drivers/ti/uart/aarch32/16550_console.S - filogic/atf - Gitiles

 /*
  * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */

 #include <arch.h>
 #include <asm_macros.S>
 #include <assert_macros.S>
 #include <console_macros.S>
 #include <drivers/ti/uart/uart_16550.h>

 	/*
 	 * "core" functions are low-level implementations that don't require
 	 * writable memory and are thus safe to call in BL1 crash context.
 	 */
 	.globl console_16550_core_init
 	.globl console_16550_core_putc
 	.globl console_16550_core_getc
 	.globl console_16550_core_flush

 	.globl console_16550_putc
 	.globl console_16550_getc
 	.globl console_16550_flush

 	/* -----------------------------------------------
 	 * int console_16550_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, 0 on error
 	 * Clobber list : r1, r2, r3
 	 * -----------------------------------------------
 	 */
 func console_16550_core_init
 	/* Check the input base address */
 	cmp	r0, #0
 	beq	init_fail
 	/* Check baud rate and uart clock for sanity */
 	cmp	r1, #0
 	beq	init_fail
 	cmp	r2, #0
 	beq	init_fail

 	/* Program the baudrate */
 	/* Divisor =  Uart clock / (16 * baudrate) */
 	lsl	r2, r2, #4
 	udiv	r2, r1, r2
 	and	r1, r2, #0xff		/* w1 = DLL */
 	lsr	r2, r2, #8
 	and	r2, r2, #0xff		/* w2 = DLLM */
 	ldr	r3, [r0, #UARTLCR]
 	orr	r3, r3, #UARTLCR_DLAB
 	str	r3, [r0, #UARTLCR]	/* enable DLL, DLLM programming */
 	str	r1, [r0, #UARTDLL]	/* program DLL */
 	str	r2, [r0, #UARTDLLM]	/* program DLLM */
 	mov	r2, #~UARTLCR_DLAB
 	and	r3, r3, r2
 	str	r3, [r0, #UARTLCR]	/* disable DLL, DLLM programming */

 	/* 8n1 */
 	mov	r3, #3
 	str	r3, [r0, #UARTLCR]
 	/* no interrupt */
 	mov	r3, #0
 	str	r3, [r0, #UARTIER]
 #ifdef TI_16550_MDR_QUIRK
 	/* UART must be enabled on some platforms via the MDR register */
 	str	r3, [r0, #UARTMDR1]
 #endif /* TI_16550_MDR_QUIRK */
 	/* enable fifo, DMA */
 	mov	r3, #(UARTFCR_FIFOEN | UARTFCR_DMAEN)
 	str	r3, [r0, #UARTFCR]
 	/* DTR + RTS */
 	mov	r3, #3
 	str	r3, [r0, #UARTMCR]
 	mov	r0, #1
 	bx	lr
 init_fail:
 	mov	r0, #0
 	bx	lr
 endfunc console_16550_core_init

 	.globl console_16550_register

 	/* -------------------------------------------------------
 	 * int console_16550_register(uintptr_t baseaddr,
 	 *     uint32_t clock, uint32_t baud,
 	 *     console_t *console);
 	 * Function to initialize and register a new 16550
 	 * console. Storage passed in for the console struct
 	 * *must* be persistent (i.e. not from the stack).
 	 * If r1 (UART clock) is 0, initialisation will be
          * skipped, relying on previous code to have done
          * this already. r2 is ignored then as well.
 	 * In: r0 - UART register base address
 	 *     r1 - UART clock in Hz
 	 *     r2 - Baud rate (ignored if r1 is 0)
 	 *     r3 - pointer to empty console_t struct
 	 * Out: return 1 on success, 0 on error
 	 * Clobber list : r0, r1, r2
 	 * -------------------------------------------------------
 	 */
 func console_16550_register
 	push	{r4, lr}
 	mov	r4, r3
 	cmp	r4, #0
 	beq	register_fail
 	str	r0, [r4, #CONSOLE_T_BASE]

 	/* A clock rate of zero means to skip the initialisation. */
 	cmp	r1, #0
 	beq	register_16550

 	bl	console_16550_core_init
 	cmp	r0, #0
 	beq	register_fail

 register_16550:
 	mov	r0, r4
 	pop	{r4, lr}
 	finish_console_register 16550 putc=1, getc=1, flush=1

 register_fail:
 	pop	{r4, pc}
 endfunc console_16550_register

 	/* --------------------------------------------------------
 	 * int console_16550_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_16550_core_putc
 #if ENABLE_ASSERTIONS
 	cmp	r1, #0
 	ASM_ASSERT(ne)
 #endif /* ENABLE_ASSERTIONS */

 	/* Prepend '\r' to '\n' */
 	cmp	r0, #0xA
 	bne	2f
 	/* Check if the transmit FIFO is full */
 1:	ldr	r2, [r1, #UARTLSR]
 	and	r2, r2, #(UARTLSR_TEMT | UARTLSR_THRE)
 	cmp	r2, #(UARTLSR_TEMT | UARTLSR_THRE)
 	bne	1b
 	mov	r2, #0xD		/* '\r' */
 	str	r2, [r1, #UARTTX]

 	/* Check if the transmit FIFO is full */
 2:	ldr	r2, [r1, #UARTLSR]
 	and	r2, r2, #(UARTLSR_TEMT | UARTLSR_THRE)
 	cmp	r2, #(UARTLSR_TEMT | UARTLSR_THRE)
 	bne	2b
 	str	r0, [r1, #UARTTX]
 	bx	lr
 endfunc console_16550_core_putc

 	/* --------------------------------------------------------
 	 * int console_16550_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_16550_putc
 #if ENABLE_ASSERTIONS
 	cmp	r1, #0
 	ASM_ASSERT(ne)
 #endif /* ENABLE_ASSERTIONS */
 	ldr	r1, [r1, #CONSOLE_T_BASE]
 	b	console_16550_core_putc
 endfunc console_16550_putc

 	/* ---------------------------------------------
 	 * int console_16550_core_getc(uintptr_t base_addr)
 	 * Function to get a character from the console.
 	 * It returns the character grabbed on success
 	 * or -1 on if no character is available.
 	 * In :  r0 - console base address
 	 * Clobber list : r0, r1
 	 * ---------------------------------------------
 	 */
 func console_16550_core_getc
 #if ENABLE_ASSERTIONS
 	cmp	r0, #0
 	ASM_ASSERT(ne)
 #endif /* ENABLE_ASSERTIONS */

 	/* Check if the receive FIFO is empty */
 1:	ldr	r1, [r0, #UARTLSR]
 	tst	r1, #UARTLSR_RDR_BIT
 	beq	no_char
 	ldr	r1, [r0, #UARTRX]
 	mov	r0, r1
 	bx	lr
 no_char:
 	mov	r0, #ERROR_NO_PENDING_CHAR
 	bx	lr
 endfunc console_16550_core_getc

 	/* ---------------------------------------------
 	 * int console_16550_getc(console_t *console)
 	 * Function to get a character from the console.
 	 * It returns the character grabbed on success
 	 * or -1 on if no character is available.
 	 * In :  r0 - pointer to console_t stucture
 	 * Out : r0 - character if available, else -1
 	 * Clobber list : r0, r1
 	 * ---------------------------------------------
 	 */
 func console_16550_getc
 #if ENABLE_ASSERTIONS
 	cmp	r0, #0
 	ASM_ASSERT(ne)
 #endif /* ENABLE_ASSERTIONS */
 	ldr	r0, [r0, #CONSOLE_T_BASE]
 	b	console_16550_core_getc
 endfunc console_16550_getc

 	/* ---------------------------------------------
 	 * void console_16550_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_16550_core_flush
 #if ENABLE_ASSERTIONS
 	cmp	r0, #0
 	ASM_ASSERT(ne)
 #endif /* ENABLE_ASSERTIONS */

 	/* Loop until the transmit FIFO is empty */
 1:	ldr	r1, [r0, #UARTLSR]
 	and	r1, r1, #(UARTLSR_TEMT | UARTLSR_THRE)
 	cmp	r1, #(UARTLSR_TEMT | UARTLSR_THRE)
 	bne	1b

 	bx	lr
 endfunc console_16550_core_flush

 	/* ---------------------------------------------
 	 * void console_16550_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_16550_flush
 #if ENABLE_ASSERTIONS
 	cmp	r0, #0
 	ASM_ASSERT(ne)
 #endif /* ENABLE_ASSERTIONS */
 	ldr	r0, [r0, #CONSOLE_T_BASE]
 	b	console_16550_core_flush
 endfunc console_16550_flush
	/*
	* Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved.
	*
	* SPDX-License-Identifier: BSD-3-Clause
	*/

	#include <arch.h>
	#include <asm_macros.S>
	#include <assert_macros.S>
	#include <console_macros.S>
	#include <drivers/ti/uart/uart_16550.h>

	/*
	* "core" functions are low-level implementations that don't require
	* writable memory and are thus safe to call in BL1 crash context.
	*/
	.globl console_16550_core_init
	.globl console_16550_core_putc
	.globl console_16550_core_getc
	.globl console_16550_core_flush

	.globl console_16550_putc
	.globl console_16550_getc
	.globl console_16550_flush

	/* -----------------------------------------------
	* int console_16550_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, 0 on error
	* Clobber list : r1, r2, r3
	* -----------------------------------------------
	*/
	func console_16550_core_init
	/* Check the input base address */
	cmp r0, #0
	beq init_fail
	/* Check baud rate and uart clock for sanity */
	cmp r1, #0
	beq init_fail
	cmp r2, #0
	beq init_fail

	/* Program the baudrate */
	/* Divisor = Uart clock / (16 * baudrate) */
	lsl r2, r2, #4
	udiv r2, r1, r2
	and r1, r2, #0xff /* w1 = DLL */
	lsr r2, r2, #8
	and r2, r2, #0xff /* w2 = DLLM */
	ldr r3, [r0, #UARTLCR]
	orr r3, r3, #UARTLCR_DLAB
	str r3, [r0, #UARTLCR] /* enable DLL, DLLM programming */
	str r1, [r0, #UARTDLL] /* program DLL */
	str r2, [r0, #UARTDLLM] /* program DLLM */
	mov r2, #~UARTLCR_DLAB
	and r3, r3, r2
	str r3, [r0, #UARTLCR] /* disable DLL, DLLM programming */

	/* 8n1 */
	mov r3, #3
	str r3, [r0, #UARTLCR]
	/* no interrupt */
	mov r3, #0
	str r3, [r0, #UARTIER]
	#ifdef TI_16550_MDR_QUIRK
	/* UART must be enabled on some platforms via the MDR register */
	str r3, [r0, #UARTMDR1]
	#endif /* TI_16550_MDR_QUIRK */
	/* enable fifo, DMA */
	mov r3, #(UARTFCR_FIFOEN \| UARTFCR_DMAEN)
	str r3, [r0, #UARTFCR]
	/* DTR + RTS */
	mov r3, #3
	str r3, [r0, #UARTMCR]
	mov r0, #1
	bx lr
	init_fail:
	mov r0, #0
	bx lr
	endfunc console_16550_core_init

	.globl console_16550_register

	/* -------------------------------------------------------
	* int console_16550_register(uintptr_t baseaddr,
	* uint32_t clock, uint32_t baud,
	* console_t *console);
	* Function to initialize and register a new 16550
	* console. Storage passed in for the console struct
	* must be persistent (i.e. not from the stack).
	* If r1 (UART clock) is 0, initialisation will be
	* skipped, relying on previous code to have done
	* this already. r2 is ignored then as well.
	* In: r0 - UART register base address
	* r1 - UART clock in Hz
	* r2 - Baud rate (ignored if r1 is 0)
	* r3 - pointer to empty console_t struct
	* Out: return 1 on success, 0 on error
	* Clobber list : r0, r1, r2
	* -------------------------------------------------------
	*/
	func console_16550_register
	push {r4, lr}
	mov r4, r3
	cmp r4, #0
	beq register_fail
	str r0, [r4, #CONSOLE_T_BASE]

	/* A clock rate of zero means to skip the initialisation. */
	cmp r1, #0
	beq register_16550

	bl console_16550_core_init
	cmp r0, #0
	beq register_fail

	register_16550:
	mov r0, r4
	pop {r4, lr}
	finish_console_register 16550 putc=1, getc=1, flush=1

	register_fail:
	pop {r4, pc}
	endfunc console_16550_register

	/* --------------------------------------------------------
	* int console_16550_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_16550_core_putc
	#if ENABLE_ASSERTIONS
	cmp r1, #0
	ASM_ASSERT(ne)
	#endif /* ENABLE_ASSERTIONS */

	/* Prepend '\r' to '\n' */
	cmp r0, #0xA
	bne 2f
	/* Check if the transmit FIFO is full */
	1: ldr r2, [r1, #UARTLSR]
	and r2, r2, #(UARTLSR_TEMT \| UARTLSR_THRE)
	cmp r2, #(UARTLSR_TEMT \| UARTLSR_THRE)
	bne 1b
	mov r2, #0xD /* '\r' */
	str r2, [r1, #UARTTX]

	/* Check if the transmit FIFO is full */
	2: ldr r2, [r1, #UARTLSR]
	and r2, r2, #(UARTLSR_TEMT \| UARTLSR_THRE)
	cmp r2, #(UARTLSR_TEMT \| UARTLSR_THRE)
	bne 2b
	str r0, [r1, #UARTTX]
	bx lr
	endfunc console_16550_core_putc

	/* --------------------------------------------------------
	* int console_16550_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_16550_putc
	#if ENABLE_ASSERTIONS
	cmp r1, #0
	ASM_ASSERT(ne)
	#endif /* ENABLE_ASSERTIONS */
	ldr r1, [r1, #CONSOLE_T_BASE]
	b console_16550_core_putc
	endfunc console_16550_putc

	/* ---------------------------------------------
	* int console_16550_core_getc(uintptr_t base_addr)
	* Function to get a character from the console.
	* It returns the character grabbed on success
	* or -1 on if no character is available.
	* In : r0 - console base address
	* Clobber list : r0, r1
	* ---------------------------------------------
	*/
	func console_16550_core_getc
	#if ENABLE_ASSERTIONS
	cmp r0, #0
	ASM_ASSERT(ne)
	#endif /* ENABLE_ASSERTIONS */

	/* Check if the receive FIFO is empty */
	1: ldr r1, [r0, #UARTLSR]
	tst r1, #UARTLSR_RDR_BIT
	beq no_char
	ldr r1, [r0, #UARTRX]
	mov r0, r1
	bx lr
	no_char:
	mov r0, #ERROR_NO_PENDING_CHAR
	bx lr
	endfunc console_16550_core_getc

	/* ---------------------------------------------
	* int console_16550_getc(console_t *console)
	* Function to get a character from the console.
	* It returns the character grabbed on success
	* or -1 on if no character is available.
	* In : r0 - pointer to console_t stucture
	* Out : r0 - character if available, else -1
	* Clobber list : r0, r1
	* ---------------------------------------------
	*/
	func console_16550_getc
	#if ENABLE_ASSERTIONS
	cmp r0, #0
	ASM_ASSERT(ne)
	#endif /* ENABLE_ASSERTIONS */
	ldr r0, [r0, #CONSOLE_T_BASE]
	b console_16550_core_getc
	endfunc console_16550_getc

	/* ---------------------------------------------
	* void console_16550_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_16550_core_flush
	#if ENABLE_ASSERTIONS
	cmp r0, #0
	ASM_ASSERT(ne)
	#endif /* ENABLE_ASSERTIONS */

	/* Loop until the transmit FIFO is empty */
	1: ldr r1, [r0, #UARTLSR]
	and r1, r1, #(UARTLSR_TEMT \| UARTLSR_THRE)
	cmp r1, #(UARTLSR_TEMT \| UARTLSR_THRE)
	bne 1b

	bx lr
	endfunc console_16550_core_flush

	/* ---------------------------------------------
	* void console_16550_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_16550_flush
	#if ENABLE_ASSERTIONS
	cmp r0, #0
	ASM_ASSERT(ne)
	#endif /* ENABLE_ASSERTIONS */
	ldr r0, [r0, #CONSOLE_T_BASE]
	b console_16550_core_flush
	endfunc console_16550_flush