avr32: Use the same entry point for reset and exception handling
Since the reset vector is always aligned to a very large boundary, we
can save a couple of KB worth of alignment padding by placing the
exception vectors at the same address.
Deciding which one it is is easy: If we're handling an exception, the
CPU is in Exception mode. If we're starting up after reset, the CPU is
in Supervisor mode. So this adds a very minimal overhead to the reset
path (only executed once) and the exception handling path (normally
never executed at all.)
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
diff --git a/board/atmel/atngw100/u-boot.lds b/board/atmel/atngw100/u-boot.lds
index 3c878d8..e736adf 100644
--- a/board/atmel/atngw100/u-boot.lds
+++ b/board/atmel/atngw100/u-boot.lds
@@ -29,6 +29,7 @@
. = 0;
_text = .;
.text : {
+ *(.exception.text)
*(.text)
*(.text.*)
}
diff --git a/board/atmel/atstk1000/u-boot.lds b/board/atmel/atstk1000/u-boot.lds
index f63bc4f..0d3b19c 100644
--- a/board/atmel/atstk1000/u-boot.lds
+++ b/board/atmel/atstk1000/u-boot.lds
@@ -29,6 +29,7 @@
. = 0;
_text = .;
.text : {
+ *(.exception.text)
*(.text)
*(.text.*)
}
diff --git a/cpu/at32ap/Makefile b/cpu/at32ap/Makefile
index 8e384c7..29f9c0d 100644
--- a/cpu/at32ap/Makefile
+++ b/cpu/at32ap/Makefile
@@ -29,7 +29,6 @@
START-y += start.o
-SOBJS-y += entry.o
COBJS-y += cpu.o
COBJS-y += hsdramc.o
COBJS-y += exception.o
diff --git a/cpu/at32ap/entry.S b/cpu/at32ap/entry.S
deleted file mode 100644
index a6fc688..0000000
--- a/cpu/at32ap/entry.S
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
- * Copyright (C) 2004-2006 Atmel Corporation
- *
- * See file CREDITS for list of people who contributed to this
- * project.
- *
- * 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 program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
- * MA 02111-1307 USA
- */
-#include <asm/sysreg.h>
-#include <asm/ptrace.h>
-
- .section .text.exception,"ax"
- .global _evba
- .type _evba,@function
- .align 10
-_evba:
- .irp x,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16
- .align 2
- rjmp unknown_exception
- .endr
-
- .global timer_interrupt_handler
- .type timer_interrupt_handler,@function
- .align 2
-timer_interrupt_handler:
- /*
- * Increment timer_overflow and re-write COMPARE with 0xffffffff.
- *
- * We're running at interrupt level 3, so we don't need to save
- * r8-r12 or lr to the stack.
- */
- lda.w r8, timer_overflow
- ld.w r9, r8[0]
- mov r10, -1
- mtsr SYSREG_COMPARE, r10
- sub r9, -1
- st.w r8[0], r9
- rete
-
- .type unknown_exception, @function
-unknown_exception:
- pushm r0-r12
- sub r8, sp, REG_R12 - REG_R0 - 4
- mov r9, lr
- mfsr r10, SYSREG_RAR_EX
- mfsr r11, SYSREG_RSR_EX
- pushm r8-r11
- mfsr r12, SYSREG_ECR
- mov r11, sp
- rcall do_unknown_exception
-1: rjmp 1b
diff --git a/cpu/at32ap/start.S b/cpu/at32ap/start.S
index ab8c2b7..907e9b1 100644
--- a/cpu/at32ap/start.S
+++ b/cpu/at32ap/start.S
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2005-2006 Atmel Corporation
+ * Copyright (C) 2005-2008 Atmel Corporation
*
* See file CREDITS for list of people who contributed to this
* project.
@@ -20,12 +20,9 @@
* MA 02111-1307 USA
*/
#include <config.h>
+#include <asm/ptrace.h>
#include <asm/sysreg.h>
-#ifndef PART_SPECIFIC_BOOTSTRAP
-# define PART_SPECIFIC_BOOTSTRAP
-#endif
-
#define SYSREG_MMUCR_I_OFFSET 2
#define SYSREG_MMUCR_S_OFFSET 4
@@ -34,11 +31,115 @@
| SYSREG_BIT(FE) | SYSREG_BIT(RE) \
| SYSREG_BIT(IBE) | SYSREG_BIT(IEE))
- .text
+ /*
+ * To save some space, we use the same entry point for
+ * exceptions and reset. This avoids lots of alignment padding
+ * since the reset vector is always suitably aligned.
+ */
+ .section .exception.text, "ax", @progbits
.global _start
+ .global _evba
+ .type _start, @function
+ .type _evba, @function
_start:
- PART_SPECIFIC_BOOTSTRAP
+ .size _start, 0
+_evba:
+ .org 0x00
+ rjmp unknown_exception /* Unrecoverable exception */
+ .org 0x04
+ rjmp unknown_exception /* TLB multiple hit */
+ .org 0x08
+ rjmp unknown_exception /* Bus error data fetch */
+ .org 0x0c
+ rjmp unknown_exception /* Bus error instruction fetch */
+ .org 0x10
+ rjmp unknown_exception /* NMI */
+ .org 0x14
+ rjmp unknown_exception /* Instruction address */
+ .org 0x18
+ rjmp unknown_exception /* ITLB protection */
+ .org 0x1c
+ rjmp unknown_exception /* Breakpoint */
+ .org 0x20
+ rjmp unknown_exception /* Illegal opcode */
+ .org 0x24
+ rjmp unknown_exception /* Unimplemented instruction */
+ .org 0x28
+ rjmp unknown_exception /* Privilege violation */
+ .org 0x2c
+ rjmp unknown_exception /* Floating-point */
+ .org 0x30
+ rjmp unknown_exception /* Coprocessor absent */
+ .org 0x34
+ rjmp unknown_exception /* Data Address (read) */
+ .org 0x38
+ rjmp unknown_exception /* Data Address (write) */
+ .org 0x3c
+ rjmp unknown_exception /* DTLB Protection (read) */
+ .org 0x40
+ rjmp unknown_exception /* DTLB Protection (write) */
+ .org 0x44
+ rjmp unknown_exception /* DTLB Modified */
+
+ .org 0x50
+ rjmp unknown_exception /* ITLB Miss */
+ .org 0x60
+ rjmp unknown_exception /* DTLB Miss (read) */
+ .org 0x70
+ rjmp unknown_exception /* DTLB Miss (write) */
+
+ .size _evba, . - _evba
+
+ .align 2
+ .type unknown_exception, @function
+unknown_exception:
+ /* Figure out whether we're handling an exception (Exception
+ * mode) or just booting (Supervisor mode). */
+ csrfcz SYSREG_M1_OFFSET
+ brcc at32ap_cpu_bootstrap
+
+ /* This is an exception. Complain. */
+ pushm r0-r12
+ sub r8, sp, REG_R12 - REG_R0 - 4
+ mov r9, lr
+ mfsr r10, SYSREG_RAR_EX
+ mfsr r11, SYSREG_RSR_EX
+ pushm r8-r11
+ mfsr r12, SYSREG_ECR
+ mov r11, sp
+ rcall do_unknown_exception
+1: rjmp 1b
+
+ /* The COUNT/COMPARE timer interrupt handler */
+ .global timer_interrupt_handler
+ .type timer_interrupt_handler,@function
+ .align 2
+timer_interrupt_handler:
+ /*
+ * Increment timer_overflow and re-write COMPARE with 0xffffffff.
+ *
+ * We're running at interrupt level 3, so we don't need to save
+ * r8-r12 or lr to the stack.
+ */
+ lda.w r8, timer_overflow
+ ld.w r9, r8[0]
+ mov r10, -1
+ mtsr SYSREG_COMPARE, r10
+ sub r9, -1
+ st.w r8[0], r9
+ rete
+ /*
+ * CPU bootstrap after reset is handled here. SoC code may
+ * override this in case they need to initialize oscillators,
+ * etc.
+ */
+ .section .text.at32ap_cpu_bootstrap, "ax", @progbits
+ .global at32ap_cpu_bootstrap
+ .weak at32ap_cpu_bootstrap
+ .type at32ap_cpu_bootstrap, @function
+ .align 2
+at32ap_cpu_bootstrap:
/* Reset the Status Register */
mov r0, lo(SR_INIT)
orh r0, hi(SR_INIT)
@@ -66,9 +167,16 @@
lddpc pc, 1f
.align 2
-1: .long 2f
+1: .long at32ap_low_level_init
+ .size _start, . - _start
-2: lddpc sp, sp_init
+ /* Common CPU bootstrap code after oscillator/cache/etc. init */
+ .section .text.avr32ap_low_level_init, "ax", @progbits
+ .global at32ap_low_level_init
+ .type at32ap_low_level_init, @function
+ .align 2
+at32ap_low_level_init:
+ lddpc sp, sp_init
/* Initialize the GOT pointer */
lddpc r6, got_init
@@ -90,6 +198,7 @@
* Relocate the u-boot image into RAM and continue from there.
* Does not return.
*/
+ .section .text.relocate_code,"ax",@progbits
.global relocate_code
.type relocate_code,@function
relocate_code:
@@ -162,3 +271,5 @@
.align 2
got_init_reloc:
.long 3b - _GLOBAL_OFFSET_TABLE_
+
+ .size relocate_code, . - relocate_code