Re: [PATCH v2 06/41] arm/acpi : Add basic ACPI initialization

[Julien Grall <julien.grall@citrix.com>]

Hi Parth,

On 17/05/15 21:03, Parth Dixit wrote:
> acpi_boot_table_init() will be called in start_xen
> to get the RSDP and all the table pointers. with this patch,
> we can get ACPI boot-time tables from firmware on ARM64.
> 
> Signed-off-by: Naresh Bhat <naresh.bhat@linaro.org>
> Signed-off-by: Parth Dixit <parth.dixit@linaro.org>
> ---
>  xen/arch/arm/acpi/Makefile |  1 +
>  xen/arch/arm/acpi/boot.c   | 56 ++++++++++++++++++++++++++++++++++++++++++++++
>  xen/arch/arm/setup.c       | 13 +++++++++--
>  3 files changed, 68 insertions(+), 2 deletions(-)
>  create mode 100644 xen/arch/arm/acpi/boot.c
> 
> diff --git a/xen/arch/arm/acpi/Makefile b/xen/arch/arm/acpi/Makefile
> index b5be22d..196c40a 100644
> --- a/xen/arch/arm/acpi/Makefile
> +++ b/xen/arch/arm/acpi/Makefile
> @@ -1 +1,2 @@
>  obj-y += lib.o
> +obj-y += boot.o
> diff --git a/xen/arch/arm/acpi/boot.c b/xen/arch/arm/acpi/boot.c
> new file mode 100644
> index 0000000..8dc69d5
> --- /dev/null
> +++ b/xen/arch/arm/acpi/boot.c
> @@ -0,0 +1,56 @@
> +/*
> + *  ARM64 Specific Low-Level ACPI Boot Support

This code is not ARM64 specific:

s/ARM64/ARM/

> + *
> + *  Copyright (C) 2014, Naresh Bhat <naresh.bhat@linaro.org>

The code within this file is a copy of arch/x86/acpi/boot.c.

Please retain the copyright and add yours if necessary.

> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + *  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.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, write to the Free Software
> + *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + */
> +
> +#include <xen/init.h>
> +#include <xen/acpi.h>
> +
> +#include <asm/acpi.h>
> +
> +/*
> + * acpi_boot_table_init() called from setup_arch(), always.
> + *      1. find RSDP and get its address, and then find XSDT
> + *      2. extract all tables and checksums them all
> + *
> + * We can parse ACPI boot-time tables such as FADT, MADT after
> + * this function is called.

It's worth to expand the commit message as done in the x86 version
to explain the return value.

> + */
> +int __init acpi_boot_table_init(void)
> +{
> +    int error;
> +
> +    /* If acpi_disabled, bail out */
> +    if ( acpi_disabled )
> +        return 1;
> +
> +    /* Initialize the ACPI boot-time table parser. */
> +    error = acpi_table_init();

I didn't find a better place for this comment. Though it's related to
the ACPI initialization...

You need to change_acpi_os_get_root_pointer, the current behavior is to
fallback on the legacy method (i.e scanning the first MB of memory) when
efi_enabled 0.

> +    if ( error )
> +    {
> +        disable_acpi();
> +        return error;
> +    }
> +
> +    return 0;
> +}
> +
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 06f8e54..5711077 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -36,6 +36,7 @@
>  #include <xen/pfn.h>
>  #include <xen/vmap.h>
>  #include <xen/libfdt/libfdt.h>
> +#include <xen/acpi.h>
>  #include <asm/page.h>
>  #include <asm/current.h>
>  #include <asm/setup.h>
> @@ -45,10 +46,12 @@
>  #include <asm/procinfo.h>
>  #include <asm/setup.h>
>  #include <xsm/xsm.h>
> +#include <asm/acpi.h>
>  
>  struct bootinfo __initdata bootinfo;
>  
>  struct cpuinfo_arm __read_mostly boot_cpu_data;
> +bool_t acpi_disabled;
>  
>  #ifdef CONFIG_ARM_32
>  static unsigned long opt_xenheap_megabytes __initdata;
> @@ -610,7 +613,6 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
>      init_xenheap_pages(pfn_to_paddr(xenheap_mfn_start),
>                         pfn_to_paddr(boot_mfn_start));
>  
> -    end_boot_allocator();
>  }
>  #else /* CONFIG_ARM_64 */
>  static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
> @@ -680,7 +682,6 @@ static void __init setup_mm(unsigned long dtb_paddr, size_t dtb_size)
>      setup_frametable_mappings(ram_start, ram_end);
>      max_page = PFN_DOWN(ram_end);
>  
> -    end_boot_allocator();

You need to explain in the commit message why this is necessary (see [1]).

Anybody who didn't follow/remember the thread will think this is wrong...

>  }
>  #endif
>  
> @@ -751,6 +752,14 @@ void __init start_xen(unsigned long boot_phys_offset,
>  
>      setup_mm(fdt_paddr, fdt_size);
>  
> +    /*
> +    * Parse the ACPI tables for possible boot-time configuration
> +    */

Coding style.

/*
 * Foo
 * bar
 */

Although the comment is fitting in a single line so
/* foo bar */

Bu

> +    if( !acpi_disabled )

The if is not necessary.

> +        acpi_boot_table_init();
> +
> +    end_boot_allocator();
> +
>      vm_init();
>      dt_unflatten_host_device_tree();
>  
> 

Regards,

[1]
http://lists.xenproject.org/archives/html/xen-devel/2015-02/msg01152.html

-- 
Julien Grall