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author | Arnd Bergmann <arnd@arndb.de> | 2013-01-31 17:51:18 +0000 |
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committer | Arnd Bergmann <arnd@arndb.de> | 2013-04-29 21:56:57 +0200 |
commit | 883a106b0866ca8d75b5520bdb3ca1cf8e3730ba (patch) | |
tree | 7145ae6e3d0ced8e04f544535d1bfc63600df252 /arch/arm/kernel | |
parent | 0682edaaa32c778ad2efac73fe3c8d9309e35991 (diff) | |
download | op-kernel-dev-883a106b0866ca8d75b5520bdb3ca1cf8e3730ba.zip op-kernel-dev-883a106b0866ca8d75b5520bdb3ca1cf8e3730ba.tar.gz |
ARM: default machine descriptor for multiplatform
Since we now have default implementations for init_time and init_irq,
the init_machine callback is the only one that is not yet optional,
but since simple DT based platforms all have the same
of_platform_populate function call in there, we can consolidate them
as well, and then actually boot with a completely empty machine_desc.
Unofortunately we cannot just default to an empty init_machine: We
cannot call of_platform_populate before init_machine because that
does not work in case of auxdata, and we cannot call it after
init_machine either because the machine might need to run code
after adding the devices.
To take the final step, this adds support for booting without defining
any machine_desc whatsoever.
For the case that CONFIG_MULTIPLATFORM is enabled, it adds a
global machine descriptor that never matches any machine but is
used as a fallback if nothing else matches. We assume that without
CONFIG_MULTIPLATFORM, we only want to boot on the systems that the kernel
is built for, so we still retain the build-time warning for missing
machine descriptors and the run-time warning when the platform does not
match in that case.
In the case that we run on a multiplatform kernel and the machine
provides a fully populated device tree, we attempt to keep booting,
hoping that no machine specific callbacks are necessary.
Finally, this also removes the misguided "select ARCH_VEXPRESS" that
was only added to avoid a build error for allnoconfig kernels.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Cc: "Russell King - ARM Linux" <linux@arm.linux.org.uk>
Cc: Rob Herring <robherring2@gmail.com>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r-- | arch/arm/kernel/devtree.c | 7 | ||||
-rw-r--r-- | arch/arm/kernel/setup.c | 13 |
2 files changed, 19 insertions, 1 deletions
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 70f1bde..5af04f6 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -180,6 +180,13 @@ struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys) unsigned long dt_root; const char *model; +#ifdef CONFIG_ARCH_MULTIPLATFORM + DT_MACHINE_START(GENERIC_DT, "Generic DT based system") + MACHINE_END + + mdesc_best = (struct machine_desc *)&__mach_desc_GENERIC_DT; +#endif + if (!dt_phys) return NULL; diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 3f6cbb2..08a627b 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -18,6 +18,7 @@ #include <linux/bootmem.h> #include <linux/seq_file.h> #include <linux/screen_info.h> +#include <linux/of_platform.h> #include <linux/init.h> #include <linux/kexec.h> #include <linux/of_fdt.h> @@ -640,9 +641,19 @@ struct screen_info screen_info = { static int __init customize_machine(void) { - /* customizes platform devices, or adds new ones */ + /* + * customizes platform devices, or adds new ones + * On DT based machines, we fall back to populating the + * machine from the device tree, if no callback is provided, + * otherwise we would always need an init_machine callback. + */ if (machine_desc->init_machine) machine_desc->init_machine(); +#ifdef CONFIG_OF + else + of_platform_populate(NULL, of_default_bus_match_table, + NULL, NULL); +#endif return 0; } arch_initcall(customize_machine); |