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/*
* 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: x0 - console base address
* w1 - Uart clock in Hz
* w2 - Baud rate
* Out: return 1 on success, 0 on error
* Clobber list : x1, x2, x3
* -----------------------------------------------
*/
func console_16550_core_init
/* Check the input base address */
cbz x0, init_fail
/* Check baud rate and uart clock for sanity */
cbz w1, init_fail
cbz w2, init_fail
/* Program the baudrate */
/* Divisor = Uart clock / (16 * baudrate) */
lsl w2, w2, #4
udiv w2, w1, w2
and w1, w2, #0xff /* w1 = DLL */
lsr w2, w2, #8
and w2, w2, #0xff /* w2 = DLLM */
ldr w3, [x0, #UARTLCR]
orr w3, w3, #UARTLCR_DLAB
str w3, [x0, #UARTLCR] /* enable DLL, DLLM programming */
str w1, [x0, #UARTDLL] /* program DLL */
str w2, [x0, #UARTDLLM] /* program DLLM */
mov w2, #~UARTLCR_DLAB
and w3, w3, w2
str w3, [x0, #UARTLCR] /* disable DLL, DLLM programming */
/* 8n1 */
mov w3, #3
str w3, [x0, #UARTLCR]
/* no interrupt */
mov w3, #0
str w3, [x0, #UARTIER]
#ifdef TI_16550_MDR_QUIRK
/* UART must be enabled on some platforms via the MDR register */
str w3, [x0, #UARTMDR1]
#endif /* TI_16550_MDR_QUIRK */
/* enable fifo, DMA */
mov w3, #(UARTFCR_FIFOEN | UARTFCR_DMAEN)
str w3, [x0, #UARTFCR]
/* DTR + RTS */
mov w3, #3
str w3, [x0, #UARTMCR]
mov w0, #1
ret
init_fail:
mov w0, #0
ret
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 w1 (UART clock) is 0, initialisation will be
* skipped, relying on previous code to have done
* this already. w2 is ignored then as well.
* In: x0 - UART register base address
* w1 - UART clock in Hz
* w2 - Baud rate (ignored if w1 is 0)
* x3 - pointer to empty console_t struct
* Out: return 1 on success, 0 on error
* Clobber list : x0, x1, x2, x6, x7, x14
* -----------------------------------------------
*/
func console_16550_register
mov x7, x30
mov x6, x3
cbz x6, register_fail
str x0, [x6, #CONSOLE_T_BASE]
/* A clock rate of zero means to skip the initialisation. */
cbz w1, register_16550
bl console_16550_core_init
cbz x0, register_fail
register_16550:
mov x0, x6
mov x30, x7
finish_console_register 16550 putc=1, getc=ENABLE_CONSOLE_GETC, flush=1
register_fail:
ret x7
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 : w0 - character to be printed
* x1 - console base address
* Out : return -1 on error else return character.
* Clobber list : x2
* --------------------------------------------------------
*/
func console_16550_core_putc
#if ENABLE_ASSERTIONS
cmp x1, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
/* Prepend '\r' to '\n' */
cmp w0, #0xA
b.ne 2f
/* Check if the transmit FIFO is full */
1: ldr w2, [x1, #UARTLSR]
and w2, w2, #(UARTLSR_TEMT | UARTLSR_THRE)
cmp w2, #(UARTLSR_TEMT | UARTLSR_THRE)
b.ne 1b
mov w2, #0xD /* '\r' */
str w2, [x1, #UARTTX]
/* Check if the transmit FIFO is full */
2: ldr w2, [x1, #UARTLSR]
and w2, w2, #(UARTLSR_TEMT | UARTLSR_THRE)
cmp w2, #(UARTLSR_TEMT | UARTLSR_THRE)
b.ne 2b
str w0, [x1, #UARTTX]
ret
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 : w0 - character to be printed
* x1 - pointer to console_t structure
* Out : return -1 on error else return character.
* Clobber list : x2
* --------------------------------------------------------
*/
func console_16550_putc
#if ENABLE_ASSERTIONS
cmp x1, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
ldr x1, [x1, #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 : x0 - console base address
* Out : w0 - character if available, else -1
* Clobber list : x0, x1
* ---------------------------------------------
*/
func console_16550_core_getc
#if ENABLE_ASSERTIONS
cmp x0, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
/* Check if the receive FIFO is empty */
1: ldr w1, [x0, #UARTLSR]
tbz w1, #UARTLSR_RDR_BIT, no_char
ldr w0, [x0, #UARTRX]
ret
no_char:
mov w0, #ERROR_NO_PENDING_CHAR
ret
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 : x0 - pointer to console_t stucture
* Out : w0 - character if available, else -1
* Clobber list : x0, x1
* ---------------------------------------------
*/
func console_16550_getc
#if ENABLE_ASSERTIONS
cmp x1, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
ldr x0, [x0, #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 : x0 - console base address
* Out : void.
* Clobber list : x0, x1
* ---------------------------------------------
*/
func console_16550_core_flush
#if ENABLE_ASSERTIONS
cmp x0, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
/* Loop until the transmit FIFO is empty */
1: ldr w1, [x0, #UARTLSR]
and w1, w1, #(UARTLSR_TEMT | UARTLSR_THRE)
cmp w1, #(UARTLSR_TEMT | UARTLSR_THRE)
b.ne 1b
ret
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 : x0 - pointer to console_t structure
* Out : void.
* Clobber list : x0, x1
* ---------------------------------------------
*/
func console_16550_flush
#if ENABLE_ASSERTIONS
cmp x0, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
ldr x0, [x0, #CONSOLE_T_BASE]
b console_16550_core_flush
endfunc console_16550_flush
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