From 883a106b0866ca8d75b5520bdb3ca1cf8e3730ba Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 31 Jan 2013 17:51:18 +0000 Subject: [PATCH] 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 Acked-by: Nicolas Pitre Acked-by: Olof Johansson Cc: "Russell King - ARM Linux" Cc: Rob Herring --- arch/arm/Kconfig | 1 - arch/arm/kernel/devtree.c | 7 +++++++ arch/arm/kernel/setup.c | 13 ++++++++++++- 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 5bfd584929c8..f0f90f06f84b 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1014,7 +1014,6 @@ config ARCH_MULTI_V7 bool "ARMv7 based platforms (Cortex-A, PJ4, Krait)" default y select ARCH_MULTI_V6_V7 - select ARCH_VEXPRESS select CPU_V7 config ARCH_MULTI_V6_V7 diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 70f1bdeb241b..5af04f6daa33 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 3f6cbb2e3eda..08a627b61b7d 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -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); -- 2.30.2