diff options
Diffstat (limited to 'drivers/arm/pl011/aarch32/pl011_console.S')
| -rw-r--r-- | drivers/arm/pl011/aarch32/pl011_console.S | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/arm/pl011/aarch32/pl011_console.S b/drivers/arm/pl011/aarch32/pl011_console.S new file mode 100644 index 00000000..3718fff4 --- /dev/null +++ b/drivers/arm/pl011/aarch32/pl011_console.S @@ -0,0 +1,163 @@ +/* + * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ +#include <arch.h> +#include <asm_macros.S> +#include <pl011.h> + +/* + * Pull in generic functions to provide backwards compatibility for + * platform makefiles + */ +#include "../../../console/aarch32/console.S" + + .globl console_core_init + .globl console_core_putc + .globl console_core_getc + .globl console_core_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_core_init + /* Check the input base address */ + cmp r0, #0 + beq core_init_fail +#if !PL011_GENERIC_UART + /* Check baud rate and uart clock for sanity */ + cmp r1, #0 + beq core_init_fail + cmp r2, #0 + beq core_init_fail + /* Disable the UART before initialization */ + ldr r3, [r0, #UARTCR] + bic r3, r3, #PL011_UARTCR_UARTEN + str r3, [r0, #UARTCR] + /* Program the baudrate */ + /* Divisor = (Uart clock * 4) / baudrate */ + lsl r1, r1, #2 + udiv r2, r1, r2 + /* IBRD = Divisor >> 6 */ + lsr r1, r2, #6 + /* Write the IBRD */ + str r1, [r0, #UARTIBRD] + /* FBRD = Divisor & 0x3F */ + and r1, r2, #0x3f + /* Write the FBRD */ + str r1, [r0, #UARTFBRD] + mov r1, #PL011_LINE_CONTROL + str r1, [r0, #UARTLCR_H] + /* Clear any pending errors */ + mov r1, #0 + str r1, [r0, #UARTECR] + /* Enable tx, rx, and uart overall */ + ldr r1, =(PL011_UARTCR_RXE | PL011_UARTCR_TXE | PL011_UARTCR_UARTEN) + str r1, [r0, #UARTCR] +#endif + mov r0, #1 + bx lr +core_init_fail: + mov r0, #0 + bx lr +endfunc console_core_init + + /* -------------------------------------------------------- + * 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_core_putc + /* Check the input parameter */ + cmp r1, #0 + beq putc_error + /* Prepend '\r' to '\n' */ + cmp r0, #0xA + bne 2f +1: + /* Check if the transmit FIFO is full */ + ldr r2, [r1, #UARTFR] + tst r2, #PL011_UARTFR_TXFF + bne 1b + mov r2, #0xD + str r2, [r1, #UARTDR] +2: + /* Check if the transmit FIFO is full */ + ldr r2, [r1, #UARTFR] + tst r2, #PL011_UARTFR_TXFF + bne 2b + str r0, [r1, #UARTDR] + bx lr +putc_error: + mov r0, #-1 + bx lr +endfunc console_core_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 + * Clobber list : r0, r1 + * --------------------------------------------- + */ +func console_core_getc + cmp r0, #0 + beq getc_error +1: + /* Check if the receive FIFO is empty */ + ldr r1, [r0, #UARTFR] + tst r1, #PL011_UARTFR_RXFE + bne 1b + ldr r1, [r0, #UARTDR] + mov r0, r1 + bx lr +getc_error: + mov r0, #-1 + bx lr +endfunc console_core_getc + + /* --------------------------------------------- + * int 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 : return -1 on error else return 0. + * Clobber list : r0, r1 + * --------------------------------------------- + */ +func console_core_flush + cmp r0, #0 + beq flush_error + +1: + /* Loop while the transmit FIFO is busy */ + ldr r1, [r0, #UARTFR] + tst r1, #PL011_UARTFR_BUSY + bne 1b + + mov r0, #0 + bx lr +flush_error: + mov r0, #-1 + bx lr +endfunc console_core_flush |