Soby Mathew
5 years ago
committed by
TrustedFirmware Code Review
3 changed files with 133 additions and 65 deletions
@ -1,108 +1,176 @@ |
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/* |
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* Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved. |
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* Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved. |
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* |
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* SPDX-License-Identifier: BSD-3-Clause |
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*/ |
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#include <asm_macros.S> |
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#include <console_macros.S> |
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/* |
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* This file contains a skeleton console implementation that can |
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* be used as basis for a real console implementation by platforms |
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* that do not contain PL011 hardware. |
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* This file contains a skeleton console driver that can be used as a |
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* basis for a real console driver. Console drivers in Trusted Firmware |
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* can be instantiated multiple times. Each instance is described by a |
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* separate console_t structure which must be registered with the common |
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* console framework via console_register(). Console drivers should |
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* define a console_xxx_register() function that initializes a new |
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* console_t structure passed in from the caller and registers it after |
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* initializing the console hardware. Drivers may define their own |
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* structures extending console_t to store private driver information. |
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* Console drivers *MUST* ensure that the console callbacks they |
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* implement only change registers allowed in the clobber lists defined |
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* in this file. (Note that in addition to the explicit clobber lists, |
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* any function may always clobber the intra-procedure-call register |
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* r12, but may never depend on it retaining its value across any |
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* function call.) |
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*/ |
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.globl console_core_init |
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.globl console_core_putc |
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.globl console_core_getc |
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.globl console_core_flush |
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.globl console_xxx_register |
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.globl console_xxx_putc |
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.globl console_xxx_getc |
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.globl console_xxx_flush |
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/* ----------------------------------------------- |
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* int console_core_init(uintptr_t base_addr, |
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* unsigned int uart_clk, unsigned int baud_rate) |
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* Function to initialize the console without a |
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* C Runtime to print debug information. This |
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* function will be accessed by console_init and |
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* crash reporting. |
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* In: r0 - console base address |
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* r1 - Uart clock in Hz |
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* r2 - Baud rate |
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* Out: return 1 on success else 0 on error |
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* Clobber list : r1, r2 |
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* int console_xxx_register(console_xxx_t *console, |
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* ...additional parameters as desired...) |
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* Function to initialize and register the console. |
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* The caller needs to pass an empty console_xxx_t |
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* structure in which *MUST* be allocated in |
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* persistent memory (e.g. a global or static local |
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* variable, *NOT* on the stack). |
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* In : r0 - pointer to empty console_t structure |
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* r1 through r7: additional parameters as desired |
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* Out: r0 - 1 on success, 0 on error |
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* Clobber list : r0 - r7 |
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* ----------------------------------------------- |
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*/ |
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func console_core_init |
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/* Check the input base address */ |
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cmp r0, #0 |
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beq core_init_fail |
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/* Check baud rate and uart clock for sanity */ |
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cmp r1, #0 |
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beq core_init_fail |
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cmp r2, #0 |
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beq core_init_fail |
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/* Insert implementation here */ |
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mov r0, #1 |
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bx lr |
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core_init_fail: |
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func console_xxx_register |
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/* |
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* Store parameters (e.g. hardware base address) in driver-specific |
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* console_xxx_t structure field if they will need to be retrieved |
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* by later console callback (e.g. putc). |
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* Example: |
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*/ |
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str r1, [r0, #CONSOLE_T_XXX_BASE] |
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str r2, [r0, #CONSOLE_T_XXX_SOME_OTHER_VALUE] |
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/* |
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* Initialize console hardware, using r1 - r7 parameters as needed. |
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* Keep console_t pointer in r0 for later. |
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*/ |
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/* |
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* Macro to finish up registration and return (needs valid r0 + lr). |
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* If any of the argument is unspecified, then the corresponding |
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* entry in console_t is set to 0. |
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*/ |
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finish_console_register xxx putc=1, getc=1, flush=1 |
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/* Jump here if hardware init fails or parameters are invalid. */ |
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register_fail: |
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mov r0, #0 |
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bx lr |
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endfunc console_core_init |
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endfunc console_xxx_register |
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|
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/* -------------------------------------------------------- |
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* int console_core_putc(int c, uintptr_t base_addr) |
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* int console_xxx_putc(int c, console_xxx_t *console) |
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* Function to output a character over the console. It |
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* returns the character printed on success or -1 on error. |
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* In : r0 - character to be printed |
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* r1 - console base address |
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* Out : return -1 on error else return character. |
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* Clobber list : r2 |
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* r1 - pointer to console_t struct |
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* Out: r0 - printed character on success, < 0 on error. |
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* Clobber list : r0, r1, r2 |
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* -------------------------------------------------------- |
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*/ |
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func console_core_putc |
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/* Check the input parameter */ |
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cmp r1, #0 |
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beq putc_error |
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/* Insert implementation here */ |
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func console_xxx_putc |
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/* |
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* Retrieve values we need (e.g. hardware base address) from |
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* console_xxx_t structure pointed to by r1. |
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* Example: |
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*/ |
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ldr r1, [r1, #CONSOLE_T_XXX_BASE] |
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/* |
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* Write r0 to hardware. |
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*/ |
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bx lr |
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/* Jump here if output fails for any reason. */ |
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putc_error: |
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mov r0, #-1 |
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bx lr |
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endfunc console_core_putc |
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endfunc console_xxx_putc |
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/* --------------------------------------------- |
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* int console_core_getc(uintptr_t base_addr) |
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* int console_xxx_getc(console_xxx_t *console) |
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* Function to get a character from the console. |
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* It returns the character grabbed on success |
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* or -1 on error. |
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* In : r0 - console base address |
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* Even though console_getc() is blocking, this |
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* callback has to be non-blocking and always |
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* return immediately to allow polling multiple |
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* drivers concurrently. |
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* Returns the character grabbed on success, |
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* ERROR_NO_PENDING_CHAR if no character was |
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* available at this time, or any value |
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* between -2 and -127 if there was an error. |
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* In : r0 - pointer to console_t struct |
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* Out: r0 - character on success, |
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* ERROR_NO_PENDING_CHAR if no char, |
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* < -1 on error |
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* Clobber list : r0, r1 |
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* --------------------------------------------- |
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*/ |
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func console_core_getc |
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cmp r0, #0 |
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beq getc_error |
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/* Insert implementation here */ |
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func console_xxx_getc |
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/* |
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* Retrieve values we need (e.g. hardware base address) from |
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* console_xxx_t structure pointed to by r0. |
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* Example: |
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*/ |
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ldr r1, [r0, #CONSOLE_T_XXX_BASE] |
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/* |
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* Try to read character into r0 from hardware. |
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*/ |
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bx lr |
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/* Jump here if there is no character available at this time. */ |
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getc_no_char: |
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mov r0, #ERROR_NO_PENDING_CHAR |
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bx lr |
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/* Jump here if there was any hardware error. */ |
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getc_error: |
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mov r0, #-1 |
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mov r0, #-2 /* may pick error codes between -2 and -127 */ |
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bx lr |
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endfunc console_core_getc |
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endfunc console_xxx_getc |
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/* --------------------------------------------- |
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* int console_core_flush(uintptr_t base_addr) |
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* int console_xxx_flush(console_xxx_t *console) |
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* Function to force a write of all buffered |
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* data that hasn't been output. |
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* In : r0 - console base address |
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* Out : return -1 on error else return 0. |
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* Clobber list : r0, r1 |
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* In : r0 - pointer to console_xxx_t struct |
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* Out: r0 - 0 on success, < 0 on error |
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* Clobber list : r0, r1, r2, r3, r4, r5 |
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* --------------------------------------------- |
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*/ |
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func console_core_flush |
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cmp r0, #0 |
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beq flush_error |
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/* Insert implementation here */ |
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func console_xxx_flush |
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/* |
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* Retrieve values we need (e.g. hardware base address) from |
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* console_xxx_t structure pointed to by r0. |
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* Example: |
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*/ |
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ldr r1, [r0, #CONSOLE_T_XXX_BASE] |
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/* |
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* Flush all remaining output from hardware FIFOs. Do not return until |
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* all data has been flushed or there was an unrecoverable error. |
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*/ |
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mov r0, #0 |
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bx lr |
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/* Jump here if an unrecoverable error has been encountered. */ |
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flush_error: |
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mov r0, #-1 |
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bx lr |
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endfunc console_core_flush |
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endfunc console_xxx_flush |
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