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    Subject[PATCH 02/15] x86: Add device tree support
    Date
    This patch adds minimal support for device tree support on x86. It will
    be passed to the kernel via setup_data which requires atleast boot
    protocol 2.09.
    Memory size, restricted memory regions, boot arguments are gathered the
    traditional way so things like cmd_line are just here to let the code
    compile.
    The current plan is use the device tree as an extension and to gather
    informations from it which can not be enumerated and have to be
    hardcoded otherwise. This includes things like
    - which devices are on this I2C/ SPI bus?
    - how are the interrupts wired to IO APIC?
    - where could my hpet be?

    Cc: devicetree-discuss@lists.ozlabs.org
    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
    ---
    Documentation/x86/boot_with_dtb.txt | 26 +++++++++++++++
    arch/x86/Kconfig | 7 ++++
    arch/x86/include/asm/bootparam.h | 1 +
    arch/x86/include/asm/prom.h | 59 +++++++++++++++++++++++++++++++++++
    arch/x86/kernel/Makefile | 1 +
    arch/x86/kernel/irqinit.c | 1 +
    arch/x86/kernel/prom.c | 54 ++++++++++++++++++++++++++++++++
    arch/x86/kernel/setup.c | 4 ++
    8 files changed, 153 insertions(+), 0 deletions(-)
    create mode 100644 Documentation/x86/boot_with_dtb.txt
    create mode 100644 arch/x86/include/asm/prom.h
    create mode 100644 arch/x86/kernel/prom.c

    diff --git a/Documentation/x86/boot_with_dtb.txt b/Documentation/x86/boot_with_dtb.txt
    new file mode 100644
    index 0000000..6a357aa
    --- /dev/null
    +++ b/Documentation/x86/boot_with_dtb.txt
    @@ -0,0 +1,26 @@
    + Booting x86 with device tree
    +=================================
    +
    +1. Introduction
    +~~~~~~~~~~~~~~~
    +This document contains device tree information which are specific to
    +the x86 platform. Generic informations as bindings can be found in
    +Documentation/powerpc/dts-bindings/
    +
    +2. Passing the device tree
    +~~~~~~~~~~~~~~~~~~~~~~~~~~
    +The pointer to the device tree block (dtb) is passed via setup_data
    +(see [0]) which requires at least boot protocol 2.09. The type filed is
    +defined as
    +
    +#define SETUP_DTB 2
    +
    +3. Purpose
    +~~~~~~~~~~~
    +The device tree is used as an extension to the "boot page". As such it does not
    +parse / consider data which are already covered by the boot page. This includes
    +memory size, command line arguments or initrd address.
    +It simply holds information which can not be retrieved otherwise like interrupt
    +routing or a list of devices behind an I2C bus.
    +
    +[0] Documentation/x86/boot.txt
    diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
    index b6fccb0..0522354 100644
    --- a/arch/x86/Kconfig
    +++ b/arch/x86/Kconfig
    @@ -299,6 +299,13 @@ config X86_BIGSMP
    ---help---
    This option is needed for the systems that have more than 8 CPUs

    +config X86_OF
    + bool "Support for device tree"
    + select OF
    + select OF_FLATTREE
    + ---help---
    + Device tree support on X86.
    +
    if X86_32
    config X86_EXTENDED_PLATFORM
    bool "Support for extended (non-PC) x86 platforms"
    diff --git a/arch/x86/include/asm/bootparam.h b/arch/x86/include/asm/bootparam.h
    index c8bfe63..e020d88 100644
    --- a/arch/x86/include/asm/bootparam.h
    +++ b/arch/x86/include/asm/bootparam.h
    @@ -12,6 +12,7 @@
    /* setup data types */
    #define SETUP_NONE 0
    #define SETUP_E820_EXT 1
    +#define SETUP_DTB 2

    /* extensible setup data list node */
    struct setup_data {
    diff --git a/arch/x86/include/asm/prom.h b/arch/x86/include/asm/prom.h
    new file mode 100644
    index 0000000..2fbe3e8
    --- /dev/null
    +++ b/arch/x86/include/asm/prom.h
    @@ -0,0 +1,59 @@
    +/*
    + * Definitions for Device tree / OpenFirmware handling on X86
    + *
    + * based on arch/powerpc/include/asm/prom.h which is
    + * Copyright (C) 1996-2005 Paul Mackerras.
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License
    + * as published by the Free Software Foundation; either version
    + * 2 of the License, or (at your option) any later version.
    + */
    +
    +#ifndef _ASM_X86_PROM_H
    +#define _ASM_X86_PROM_H
    +#ifndef __ASSEMBLY__
    +
    +#include <linux/of.h>
    +#include <linux/types.h>
    +#include <asm/irq.h>
    +#include <asm/atomic.h>
    +#include <asm/setup.h>
    +
    +#ifdef CONFIG_OF
    +extern void add_dtb(u64 data);
    +#else
    +static inline void add_dtb(u64 data) { }
    +#endif
    +
    +extern char cmd_line[COMMAND_LINE_SIZE];
    +/* This number is used when no interrupt has been assigned */
    +#define NO_IRQ (-1)
    +
    +#define pci_address_to_pio pci_address_to_pio
    +unsigned long pci_address_to_pio(phys_addr_t addr);
    +
    +/**
    + * irq_dispose_mapping - Unmap an interrupt
    + * @virq: linux virq number of the interrupt to unmap
    + *
    + * FIXME: We really should implement proper virq handling like power,
    + * but that's going to be major surgery.
    + */
    +static inline void irq_dispose_mapping(unsigned int virq) { }
    +
    +#define HAVE_ARCH_DEVTREE_FIXUPS
    +
    +#endif /* __ASSEMBLY__ */
    +
    +/*
    + * These includes are put at the bottom because they may contain things
    + * that are overridden by this file. Ideally they shouldn't be included
    + * by this file, but there are a bunch of .c files that currently depend
    + * on it. Eventually they will be cleaned up.
    + */
    +#include <linux/of_fdt.h>
    +#include <linux/of_irq.h>
    +#include <linux/platform_device.h>
    +
    +#endif
    diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
    index f60153d..40bc33d 100644
    --- a/arch/x86/kernel/Makefile
    +++ b/arch/x86/kernel/Makefile
    @@ -108,6 +108,7 @@ obj-$(CONFIG_MICROCODE) += microcode.o
    obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o

    obj-$(CONFIG_SWIOTLB) += pci-swiotlb.o
    +obj-$(CONFIG_X86_OF) += prom.o

    ###
    # 64 bit specific files
    diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
    index c752e97..149c87f 100644
    --- a/arch/x86/kernel/irqinit.c
    +++ b/arch/x86/kernel/irqinit.c
    @@ -25,6 +25,7 @@
    #include <asm/setup.h>
    #include <asm/i8259.h>
    #include <asm/traps.h>
    +#include <asm/prom.h>

    /*
    * ISA PIC or low IO-APIC triggered (INTA-cycle or APIC) interrupts:
    diff --git a/arch/x86/kernel/prom.c b/arch/x86/kernel/prom.c
    new file mode 100644
    index 0000000..249ebd3
    --- /dev/null
    +++ b/arch/x86/kernel/prom.c
    @@ -0,0 +1,54 @@
    +/*
    + * Architecture specific OF callbacks.
    + */
    +#include <linux/bootmem.h>
    +#include <linux/io.h>
    +#include <linux/list.h>
    +#include <linux/of.h>
    +#include <linux/of_platform.h>
    +#include <linux/slab.h>
    +
    +char __initdata cmd_line[COMMAND_LINE_SIZE];
    +
    +unsigned int irq_create_of_mapping(struct device_node *controller,
    + const u32 *intspec, unsigned int intsize)
    +{
    + return intspec[0];
    +
    +}
    +EXPORT_SYMBOL_GPL(irq_create_of_mapping);
    +
    +unsigned long pci_address_to_pio(phys_addr_t address)
    +{
    + /*
    + * The ioport address can be directly used by inX / outX
    + */
    + BUG_ON(address >= (1 << 16));
    + return (unsigned long)address;
    +}
    +EXPORT_SYMBOL_GPL(pci_address_to_pio);
    +
    +void __init early_init_dt_scan_chosen_arch(unsigned long node)
    +{
    + BUG();
    +}
    +
    +void __init early_init_dt_add_memory_arch(u64 base, u64 size)
    +{
    + BUG();
    +}
    +
    +u64 __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
    +{
    + void *mem;
    +
    + mem = __alloc_bootmem(size, align, __pa(MAX_DMA_ADDRESS));
    + return virt_to_phys(mem);
    +}
    +
    +void __init add_dtb(u64 data)
    +{
    + initial_boot_params = (struct boot_param_header *)
    + phys_to_virt((u64) (u32) data +
    + offsetof(struct setup_data, data));
    +}
    diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
    index 577d06b..26f2c9a 100644
    --- a/arch/x86/kernel/setup.c
    +++ b/arch/x86/kernel/setup.c
    @@ -113,6 +113,7 @@
    #endif
    #include <asm/mce.h>
    #include <asm/alternative.h>
    +#include <asm/prom.h>

    /*
    * end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
    @@ -445,6 +446,9 @@ static void __init parse_setup_data(void)
    case SETUP_E820_EXT:
    parse_e820_ext(data);
    break;
    + case SETUP_DTB:
    + add_dtb(pa_data);
    + break;
    default:
    break;
    }
    --
    1.7.3.2


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