Re: [PATCH TIP 02/14] x86: Add device tree support

[Sebastian Andrzej Siewior]

Grant Likely wrote:
> Hi Sebastian,
Hi Grant,

> Relatively minor comments below.  You can go ahead and add the
> following when you respin:
>
> Acked-by: Grant Likely <grant.likely@xxxxxxxxxxxx>

Cool.

> > 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
>
> Please also add a brief description to section I of
> Documentation/devicetree/booting-without-of.txt

I assumed this file is powerpc only. Since you added arm there I have no
problem to move this content there.

> > diff --git a/arch/x86/include/asm/prom.h b/arch/x86/include/asm/prom.h
> > index b4ec95f..b227ba7 100644
> > --- a/arch/x86/include/asm/prom.h
> > +++ b/arch/x86/include/asm/prom.h
> > @@ -1 +1,59 @@
> > -/* dummy prom.h; here to make linux/of.h's #includes happy */
> > +/*
> > + * 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		(0)
>
> This line should no longer be necessary.  drivers/of/irq.c defines
> NO_IRQ if it isn't already defined by the architecture.  I'm trying to
> limit the exposure of NO_IRQ in dt code.

okay, I will to remove that.

> > +#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>
>
> You should be able to remove these includes.  The problems described
> in the header are mostly with device drivers and architecture code.
> You shouldn't run into any of those issue, and if you do they should
> be fixed at the source.
okay.

> > 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>
>
> I'm probably missing something.  I don't see any changes to irqinit.c
> other than this.  What symbol definition has been moved to prom.h that
> irqinit.c needs?

This hunk was folded into the wrong patch. It should been folded into
"x86/ioapic: Add OF bindings for IO-APIC".

> >  /*
> >   * 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..4969ffa
> > --- /dev/null
> > +++ b/arch/x86/kernel/prom.c
>
> You don't need to name this prom.c.  devicetree.c would make more sense.
> prom is a legacy name from when only Open Firmware systems were using
> the dt code.

okay.

> > @@ -0,0 +1,51 @@

> > +
> > +void __init add_dtb(u64 data)
> > +{
> > +	initial_boot_params = (struct boot_param_header *)
> > +		phys_to_virt((u64) (u32) data +
> > +				offsetof(struct setup_data, data));
>
> (struct boot_param_header *) cast unnecessary since phys_to_virt
> should return a void*.

removed.

> > +}

Sebastian
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/