ARM: ARMv7-M: implement restart routine common to all v7-M machines

PATCH New Uwe Kleine-König 2 participants 4 messages Aug 14, 2013 – Aug 15, 2013 Arm (32-bit)

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Uwe Kleine-König

author

2013-08-14 15:37 UTC #0 lore raw

PATCH 1/1 ARM: ARMv7-M: implement restart routine common to all v7-M machines

Signed-off-by Uwe Kleine-K?nig <[email protected]>

---
 arch/arm/include/asm/v7m.h   | 12 ++++++++++++
 arch/arm/kernel/Makefile     |  2 +-
 arch/arm/kernel/common-v7m.c | 19 +++++++++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm/kernel/common-v7m.c

arch/arm/include/asm/v7m.h +12 -0

index fa88d09..615781c 100644
@@ -15,6 +15,10 @@
 
 #define V7M_SCB_VTOR			0x08
 
+#define V7M_SCB_AIRCR			0x0c
+#define V7M_SCB_AIRCR_VECTKEY			(0x05fa << 16)
+#define V7M_SCB_AIRCR_SYSRESETREQ		(1 << 2)
+
 #define V7M_SCB_SCR			0x10
 #define V7M_SCB_SCR_SLEEPDEEP			(1 << 2)

@@ -42,3 +46,11 @@
  */
 #define EXC_RET_STACK_MASK			0x00000004
 #define EXC_RET_THREADMODE_PROCESSSTACK		0xfffffffd
+
+#ifndef __ASSEMBLY__
+
+enum reboot_mode;
+
+void armv7m_restart(enum reboot_mode mode, const char *cmd);
+
+#endif /* __ASSEMBLY__ */

arch/arm/kernel/Makefile +1 -1

index 86d10dd..688b8be 100644
@@ -24,7 +24,7 @@ obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
 obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
 ifeq ($(CONFIG_CPU_V7M),y)
-obj-y		+= entry-v7m.o
+obj-y		+= entry-v7m.o common-v7m.o
 else
 obj-y		+= entry-armv.o
 endif

arch/arm/kernel/common-v7m.c new file +19 -0

new file mode 100644
index 0000000..4d2cba9
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2013 Uwe Kleine-Koenig for Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation.
+ */
+#include <linux/io.h>
+#include <linux/reboot.h>
+#include <asm/barrier.h>
+#include <asm/v7m.h>
+
+void armv7m_restart(enum reboot_mode mode, const char *cmd)
+{
+	dsb();
+	__raw_writel(V7M_SCB_AIRCR_VECTKEY | V7M_SCB_AIRCR_SYSRESETREQ,
+			BASEADDR_V7M_SCB + V7M_SCB_AIRCR);
+	dsb();
+}

Signature · 1 line

1.8.4.rc0

Jonathan Austin

2013-08-14 16:44 UTC #1 lore raw

PATCH 1/1 ARM: ARMv7-M: implement restart routine common to all v7-M machines

Quoted 1 line · Uwe Kleine-K?nig

Signed-off-by Uwe Kleine-K?nig <[email protected]>

Do we get a commit message? ;)

Quoted 12 lines

---
  arch/arm/include/asm/v7m.h   | 12 ++++++++++++
  arch/arm/kernel/Makefile     |  2 +-
  arch/arm/kernel/common-v7m.c | 19 +++++++++++++++++++
  3 files changed, 32 insertions(+), 1 deletion(-)

create mode 100644 arch/arm/kernel/common-v7m.c

arch/arm/include/asm/v7m.h +0 -0

index fa88d09..615781c 100644

arch/arm/include/asm/v7m.h line 21

Quoted 7 lines

arch/arm/include/asm/v7m.h +4 -0

@@ -15,6 +15,10 @@
 
  #define V7M_SCB_VTOR			0x08
 
+#define V7M_SCB_AIRCR			0x0c
+#define V7M_SCB_AIRCR_VECTKEY			(0x05fa << 16)
+#define V7M_SCB_AIRCR_SYSRESETREQ		(1 << 2)
+

These all look good, happy with the names too.

arch/arm/include/asm/v7m.h line 52

Quoted 11 lines

arch/arm/include/asm/v7m.h +4 -0

  #define V7M_SCB_SCR			0x10
  #define V7M_SCB_SCR_SLEEPDEEP			(1 << 2)

@@ -42,3 +46,11 @@
   */
  #define EXC_RET_STACK_MASK			0x00000004
  #define EXC_RET_THREADMODE_PROCESSSTACK		0xfffffffd
+
+#ifndef __ASSEMBLY__
+
+enum reboot_mode;

Certainly worth introducing what the plans for this are in the long run
- but I suspect the commit message might have contained that info?

arch/arm/kernel/common-v7m.c

Quoted 22 lines

arch/arm/include/asm/v7m.h +4 -0

+
+void armv7m_restart(enum reboot_mode mode, const char *cmd);
+
+#endif /* __ASSEMBLY__ */

arch/arm/kernel/Makefile +1 -1

index 86d10dd..688b8be 100644
@@ -24,7 +24,7 @@ obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
  obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
  ifeq ($(CONFIG_CPU_V7M),y)
-obj-y		+= entry-v7m.o
+obj-y		+= entry-v7m.o common-v7m.o
  else
  obj-y		+= entry-armv.o
  endif

arch/arm/kernel/common-v7m.c new file +0 -0

new file mode 100644
index 0000000..4d2cba9

Is this really the right place for such a function? My immediate thought is that such a thing belongs in proc-v7m.S

Is this fitting in to a an existing framework or pattern that I'm missing?

Quoted 21 lines

arch/arm/kernel/common-v7m.c new file +19 -0

@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2013 Uwe Kleine-Koenig for Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation.
+ */
+#include <linux/io.h>
+#include <linux/reboot.h>
+#include <asm/barrier.h>
+#include <asm/v7m.h>
+
+void armv7m_restart(enum reboot_mode mode, const char *cmd)
+{
+	dsb();
+	__raw_writel(V7M_SCB_AIRCR_VECTKEY | V7M_SCB_AIRCR_SYSRESETREQ,
+			BASEADDR_V7M_SCB + V7M_SCB_AIRCR);
+	dsb();
+}

Uwe Kleine-König

author

2013-08-14 18:01 UTC #2 lore raw

PATCH 1/1 ARM: ARMv7-M: implement restart routine common to all v7-M machines

Quoted 4 lines · Jonathan Austin

Quoted 1 line · Uwe Kleine-K?nig
Signed-off-by Uwe Kleine-K?nig <[email protected]>
Do we get a commit message? ;)

You did see the Subject line? I guess you did and it's not enough to understand it. The new function is used as .restart member of {DT_,}MACHINE_START.

Quoted 64 lines

Quoted 13 lines
---
 arch/arm/include/asm/v7m.h   | 12 ++++++++++++
 arch/arm/kernel/Makefile     |  2 +-
 arch/arm/kernel/common-v7m.c | 19 +++++++++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm/kernel/common-v7m.c
arch/arm/include/asm/v7m.h +0 -0
index fa88d09..615781c 100644
arch/arm/include/asm/v7m.h line 21
Quoted 7 lines
arch/arm/include/asm/v7m.h +4 -0
@@ -15,6 +15,10 @@
 
 #define V7M_SCB_VTOR			0x08
 
+#define V7M_SCB_AIRCR			0x0c
+#define V7M_SCB_AIRCR_VECTKEY			(0x05fa << 16)
+#define V7M_SCB_AIRCR_SYSRESETREQ		(1 << 2)
+
These all look good, happy with the names too.
arch/arm/include/asm/v7m.h line 52
Quoted 11 lines
arch/arm/include/asm/v7m.h +4 -0
 #define V7M_SCB_SCR			0x10
 #define V7M_SCB_SCR_SLEEPDEEP			(1 << 2)
 
@@ -42,3 +46,11 @@
  */
 #define EXC_RET_STACK_MASK			0x00000004
 #define EXC_RET_THREADMODE_PROCESSSTACK		0xfffffffd
+
+#ifndef __ASSEMBLY__
+
+enum reboot_mode;
Certainly worth introducing what the plans for this are in the long run - but I suspect the commit message might have contained that info?
arch/arm/kernel/common-v7m.c
Quoted 22 lines
arch/arm/include/asm/v7m.h +4 -0
+
+void armv7m_restart(enum reboot_mode mode, const char *cmd);
+
+#endif /* __ASSEMBLY__ */
arch/arm/kernel/Makefile +1 -1
index 86d10dd..688b8be 100644
@@ -24,7 +24,7 @@ obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
 obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
 ifeq ($(CONFIG_CPU_V7M),y)
-obj-y		+= entry-v7m.o
+obj-y		+= entry-v7m.o common-v7m.o
 else
 obj-y		+= entry-armv.o
 endif
arch/arm/kernel/common-v7m.c new file +0 -0
new file mode 100644
index 0000000..4d2cba9
Is this really the right place for such a function? My immediate thought is that such a thing belongs in proc-v7m.S

Quoted 1 line

Is this fitting in to a an existing framework or pattern that I'm missing?

proc-v7m.S doesn't work as my function is coded in C :-)

Here are some other restart functions with the file they are defined in:

davinci_restart   | arch/arm/mach-davinci/devices.c
exynos4_restart   | arch/arm/mach-exynos/common.c
highbank_restart  | arch/arm/mach-highbank/system.c
mxc_restart       | arch/arm/mach-imx/system.c
omap3xxx_restart  | arch/arm/mach-omap2/omap3-restart.c
pxa_restart       | arch/arm/mach-pxa/reset.c
versatile_restart | arch/arm/mach-versatile/core.c

at91 doesn't seem to have a restart function.

Hmm, I'm still happy with arch/arm/kernel/common-v7m.c.

Quoted 12 lines

arch/arm/kernel/common-v7m.c new file +11 -0

@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2013 Uwe Kleine-Koenig for Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation.
+ */
+#include <linux/io.h>
+#include <linux/reboot.h>
+#include <asm/barrier.h>
+#include <asm/v7m.h>

Quoted 8 lines

arch/arm/kernel/common-v7m.c line 19

Quoted 8 lines

arch/arm/kernel/common-v7m.c new file +8 -0

+
+void armv7m_restart(enum reboot_mode mode, const char *cmd)
+{
+	dsb();
+	__raw_writel(V7M_SCB_AIRCR_VECTKEY | V7M_SCB_AIRCR_SYSRESETREQ,
+			BASEADDR_V7M_SCB + V7M_SCB_AIRCR);
+	dsb();
+}

Best regards
Uwe

Signature · 2 lines

Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

Jonathan Austin

2013-08-15 14:27 UTC #3 lore raw

PATCH 1/1 ARM: ARMv7-M: implement restart routine common to all v7-M machines

Quoted 9 lines · Uwe Kleine-K?nig

Quoted 4 lines · Jonathan Austin
Quoted 1 line · Uwe Kleine-K?nig
Signed-off-by Uwe Kleine-K?nig <[email protected]>
Do we get a commit message? ;)
You did see the Subject line? I guess you did and it's not enough to understand it. The new function is used as .restart member of {DT_,}MACHINE_START.

Yea, I saw it but think it is always useful to have the commit message!

Quoted 64 lines

Quoted 64 lines
Quoted 13 lines
---
  arch/arm/include/asm/v7m.h   | 12 ++++++++++++
  arch/arm/kernel/Makefile     |  2 +-
  arch/arm/kernel/common-v7m.c | 19 +++++++++++++++++++
  3 files changed, 32 insertions(+), 1 deletion(-)
create mode 100644 arch/arm/kernel/common-v7m.c
arch/arm/include/asm/v7m.h +0 -0
index fa88d09..615781c 100644
arch/arm/include/asm/v7m.h line 21
Quoted 7 lines
arch/arm/include/asm/v7m.h +4 -0
@@ -15,6 +15,10 @@
 
  #define V7M_SCB_VTOR			0x08
 
+#define V7M_SCB_AIRCR			0x0c
+#define V7M_SCB_AIRCR_VECTKEY			(0x05fa << 16)
+#define V7M_SCB_AIRCR_SYSRESETREQ		(1 << 2)
+
These all look good, happy with the names too.
arch/arm/include/asm/v7m.h line 52
Quoted 11 lines
arch/arm/include/asm/v7m.h +4 -0
  #define V7M_SCB_SCR			0x10
  #define V7M_SCB_SCR_SLEEPDEEP			(1 << 2)
 
@@ -42,3 +46,11 @@
   */
  #define EXC_RET_STACK_MASK			0x00000004
  #define EXC_RET_THREADMODE_PROCESSSTACK		0xfffffffd
+
+#ifndef __ASSEMBLY__
+
+enum reboot_mode;
Certainly worth introducing what the plans for this are in the long run - but I suspect the commit message might have contained that info?
arch/arm/kernel/common-v7m.c
Quoted 22 lines
arch/arm/include/asm/v7m.h +4 -0
+
+void armv7m_restart(enum reboot_mode mode, const char *cmd);
+
+#endif /* __ASSEMBLY__ */
arch/arm/kernel/Makefile +1 -1
index 86d10dd..688b8be 100644
@@ -24,7 +24,7 @@ obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
  obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
  ifeq ($(CONFIG_CPU_V7M),y)
-obj-y		+= entry-v7m.o
+obj-y		+= entry-v7m.o common-v7m.o
  else
  obj-y		+= entry-armv.o
  endif
arch/arm/kernel/common-v7m.c new file +0 -0
new file mode 100644
index 0000000..4d2cba9
Is this really the right place for such a function? My immediate thought is that such a thing belongs in proc-v7m.S

Quoted 2 lines

Quoted 1 line
Is this fitting in to a an existing framework or pattern that I'm missing?
proc-v7m.S doesn't work as my function is coded in C :-)

Well, what you have at the moment is in C, but it certainly could be asm, might even be easier to read as asm ;)

That said, everyone else uses C, so there should be a place for it to go...

Quoted 11 lines

Here are some other restart functions with the file they are defined in:

davinci_restart   | arch/arm/mach-davinci/devices.c
exynos4_restart   | arch/arm/mach-exynos/common.c
highbank_restart  | arch/arm/mach-highbank/system.c
mxc_restart       | arch/arm/mach-imx/system.c
omap3xxx_restart  | arch/arm/mach-omap2/omap3-restart.c
pxa_restart       | arch/arm/mach-pxa/reset.c
versatile_restart | arch/arm/mach-versatile/core.c

Quoted 3 lines

at91 doesn't seem to have a restart function.
Hmm, I'm still happy with arch/arm/kernel/common-v7m.c.

What else might go in that file in time? It certainly breaks the pattern we see above - but then this is architectural not machine defined in V7M so that also makes sense...

How about arch/arm/kernel/v7m.c instead?

Quoted 11 lines

arch/arm/kernel/common-v7m.c new file +9 -0

@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2013 Uwe Kleine-Koenig for Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation.
+ */
+#include <linux/io.h>
+#include <linux/reboot.h>

Quoted 8 lines

arch/arm/kernel/common-v7m.c line 17

Quoted 8 lines

arch/arm/kernel/common-v7m.c new file +8 -0

+#include <asm/barrier.h>
+#include <asm/v7m.h>
+
+void armv7m_restart(enum reboot_mode mode, const char *cmd)
+{
+	dsb();
+	__raw_writel(V7M_SCB_AIRCR_VECTKEY | V7M_SCB_AIRCR_SYSRESETREQ,
+			BASEADDR_V7M_SCB + V7M_SCB_AIRCR);

Are we definitely okay to ignore that reboot_mode value? I'm not sure what I would expect REBOOT_GPIO to mean in this case? or even the difference between REBOOT_SOFT? I think it looks like we can (certainly other people do!)

Jonny