drivers/st/uart/aarch32/stm32_console.S - filogic/atf - Gitiles

 /*
  * Copyright (c) 2018-2022, 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)
 	/* Skip UART initialization if it is already enabled */
 	ldr	r3, [r0, #USART_CR1]
 	ands	r3, r3, #USART_CR1_UE
 	bne	1f
 #endif /* 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 */
 	lsr	r3, r2, #1
 	add	r3, r1, r3
 	udiv	r3, r3, r2
 	cmp	r3, #16
 	bhi	2f
 	/* Oversampling 8 */
 	/* Divisor =  (2 * Uart clock + (baudrate / 2)) / baudrate */
 	lsr	r3, r2, #1
 	add	r3, r3, r1, lsl #1
 	udiv	r3, r3, r2
 	and	r1, r3, #USART_BRR_DIV_FRACTION
 	lsr	r1, r1, #1
 	bic	r3, r3, #USART_BRR_DIV_FRACTION
 	orr	r3, r3, r1
 	ldr	r1, [r0, #USART_CR1]
 	orr	r1, r1, #USART_CR1_OVER8
 	str	r1, [r0, #USART_CR1]
 2:
 	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
 1:
 	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
	/*
	* Copyright (c) 2018-2022, 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)
	/* Skip UART initialization if it is already enabled */
	ldr r3, [r0, #USART_CR1]
	ands r3, r3, #USART_CR1_UE
	bne 1f
	#endif /* 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 */
	lsr r3, r2, #1
	add r3, r1, r3
	udiv r3, r3, r2
	cmp r3, #16
	bhi 2f
	/* Oversampling 8 */
	/* Divisor = (2 * Uart clock + (baudrate / 2)) / baudrate */
	lsr r3, r2, #1
	add r3, r3, r1, lsl #1
	udiv r3, r3, r2
	and r1, r3, #USART_BRR_DIV_FRACTION
	lsr r1, r1, #1
	bic r3, r3, #USART_BRR_DIV_FRACTION
	orr r3, r3, r1
	ldr r1, [r0, #USART_CR1]
	orr r1, r1, #USART_CR1_OVER8
	str r1, [r0, #USART_CR1]
	2:
	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
	1:
	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