diff options
Diffstat (limited to 'drivers/marvell/uart/a3700_console.S')
| -rw-r--r-- | drivers/marvell/uart/a3700_console.S | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/drivers/marvell/uart/a3700_console.S b/drivers/marvell/uart/a3700_console.S new file mode 100644 index 0000000..c7eb165 --- /dev/null +++ b/drivers/marvell/uart/a3700_console.S @@ -0,0 +1,271 @@ +/* + * Copyright (C) 2016 Marvell International Ltd. + * + * SPDX-License-Identifier: BSD-3-Clause + * https://spdx.org/licenses + */ + +#include <arch.h> +#include <asm_macros.S> +#include <console_macros.S> +#include <drivers/marvell/uart/a3700_console.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_a3700_core_putc + .globl console_a3700_core_init + .globl console_a3700_core_getc + .globl console_a3700_core_flush + + .globl console_a3700_putc + .globl console_a3700_getc + .globl console_a3700_flush + + /* ----------------------------------------------- + * int console_a3700_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, x3, x4 + * ----------------------------------------------- + */ +func console_a3700_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 + + /* + * Wait for the TX (THR and TSR) to be empty. If wait for 3ms, the TX FIFO is + * still not empty, TX FIFO will reset by all means. + */ + mov w4, #30 /* max time out 30 * 100 us */ +2: + /* Check whether TX (THR and TSR) is empty */ + ldr w3, [x0, #UART_STATUS_REG] + and w3, w3, #UARTLSR_TXEMPTY + cmp w3, #0 + b.ne 4f + + /* Delay */ + mov w3, #60000 /* 60000 cycles of below 3 instructions on 1200 MHz CPU ~~ 100 us */ +3: + sub w3, w3, #1 + cmp w3, #0 + b.ne 3b + + /* Check whether wait timeout expired */ + sub w4, w4, #1 + cmp w4, #0 + b.ne 2b + +4: + /* Reset UART via North Bridge Peripheral */ + mov_imm x4, MVEBU_NB_RESET_REG + ldr w3, [x4] + bic w3, w3, #MVEBU_NB_RESET_UART_N + str w3, [x4] + orr w3, w3, #MVEBU_NB_RESET_UART_N + str w3, [x4] + + /* Reset FIFO */ + mov w3, #UART_CTRL_RXFIFO_RESET + orr w3, w3, #UART_CTRL_TXFIFO_RESET + str w3, [x0, #UART_CTRL_REG] + + /* Delay */ + mov w3, #2000 +1: + sub w3, w3, #1 + cmp w3, #0 + b.ne 1b + + /* Program the baudrate */ + /* Divisor = Round(Uartclock / (16 * baudrate)) */ + lsl w2, w2, #4 + add w1, w1, w2, lsr #1 + udiv w2, w1, w2 + and w2, w2, #0x3ff /* clear all other bits to use default clock */ + + str w2, [x0, #UART_BAUD_REG]/* set baud rate divisor */ + + /* Set UART to default 16X scheme */ + mov w3, #0 + str w3, [x0, #UART_POSSR_REG] + + /* No Parity, 1 Stop */ + mov w3, #0 + str w3, [x0, #UART_CTRL_REG] + + mov w0, #1 + ret +init_fail: + mov w0, #0 + ret +endfunc console_a3700_core_init + + .globl console_a3700_register + + /* ----------------------------------------------- + * int console_a3700_register(console_t *console, + uintptr_t base, uint32_t clk, uint32_t baud) + * Function to initialize and register a new a3700 + * console. Storage passed in for the console struct + * *must* be persistent (i.e. not from the stack). + * In: x0 - UART register base address + * w1 - UART clock in Hz + * w2 - Baud rate + * x3 - pointer to empty console_t struct + * Out: return 1 on success, 0 on error + * Clobber list : x0, x1, x2, x3, x4, x6, x7, x14 + * ----------------------------------------------- + */ +func console_a3700_register + mov x7, x30 + mov x6, x3 + cbz x6, register_fail + str x0, [x6, #CONSOLE_T_BASE] + + bl console_a3700_core_init + cbz x0, register_fail + + mov x0, x6 + mov x30, x7 + finish_console_register a3700, putc=1, getc=1, flush=1 + +register_fail: + ret x7 +endfunc console_a3700_register + + /* -------------------------------------------------------- + * int console_a3700_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_a3700_core_putc + /* Check the input parameter */ + cbz x1, putc_error + + /* Prepend '\r' to '\n' */ + cmp w0, #0xA + b.ne 2f + /* Check if the transmit FIFO is full */ +1: ldr w2, [x1, #UART_STATUS_REG] + and w2, w2, #UARTLSR_TXFIFOFULL + cmp w2, #UARTLSR_TXFIFOFULL + b.eq 1b + mov w2, #0xD /* '\r' */ + str w2, [x1, #UART_TX_REG] + + /* Check if the transmit FIFO is full */ +2: ldr w2, [x1, #UART_STATUS_REG] + and w2, w2, #UARTLSR_TXFIFOFULL + cmp w2, #UARTLSR_TXFIFOFULL + b.eq 2b + str w0, [x1, #UART_TX_REG] + ret +putc_error: + mov w0, #-1 + ret +endfunc console_a3700_core_putc + + /* -------------------------------------------------------- + * int console_a3700_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_a3700_putc + ldr x1, [x1, #CONSOLE_T_BASE] + b console_a3700_core_putc +endfunc console_a3700_putc + + /* --------------------------------------------- + * int console_a3700_core_getc(void) + * Function to get a character from the console. + * It returns the character grabbed on success + * or -1 if no character is available. + * In : w0 - console base address + * Out : w0 - character if available, else -1 + * Clobber list : x0, x1 + * --------------------------------------------- + */ +func console_a3700_core_getc + /* Check if there is a pending character */ + ldr w1, [x0, #UART_STATUS_REG] + and w1, w1, #UARTLSR_RXRDY + cmp w1, #UARTLSR_RXRDY + b.ne getc_no_char + ldr w0, [x0, #UART_RX_REG] + and w0, w0, #0xff + ret +getc_no_char: + mov w0, #ERROR_NO_PENDING_CHAR + ret +endfunc console_a3700_core_getc + + /* --------------------------------------------- + * int console_a3700_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 structure + * Out : w0 - character if available, else -1 + * Clobber list : x0, x1 + * --------------------------------------------- + */ +func console_a3700_getc + ldr x0, [x0, #CONSOLE_T_BASE] + b console_a3700_core_getc +endfunc console_a3700_getc + + /* --------------------------------------------- + * void console_a3700_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_a3700_core_flush + /* Wait for the TX (THR and TSR) to be empty */ +1: ldr w1, [x0, #UART_STATUS_REG] + and w1, w1, #UARTLSR_TXEMPTY + cmp w1, #UARTLSR_TXEMPTY + b.ne 1b + ret +endfunc console_a3700_core_flush + + /* --------------------------------------------- + * void console_a3700_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_a3700_flush + ldr x0, [x0, #CONSOLE_T_BASE] + b console_a3700_core_flush +endfunc console_a3700_flush + |