[PATCH 0/4] arm/versatile: no-MMU support

[PATCH 0/4] arm/versatile: no-MMU support

[Greg Ungerer]

The following patches support configuring and building the versatile
machine with a no-MMU kernel.

There is only a minor few changes required. It was previously possible
in older kernels to build for versatile with CONFIG_MMU disabled, but
the change to devicetree lost that capability. These changes make it
possible again.

One patch is a fix for address translation (broken on older kernels too),
two are build problems when CONFIG_MMU is disabled, and the last is the
actuall configuration changes needed.

The motivation for this is that the versatile machine is well supported
in qemu. And this provides an excellent platform for development and
testing no-MMU support on ARM in general. With these patches applied
it is possible to build and run a kernel with MMU disabled on qemu.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
 arch/arm/Kconfig                       |   10 ++++++++++
 arch/arm/Kconfig.debug                 |    3 ++-
 arch/arm/include/asm/mach/map.h        |    1 +
 arch/arm/mach-versatile/Kconfig        |    3 ++-
 arch/arm/mach-versatile/Makefile.boot  |    3 +++
 arch/arm/mach-versatile/versatile_dt.c |    4 ++++
 6 files changed, 22 insertions(+), 2 deletions(-)

[PATCH 1/4] arm/versatile: support no-MMU mode addressing

[Greg Ungerer]

Currently for the versatile boards the IO_ADDRESS() macro applies static
virtual address mapping for built-in IO devices. When operating without
the MMU enabled IO devices are accessed at their physical address, no
address translation is required.

For the !CONFIG_MMU case then define the IO_ADDRESS() macro to return the
physical address.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
 arch/arm/mach-versatile/versatile_dt.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/mach-versatile/versatile_dt.c b/arch/arm/mach-versatile/versatile_dt.c
index 3c8d39c..8cfa05a 100644
--- a/arch/arm/mach-versatile/versatile_dt.c
+++ b/arch/arm/mach-versatile/versatile_dt.c
@@ -37,7 +37,11 @@
 #include <asm/mach/map.h>
 
 /* macro to get at MMIO space when running virtually */
+#ifdef CONFIG_MMU
 #define IO_ADDRESS(x)		(((x) & 0x0fffffff) + (((x) >> 4) & 0x0f000000) + 0xf0000000)
+#else
+#define IO_ADDRESS(x)		(x)
+#endif
 #define __io_address(n)		((void __iomem __force *)IO_ADDRESS(n))
 
 /*
-- 
1.9.1

[PATCH 2/4] arm/versatile: define empty debug_ll_io_init() for no-MMU

[Greg Ungerer]

No-MMU configured targets have no definition for debug_ll_io_init().
Not all machines use this and it will only be required if CONFIG_DEBUG_LL
is enabled.

But when compiling for a target that uses it and it is configured for
no-MMU (!CONFIG_MMU), for example the versatile machine, you will get:

  CC      arch/arm/mach-versatile/versatile_dt.o
arch/arm/mach-versatile/versatile_dt.c: In function ?versatile_map_io?:
arch/arm/mach-versatile/versatile_dt.c:283:2: error: implicit declaration of function ?debug_ll_io_init? [-Werror=implicit-function-declaration]
  debug_ll_io_init();
  ^

Fix by adding a macro for it to the !CONFIG_MMU path in map.h.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
 arch/arm/include/asm/mach/map.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/include/asm/mach/map.h b/arch/arm/include/asm/mach/map.h
index 9b7c328..b1fe9c8 100644
--- a/arch/arm/include/asm/mach/map.h
+++ b/arch/arm/include/asm/mach/map.h
@@ -62,6 +62,7 @@ extern int ioremap_page(unsigned long virt, unsigned long phys,
 #else
 #define iotable_init(map,num)	do { } while (0)
 #define vm_reserve_area_early(a,s,c)	do { } while (0)
+#define debug_ll_io_init()	do { } while (0)
 #endif
 
 #endif
-- 
1.9.1

[PATCH 3/4] arm/versatile: empty Makefile.boot needed for no-MMU compile

[Greg Ungerer]

To compile the arm versatile board with the MMU disabled (!CONFIG_MMU)
a Makefile.boot is required. Without it you get:

  SYSMAP  System.map
arch/arm/boot/Makefile:15: arch/arm/mach-versatile//Makefile.boot: No such file or directory
make[2]: *** No rule to make target `arch/arm/mach-versatile//Makefile.boot'.  Stop.

Create an empty Makefile.boot for the versatile machine. This is a
copy of the other empty machine Makefile.boot files. (A few have this
same commented empty file: stm32, ep93xx, lpc18xx, efm32 and vexpress).

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
 arch/arm/mach-versatile/Makefile.boot | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 arch/arm/mach-versatile/Makefile.boot

diff --git a/arch/arm/mach-versatile/Makefile.boot b/arch/arm/mach-versatile/Makefile.boot
new file mode 100644
index 0000000..eacfc3f
--- /dev/null
+++ b/arch/arm/mach-versatile/Makefile.boot
@@ -0,0 +1,3 @@
+# Empty file waiting for deletion once Makefile.boot isn't needed any more.
+# Patch waits for application at
+# http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=7889/1 .
-- 
1.9.1

[PATCH 4/4] arm/versatile: support configuring versatile machine for no-MMU

[Greg Ungerer]

Allow the arm versatile machine to be configured for no-MMU operation.
The approach taken is similar to the support for no-MMU arm v7 machines.

A new define, CONFIG_ARM_SINGLE_ARMV5, is used to enable a class of v5
core based machines that are supported for building with !CONFIG_MMU.
Currently only the versatile machine is configured to support this.

Older kernels had the ability to build the versatile machine with the MMU
disabled (!CONFIG_MMU). Recent changes to convert the versatile machine
to device tree lost this ability. (Although older kernels could be built
they did not run due to a bug in the IO_ADDRESS() mapping on this machine).

The motivation for this is that the versatile machine is well supported
in qemu. And this provides an excellent platform for development and
testing no-MMU support on ARM in general.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
 arch/arm/Kconfig                | 10 ++++++++++
 arch/arm/Kconfig.debug          |  3 ++-
 arch/arm/mach-versatile/Kconfig |  3 ++-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a9c4e48..f44fe7b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -353,6 +353,16 @@ config ARM_SINGLE_ARMV7M
 	select SPARSE_IRQ
 	select USE_OF
 
+config ARM_SINGLE_ARMV5
+	bool "ARMv5 based platforms (ARM926T)"
+	depends on !MMU
+	select AUTO_ZRELADDR
+	select CLKSRC_OF
+	select COMMON_CLK
+	select GENERIC_CLOCKEVENTS
+	select SPARSE_IRQ
+	select USE_OF
+
 config ARCH_GEMINI
 	bool "Cortina Systems Gemini"
 	select CLKSRC_MMIO
diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index a9693b6..9897348 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -1712,7 +1712,8 @@ config DEBUG_UNCOMPRESS
 config UNCOMPRESS_INCLUDE
 	string
 	default "debug/uncompress.h" if ARCH_MULTIPLATFORM || ARCH_MSM || \
-					PLAT_SAMSUNG || ARM_SINGLE_ARMV7M
+					PLAT_SAMSUNG || ARM_SINGLE_ARMV7M || \
+					ARM_SINGLE_ARMV5
 	default "mach/uncompress.h"
 
 config EARLY_PRINTK
diff --git a/arch/arm/mach-versatile/Kconfig b/arch/arm/mach-versatile/Kconfig
index b0cc262..904a012 100644
--- a/arch/arm/mach-versatile/Kconfig
+++ b/arch/arm/mach-versatile/Kconfig
@@ -1,6 +1,6 @@
 config ARCH_VERSATILE
 	bool "ARM Ltd. Versatile family"
-	depends on ARCH_MULTI_V5
+	depends on ARCH_MULTI_V5 || ARM_SINGLE_ARMV5
 	select ARM_AMBA
 	select ARM_TIMER_SP804
 	select ARM_VIC
@@ -14,6 +14,7 @@ config ARCH_VERSATILE
 	select POWER_RESET
 	select POWER_RESET_VERSATILE
 	select VERSATILE_FPGA_IRQ
+	select GPIOLIB
 	help
 	  This enables support for ARM Ltd Versatile board.
 
-- 
1.9.1