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authorThomas Martitz <kugel@rockbox.org>2013-12-04 17:06:17 +0100
committerThomas Martitz <kugel@rockbox.org>2014-03-03 18:11:57 +0100
commit382d1861af12741af4ff235b9d18f179c0adc4c5 (patch)
tree26166c130d2889bb1ae1082e8f7aba103534f49e /firmware/asm
parent8bae5f2644b5d5759499fbf1066b9c35c6f859ad (diff)
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kernel: Break out kernel primitives into separate files and move to separate dir.
No code changed, just shuffling stuff around. This should make it easier to build only select parts kernel and use different implementations. Change-Id: Ie1f00f93008833ce38419d760afd70062c5e22b5
Diffstat (limited to 'firmware/asm')
-rw-r--r--firmware/asm/arm/corelock.c96
-rw-r--r--firmware/asm/corelock.c67
2 files changed, 163 insertions, 0 deletions
diff --git a/firmware/asm/arm/corelock.c b/firmware/asm/arm/corelock.c
new file mode 100644
index 0000000000..713164e49b
--- /dev/null
+++ b/firmware/asm/arm/corelock.c
@@ -0,0 +1,96 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2007 by Daniel Ankers
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+/* Core locks using Peterson's mutual exclusion algorithm.
+ * ASM optimized version of C code, see firmware/asm/corelock.c */
+
+#include "cpu.h"
+
+/*---------------------------------------------------------------------------
+ * Wait for the corelock to become free and acquire it when it does.
+ *---------------------------------------------------------------------------
+ */
+void __attribute__((naked)) corelock_lock(struct corelock *cl)
+{
+ /* Relies on the fact that core IDs are complementary bitmasks (0x55,0xaa) */
+ asm volatile (
+ "mov r1, %0 \n" /* r1 = PROCESSOR_ID */
+ "ldrb r1, [r1] \n"
+ "strb r1, [r0, r1, lsr #7] \n" /* cl->myl[core] = core */
+ "eor r2, r1, #0xff \n" /* r2 = othercore */
+ "strb r2, [r0, #2] \n" /* cl->turn = othercore */
+ "1: \n"
+ "ldrb r3, [r0, r2, lsr #7] \n" /* cl->myl[othercore] == 0 ? */
+ "cmp r3, #0 \n" /* yes? lock acquired */
+ "bxeq lr \n"
+ "ldrb r3, [r0, #2] \n" /* || cl->turn == core ? */
+ "cmp r3, r1 \n"
+ "bxeq lr \n" /* yes? lock acquired */
+ "b 1b \n" /* keep trying */
+ : : "i"(&PROCESSOR_ID)
+ );
+ (void)cl;
+}
+
+/*---------------------------------------------------------------------------
+ * Try to aquire the corelock. If free, caller gets it, otherwise return 0.
+ *---------------------------------------------------------------------------
+ */
+int __attribute__((naked)) corelock_try_lock(struct corelock *cl)
+{
+ /* Relies on the fact that core IDs are complementary bitmasks (0x55,0xaa) */
+ asm volatile (
+ "mov r1, %0 \n" /* r1 = PROCESSOR_ID */
+ "ldrb r1, [r1] \n"
+ "mov r3, r0 \n"
+ "strb r1, [r0, r1, lsr #7] \n" /* cl->myl[core] = core */
+ "eor r2, r1, #0xff \n" /* r2 = othercore */
+ "strb r2, [r0, #2] \n" /* cl->turn = othercore */
+ "ldrb r0, [r3, r2, lsr #7] \n" /* cl->myl[othercore] == 0 ? */
+ "eors r0, r0, r2 \n" /* yes? lock acquired */
+ "bxne lr \n"
+ "ldrb r0, [r3, #2] \n" /* || cl->turn == core? */
+ "ands r0, r0, r1 \n"
+ "streqb r0, [r3, r1, lsr #7] \n" /* if not, cl->myl[core] = 0 */
+ "bx lr \n" /* return result */
+ : : "i"(&PROCESSOR_ID)
+ );
+
+ return 0;
+ (void)cl;
+}
+
+/*---------------------------------------------------------------------------
+ * Release ownership of the corelock
+ *---------------------------------------------------------------------------
+ */
+void __attribute__((naked)) corelock_unlock(struct corelock *cl)
+{
+ asm volatile (
+ "mov r1, %0 \n" /* r1 = PROCESSOR_ID */
+ "ldrb r1, [r1] \n"
+ "mov r2, #0 \n" /* cl->myl[core] = 0 */
+ "strb r2, [r0, r1, lsr #7] \n"
+ "bx lr \n"
+ : : "i"(&PROCESSOR_ID)
+ );
+ (void)cl;
+}
diff --git a/firmware/asm/corelock.c b/firmware/asm/corelock.c
new file mode 100644
index 0000000000..51d1d71961
--- /dev/null
+++ b/firmware/asm/corelock.c
@@ -0,0 +1,67 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2007 by Daniel Ankers
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "config.h"
+#include "corelock.h"
+/* Core locks using Peterson's mutual exclusion algorithm. */
+
+#ifdef CPU_ARM
+#include "arm/corelock.c"
+#else
+
+void corelock_lock(struct corelock *cl)
+{
+ const unsigned int core = CURRENT_CORE;
+ const unsigned int othercore = 1 - core;
+
+ cl->myl[core] = core;
+ cl->turn = othercore;
+
+ for (;;)
+ {
+ if (cl->myl[othercore] == 0 || cl->turn == core)
+ break;
+ }
+}
+
+int corelock_try_lock(struct corelock *cl)
+{
+ const unsigned int core = CURRENT_CORE;
+ const unsigned int othercore = 1 - core;
+
+ cl->myl[core] = core;
+ cl->turn = othercore;
+
+ if (cl->myl[othercore] == 0 || cl->turn == core)
+ {
+ return 1;
+ }
+
+ cl->myl[core] = 0;
+ return 0;
+}
+
+void corelock_unlock(struct corelock *cl)
+{
+ cl->myl[CURRENT_CORE] = 0;
+}
+
+#endif