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https://github.com/ARM-software/arm-trusted-firmware.git
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168 lines
4.1 KiB
ArmAsm
168 lines
4.1 KiB
ArmAsm
/*
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* Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <asm_macros.S>
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#include <stm32_uart_regs.h>
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#define USART_TIMEOUT 0x1000
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.globl console_core_init
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.globl console_core_putc
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.globl console_core_getc
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.globl console_core_flush
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/* -----------------------------------------------------------------
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* int console_core_init(uintptr_t base_addr,
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* unsigned int uart_clk,
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* unsigned int baud_rate)
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*
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* Function to initialize the console without a C Runtime to print
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* debug information. This function will be accessed by console_init
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* and crash reporting.
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*
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* In: r0 - console base address
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* r1 - Uart clock in Hz
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* r2 - Baud rate
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* Out: return 1 on success else 0 on error
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* Clobber list : r1, r2, r3
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* -----------------------------------------------------------------
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*/
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func console_core_init
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/* Check the input base address */
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cmp r0, #0
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beq core_init_fail
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#if defined(IMAGE_BL2)
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/* Check baud rate and uart clock for sanity */
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cmp r1, #0
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beq core_init_fail
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cmp r2, #0
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beq core_init_fail
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/* Disable UART */
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ldr r3, [r0, #USART_CR1]
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bic r3, r3, #USART_CR1_UE
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str r3, [r0, #USART_CR1]
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/* Configure UART */
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orr r3, r3, #(USART_CR1_TE | USART_CR1_FIFOEN)
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str r3, [r0, #USART_CR1]
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ldr r3, [r0, #USART_CR2]
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bic r3, r3, #USART_CR2_STOP
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str r3, [r0, #USART_CR2]
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/* Divisor = (Uart clock + (baudrate / 2)) / baudrate */
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lsl r3, r2, #1
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add r3, r1, r3
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udiv r3, r3, r2
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str r3, [r0, #USART_BRR]
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/* Enable UART */
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ldr r3, [r0, #USART_CR1]
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orr r3, r3, #USART_CR1_UE
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str r3, [r0, #USART_CR1]
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/* Check TEACK bit */
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mov r2, #USART_TIMEOUT
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teack_loop:
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subs r2, r2, #1
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beq core_init_fail
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ldr r3, [r0, #USART_ISR]
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tst r3, #USART_ISR_TEACK
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beq teack_loop
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#endif /* IMAGE_BL2 */
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mov r0, #1
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bx lr
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core_init_fail:
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mov r0, #0
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bx lr
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endfunc console_core_init
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/* ---------------------------------------------------------------
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* int console_core_putc(int c, uintptr_t base_addr)
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*
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* Function to output a character over the console. It returns the
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* character printed on success or -1 on error.
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*
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* In : r0 - character to be printed
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* r1 - console base address
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* Out : return -1 on error else return character.
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* Clobber list : r2
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* ---------------------------------------------------------------
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*/
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func console_core_putc
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/* Check the input parameter */
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cmp r1, #0
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beq putc_error
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/* Prepend '\r' to '\n' */
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cmp r0, #0xA
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bne 2f
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1:
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/* Check Transmit Data Register Empty */
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txe_loop_1:
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ldr r2, [r1, #USART_ISR]
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tst r2, #USART_ISR_TXE
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beq txe_loop_1
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mov r2, #0xD
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str r2, [r1, #USART_TDR]
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/* Check transmit complete flag */
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tc_loop_1:
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ldr r2, [r1, #USART_ISR]
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tst r2, #USART_ISR_TC
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beq tc_loop_1
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2:
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/* Check Transmit Data Register Empty */
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txe_loop_2:
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ldr r2, [r1, #USART_ISR]
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tst r2, #USART_ISR_TXE
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beq txe_loop_2
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str r0, [r1, #USART_TDR]
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/* Check transmit complete flag */
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tc_loop_2:
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ldr r2, [r1, #USART_ISR]
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tst r2, #USART_ISR_TC
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beq tc_loop_2
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bx lr
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putc_error:
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mov r0, #-1
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bx lr
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endfunc console_core_putc
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/* -----------------------------------------------------------
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* int console_core_getc(uintptr_t base_addr)
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*
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* Function to get a character from the console.
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* It returns the character grabbed on success or -1 on error.
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*
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* In : r0 - console base address
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* Out : return -1.
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* Clobber list : r0, r1
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* -----------------------------------------------------------
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*/
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func console_core_getc
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/* Not supported */
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mov r0, #-1
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bx lr
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endfunc console_core_getc
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/* ---------------------------------------------------------------
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* int console_core_flush(uintptr_t base_addr)
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*
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* Function to force a write of all buffered data that hasn't been
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* output.
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*
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* In : r0 - console base address
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* Out : return -1 on error else return 0.
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* Clobber list : r0, r1
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* ---------------------------------------------------------------
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*/
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func console_core_flush
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cmp r0, #0
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beq flush_error
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/* Check Transmit Data Register Empty */
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txe_loop_3:
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ldr r1, [r0, #USART_ISR]
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tst r1, #USART_ISR_TXE
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beq txe_loop_3
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mov r0, #0
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bx lr
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flush_error:
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mov r0, #-1
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bx lr
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endfunc console_core_flush
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