arm-trusted-firmware/drivers/st/uart/aarch32/stm32_console.S
Jimmy Brisson 831b0e9824 Don't return error information from console_flush
And from crash_console_flush.

We ignore the error information return by console_flush in _every_
place where we call it, and casting the return type to void does not
work around the MISRA violation that this causes. Instead, we collect
the error information from the driver (to avoid changing that API), and
don't return it to the caller.

Change-Id: I1e35afe01764d5c8f0efd04f8949d333ffb688c1
Signed-off-by: Jimmy Brisson <jimmy.brisson@arm.com>
2020-10-09 10:21:50 -05:00

235 lines
6.2 KiB
ArmAsm

/*
* Copyright (c) 2018-2020, 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
/* ---------------------------------------------------------------
* void 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 : void.
* Clobber list : r0, r1
* ---------------------------------------------------------------
*/
func console_stm32_core_flush
#if ENABLE_ASSERTIONS
cmp r0, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
/* Check Transmit Data Register Empty */
txe_loop_3:
ldr r1, [r0, #USART_ISR]
tst r1, #USART_ISR_TXE
beq txe_loop_3
bx lr
endfunc console_stm32_core_flush
/* ------------------------------------------------------
* void 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 : void.
* 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