.
*
* CONFIG_SYS_CLK_FREQ should be defined as the input frequency of the PLL.
*
* get_FCLK(), get_HCLK(), get_PCLK() return the clock of
* the specified bus in HZ.
*/
/* ------------------------------------------------------------------------- */
ulong get_PLLCLK (void)
{
return CONFIG_SYS_CLK_FREQ;
}
/* return FCLK frequency */
ulong get_FCLK (void)
{
lh7a40x_csc_t* csc = LH7A40X_CSC_PTR;
ulong maindiv1, maindiv2, prediv, ps;
/*
* from userguide 6.1.1.2
*
* FCLK = ((MAINDIV1 +2) * (MAINDIV2 +2) * 14.7456MHz) /
* ((PREDIV+2) * (2^PS))
*/
maindiv2 = (csc->clkset & CLKSET_MAINDIV2) >> 11;
maindiv1 = (csc->clkset & CLKSET_MAINDIV1) >> 7;
prediv = (csc->clkset & CLKSET_PREDIV) >> 2;
ps = (csc->clkset & CLKSET_PS) >> 16;
return (((maindiv2 + 2) * (maindiv1 + 2) * CONFIG_SYS_CLK_FREQ) /
((prediv + 2) * (1 << ps)));
}
/* return HCLK frequency */
ulong get_HCLK (void)
{
lh7a40x_csc_t* csc = LH7A40X_CSC_PTR;
return (get_FCLK () / ((csc->clkset & CLKSET_HCLKDIV) + 1));
}
/* return PCLK frequency */
ulong get_PCLK (void)
{
lh7a40x_csc_t* csc = LH7A40X_CSC_PTR;
return (get_HCLK () /
(1 << (((csc->clkset & CLKSET_PCLKDIV) >> 16) + 1)));
}