drivers/console: Reimplement MUTLI_CONSOLE_API framework in C
Now that we have switched to using the stack in MULTI_CONSOLE_API
framework functions and have factored all code involved in crash
reporting out into a separate file, there's really no reason to keep the
main framework code in assembly anymore. This patch rewrites it in C
which allows us to have a single implementation across aarch32/64 and
should be much easier to maintain going forward.
Change-Id: I6c85a01e89a79e8b233f3f8bee812f0dbd026221
Signed-off-by: Julius Werner <jwerner@chromium.org>
diff --git a/Makefile b/Makefile
index 63f283f..eed7c7a 100644
--- a/Makefile
+++ b/Makefile
@@ -214,7 +214,7 @@
BL_COMMON_SOURCES += common/bl_common.c \
common/tf_log.c \
common/${ARCH}/debug.S \
- drivers/console/${ARCH}/multi_console.S \
+ drivers/console/multi_console.c \
lib/${ARCH}/cache_helpers.S \
lib/${ARCH}/misc_helpers.S \
plat/common/plat_bl_common.c \
diff --git a/drivers/console/aarch32/multi_console.S b/drivers/console/aarch32/multi_console.S
deleted file mode 100644
index 713dc3c..0000000
--- a/drivers/console/aarch32/multi_console.S
+++ /dev/null
@@ -1,322 +0,0 @@
-/*
- * 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 */
diff --git a/drivers/console/aarch64/multi_console.S b/drivers/console/aarch64/multi_console.S
deleted file mode 100644
index 40d500d..0000000
--- a/drivers/console/aarch64/multi_console.S
+++ /dev/null
@@ -1,329 +0,0 @@
-/*
- * 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
- .globl console_list
-
- /*
- * 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
- * -----------------------------------------------
- */
-func console_register
- stp x21, x30, [sp, #-16]!
-#if ENABLE_ASSERTIONS
- /* Assert that x0 isn't a NULL pointer */
- cmp x0, #0
- ASM_ASSERT(ne)
- /* Assert that the struct isn't in the stack */
- 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:
- /* Assert that this struct isn't in the list */
- mov x1, x0 /* Preserve x0 and x30 */
- bl console_is_registered
- cmp x0, #0
- ASM_ASSERT(eq)
- mov x0, x1
-#endif /* ENABLE_ASSERTIONS */
- adrp x21, console_list
- ldr x1, [x21, :lo12:console_list] /* X1 = first struct in list */
- str x0, [x21, :lo12:console_list] /* list head = new console */
- str x1, [x0, #CONSOLE_T_NEXT] /* new console next ptr = X1 */
- mov x0, #1
- ldp x21, x30, [sp], #16
- 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
- * -----------------------------------------------
- */
-func console_unregister
-#if ENABLE_ASSERTIONS
- /* Assert that x0 isn't a NULL pointer */
- cmp x0, #0
- ASM_ASSERT(ne)
-#endif /* ENABLE_ASSERTIONS */
- stp x21, xzr, [sp, #-16]!
- adrp x21, console_list
- add x21, x21, :lo12:console_list /* X21 = ptr to first struct */
- ldr x1, [x21] /* X1 = first struct */
-
-unregister_loop:
- cbz x1, unregister_not_found
- cmp x0, x1
- b.eq unregister_found
- ldr x21, [x21] /* X21 = next ptr of struct */
- ldr x1, [x21] /* X1 = next struct */
- b unregister_loop
-
-unregister_found:
- ldr x1, [x1] /* X1 = next struct */
- str x1, [x21] /* prev->next = cur->next */
- ldp x21, xzr, [sp], #16
- ret
-
-unregister_not_found:
- mov x0, #0 /* return NULL if not found */
- ldp x21, xzr, [sp], #16
- ret
-endfunc console_unregister
-
- /* -----------------------------------------------
- * int console_is_registered(console_t *console)
- * Function to detect if a specific console is
- * registered or not.
- * In: x0 - address of console_t struct to remove
- * Out: x0 - 1 if it is registered, 0 if not.
- * Clobber list: x0
- * -----------------------------------------------
- */
-func console_is_registered
-#if ENABLE_ASSERTIONS
- /* Assert that x0 isn't a NULL pointer */
- cmp x0, #0
- ASM_ASSERT(ne)
-#endif /* ENABLE_ASSERTIONS */
- stp x21, xzr, [sp, #-16]!
- adrp x21, console_list
- ldr x21, [x21, :lo12:console_list] /* X21 = first console struct */
-check_registered_loop:
- cbz x21, console_not_registered /* Check if end of list */
- cmp x0, x21 /* Check if the pointers are different */
- b.eq console_registered
- ldr x21, [x21, #CONSOLE_T_NEXT] /* Get pointer to next struct */
- b check_registered_loop
-console_not_registered:
- mov x0, #0
- ldp x21, xzr, [sp], #16
- ret
-console_registered:
- mov x0, #1
- ldp x21, xzr, [sp], #16
- ret
-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 : 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
- * ---------------------------------------------
- */
-func console_putc
- stp x21, x30, [sp, #-16]!
- stp x19, x20, [sp, #-16]!
- mov w20, #ERROR_NO_VALID_CONSOLE /* W20 = current return value */
- mov w19, w0 /* W19 = character to print */
- adrp x21, console_list
- ldr x21, [x21, :lo12:console_list] /* X21 = first console struct */
-
-putc_loop:
- cbz x21, putc_done
- adrp x1, console_state
- ldrb w1, [x1, :lo12:console_state]
- ldr w2, [x21, #CONSOLE_T_FLAGS]
- tst w1, w2
- b.eq putc_continue
- ldr x2, [x21, #CONSOLE_T_PUTC]
- cbz x2, putc_continue
- mov w0, w19
- mov x1, x21
- blr x2
- cmp w20, #ERROR_NO_VALID_CONSOLE /* update W20 if it's NOVALID */
- ccmp w0, #0, #0x8, ne /* else update it if W0 < 0 */
- csel w20, w0, w20, lt
-putc_continue:
- ldr x21, [x21] /* X21 = next struct */
- b putc_loop
-
-putc_done:
- mov w0, w20
- ldp x19, x20, [sp], #16
- ldp x21, x30, [sp], #16
- ret
-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
- * ---------------------------------------------
- */
-func console_getc
- stp x30, xzr, [sp, #-16]!
- stp x20, x21, [sp, #-16]!
-getc_try_again:
- mov w20, #ERROR_NO_VALID_CONSOLE /* W20 = current return value */
- adrp x21, console_list
- ldr x21, [x21, :lo12:console_list] /* X21 = first console struct */
- cbnz x21, getc_loop
- mov w0, w20 /* If no consoles registered */
- ldp x20, x21, [sp], #16
- ldp x30, xzr, [sp], #16
- ret /* return immediately. */
-
-getc_loop:
- adrp x0, console_state
- ldrb w0, [x0, :lo12:console_state]
- ldr w1, [x21, #CONSOLE_T_FLAGS]
- tst w0, w1
- b.eq getc_continue
- ldr x1, [x21, #CONSOLE_T_GETC]
- cbz x1, getc_continue
- mov x0, x21
- blr x1
- cmp w0, #0 /* if X0 >= 0: return */
- b.ge getc_found
- cmp w20, #ERROR_NO_PENDING_CHAR /* may update W20 (NOCHAR has */
- csel w20, w20, w0, eq /* precedence vs real errors) */
-getc_continue:
- ldr x21, [x21] /* X21 = next struct */
- cbnz x21, getc_loop
- cmp w20, #ERROR_NO_PENDING_CHAR /* Keep scanning if at least */
- b.eq getc_try_again /* one console returns NOCHAR */
- mov w0, w20
-
-getc_found:
- ldp x20, x21, [sp], #16
- ldp x30, xzr, [sp], #16
- ret
-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
- * ---------------------------------------------
- */
-func console_flush
- stp x30, xzr, [sp, #-16]!
- stp x20, x21, [sp, #-16]!
- mov w20, #ERROR_NO_VALID_CONSOLE /* W20 = current return value */
- adrp x21, console_list
- ldr x21, [x21, :lo12:console_list] /* X21 = first console struct */
-
-flush_loop:
- cbz x21, flush_done
- adrp x1, console_state
- ldrb w1, [x1, :lo12:console_state]
- ldr w2, [x21, #CONSOLE_T_FLAGS]
- tst w1, w2
- b.eq flush_continue
- ldr x1, [x21, #CONSOLE_T_FLUSH]
- cbz x1, flush_continue
- mov x0, x21
- blr x1
- cmp w20, #ERROR_NO_VALID_CONSOLE /* update W20 if it's NOVALID */
- ccmp w0, #0, #0x8, ne /* else update it if W0 < 0 */
- csel w20, w0, w20, lt
-flush_continue:
- ldr x21, [x21] /* X21 = next struct */
- b flush_loop
-
-flush_done:
- mov w0, w20
- ldp x20, x21, [sp], #16
- ldp x30, xzr, [sp], #16
- ret
-endfunc console_flush
-
-#endif /* MULTI_CONSOLE_API */
diff --git a/drivers/console/multi_console.c b/drivers/console/multi_console.c
new file mode 100644
index 0000000..c678de0
--- /dev/null
+++ b/drivers/console/multi_console.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#if MULTI_CONSOLE_API
+
+#include <assert.h>
+#include <drivers/console.h>
+
+console_t *console_list;
+uint8_t console_state = CONSOLE_FLAG_BOOT;
+
+int console_register(console_t *console)
+{
+ IMPORT_SYM(console_t *, __STACKS_START__, stacks_start)
+ IMPORT_SYM(console_t *, __STACKS_END__, stacks_end)
+
+ /* Assert that the struct is not on the stack (common mistake). */
+ assert((console < stacks_start) || (console >= stacks_end));
+ /* Assert that we won't make a circle in the list. */
+ assert(!console_is_registered(console));
+
+ console->next = console_list;
+ console_list = console;
+
+ /* Return 1 for convenient tail-calling from console_xxx_register(). */
+ return 1;
+}
+
+console_t *console_unregister(console_t *to_be_deleted)
+{
+ console_t **ptr;
+
+ assert(to_be_deleted != NULL);
+
+ for (ptr = &console_list; *ptr != NULL; ptr = &(*ptr)->next)
+ if (*ptr == to_be_deleted) {
+ *ptr = (*ptr)->next;
+ return to_be_deleted;
+ }
+
+ return NULL;
+}
+
+int console_is_registered(console_t *to_find)
+{
+ console_t *console;
+
+ assert(to_find != NULL);
+
+ for (console = console_list; console != NULL; console = console->next)
+ if (console == to_find)
+ return 1;
+
+ return 0;
+}
+
+void console_switch_state(unsigned int new_state)
+{
+ console_state = new_state;
+}
+
+void console_set_scope(console_t *console, unsigned int scope)
+{
+ assert(console != NULL);
+
+ console->flags = (console->flags & ~CONSOLE_FLAG_SCOPE_MASK) | scope;
+}
+
+int console_putc(int c)
+{
+ int err = ERROR_NO_VALID_CONSOLE;
+ console_t *console;
+
+ for (console = console_list; console != NULL; console = console->next)
+ if (console->flags & console_state) {
+ int ret = console->putc(c, console);
+ if ((err == ERROR_NO_VALID_CONSOLE) || (ret < err))
+ err = ret;
+ }
+
+ return err;
+}
+
+int console_getc(void)
+{
+ int err = ERROR_NO_VALID_CONSOLE;
+ console_t *console;
+
+ do { /* Keep polling while at least one console works correctly. */
+ for (console = console_list; console != NULL;
+ console = console->next)
+ if (console->flags & console_state) {
+ int ret = console->getc(console);
+ if (ret >= 0)
+ return ret;
+ if (err != ERROR_NO_PENDING_CHAR)
+ err = ret;
+ }
+ } while (err == ERROR_NO_PENDING_CHAR);
+
+ return err;
+}
+
+int console_flush(void)
+{
+ int err = ERROR_NO_VALID_CONSOLE;
+ console_t *console;
+
+ for (console = console_list; console != NULL; console = console->next)
+ if (console->flags & console_state) {
+ int ret = console->flush(console);
+ if ((err == ERROR_NO_VALID_CONSOLE) || (ret < err))
+ err = ret;
+ }
+
+ return err;
+}
+
+#endif /* MULTI_CONSOLE_API */