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/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Clocks and power management settings */
#include <stdint.h>
#include "board.h"
#include "clock.h"
#include "config.h"
#include "console.h"
#include "gpio.h"
#include "task.h"
#include "timer.h"
#include "uart.h"
#include "registers.h"
#include "util.h"
/**
* Idle task
* executed when no task are ready to be scheduled
*/
void __idle(void)
{
while (1) {
/* wait for the irq event */
asm("wfi");
/* TODO more power management here */
}
}
/* simple busy waiting before clocks are initialized */
static void wait_cycles(uint32_t cycles)
{
asm("1: subs %0, #1\n"
" bne 1b\n" :: "r"(cycles));
}
/**
* Function to measure baseline for power consumption.
*
* Levels :
* 0 : CPU running in tight loop
* 1 : CPU running in tight loop but peripherals gated
* 2 : CPU in sleep mode
* 3 : CPU in sleep mode and peripherals gated
* 4 : CPU in deep sleep mode
* 5 : CPU in deep sleep mode and peripherals gated
*/
static int command_sleep(int argc, char **argv)
{
int level = 0;
int clock = 0;
uint32_t uartibrd = 0;
uint32_t uartfbrd = 0;
if (argc >= 2) {
level = strtoi(argv[1], NULL, 10);
}
if (argc >= 3) {
clock = strtoi(argv[2], NULL, 10);
}
/* remove LED current sink */
gpio_set(EC_GPIO_DEBUG_LED, 0);
uart_printf("Going to sleep : level %d clock %d...\n", level, clock);
uart_flush_output();
/* clock setting */
if (clock) {
/* Use ROM code function to set the clock */
void **func_table = (void **)*(uint32_t *)0x01000044;
void (*rom_clock_set)(uint32_t rcc) = func_table[23];
/* disable interrupts */
asm volatile("cpsid i");
switch (clock) {
case 1: /* 16MHz IOSC */
uartibrd = 17;
uartfbrd = 23;
rom_clock_set(0x00000d51);
break;
case 2: /* 1MHz IOSC */
uartibrd = 1;
uartfbrd = 5;
rom_clock_set(0x07C00d51);
break;
case 3: /* 30 kHz */
uartibrd = 0;
uartfbrd = 0;
rom_clock_set(0x00000d71);
break;
}
/* TODO: move this to the UART module; ugly to have
UARTisms here. Also note this only fixes UART0,
not UART1. */
if (uartfbrd) {
/* Disable the port via UARTCTL and add HSE */
LM4_UART_CTL(0) = 0x0320;
/* Set the baud rate divisor */
LM4_UART_IBRD(0) = uartibrd;
LM4_UART_FBRD(0) = uartfbrd;
/* Poke UARTLCRH to make the new divisor take effect. */
LM4_UART_LCRH(0) = LM4_UART_LCRH(0);
/* Enable the port */
LM4_UART_CTL(0) |= 0x0001;
}
asm volatile("cpsie i");
}
if (uartfbrd) {
uart_printf("We are still alive. RCC=%08x\n", LM4_SYSTEM_RCC);
uart_flush_output();
}
asm volatile("cpsid i");
/* gate peripheral clocks */
if (level & 1) {
LM4_SYSTEM_RCGCTIMER = 0;
LM4_SYSTEM_RCGCGPIO = 0;
LM4_SYSTEM_RCGCDMA = 0;
LM4_SYSTEM_RCGCUART = 0;
LM4_SYSTEM_RCGCLPC = 0;
LM4_SYSTEM_RCGCWTIMER = 0;
}
/* set deep sleep bit */
if (level >= 4)
LM4_SCB_SYSCTRL |= 0x4;
/* go to low power mode (forever ...) */
if (level > 1)
while (1)
asm("wfi");
else
while(1);
return EC_SUCCESS;
}
static const struct console_command clock_commands[] = {
{"sleep", command_sleep}
};
static const struct console_group clock_group = {
"Clock", clock_commands, ARRAY_SIZE(clock_commands)
};
static void clock_init_pll(uint32_t value)
{
/**
* at startup, OSCSRC is PIOSC (precision internal oscillator)
* PLL and PLL2 are in power-down
*/
/* PLL already setup */
if (LM4_SYSTEM_PLLSTAT & 1)
return;
/* Put a bypass on the system clock PLLs, no divider */
LM4_SYSTEM_RCC = (LM4_SYSTEM_RCC | 0x800) & ~0x400000;
LM4_SYSTEM_RCC2 = (LM4_SYSTEM_RCC2 | 0x800) & ~0x80000000;
/* Enable main and precision internal oscillators */
LM4_SYSTEM_RCC &= ~0x3;
/* wait 1 million CPU cycles */
wait_cycles(512 * 1024);
/* clear PLL lock flag (aka PLLLMIS) */
LM4_SYSTEM_MISC = 0x40;
/* clear powerdown / set XTAL frequency and divider */
LM4_SYSTEM_RCC = (LM4_SYSTEM_RCC & ~0x07c027c0) | (value & 0x07c007c0);
/* wait 32 CPU cycles */
wait_cycles(16);
/* wait for PLL to lock */
while (!(LM4_SYSTEM_RIS & 0x40));
/* Remove bypass on PLL and set oscillator source to main */
LM4_SYSTEM_RCC = LM4_SYSTEM_RCC & ~0x830;
}
int clock_init(void)
{
/* Use 66.667Mhz clock from PLL */
BUILD_ASSERT(CPU_CLOCK == 66666667);
/* CPU clock = PLL/3 ; System clock = PLL
* Osc source = main OSC ; external crystal = 16 Mhz
*/
clock_init_pll(0x01400540);
#ifdef CONFIG_DEBUG
/* Register our internal commands */
console_register_commands(&clock_group);
#endif
return EC_SUCCESS;
}
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