summaryrefslogtreecommitdiffstats
path: root/drivers/console/aarch32
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 09:13:47 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 09:13:47 +0000
commit102b0d2daa97dae68d3eed54d8fe37a9cc38a892 (patch)
treebcf648efac40ca6139842707f0eba5a4496a6dd2 /drivers/console/aarch32
parentInitial commit. (diff)
downloadarm-trusted-firmware-upstream/2.8.0+dfsg.tar.xz
arm-trusted-firmware-upstream/2.8.0+dfsg.zip
Adding upstream version 2.8.0+dfsg.upstream/2.8.0+dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/console/aarch32')
-rw-r--r--drivers/console/aarch32/skeleton_console.S170
1 files changed, 170 insertions, 0 deletions
diff --git a/drivers/console/aarch32/skeleton_console.S b/drivers/console/aarch32/skeleton_console.S
new file mode 100644
index 0000000..a9e13ec
--- /dev/null
+++ b/drivers/console/aarch32/skeleton_console.S
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2016-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include <asm_macros.S>
+#include <console_macros.S>
+
+ /*
+ * This file contains a skeleton console driver that can be used as a
+ * basis for a real console driver. Console drivers in Trusted Firmware
+ * can be instantiated multiple times. Each instance is described by a
+ * separate console_t structure which must be registered with the common
+ * console framework via console_register(). Console drivers should
+ * define a console_xxx_register() function that initializes a new
+ * console_t structure passed in from the caller and registers it after
+ * initializing the console hardware. Drivers may define their own
+ * structures extending console_t to store private driver information.
+ * Console drivers *MUST* ensure that the console callbacks they
+ * implement only change registers allowed in the clobber lists defined
+ * in this file. (Note that in addition to the explicit clobber lists,
+ * any function may always clobber the intra-procedure-call register
+ * r12, but may never depend on it retaining its value across any
+ * function call.)
+ */
+
+ .globl console_xxx_register
+ .globl console_xxx_putc
+ .globl console_xxx_getc
+ .globl console_xxx_flush
+
+ /* -----------------------------------------------
+ * int console_xxx_register(console_xxx_t *console,
+ * ...additional parameters as desired...)
+ * Function to initialize and register the console.
+ * The caller needs to pass an empty console_xxx_t
+ * structure in which *MUST* be allocated in
+ * persistent memory (e.g. a global or static local
+ * variable, *NOT* on the stack).
+ * In : r0 - pointer to empty console_t structure
+ * r1 through r7: additional parameters as desired
+ * Out: r0 - 1 on success, 0 on error
+ * Clobber list : r0 - r7
+ * -----------------------------------------------
+ */
+func console_xxx_register
+ /*
+ * Store parameters (e.g. hardware base address) in driver-specific
+ * console_xxx_t structure field if they will need to be retrieved
+ * by later console callback (e.g. putc).
+ * Example:
+ */
+ str r1, [r0, #CONSOLE_T_BASE]
+ str r2, [r0, #CONSOLE_T_XXX_SOME_OTHER_VALUE]
+
+ /*
+ * Initialize console hardware, using r1 - r7 parameters as needed.
+ * Keep console_t pointer in r0 for later.
+ */
+
+ /*
+ * Macro to finish up registration and return (needs valid r0 + lr).
+ * If any of the argument is unspecified, then the corresponding
+ * entry in console_t is set to 0.
+ */
+ finish_console_register xxx putc=1, getc=1, flush=1
+
+ /* Jump here if hardware init fails or parameters are invalid. */
+register_fail:
+ mov r0, #0
+ bx lr
+endfunc console_xxx_register
+
+ /* --------------------------------------------------------
+ * int console_xxx_putc(int c, console_xxx_t *console)
+ * Function to output a character over the console. It
+ * returns the character printed on success or -1 on error.
+ * In : r0 - character to be printed
+ * r1 - pointer to console_t struct
+ * Out: r0 - printed character on success, < 0 on error.
+ * Clobber list : r0, r1, r2
+ * --------------------------------------------------------
+ */
+func console_xxx_putc
+ /*
+ * Retrieve values we need (e.g. hardware base address) from
+ * console_xxx_t structure pointed to by r1.
+ * Example:
+ */
+ ldr r1, [r1, #CONSOLE_T_BASE]
+
+ /*
+ * Write r0 to hardware.
+ */
+
+ bx lr
+
+ /* Jump here if output fails for any reason. */
+putc_error:
+ mov r0, #-1
+ bx lr
+endfunc console_xxx_putc
+
+ /* ---------------------------------------------
+ * int console_xxx_getc(console_xxx_t *console)
+ * Function to get a character from the console.
+ * Even though console_getc() is blocking, this
+ * callback has to be non-blocking and always
+ * return immediately to allow polling multiple
+ * drivers concurrently.
+ * Returns the character grabbed on success,
+ * ERROR_NO_PENDING_CHAR if no character was
+ * available at this time, or any value
+ * between -2 and -127 if there was an error.
+ * In : r0 - pointer to console_t struct
+ * Out: r0 - character on success,
+ * ERROR_NO_PENDING_CHAR if no char,
+ * < -1 on error
+ * Clobber list : r0, r1
+ * ---------------------------------------------
+ */
+func console_xxx_getc
+ /*
+ * Retrieve values we need (e.g. hardware base address) from
+ * console_xxx_t structure pointed to by r0.
+ * Example:
+ */
+ ldr r1, [r0, #CONSOLE_T_BASE]
+
+ /*
+ * Try to read character into r0 from hardware.
+ */
+
+ bx lr
+
+ /* Jump here if there is no character available at this time. */
+getc_no_char:
+ mov r0, #ERROR_NO_PENDING_CHAR
+ bx lr
+
+ /* Jump here if there was any hardware error. */
+getc_error:
+ mov r0, #-2 /* may pick error codes between -2 and -127 */
+ bx lr
+endfunc console_xxx_getc
+
+ /* ---------------------------------------------
+ * int console_xxx_flush(console_xxx_t *console)
+ * Function to force a write of all buffered
+ * data that hasn't been output.
+ * In : r0 - pointer to console_xxx_t struct
+ * Out: void
+ * Clobber list : r0, r1, r2, r3, r4, r5
+ * ---------------------------------------------
+ */
+func console_xxx_flush
+ /*
+ * Retrieve values we need (e.g. hardware base address) from
+ * console_xxx_t structure pointed to by r0.
+ * Example:
+ */
+ ldr r1, [r0, #CONSOLE_T_BASE]
+
+ /*
+ * Flush all remaining output from hardware FIFOs. Do not return until
+ * all data has been flushed or there was an unrecoverable error.
+ */
+
+ bx lr
+endfunc console_xxx_flush