/*
* Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <asm_macros.S>
#include <assert_macros.S>
#include <console_macros.S>
#include <drivers/st/stm32_console.h>
#include <drivers/st/stm32_uart_regs.h>
#define USART_TIMEOUT 0x1000
/*
* "core" functions are low-level implementations that don't require
* writeable memory and are thus safe to call in BL1 crash context.
*/
.globl console_stm32_core_init
.globl console_stm32_core_putc
.globl console_stm32_core_getc
.globl console_stm32_core_flush
.globl console_stm32_putc
.globl console_stm32_flush
/* -----------------------------------------------------------------
* int console_core_init(uintptr_t base_addr,
* unsigned int uart_clk,
* unsigned int baud_rate)
*
* Function to initialize the console without a C Runtime to print
* debug information. This function will be accessed by console_init
* and crash reporting.
*
* In: r0 - console base address
* r1 - Uart clock in Hz
* r2 - Baud rate
* Out: return 1 on success else 0 on error
* Clobber list : r1, r2, r3
* -----------------------------------------------------------------
*/
func console_stm32_core_init
/* Check the input base address */
cmp r0, #0
beq core_init_fail
#if defined(IMAGE_BL2)
/* Check baud rate and uart clock for sanity */
cmp r1, #0
beq core_init_fail
cmp r2, #0
beq core_init_fail
/* Disable UART */
ldr r3, [r0, #USART_CR1]
bic r3, r3, #USART_CR1_UE
str r3, [r0, #USART_CR1]
/* Configure UART */
orr r3, r3, #(USART_CR1_TE | USART_CR1_FIFOEN)
str r3, [r0, #USART_CR1]
ldr r3, [r0, #USART_CR2]
bic r3, r3, #USART_CR2_STOP
str r3, [r0, #USART_CR2]
/* Divisor = (Uart clock + (baudrate / 2)) / baudrate */
lsl r3, r2, #1
add r3, r1, r3
udiv r3, r3, r2
str r3, [r0, #USART_BRR]
/* Enable UART */
ldr r3, [r0, #USART_CR1]
orr r3, r3, #USART_CR1_UE
str r3, [r0, #USART_CR1]
/* Check TEACK bit */
mov r2, #USART_TIMEOUT
teack_loop:
subs r2, r2, #1
beq core_init_fail
ldr r3, [r0, #USART_ISR]
tst r3, #USART_ISR_TEACK
beq teack_loop
#endif /* IMAGE_BL2 */
mov r0, #1
bx lr
core_init_fail:
mov r0, #0
bx lr
endfunc console_stm32_core_init
.globl console_stm32_register
/* -------------------------------------------------------
* int console_stm32_register(uintptr_t baseaddr,
* uint32_t clock, uint32_t baud,
* console_t *console);
* Function to initialize and register a new STM32
* console. Storage passed in for the console struct
* *must* be persistent (i.e. not from the stack).
* In: r0 - UART register base address
* r1 - UART clock in Hz
* r2 - Baud rate
* r3 - pointer to empty console_t struct
* Out: return 1 on success, 0 on error
* Clobber list : r0, r1, r2
* -------------------------------------------------------
*/
func console_stm32_register
push {r4, lr}
mov r4, r3
cmp r4, #0
beq register_fail
str r0, [r4, #CONSOLE_T_BASE]
bl console_stm32_core_init
cmp r0, #0
beq register_fail
mov r0, r4
pop {r4, lr}
finish_console_register stm32 putc=1, getc=0, flush=1
register_fail:
pop {r4, pc}
endfunc console_stm32_register
/* ---------------------------------------------------------------
* int console_core_putc(int c, uintptr_t base_addr)
*
* Function to output a character over the console. It returns the
* character printed on success or -1 on error.
*
* In : r0 - character to be printed
* r1 - console base address
* Out : return -1 on error else return character.
* Clobber list : r2
* ---------------------------------------------------------------
*/
func console_stm32_core_putc
/* Check the input parameter */
cmp r1, #0
beq putc_error
/* Check Transmit Data Register Empty */
txe_loop:
ldr r2, [r1, #USART_ISR]
tst r2, #USART_ISR_TXE
beq txe_loop
str r0, [r1, #USART_TDR]
/* Check transmit complete flag */
tc_loop:
ldr r2, [r1, #USART_ISR]
tst r2, #USART_ISR_TC
beq tc_loop
bx lr
putc_error:
mov r0, #-1
bx lr
endfunc console_stm32_core_putc
/* ------------------------------------------------------------
* int console_stm32_putc(int c, console_t *console)
* Function to output a character over the console. It
* returns the character printed on success or -1 on error.
* In: r0 - character to be printed
* r1 - pointer to console_t structure
* Out : return -1 on error else return character.
* Clobber list: r2
* ------------------------------------------------------------
*/
func console_stm32_putc
#if ENABLE_ASSERTIONS
cmp r1, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
ldr r1, [r1, #CONSOLE_T_BASE]
b console_stm32_core_putc
endfunc console_stm32_putc
/* -----------------------------------------------------------
* int console_core_getc(uintptr_t base_addr)
*
* Function to get a character from the console.
* It returns the character grabbed on success or -1 on error.
*
* In : r0 - console base address
* Out : return -1.
* Clobber list : r0, r1
* -----------------------------------------------------------
*/
func console_stm32_core_getc
/* Not supported */
mov r0, #-1
bx lr
endfunc console_stm32_core_getc
/* ---------------------------------------------------------------
* int console_core_flush(uintptr_t base_addr)
*
* Function to force a write of all buffered data that hasn't been
* output.
*
* In : r0 - console base address
* Out : return -1 on error else return 0.
* Clobber list : r0, r1
* ---------------------------------------------------------------
*/
func console_stm32_core_flush
cmp r0, #0
beq flush_error
/* Check Transmit Data Register Empty */
txe_loop_3:
ldr r1, [r0, #USART_ISR]
tst r1, #USART_ISR_TXE
beq txe_loop_3
mov r0, #0
bx lr
flush_error:
mov r0, #-1
bx lr
endfunc console_stm32_core_flush
/* ------------------------------------------------------
* int console_stm32_flush(console_t *console)
* Function to force a write of all buffered
* data that hasn't been output.
* In : r0 - pointer to console_t structure
* Out : return -1 on error else return 0.
* Clobber list: r0, r1
* ------------------------------------------------------
*/
func console_stm32_flush
#if ENABLE_ASSERTIONS
cmp r0, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
ldr r0, [r0, #CONSOLE_T_BASE]
b console_stm32_core_flush
endfunc console_stm32_flush
