Re: [Qemu-devel] [PATCH v2 01/47] acpi: introduce AML composer aml_append()

[Igor Mammedov]

On Fri, 23 Jan 2015 10:11:19 +0200
"Michael S. Tsirkin" <address@hidden> wrote:

> On Thu, Jan 22, 2015 at 02:49:45PM +0000, Igor Mammedov wrote:
> > Adds for dynamic AML creation, which will be used
> > for piecing ASL/AML primitives together and hiding
> > from user/caller details about how nested context
> > should be closed/packed leaving less space for
> > mistakes and necessity to know how AML should be
> > encoded, allowing user to concentrate on ASL
> > representation instead.
> > 
> > For example it will allow to create AML like this:
> > 
> > AcpiAml scope = acpi_scope("PCI0")
> > AcpiAml dev = acpi_device("PM")
> >     aml_append(&dev, acpi_name_decl("_ADR", acpi_int(addr)))
> > aml_append(&scope, dev);
> > 
> > Signed-off-by: Igor Mammedov <address@hidden>
> > ---
> >  hw/acpi/acpi-build-utils.c         | 39 
> > ++++++++++++++++++++++++++++++++++++++
> >  include/hw/acpi/acpi-build-utils.h | 16 ++++++++++++++++
> >  2 files changed, 55 insertions(+)
> > 
> > diff --git a/hw/acpi/acpi-build-utils.c b/hw/acpi/acpi-build-utils.c
> > index 602e68c..547ecaa 100644
> > --- a/hw/acpi/acpi-build-utils.c
> > +++ b/hw/acpi/acpi-build-utils.c
> > @@ -267,3 +267,42 @@ void build_append_int(GArray *table, uint32_t value)
> >          build_append_value(table, value, 4);
> >      }
> >  }
> > +
> > +static void build_prepend_int(GArray *array, uint32_t value)
> > +{
> > +    GArray *data = build_alloc_array();
> > +
> > +    build_append_int(data, value);
> > +    g_array_prepend_vals(array, data->data, data->len);
> > +    build_free_array(data);
> > +}
> 
> I don't think prepend is generally justified:
> it makes code hard to follow and debug.
> 
> Adding length is different: of course you need
> to first have the package before you can add length.
> 
> We currently have build_prepend_package_length - just move it
> to utils, and use everywhere.
[...]
> > +    case BUFFER:
> > +        build_prepend_int(child.buf, child.buf->len);
> > +        build_package(child.buf, child.op);
Buffer uses the same concept as package, but adds its own additional length.
Therefore I've added build_prepend_int(),
I can create build_buffer() and mimic build_package()
but it won't change picture.

As for moving to to another file, during all this series lowlevel
build_(some_aml_related_costruct_helper)s are moved into this file
and should be make static to hide from user lowlevel helpers
(including build_package).
That will leave only high level API available.

TODO for me: make sure that moved lowlevel helpers are static


> > +        break;
> > +    default:
> > +        break;
> > +    }
> > +    build_append_array(parent_ctx->buf, child.buf);
> > +    build_free_array(child.buf);
> > +}
> > diff --git a/include/hw/acpi/acpi-build-utils.h 
> > b/include/hw/acpi/acpi-build-utils.h
> > index 199f003..64e7ec3 100644
> > --- a/include/hw/acpi/acpi-build-utils.h
> > +++ b/include/hw/acpi/acpi-build-utils.h
> > @@ -5,6 +5,22 @@
> >  #include <glib.h>
> >  #include "qemu/compiler.h"
> >  
> > +typedef enum {
> > +    NON_BLOCK,
> > +    PACKAGE,
> > +    EXT_PACKAGE,
> > +    BUFFER,
> > +    RES_TEMPLATE,
> > +} AcpiBlockFlags;
> > +
> > +typedef struct AcpiAml {
> > +    GArray *buf;
> > +    uint8_t op;
> > +    AcpiBlockFlags block_flags;
> > +} AcpiAml;
> > +
> > +void aml_append(AcpiAml *parent_ctx, AcpiAml child);
> > +
> >  GArray *build_alloc_array(void);
> >  void build_free_array(GArray *array);
> >  void build_prepend_byte(GArray *array, uint8_t val);
> > -- 
> > 1.8.3.1