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Diffstat (limited to '')
| -rw-r--r-- | drivers/ti/uart/aarch64/16550_console.S | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/drivers/ti/uart/aarch64/16550_console.S b/drivers/ti/uart/aarch64/16550_console.S new file mode 100644 index 0000000..cb21512 --- /dev/null +++ b/drivers/ti/uart/aarch64/16550_console.S @@ -0,0 +1,267 @@ +/* + * 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=1, 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 |