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    SubjectRe: [PATCH 02/15] x86: Add device tree support
    On Fri, Dec 17, 2010 at 04:33:40PM +0100, Sebastian Andrzej Siewior wrote:
    > 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>

    Mostly looks good. Some comments below.

    g.

    > ---
    > 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)

    0 means NO_IRQ on x86 and most architectures. I will change this when
    I pick up the patch.

    > +
    > +#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;

    Why is the physical address being passed in when the virtual address
    is needed to be stored in initial_boot_params by add_dtb()?


    > default:
    > break;
    > }
    > --
    > 1.7.3.2
    >
    > _______________________________________________
    > devicetree-discuss mailing list
    > devicetree-discuss@lists.ozlabs.org
    > https://lists.ozlabs.org/listinfo/devicetree-discuss


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