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Re: [PATCH 03/18] MIPS: add generic support for multiple machines within

To: Gabor Juhos <juhosg@openwrt.org>, Felix Fietkau <nbd@openwrt.org>
Subject: Re: [PATCH 03/18] MIPS: add generic support for multiple machines within a single kernel
From: Arnaud Lacombe <lacombar@gmail.com>
Date: Tue, 23 Nov 2010 13:29:49 -0500
Cc: Ralf Baechle <ralf@linux-mips.org>, linux-mips@linux-mips.org, kaloz@openwrt.org, "Luis R. Rodriguez" <lrodriguez@atheros.com>, Cliff Holden <Cliff.Holden@atheros.com>
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In-reply-to: <1290524800-21419-4-git-send-email-juhosg@openwrt.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1290524800-21419-1-git-send-email-juhosg@openwrt.org> <1290524800-21419-4-git-send-email-juhosg@openwrt.org>
Sender: linux-mips-bounce@linux-mips.org
Hi,

On Tue, Nov 23, 2010 at 10:06 AM, Gabor Juhos <juhosg@openwrt.org> wrote:
> This patch adds a generic solution to support multiple machines based on
> a given SoC within a single kernel image. It is implemented already for
> several other architectures but MIPS has no generic support for that yet.
>
Is this the way `arch/mips' wants to go to support multiple machine
within a same kernel image ? Flattened Device Tree is the other way to
achieve that. I remind the latter being proposed by Felix Fietkau on
#openwrt.

Thanks,
 - Arnaud

> Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
> ---
>
> Changes since RFC: ---
>
>  arch/mips/Kconfig                    |    3 +
>  arch/mips/include/asm/mips_machine.h |   54 +++++++++++++++++++++
>  arch/mips/kernel/Makefile            |    1 +
>  arch/mips/kernel/mips_machine.c      |   86 
> ++++++++++++++++++++++++++++++++++
>  arch/mips/kernel/proc.c              |    7 ++-
>  arch/mips/kernel/vmlinux.lds.S       |    7 +++
>  6 files changed, 157 insertions(+), 1 deletions(-)
>  create mode 100644 arch/mips/include/asm/mips_machine.h
>  create mode 100644 arch/mips/kernel/mips_machine.c
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index ec69df5..307c2e4 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -899,6 +899,9 @@ config MIPS_DISABLE_OBSOLETE_IDE
>  config SYNC_R4K
>        bool
>
> +config MIPS_MACHINE
> +       def_bool n
> +
>  config NO_IOPORT
>        def_bool n
>
> diff --git a/arch/mips/include/asm/mips_machine.h 
> b/arch/mips/include/asm/mips_machine.h
> new file mode 100644
> index 0000000..363bb35
> --- /dev/null
> +++ b/arch/mips/include/asm/mips_machine.h
> @@ -0,0 +1,54 @@
> +/*
> + *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
> + *
> + *  This program is free software; you can redistribute it and/or modify it
> + *  under the terms of the GNU General Public License version 2 as published
> + *  by the Free Software Foundation.
> + *
> + */
> +
> +#ifndef __ASM_MIPS_MACHINE_H
> +#define __ASM_MIPS_MACHINE_H
> +
> +#include <linux/init.h>
> +#include <linux/stddef.h>
> +
> +#include <asm/bootinfo.h>
> +
> +struct mips_machine {
> +       unsigned long           mach_type;
> +       const char              *mach_id;
> +       const char              *mach_name;
> +       void                    (*mach_setup)(void);
> +};
> +
> +#define MIPS_MACHINE(_type, _id, _name, _setup)                        \
> +static const char machine_name_##_type[] __initconst           \
> +                       __aligned(1) = _name;                   \
> +static const char machine_id_##_type[] __initconst             \
> +                       __aligned(1) = _id;                     \
> +static struct mips_machine machine_##_type                     \
> +               __used __section(.mips.machines.init) =         \
> +{                                                              \
> +       .mach_type      = _type,                                \
> +       .mach_id        = machine_id_##_type,                   \
> +       .mach_name      = machine_name_##_type,                 \
> +       .mach_setup     = _setup,                               \
> +};
> +
> +extern long __mips_machines_start;
> +extern long __mips_machines_end;
> +
> +#ifdef CONFIG_MIPS_MACHINE
> +int  mips_machtype_setup(char *id) __init;
> +void mips_machine_setup(void) __init;
> +void mips_set_machine_name(const char *name) __init;
> +char *mips_get_machine_name(void);
> +#else
> +static inline int mips_machtype_setup(char *id) { return 1; }
> +static inline void mips_machine_setup(void) { }
> +static inline void mips_set_machine_name(const char *name) { }
> +static inline char *mips_get_machine_name(void) { return NULL; }
> +#endif /* CONFIG_MIPS_MACHINE */
> +
> +#endif /* __ASM_MIPS_MACHINE_H */
> diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
> index 22b2e0e..3977397 100644
> --- a/arch/mips/kernel/Makefile
> +++ b/arch/mips/kernel/Makefile
> @@ -95,6 +95,7 @@ obj-$(CONFIG_GPIO_TXX9)               += gpio_txx9.o
>  obj-$(CONFIG_KEXEC)            += machine_kexec.o relocate_kernel.o
>  obj-$(CONFIG_EARLY_PRINTK)     += early_printk.o
>  obj-$(CONFIG_SPINLOCK_TEST)    += spinlock_test.o
> +obj-$(CONFIG_MIPS_MACHINE)     += mips_machine.o
>
>  obj-$(CONFIG_OF)               += prom.o
>
> diff --git a/arch/mips/kernel/mips_machine.c b/arch/mips/kernel/mips_machine.c
> new file mode 100644
> index 0000000..411a058
> --- /dev/null
> +++ b/arch/mips/kernel/mips_machine.c
> @@ -0,0 +1,86 @@
> +/*
> + *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
> + *
> + *  This program is free software; you can redistribute it and/or modify it
> + *  under the terms of the GNU General Public License version 2 as published
> + *  by the Free Software Foundation.
> + *
> + */
> +#include <linux/mm.h>
> +#include <linux/string.h>
> +#include <linux/slab.h>
> +
> +#include <asm/mips_machine.h>
> +
> +static struct mips_machine *mips_machine __initdata;
> +static char *mips_machine_name = "Unknown";
> +
> +#define for_each_machine(mach) \
> +       for ((mach) = (struct mips_machine *)&__mips_machines_start; \
> +            (mach) && \
> +            (unsigned long)(mach) < (unsigned long)&__mips_machines_end; \
> +            (mach)++)
> +
> +__init void mips_set_machine_name(const char *name)
> +{
> +       char *p;
> +
> +       if (name == NULL)
> +               return;
> +
> +       p = kstrdup(name, GFP_KERNEL);
> +       if (!p)
> +               pr_err("MIPS: no memory for machine_name\n");
> +
> +       mips_machine_name = p;
> +}
> +
> +char *mips_get_machine_name(void)
> +{
> +       return mips_machine_name;
> +}
> +
> +__init int mips_machtype_setup(char *id)
> +{
> +       struct mips_machine *mach;
> +
> +       for_each_machine(mach) {
> +               if (mach->mach_id == NULL)
> +                       continue;
> +
> +               if (strcmp(mach->mach_id, id) == 0) {
> +                       mips_machtype = mach->mach_type;
> +                       return 0;
> +               }
> +       }
> +
> +       pr_err("MIPS: no machine found for id '%s', supported machines:\n", 
> id);
> +       pr_err("%-24s %s\n", "id", "name");
> +       for_each_machine(mach)
> +               pr_err("%-24s %s\n", mach->mach_id, mach->mach_name);
> +
> +       return 1;
> +}
> +
> +__setup("machtype=", mips_machtype_setup);
> +
> +__init void mips_machine_setup(void)
> +{
> +       struct mips_machine *mach;
> +
> +       for_each_machine(mach) {
> +               if (mips_machtype == mach->mach_type) {
> +                       mips_machine = mach;
> +                       break;
> +               }
> +       }
> +
> +       if (!mips_machine)
> +               return;
> +
> +       mips_set_machine_name(mips_machine->mach_name);
> +       pr_info("MIPS: machine is %s\n", mips_machine_name);
> +
> +       if (mips_machine->mach_setup)
> +               mips_machine->mach_setup();
> +}
> diff --git a/arch/mips/kernel/proc.c b/arch/mips/kernel/proc.c
> index 26109c4..4195abb 100644
> --- a/arch/mips/kernel/proc.c
> +++ b/arch/mips/kernel/proc.c
> @@ -12,6 +12,7 @@
>  #include <asm/cpu-features.h>
>  #include <asm/mipsregs.h>
>  #include <asm/processor.h>
> +#include <asm/mips_machine.h>
>
>  unsigned int vced_count, vcei_count;
>
> @@ -31,8 +32,12 @@ static int show_cpuinfo(struct seq_file *m, void *v)
>        /*
>         * For the first processor also print the system type
>         */
> -       if (n == 0)
> +       if (n == 0) {
>                seq_printf(m, "system type\t\t: %s\n", get_system_type());
> +               if (mips_get_machine_name())
> +                       seq_printf(m, "machine\t\t\t: %s\n",
> +                                  mips_get_machine_name());
> +       }
>
>        seq_printf(m, "processor\t\t: %ld\n", n);
>        sprintf(fmt, "cpu model\t\t: %%s V%%d.%%d%s\n",
> diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
> index f25df73..570607b 100644
> --- a/arch/mips/kernel/vmlinux.lds.S
> +++ b/arch/mips/kernel/vmlinux.lds.S
> @@ -98,6 +98,13 @@ SECTIONS
>        INIT_TEXT_SECTION(PAGE_SIZE)
>        INIT_DATA_SECTION(16)
>
> +       . = ALIGN(4);
> +       .mips.machines.init : AT(ADDR(.mips.machines.init) - LOAD_OFFSET) {
> +               __mips_machines_start = .;
> +               *(.mips.machines.init)
> +               __mips_machines_end = .;
> +       }
> +
>        /* .exit.text is discarded at runtime, not link time, to deal with
>         * references from .rodata
>         */
> --
> 1.7.2.1
>
>
>

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