cpu_init.c
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/* Initializes CPU and basic hardware such as memory
* controllers, IRQ controller and system timer 0.
*
* (C) Copyright 2007
* Daniel Hellstrom, Gaisler Research, daniel@gaisler.com
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/asi.h>
#include <asm/leon.h>
#include <config.h>
#define TIMER_BASE_CLK 1000000
#define US_PER_TICK (1000000 / CONFIG_SYS_HZ)
DECLARE_GLOBAL_DATA_PTR;
/* reset CPU (jump to 0, without reset) */
void start(void);
struct {
gd_t gd_area;
bd_t bd;
} global_data;
/*
* Breath some life into the CPU...
*
* Set up the memory map,
* initialize a bunch of registers.
*
* Run from FLASH/PROM:
* - until memory controller is set up, only registers available
* - no global variables available for writing
* - constants available
*/
void cpu_init_f(void)
{
LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
/* initialize the IRQMP */
leon2->Interrupt_Force = 0;
leon2->Interrupt_Pending = 0;
leon2->Interrupt_Clear = 0xfffe; /* clear all old pending interrupts */
leon2->Interrupt_Mask = 0xfffe0000; /* mask all IRQs */
/* cache */
/* I/O port setup */
#ifdef LEON2_IO_PORT_DIR
leon2->PIO_Direction = LEON2_IO_PORT_DIR;
#endif
#ifdef LEON2_IO_PORT_DATA
leon2->PIO_Data = LEON2_IO_PORT_DATA;
#endif
#ifdef LEON2_IO_PORT_INT
leon2->PIO_Interrupt = LEON2_IO_PORT_INT;
#else
leon2->PIO_Interrupt = 0;
#endif
}
void cpu_init_f2(void)
{
}
/*
* initialize higher level parts of CPU like time base and timers
*/
int cpu_init_r(void)
{
LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
/* initialize prescaler common to all timers to 1MHz */
leon2->Scaler_Counter = leon2->Scaler_Reload =
(((CONFIG_SYS_CLK_FREQ / 1000) + 500) / 1000) - 1;
return (0);
}
/* Uses Timer 0 to get accurate
* pauses. Max 2 raised to 32 ticks
*
*/
void cpu_wait_ticks(unsigned long ticks)
{
unsigned long start = get_timer(0);
while (get_timer(start) < ticks) ;
}
/* initiate and setup timer0 interrupt to configured HZ. Base clock is 1MHz.
* Return irq number for timer int or a negative number for
* dealing with self
*/
int timer_interrupt_init_cpu(void)
{
LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
/* SYS_HZ ticks per second */
leon2->Timer_Counter_1 = 0;
leon2->Timer_Reload_1 = (TIMER_BASE_CLK / CONFIG_SYS_HZ) - 1;
leon2->Timer_Control_1 =
(LEON2_TIMER_CTRL_EN | LEON2_TIMER_CTRL_RS | LEON2_TIMER_CTRL_LD);
return LEON2_TIMER1_IRQNO;
}
/*
* This function is intended for SHORT delays only.
*/
unsigned long cpu_usec2ticks(unsigned long usec)
{
if (usec < US_PER_TICK)
return 1;
return usec / US_PER_TICK;
}
unsigned long cpu_ticks2usec(unsigned long ticks)
{
return ticks * US_PER_TICK;
}