diff options
Diffstat (limited to 'drivers/arm/pl011/pl011_console.S')
| -rw-r--r-- | drivers/arm/pl011/pl011_console.S | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/drivers/arm/pl011/pl011_console.S b/drivers/arm/pl011/pl011_console.S new file mode 100644 index 0000000..5ff1582 --- /dev/null +++ b/drivers/arm/pl011/pl011_console.S @@ -0,0 +1,178 @@ +/* + * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of ARM nor the names of its contributors may be used + * to endorse or promote products derived from this software without specific + * prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ +#include <arch.h> +#include <asm_macros.S> +#include <pl011.h> + + .globl console_init + .globl console_putc + .globl console_core_init + .globl console_core_putc + .globl console_getc + + /* + * The console base is in the data section and not in .bss + * even though it is zero-init. In particular, this allows + * the console functions to start using this variable before + * the runtime memory is initialized for images which do not + * need to copy the .data section from ROM to RAM. + */ +.section .data.console_base ; .align 3 + console_base: .quad 0x0 + + /* ----------------------------------------------- + * int console_init(unsigned long base_addr, + * unsigned int uart_clk, unsigned int baud_rate) + * Function to initialize the console without a + * C Runtime to print debug information. It saves + * the console base to the data section. + * In: x0 - console base address + * w1 - Uart clock in Hz + * w2 - Baud rate + * out: return 1 on success. + * Clobber list : x1 - x3 + * ----------------------------------------------- + */ +func console_init + adrp x3, console_base + str x0, [x3, :lo12:console_base] + b console_core_init + + /* ----------------------------------------------- + * int console_core_init(unsigned long 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 + * Clobber list : x1, x2 + * ----------------------------------------------- + */ +func console_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 * 4) / baudrate */ + lsl w1, w1, #2 + udiv w2, w1, w2 + /* IBRD = Divisor >> 6 */ + lsr w1, w2, #6 + /* Write the IBRD */ + str w1, [x0, #UARTIBRD] + /* FBRD = Divisor & 0x3F */ + and w1, w2, #0x3f + /* Write the FBRD */ + str w1, [x0, #UARTFBRD] + mov w1, #PL011_LINE_CONTROL + str w1, [x0, #UARTLCR_H] + /* Clear any pending errors */ + str wzr, [x0, #UARTECR] + /* Enable tx, rx, and uart overall */ + mov w1, #(PL011_UARTCR_RXE | PL011_UARTCR_TXE | PL011_UARTCR_UARTEN) + str w1, [x0, #UARTCR] + mov w0, #1 +init_fail: + ret + + /* --------------------------------------------- + * int console_putc(int c) + * Function to output a character over the + * console. It returns the character printed on + * success or -1 on error. + * In : x0 - character to be printed + * Out : return -1 on error else return character. + * Clobber list : x1, x2 + * --------------------------------------------- + */ +func console_putc + adrp x2, console_base + ldr x1, [x2, :lo12:console_base] + b console_core_putc + + /* -------------------------------------------------------- + * int console_core_putc(int c, unsigned int 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_core_putc + /* Check the input parameter */ + cbz x1, putc_error + /* Prepend '\r' to '\n' */ + cmp w0, #0xA + b.ne 2f +1: + /* Check if the transmit FIFO is full */ + ldr w2, [x1, #UARTFR] + tbnz w2, #PL011_UARTFR_TXFF_BIT, 1b + mov w2, #0xD + str w2, [x1, #UARTDR] +2: + /* Check if the transmit FIFO is full */ + ldr w2, [x1, #UARTFR] + tbnz w2, #PL011_UARTFR_TXFF_BIT, 2b + str w0, [x1, #UARTDR] + ret +putc_error: + mov w0, #-1 + ret + + /* --------------------------------------------- + * int console_getc(void) + * Function to get a character from the console. + * It returns the character grabbed on success + * or -1 on error. + * Clobber list : x0, x1 + * --------------------------------------------- + */ +func console_getc + adrp x0, console_base + ldr x1, [x0, :lo12:console_base] + cbz x1, getc_error +1: + /* Check if the receive FIFO is empty */ + ldr w0, [x1, #UARTFR] + tbnz w0, #PL011_UARTFR_RXFE_BIT, 1b + ldr w0, [x1, #UARTDR] + ret +getc_error: + mov w0, #-1 + ret |