u-boot/board/hidden_dragon/speed.h

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/*
* (C) Copyright 2000
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*-----------------------------------------------------------------------
* Timer value for timer 2, ICLK = 10
*
* SPEED_FCOUNT2 = GCLK / (16 * (TIMER_TMR_PS + 1))
* SPEED_TMR3_PS = (GCLK / (16 * SPEED_FCOUNT3)) - 1
*
* SPEED_FCOUNT2 timer 2 counting frequency
* GCLK CPU clock
* SPEED_TMR2_PS prescaler
*/
#define SPEED_TMR2_PS (250 - 1) /* divide by 250 */
/*-----------------------------------------------------------------------
* Timer value for PIT
*
* PIT_TIME = SPEED_PITC / PITRTCLK
* PITRTCLK = 8192
*/
#define SPEED_PITC (82 << 16) /* start counting from 82 */
/*
* The new value for PTA is calculated from
*
* PTA = (gclk * Trefresh) / (2 ^ (2 * DFBRG) * PTP * NCS)
*
* gclk CPU clock (not bus clock !)
* Trefresh Refresh cycle * 4 (four word bursts used)
* DFBRG For normal mode (no clock reduction) always 0
* PTP Prescaler (already adjusted for no. of banks and 4K / 8K refresh)
* NCS Number of SDRAM banks (chip selects) on this UPM.
*/