| Bryan O'Donoghue | 967ed97 | 2018-05-25 17:35:09 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) Linaro 2018 Limited and Contributors. All rights reserved. |
| 3 | * |
| 4 | * SPDX-License-Identifier: BSD-3-Clause |
| 5 | */ |
| 6 | #include <arch.h> |
| 7 | #include <asm_macros.S> |
| 8 | #include <assert_macros.S> |
| 9 | #include <imx_uart.h> |
| 10 | #include <platform_def.h> |
| 11 | |
| 12 | .globl imx_crash_uart_init |
| 13 | .globl imx_crash_uart_putc |
| 14 | |
| 15 | /* ----------------------------------------------- |
| 16 | * int imx_crash_uart_init(uintptr_t base_addr, |
| 17 | * unsigned int uart_clk, unsigned int baud_rate) |
| 18 | * Function to initialize the console without a |
| 19 | * C Runtime to print debug information. This |
| 20 | * function will be accessed by console_init and |
| 21 | * crash reporting. |
| 22 | * In: r0 - console base address |
| 23 | * r1 - Uart clock in Hz |
| 24 | * r2 - Baud rate |
| 25 | * Out: return 1 on success else 0 on error |
| 26 | * Clobber list : r1, r2, r3, r4 |
| 27 | * ----------------------------------------------- |
| 28 | */ |
| 29 | func imx_crash_uart_init |
| 30 | /* Free up r1 as a scratch reg */ |
| 31 | mov r4, r0 |
| 32 | mov r0, r1 |
| 33 | |
| 34 | /* Reset UART via CR2 */ |
| 35 | add r1, r4, #IMX_UART_CR2_OFFSET |
| 36 | movs r3, #0 |
| 37 | str r3, [r4, #IMX_UART_CR2_OFFSET] |
| 38 | |
| 39 | /* Wait for reset complete */ |
| 40 | __wait_cr2_reset: |
| 41 | ldr r3, [r1, #0] |
| 42 | ands r3, #IMX_UART_CR2_SRST |
| 43 | beq __wait_cr2_reset |
| 44 | |
| 45 | /* Enable UART */ |
| 46 | movs r3, #IMX_UART_CR1_UARTEN |
| 47 | mov r1, r2 |
| 48 | str r3, [r4, #IMX_UART_CR1_OFFSET] |
| 49 | |
| 50 | /* |
| 51 | * Ignore RTC/CTS - disable reset |
| 52 | * Magic value #16423 => |
| 53 | * IMX_UART_CR2_IRTS | IMX_UART_CR2_WS | IMX_UART_CR2_TXEN | IMX_UART_CR2_RXEN | IMX_UART_CR2_SRST |
| 54 | */ |
| 55 | movw r3, #16423 |
| 56 | str r3, [r4, #IMX_UART_CR2_OFFSET] |
| 57 | |
| 58 | /* |
| 59 | * No parity, autobaud detect-old, rxdmuxsel=1 (fixed i.mx7) |
| 60 | * Magic value => #132 |
| 61 | * IMX_UART_CR3_ADNIMP | IMX_UART_CR3_RXDMUXSEL |
| 62 | */ |
| 63 | movs r3, #132 |
| 64 | str r3, [r4, #IMX_UART_CR3_OFFSET] |
| 65 | |
| 66 | /* |
| 67 | * Set CTS FIFO trigger to 32 bytes bits 15:10 |
| 68 | * Magic value => #32768 |
| 69 | * FIFO trigger bitmask 100000 |
| 70 | * */ |
| 71 | mov r3, #32768 |
| 72 | str r3, [r4, #IMX_UART_CR4_OFFSET] |
| 73 | |
| 74 | /* |
| 75 | * TX/RX-thresh = 2 bytes, DCE (bit6 = 0), refclk @24MHz / 4 |
| 76 | * Magic value #2562 |
| 77 | * IMX_UART_FCR_TXTL(TX_RX_THRESH) | IMX_UART_FCR_RXTL(TX_RX_THRESH) | IMX_UART_FCR_RFDIV2 |
| 78 | */ |
| 79 | #ifdef IMX_UART_DTE |
| 80 | movw r3, #2626 |
| 81 | #else |
| 82 | movw r3, #2562 |
| 83 | #endif |
| 84 | str r3, [r4, #IMX_UART_FCR_OFFSET] |
| 85 | |
| 86 | /* This BIR should be set to 0x0F prior to writing the BMR */ |
| 87 | movs r3, #15 |
| 88 | str r3, [r4, #IMX_UART_BIR_OFFSET] |
| 89 | |
| 90 | /* Hard-code to 115200 @ 24 MHz */ |
| 91 | movs r0, #104 |
| 92 | str r0, [r4, #IMX_UART_BMR_OFFSET] |
| 93 | |
| 94 | /* Indicate success */ |
| 95 | movs r0, #1 |
| 96 | bx lr |
| 97 | endfunc imx_crash_uart_init |
| 98 | |
| 99 | /* -------------------------------------------------------- |
| 100 | * int imx_crash_uart_putc(int c, uintptr_t base_addr) |
| 101 | * Function to output a character over the console. It |
| 102 | * returns the character printed on success or -1 on error. |
| 103 | * In : r0 - character to be printed |
| 104 | * r1 - console base address |
| 105 | * Out : return -1 on error else return character. |
| 106 | * Clobber list : r2 |
| 107 | * -------------------------------------------------------- |
| 108 | */ |
| 109 | func imx_crash_uart_putc |
| 110 | /* Output specified character to UART shift-register */ |
| 111 | str r0, [r1, #IMX_UART_TXD_OFFSET] |
| 112 | |
| 113 | /* Wait for transmit IMX_UART_STAT2_OFFSET.IMX_UART_STAT2_TXDC == 1 */ |
| 114 | __putc_spin_ready: |
| 115 | ldr r2, [r1, #IMX_UART_STAT2_OFFSET] |
| 116 | ands r2, #IMX_UART_STAT2_TXDC |
| 117 | beq __putc_spin_ready |
| 118 | |
| 119 | /* Transmit complete do we need to fixup \n to \n\r */ |
| 120 | cmp r0, #10 |
| 121 | beq __putc_fixup_lf |
| 122 | |
| 123 | /* No fixup necessary - exit here */ |
| 124 | movs r0, #0 |
| 125 | bx lr |
| 126 | |
| 127 | /* Fixup \n to \n\r */ |
| 128 | __putc_fixup_lf: |
| 129 | movs r0, #13 |
| 130 | b imx_crash_uart_putc |
| 131 | endfunc imx_crash_uart_putc |