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

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Fri, 2018-01-12 at 17:00 +0800, Bin Meng wrote:
> Hi Andy,
> 
> On Thu, Jan 11, 2018 at 1:40 AM, Andy Shevchenko
> <andriy.shevchenko@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?

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=2
f74cbf947f45fa082dda8eac1a1f1299a372f49

> > for the details.
> > 
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@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 .

OK.

> 
> > +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@gmail.com>
> 
> I can fix the nits when applying if you like.

If you have a chance to do it soon, please, do, otherwise I would send a
new version later (next week I suppose).

Thanks!

> 
> Regards,
> Bin

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy