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Xtensa: Add NMI handler

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This commit is contained in:
Gregory Nutt 2016-10-23 16:24:09 -06:00
parent 261eec110b
commit 2514ddec8b
5 changed files with 169 additions and 16 deletions
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9
arch/xtensa/src/common/xtensa_inthandlers.S
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@ -606,6 +606,9 @@ _xtensa_level6_handler:
* a way to save and restore registers it uses without touching the
* interrupted stack.
*
* A template and example can be found in the Cadence Design Systems tools
* documentation: "Microprocessor Programmer's Guide".
*
* Each vector goes at a predetermined location according to the Xtensa
* hardware configuration, which is ensured by its placement in a special
* section known to the Xtensa linker support package (LSP). It performs
@ -613,12 +616,6 @@ _xtensa_level6_handler:
*
****************************************************************************/
/*
Currently only shells for high priority interrupt handlers are provided
here. However a template and example can be found in the Cadence Design Systems tools
documentation: "Microprocessor Programmer's Guide".
*/
#if XCHAL_INT_NLEVELS >=2 && XCHAL_EXCM_LEVEL < 2 && XCHAL_DEBUGLEVEL !=2
.section .iram1,"ax"
.type _xtensa_level2_handler, @function

126
arch/xtensa/src/common/xtensa_nmihandler.S Normal file
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@ -0,0 +1,126 @@
/****************************************************************************
* arch/xtensa/src/common/xtensa_nmihandler.S
*
* Adapted from use in NuttX by:
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Derives from logic originally provided by Cadence Design Systems Inc.
*
* Copyright (c) 2006-2015 Cadence Design Systems Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
****************************************************************************/
.file "xtensa_nmihandler.S"
/* NOTES on the use of 'call0' for long jumps instead of 'j':
*
* 1. This file should be assembled with the -mlongcalls option to xt-xcc.
*
* 2. The -mlongcalls compiler option causes 'call0 dest' to be expanded to
* a sequence 'l32r a0, dest' 'callx0 a0' which works regardless of the
* distance from the call to the destination. The linker then relaxes
* it back to 'call0 dest' if it determines that dest is within range.
* This allows more flexibility in locating code without the performance
* overhead of the 'l32r' literal data load in cases where the destination
* is in range of 'call0'. There is an additional benefit in that 'call0'
* has a longer range than 'j' due to the target being word-aligned, so
* the 'l32r' sequence is less likely needed.
*
* 3. The use of 'call0' with -mlongcalls requires that register a0 not be
* live at the time of the call, which is always the case for a function
* call but needs to be ensured if 'call0' is used as a jump in lieu of 'j'.
*
* 4. This use of 'call0' is independent of the C function call ABI.
*/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <arch/irq.h>
#include <arch/chip/core-isa.h>
#include <arch/xtensa/xtensa_specregs.h>
#include "xtensa_macros.h"
#include "xtensa_timer.h"
/****************************************************************************
* Assembly Language Macros
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* HIGH PRIORITY NMI LOW-LEVEL HANDLER
*
* High priority interrupts are by definition those with priorities greater
* than XCHAL_EXCM_LEVEL. This includes non-maskable (NMI). High priority
* interrupts cannot interact with the RTOS, that is they must save all regs
* they use and not call any RTOS function.
*
* A further restriction imposed by the Xtensa windowed architecture is that
* high priority interrupts must not modify the stack area even logically
* "above" the top of the interrupted stack (they need to provide their
* own stack or static save area).
*
* Cadence Design Systems recommends high priority interrupt handlers be
* coded in assembly and used for purposes requiring very short service
* times.
*
* The NMI vector goes at a predetermined location according to the Xtensa
* hardware configuration, which is ensured by its placement in a special
* section known to the Xtensa linker support package (LSP). It performs
* the minimum necessary before jumping to the NMI andler.
*
* Below is a template for the high priority NMI interrupt handler.
* A template and example can be found in the Cadence Design Systems tools
* documentation: "Microprocessor Programmer's Guide".
*
****************************************************************************/
#if XCHAL_HAVE_NMI
.section .iram1,"ax"
.type _xt_nmi,@function
.align 4
_xt_nmi:
#ifdef XT_INTEXC_HOOKS
/* Call interrupt hook if present to (pre)handle interrupts. */
movi a0, _xt_intexc_hooks
l32i a0, a0, XCHAL_NMILEVEL << 2
beqz a0, 1f
callx0 a0 /* Must NOT disturb stack! */
1:
#endif
/* Add high priority non-maskable interrupt (NMI) handler code here. */
rsr a0, EXCSAVE + XCHAL_NMILEVEL /* Restore a0 */
rfi XCHAL_NMILEVEL
#endif /* XCHAL_HAVE_NMI */

38
arch/xtensa/src/common/xtensa_intvectors.S → arch/xtensa/src/common/xtensa_vectors.S
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@ -1,5 +1,5 @@
/****************************************************************************
* arch/xtensa/src/common/xtensa_intvectors.S
* arch/xtensa/src/common/xtensa_vectors.S
*
* Adapted from use in NuttX by:
*
@ -131,9 +131,8 @@ _xtensa_level5_vector:
/* Never returns here - call0 is used as a jump */
.end literal_prefix
.size _xtensa_level5_vector, . - _xtensa_level5_vector
.end literal_prefix
#endif
#if XCHAL_EXCM_LEVEL >= 6
@ -150,7 +149,36 @@ _xtensa_level6_vector:
/* Never returns here - call0 is used as a jump */
.end literal_prefix
.size _xtensa_level6_vector, . - _xtensa_level6_vector
.end literal_prefix
#endif
/****************************************************************************
* C Prototype:
* void _xtensa_nmi_vector(void)
*
* Description:
* Xtensa NMI vectors. This vector goes at a predetermined location
* according to the Xtensa hardware configuration, which is ensured by its
* placement in a special section known to the NuttX linker script. The
* vector logic performs the minimum necessary operations before jumping
* to the handler.
*
****************************************************************************/
#if XCHAL_HAVE_NMI
.begin literal_prefix .nmi_vector
.section .nmi_vector.text, "ax"
.global _xtensa_nmi_vector
.type _xtensa_nmi_vector, @function
.align 4
_xtensa_nmi_vector:
wsr a0, EXCSAVE + XCHAL_NMILEVEL _ /* preserve a0 */
call0 _xt_nmi /* load interrupt handler */
/* Never returns here - call0 is used as a jump */
.size _xtensa_nmi_vector, . - _xtensa_nmi_vector
.end literal_prefix
#endif

4
arch/xtensa/src/esp32/Make.defs
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@ -40,7 +40,9 @@ HEAD_CSRC = esp32_start.c
# Common XTENSA files (arch/xtensa/src/common)
CMN_ASRCS = xtensa_context.S xtensa_intvectors.S
CMN_ASRCS = xtensa_context.S xtensa_vectors.S xtensa_inthandlers.S
CMN_ASRCS += xtensa_nmihandler.S
CMN_CSRCS = xtensa_assert.c xtensa_blocktask.c xtensa_copystate.c
CMN_CSRCS += xtensa_createstack.c xtensa_exit.c xtensa_idle.c
CMN_CSRCS += xtensa_initialize.c xtensa_initialstate.c

2
configs/esp32-core/scripts/esp32_common.ld
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@ -31,7 +31,7 @@ SECTIONS
. = 0x280;
KEEP(*(.DebugExceptionVector.text));
. = 0x2c0;
KEEP(*(.NMIExceptionVector.text));
KEEP(*(.nmi_vector.text));
. = 0x300;
KEEP(*(.KernelExceptionVector.text));
. = 0x340;