/*
* Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <asm_macros.S>
#include <assert_macros.S>
#include <console.h>
.globl console_register
.globl console_unregister
.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 3
console_list: .quad 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 : x0 - address of console_t structure
* Out: x0 - Always 1 (for easier tail calling)
* Clobber list: x0, x1, x14
* -----------------------------------------------
*/
func console_register
#if ENABLE_ASSERTIONS
cmp x0, #0
ASM_ASSERT(ne)
adrp x1, __STACKS_START__
add x1, x1, :lo12:__STACKS_START__
cmp x0, x1
b.lo not_on_stack
adrp x1, __STACKS_END__
add x1, x1, :lo12:__STACKS_END__
cmp x0, x1
ASM_ASSERT(hs)
not_on_stack:
#endif /* ENABLE_ASSERTIONS */
adrp x14, console_list
ldr x1, [x14, :lo12:console_list] /* X1 = first struct in list */
str x0, [x14, :lo12:console_list] /* list head = new console */
str x1, [x0, #CONSOLE_T_NEXT] /* new console next ptr = X1 */
mov x0, #1
ret
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: x0 - address of console_t struct to remove
* Out: x0 - removed address, or NULL if not found
* Clobber list: x0, x1, x14
* -----------------------------------------------
*/
func console_unregister
adrp x14, console_list
add x14, x14, :lo12:console_list /* X14 = ptr to first struct */
ldr x1, [x14] /* X1 = first struct */
unregister_loop:
cbz x1, unregister_not_found
cmp x0, x1
b.eq unregister_found
ldr x14, [x14] /* X14 = next ptr of struct */
ldr x1, [x14] /* X1 = next struct */
b unregister_loop
unregister_found:
ldr x1, [x1] /* X1 = next struct */
str x1, [x14] /* prev->next = cur->next */
ret
unregister_not_found:
mov x0, #0 /* return NULL if not found */
ret
endfunc console_unregister
/* -----------------------------------------------
* 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 : w0 - global console state to move to
* Clobber list: x0, x1
* -----------------------------------------------
*/
func console_switch_state
adrp x1, console_state
strb w0, [x1, :lo12:console_state]
ret
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 : x0 - pointer to console_t struct
* : w1 - new active state mask
* Clobber list: x0, x1, x2
* -----------------------------------------------
*/
func console_set_scope
#if ENABLE_ASSERTIONS
tst w1, #~CONSOLE_FLAG_SCOPE_MASK
ASM_ASSERT(eq)
#endif /* ENABLE_ASSERTIONS */
ldr w2, [x0, #CONSOLE_T_FLAGS]
and w2, w2, #~CONSOLE_FLAG_SCOPE_MASK
orr w2, w2, w1
str w2, [x0, #CONSOLE_T_FLAGS]
ret
endfunc console_set_scope
/* ---------------------------------------------
* int console_putc(int c)
* Function to output a character. Calls all
* active console's putc() handlers in succession.
* In : x0 - character to be printed
* Out: x0 - printed character on success, or < 0
if at least one console had an error
* Clobber list : x0, x1, x2, x12, x13, x14, x15
* ---------------------------------------------
*/
func console_putc
mov x15, x30
mov w13, #ERROR_NO_VALID_CONSOLE /* W13 = current return value */
mov w12, w0 /* W12 = character to print */
adrp x14, console_list
ldr x14, [x14, :lo12:console_list] /* X14 = first console struct */
putc_loop:
cbz x14, putc_done
adrp x1, console_state
ldrb w1, [x1, :lo12:console_state]
ldr x2, [x14, #CONSOLE_T_FLAGS]
tst w1, w2
b.eq putc_continue
ldr x2, [x14, #CONSOLE_T_PUTC]
cbz x2, putc_continue
mov w0, w12
mov x1, x14
blr x2
cmp w13, #ERROR_NO_VALID_CONSOLE /* update W13 if it's NOVALID */
ccmp w0, #0, #0x8, ne /* else update it if W0 < 0 */
csel w13, w0, w13, lt
putc_continue:
ldr x14, [x14] /* X14 = next struct */
b putc_loop
putc_done:
mov w0, w13
ret x15
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 : x0 - read character, or < 0 on error
* Clobber list : x0, x1, x13, x14, x15
* ---------------------------------------------
*/
func console_getc
mov x15, x30
getc_try_again:
mov w13, #ERROR_NO_VALID_CONSOLE /* W13 = current return value */
adrp x14, console_list
ldr x14, [x14, :lo12:console_list] /* X14 = first console struct */
cbnz x14, getc_loop
mov w0, w13 /* If no consoles registered */
ret x15 /* return immediately. */
getc_loop:
adrp x0, console_state
ldrb w0, [x0, :lo12:console_state]
ldr x1, [x14, #CONSOLE_T_FLAGS]
tst w0, w1
b.eq getc_continue
ldr x1, [x14, #CONSOLE_T_GETC]
cbz x1, getc_continue
mov x0, x14
blr x1
cmp w0, #0 /* if X0 >= 0: return */
b.ge getc_found
cmp w13, #ERROR_NO_PENDING_CHAR /* may update W13 (NOCHAR has */
csel w13, w13, w0, eq /* precedence vs real errors) */
getc_continue:
ldr x14, [x14] /* X14 = next struct */
cbnz x14, getc_loop
cmp w13, #ERROR_NO_PENDING_CHAR /* Keep scanning if at least */
b.eq getc_try_again /* one console returns NOCHAR */
mov w0, w13
getc_found:
ret x15
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: x0 - 0 on success, < 0 if at least one error
* Clobber list : x0, x1, x2, x3, x4, x5, x13, x14, x15
* ---------------------------------------------
*/
func console_flush
mov x15, x30
mov w13, #ERROR_NO_VALID_CONSOLE /* W13 = current return value */
adrp x14, console_list
ldr x14, [x14, :lo12:console_list] /* X14 = first console struct */
flush_loop:
cbz x14, flush_done
adrp x1, console_state
ldrb w1, [x1, :lo12:console_state]
ldr x2, [x14, #CONSOLE_T_FLAGS]
tst w1, w2
b.eq flush_continue
ldr x1, [x14, #CONSOLE_T_FLUSH]
cbz x1, flush_continue
mov x0, x14
blr x1
cmp w13, #ERROR_NO_VALID_CONSOLE /* update W13 if it's NOVALID */
ccmp w0, #0, #0x8, ne /* else update it if W0 < 0 */
csel w13, w0, w13, lt
flush_continue:
ldr x14, [x14] /* X14 = next struct */
b flush_loop
flush_done:
mov w0, w13
ret x15
endfunc console_flush
