[U-Boot] [PATCH v1 2/2] x86: zImage: Propagate acpi_rsdp_addr to kernel via boot parameters

[Bin Meng]

Hi Andy,

On Thu, Jan 11, 2018 at 1:40 AM, Andy Shevchenko
<andriy.shevchenko at linux.intel.com> wrote:
> New field acpi_rsdp_addr, which has been introduced in boot protocol
> v2.14 [1], in boot parameters tells kernel the exact address of RDSP
> ACPI table. Knowing it increases robustness of the kernel by avoiding
> in some cases traversal through a part of physical memory.
> It will slightly reduce boot time by the same reason.
>
> [1] See Linux kernel commit
>
>   2f74cbf947f4 ("x86/boot: Add the ACPI RSDP address to struct setup_header::acpi_rdsp_addr")

I don't see this commit id in my linux tree. Is this in some custodian's tree?

>
> for the details.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
> ---
>  arch/x86/include/asm/bootparam.h |  1 +
>  arch/x86/lib/acpi_table.c        |  7 +++++++
>  arch/x86/lib/acpi_table.h        | 10 ++++++++++
>  arch/x86/lib/zimage.c            |  6 ++++++
>  4 files changed, 24 insertions(+)
>  create mode 100644 arch/x86/lib/acpi_table.h
>
> diff --git a/arch/x86/include/asm/bootparam.h b/arch/x86/include/asm/bootparam.h
> index 48b138c6b0..90768a99ce 100644
> --- a/arch/x86/include/asm/bootparam.h
> +++ b/arch/x86/include/asm/bootparam.h
> @@ -66,6 +66,7 @@ struct setup_header {
>         __u64   pref_address;
>         __u32   init_size;
>         __u32   handover_offset;
> +       __u64   acpi_rsdp_addr;
>  } __attribute__((packed));
>
>  struct sys_desc_table {
> diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
> index 7b33cd371e..45bfc111ef 100644
> --- a/arch/x86/lib/acpi_table.c
> +++ b/arch/x86/lib/acpi_table.c
> @@ -20,6 +20,7 @@
>  #include <asm/mpspec.h>
>  #include <asm/tables.h>
>  #include <asm/arch/global_nvs.h>
> +#include "acpi_table.h"
>
>  /*
>   * IASL compiles the dsdt entries and writes the hex values
> @@ -27,6 +28,11 @@
>   */
>  extern const unsigned char AmlCode[];
>
> +/*
> + * ACPI RSDP address to be used in boot parameters.
> + */

nits: use single line comment format without the ending .

> +unsigned long acpi_rsdp_addr;
> +
>  static void acpi_write_rsdp(struct acpi_rsdp *rsdp, struct acpi_rsdt *rsdt,
>                             struct acpi_xsdt *xsdt)
>  {
> @@ -460,6 +466,7 @@ ulong write_acpi_tables(ulong start)
>
>         debug("current = %x\n", current);
>
> +       acpi_rsdp_addr = (unsigned long)rsdp;
>         debug("ACPI: done\n");
>
>         /* Don't touch ACPI hardware on HW reduced platforms */
> diff --git a/arch/x86/lib/acpi_table.h b/arch/x86/lib/acpi_table.h
> new file mode 100644
> index 0000000000..cece5d1420
> --- /dev/null
> +++ b/arch/x86/lib/acpi_table.h
> @@ -0,0 +1,10 @@
> +/*
> + * SPDX-License-Identifier:    GPL-2.0
> + */
> +
> +#ifndef _X86_LIB_ACPI_TABLES_H
> +#define _X86_LIB_ACPI_TABLES_H
> +
> +extern unsigned long acpi_rsdp_addr;
> +
> +#endif
> diff --git a/arch/x86/lib/zimage.c b/arch/x86/lib/zimage.c
> index d224db4e07..eae26635b1 100644
> --- a/arch/x86/lib/zimage.c
> +++ b/arch/x86/lib/zimage.c
> @@ -24,6 +24,7 @@
>  #include <asm/arch/timestamp.h>
>  #endif
>  #include <linux/compiler.h>
> +#include "acpi_table.h"
>
>  DECLARE_GLOBAL_DATA_PTR;
>
> @@ -255,6 +256,11 @@ int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
>                 hdr->hardware_subarch = X86_SUBARCH_INTEL_MID;
>  #endif
>
> +#ifdef CONFIG_GENERATE_ACPI_TABLE
> +       if (bootproto >= 0x020e)
> +               hdr->acpi_rsdp_addr = acpi_rsdp_addr;
> +#endif
> +
>         setup_video(&setup_base->screen_info);
>
>         return 0;
> --

Other than the above nits,
Reviewed-by: Bin Meng <bmeng.cn at gmail.com>

I can fix the nits when applying if you like.

Regards,
Bin