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/*
* Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#if MULTI_CONSOLE_API
#include <asm_macros.S>
#include <assert_macros.S>
#include <console.h>
.globl console_register
.globl console_unregister
.globl console_is_registered
.globl console_set_scope
.globl console_switch_state
.globl console_putc
.globl console_getc
.globl console_flush
/*
* The console list pointer 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_list ; .align 2
console_list: .word 0x0
.section .data.console_state ; .align 0
console_state: .byte CONSOLE_FLAG_BOOT
/* -----------------------------------------------
* int console_register(console_t *console)
* Function to insert a new console structure into
* the console list. Should usually be called by
* console_<driver>_register implementations. The
* data structure passed will be taken over by the
* console framework and *MUST* be allocated in
* persistent memory (e.g. the data section).
* In : r0 - address of console_t structure
* Out: r0 - Always 1 (for easier tail calling)
* Clobber list: r0, r1
* -----------------------------------------------
*/
func console_register
push {r6, lr}
#if ENABLE_ASSERTIONS
/* Assert that r0 isn't a NULL pointer */
cmp r0, #0
ASM_ASSERT(ne)
/* Assert that the struct isn't in the stack */
ldr r1, =__STACKS_START__
cmp r0, r1
blo not_on_stack
ldr r1, =__STACKS_END__
cmp r0, r1
ASM_ASSERT(hs)
not_on_stack:
/* Assert that this struct isn't in the list */
mov r1, r0 /* Preserve r0 and lr */
bl console_is_registered
cmp r0, #0
ASM_ASSERT(eq)
mov r0, r1
#endif /* ENABLE_ASSERTIONS */
ldr r6, =console_list
ldr r1, [r6] /* R1 = first struct in list */
str r0, [r6] /* list head = new console */
str r1, [r0, #CONSOLE_T_NEXT] /* new console next ptr = R1 */
mov r0, #1
pop {r6, pc}
endfunc console_register
/* -----------------------------------------------
* int console_unregister(console_t *console)
* Function to find a specific console in the list
* of currently active consoles and remove it.
* In: r0 - address of console_t struct to remove
* Out: r0 - removed address, or NULL if not found
* Clobber list: r0, r1
* -----------------------------------------------
*/
func console_unregister
#if ENABLE_ASSERTIONS
/* Assert that r0 isn't a NULL pointer */
cmp r0, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
push {r6}
ldr r6, =console_list /* R6 = ptr to first struct */
ldr r1, [r6] /* R1 = first struct */
unregister_loop:
cmp r1, #0
beq unregister_not_found
cmp r0, r1
beq unregister_found
ldr r6, [r6] /* R6 = next ptr of struct */
ldr r1, [r6] /* R1 = next struct */
b unregister_loop
unregister_found:
ldr r1, [r1] /* R1 = next struct */
str r1, [r6] /* prev->next = cur->next */
pop {r6}
bx lr
unregister_not_found:
mov r0, #0 /* return NULL if not found */
pop {r6}
bx lr
endfunc console_unregister
/* -----------------------------------------------
* int console_is_registered(console_t *console)
* Function to detect if a specific console is
* registered or not.
* In: r0 - address of console_t struct to remove
* Out: r0 - 1 if it is registered, 0 if not.
* Clobber list: r0
* -----------------------------------------------
*/
func console_is_registered
#if ENABLE_ASSERTIONS
/* Assert that r0 isn't a NULL pointer */
cmp r0, #0
ASM_ASSERT(ne)
#endif /* ENABLE_ASSERTIONS */
push {r6}
ldr r6, =console_list
ldr r6, [r6] /* R6 = first console struct */
check_registered_loop:
cmp r6, #0 /* Check if end of list */
beq console_not_registered
cmp r0, r6 /* Check if the pointers are different */
beq console_registered
ldr r6, [r6, #CONSOLE_T_NEXT] /* Get pointer to next struct */
b check_registered_loop
console_not_registered:
mov r0, #0
pop {r6}
bx lr
console_registered:
mov r0, #1
pop {r6}
bx lr
endfunc console_is_registered
/* -----------------------------------------------
* void console_switch_state(unsigned int new_state)
* Function to switch the current console state.
* The console state determines which of the
* registered consoles are actually used at a time.
* In : r0 - global console state to move to
* Clobber list: r0, r1
* -----------------------------------------------
*/
func console_switch_state
ldr r1, =console_state
strb r0, [r1]
bx lr
endfunc console_switch_state
/* -----------------------------------------------
* void console_set_scope(console_t *console,
* unsigned int scope)
* Function to update the states that a given console
* may be active in.
* In : r0 - pointer to console_t struct
* : r1 - new active state mask
* Clobber list: r0, r1, r2
* -----------------------------------------------
*/
func console_set_scope
#if ENABLE_ASSERTIONS
ands r2, r1, #~CONSOLE_FLAG_SCOPE_MASK
ASM_ASSERT(eq)
#endif /* ENABLE_ASSERTIONS */
ldr r2, [r0, #CONSOLE_T_FLAGS]
and r2, r2, #~CONSOLE_FLAG_SCOPE_MASK
orr r2, r2, r1
str r2, [r0, #CONSOLE_T_FLAGS]
bx lr
endfunc console_set_scope
/* ---------------------------------------------
* int console_putc(int c)
* Function to output a character. Calls all
* active console's putc() handlers in succession.
* In : r0 - character to be printed
* Out: r0 - printed character on success, or < 0
if at least one console had an error
* Clobber list : r0, r1, r2
* ---------------------------------------------
*/
func console_putc
push {r4-r6, lr}
mov r5, #ERROR_NO_VALID_CONSOLE /* R5 = current return value */
mov r4, r0 /* R4 = character to print */
ldr r6, =console_list
ldr r6, [r6] /* R6 = first console struct */
putc_loop:
cmp r6, #0
beq putc_done
ldr r1, =console_state
ldrb r1, [r1]
ldr r2, [r6, #CONSOLE_T_FLAGS]
tst r1, r2
beq putc_continue
ldr r2, [r6, #CONSOLE_T_PUTC]
cmp r2, #0
beq putc_continue
mov r0, r4
mov r1, r6
blx r2
cmp r5, #ERROR_NO_VALID_CONSOLE /* update R5 if it's NOVALID */
cmpne r0, #0 /* else update it if R0 < 0 */
movlt r5, r0
putc_continue:
ldr r6, [r6] /* R6 = next struct */
b putc_loop
putc_done:
mov r0, r5
pop {r4-r6, pc}
endfunc console_putc
/* ---------------------------------------------
* int console_getc(void)
* Function to get a character from any console.
* Keeps looping through all consoles' getc()
* handlers until one of them returns a
* character, then stops iterating and returns
* that character to the caller. Will stop looping
* if all active consoles report real errors
* (other than just not having a char available).
* Out : r0 - read character, or < 0 on error
* Clobber list : r0, r1
* ---------------------------------------------
*/
func console_getc
push {r5-r6, lr}
getc_try_again:
mov r5, #ERROR_NO_VALID_CONSOLE /* R5 = current return value */
ldr r6, =console_list
ldr r6, [r6] /* R6 = first console struct */
cmp r6, #0
bne getc_loop
mov r0, r5 /* If no consoles registered */
pop {r5-r6, pc} /* return immediately. */
getc_loop:
ldr r0, =console_state
ldrb r0, [r0]
ldr r1, [r6, #CONSOLE_T_FLAGS]
tst r0, r1
beq getc_continue
ldr r1, [r6, #CONSOLE_T_GETC]
cmp r1, #0
beq getc_continue
mov r0, r6
blx r1
cmp r0, #0 /* if R0 >= 0: return */
bge getc_found
cmp r5, #ERROR_NO_PENDING_CHAR /* may update R5 (NOCHAR has */
movne r5, r0 /* precedence vs real errors) */
getc_continue:
ldr r6, [r6] /* R6 = next struct */
cmp r6, #0
bne getc_loop
cmp r5, #ERROR_NO_PENDING_CHAR /* Keep scanning if at least */
beq getc_try_again /* one console returns NOCHAR */
mov r0, r5
getc_found:
pop {r5-r6, pc}
endfunc console_getc
/* ---------------------------------------------
* int console_flush(void)
* Function to force a write of all buffered
* data that hasn't been output. Calls all
* console's flush() handlers in succession.
* Out: r0 - 0 on success, < 0 if at least one error
* Clobber list : r0, r1, r2
* ---------------------------------------------
*/
func console_flush
push {r5-r6, lr}
mov r5, #ERROR_NO_VALID_CONSOLE /* R5 = current return value */
ldr r6, =console_list
ldr r6, [r6] /* R6 = first console struct */
flush_loop:
cmp r6, #0
beq flush_done
ldr r1, =console_state
ldrb r1, [r1]
ldr r2, [r6, #CONSOLE_T_FLAGS]
tst r1, r2
beq flush_continue
ldr r1, [r6, #CONSOLE_T_FLUSH]
cmp r1, #0
beq flush_continue
mov r0, r6
blx r1
cmp r5, #ERROR_NO_VALID_CONSOLE /* update R5 if it's NOVALID */
cmpne r0, #0 /* else update it if R0 < 0 */
movlt r5, r0
flush_continue:
ldr r6, [r6] /* R6 = next struct */
b flush_loop
flush_done:
mov r0, r5
pop {r5-r6, pc}
endfunc console_flush
#endif /* MULTI_CONSOLE_API */