sys-rtc.c File Reference

System RTC (Real-Time Clock) driver for Allwinner (sunxi) platforms. More...

#include <io.h>
#include <log.h>
#include <mmu.h>
#include <cache.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <timer.h>
#include <types.h>
#include <reg-ncat.h>
#include <sys-rtc.h>

Include dependency graph for sys-rtc.c:

Functions
void	rtc_write_data (int index, uint32_t val)
	Write data to an RTC register.
uint32_t	rtc_read_data (int index)
	Read data from an RTC register.
void	rtc_set_fel_flag (void)
	Set the FEL (Fastboot External Loader) flag.
void	rtc_set_start_time_ms (void)
	Set the initialization timestamp.
void	rtc_set_dram_para (uint32_t dram_para_addr)
	Sets the parameters for Dynamic Random Access Memory (DRAM).
uint32_t	rtc_probe_fel_flag (void)
	Check if the FEL flag is set.
void	rtc_clear_fel_flag (void)
	Clear the FEL (Fastboot External Loader) flag.
int	rtc_set_bootmode_flag (uint8_t flag)
	Set the boot mode flag.
int	rtc_get_bootmode_flag (void)
	Get the boot mode flag.

Detailed Description

System RTC (Real-Time Clock) driver for Allwinner (sunxi) platforms.

This file implements RTC functionality for Allwinner SoCs, providing interface functions to read from and write to RTC registers. The RTC is used to store various persistent flags and parameters, including FEL (Fastboot External Loader) mode flag, boot mode information, DRAM parameters, and initialization timestamp. These values are retained even when the system is powered off, as long as there is backup battery power.

Function Documentation

rtc_clear_fel_flag()

void rtc_clear_fel_flag

(

void

)

Clear the FEL (Fastboot External Loader) flag.

Clear the FEL (Fastboot External Loader) flag in the RTC register.

Clears the FEL flag in the RTC register after it has been processed. The function verifies the write operation was successful by reading back the value.

rtc_get_bootmode_flag()

int rtc_get_bootmode_flag

(

void

)

Get the boot mode flag.

Get the bootmode flag from the RTC register.

Reads the boot mode flag from the RTC register. This is used to determine how the system should boot. The operation is designed to be compatible with how the kernel reads this value.

Returns

The value of the boot mode flag

rtc_probe_fel_flag()

uint32_t rtc_probe_fel_flag

(

void

)

Check if the FEL flag is set.

Probe the FEL (Fastboot External Loader) flag in the RTC register.

Reads the FEL flag from the RTC register and returns whether it is set.

Returns

1 if the FEL flag is set, 0 otherwise

rtc_read_data()

uint32_t rtc_read_data

(

int

index

)

Read data from an RTC register.

Read data from the RTC register at the specified index.

Reads a 32-bit value from the RTC register at the specified index.

Parameters

index

The index of the RTC register to read data from

Returns

The value read from the RTC register

rtc_set_bootmode_flag()

int rtc_set_bootmode_flag

(

uint8_t

flag

)

Set the boot mode flag.

Set the bootmode flag in the RTC register.

Sets the boot mode flag in the RTC register, which determines how the system will boot. The function verifies the write operation was successful.

Parameters

flag	The boot mode flag value to set

Returns

0 if successful

rtc_set_dram_para()

void rtc_set_dram_para

(

uint32_t

dram_para_addr

)

Sets the parameters for Dynamic Random Access Memory (DRAM).

This function is used to set the parameters for DRAM and ensures the success of parameter setting through a loop.

Parameters

dram_para_addr

Address for DRAM parameters to be set.

Returns

None.

Note

This function continuously attempts to set DRAM parameters until it succeeds.

rtc_set_fel_flag()

void rtc_set_fel_flag

(

void

)

Set the FEL (Fastboot External Loader) flag.

Set the FEL (Fastboot External Loader) flag in the RTC register.

Sets the FEL flag in the RTC register, which indicates that the system should enter Fastboot mode. The function verifies the write operation was successful by reading back the value.

rtc_set_start_time_ms()

void rtc_set_start_time_ms

(

void

)

Set the initialization timestamp.

Set the start time in milliseconds in the RTC register.

Stores the initialization timestamp (in milliseconds) in the RTC register. This value can be used for timing operations or to determine the system uptime. The function verifies the write operation was successful.

rtc_write_data()

void rtc_write_data	(	int	index,
		uint32_t	val
	)

Write data to an RTC register.

Write data to the RTC register at the specified index.

Writes a 32-bit value to the RTC register at the specified index.

Parameters

index	The index of the RTC register to write data to
val	The value to write to the RTC register