Re: [Qemu-devel] [PATCH 08/13] spapr: Consolidate construction of /chosen device tree node

From: David Gibson <david@gibson.dropbear.id.au>
To: Thomas Huth <thuth@redhat.com>
Cc: aik@ozlabs.ru, mdroth@linux.vnet.ibm.com, groug@kaod.org,
	agraf@suse.de, lvivier@redhat.com, qemu-ppc@nongnu.org,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 08/13] spapr: Consolidate construction of /chosen device tree node
Date: Fri, 21 Oct 2016 12:41:43 +1100	[thread overview]
Message-ID: <20161021014142.GB3706@umbus.fritz.box> (raw)
In-Reply-To: <c6443ca3-02bd-346c-f533-aebe05b4a398@redhat.com>

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On Thu, Oct 20, 2016 at 09:49:42AM +0200, Thomas Huth wrote:
> On 20.10.2016 07:12, David Gibson wrote:
> > For historical reasons, building the /chosen node in the guest device tree
> > is split across several places and includes both parts which write the DT
> > sequentially and others which use random access functions.
> > 
> > This patch consolidates construction of the node into one place, using
> > random access functions throughout.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  hw/ppc/spapr.c             | 131 ++++++++++++++++++++++-----------------------
> >  hw/ppc/spapr_vio.c         |  17 ++----
> >  include/hw/ppc/spapr_vio.h |   2 +-
> >  3 files changed, 70 insertions(+), 80 deletions(-)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 2faae32..c608ec8 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -273,14 +273,10 @@ static void add_str(GString *s, const gchar *s1)
> >  
> >  static void *spapr_create_fdt_skel(sPAPRMachineState *spapr)
> >  {
> > -    MachineState *machine = MACHINE(spapr);
> >      void *fdt;
> > -    uint32_t start_prop = cpu_to_be32(spapr->initrd_base);
> > -    uint32_t end_prop = cpu_to_be32(spapr->initrd_base + spapr->initrd_size);
> >      GString *hypertas = g_string_sized_new(256);
> >      GString *qemu_hypertas = g_string_sized_new(256);
> >      uint32_t refpoints[] = {cpu_to_be32(0x4), cpu_to_be32(0x4)};
> > -    unsigned char vec5[] = {0x0, 0x0, 0x0, 0x0, 0x0, 0x80};
> >      char *buf;
> >  
> >      add_str(hypertas, "hcall-pft");
> > @@ -337,35 +333,6 @@ static void *spapr_create_fdt_skel(sPAPRMachineState *spapr)
> >      _FDT((fdt_property_cell(fdt, "#address-cells", 0x2)));
> >      _FDT((fdt_property_cell(fdt, "#size-cells", 0x2)));
> >  
> > -    /* /chosen */
> > -    _FDT((fdt_begin_node(fdt, "chosen")));
> > -
> > -    /* Set Form1_affinity */
> > -    _FDT((fdt_property(fdt, "ibm,architecture-vec-5", vec5, sizeof(vec5))));
> > -
> > -    _FDT((fdt_property_string(fdt, "bootargs", machine->kernel_cmdline)));
> > -    _FDT((fdt_property(fdt, "linux,initrd-start",
> > -                       &start_prop, sizeof(start_prop))));
> > -    _FDT((fdt_property(fdt, "linux,initrd-end",
> > -                       &end_prop, sizeof(end_prop))));
> > -    if (spapr->kernel_size) {
> > -        uint64_t kprop[2] = { cpu_to_be64(KERNEL_LOAD_ADDR),
> > -                              cpu_to_be64(spapr->kernel_size) };
> > -
> > -        _FDT((fdt_property(fdt, "qemu,boot-kernel", &kprop, sizeof(kprop))));
> > -        if (spapr->kernel_le) {
> > -            _FDT((fdt_property(fdt, "qemu,boot-kernel-le", NULL, 0)));
> > -        }
> > -    }
> > -    if (boot_menu) {
> > -        _FDT((fdt_property_cell(fdt, "qemu,boot-menu", boot_menu)));
> > -    }
> > -    _FDT((fdt_property_cell(fdt, "qemu,graphic-width", graphic_width)));
> > -    _FDT((fdt_property_cell(fdt, "qemu,graphic-height", graphic_height)));
> > -    _FDT((fdt_property_cell(fdt, "qemu,graphic-depth", graphic_depth)));
> > -
> > -    _FDT((fdt_end_node(fdt)));
> > -
> >      /* RTAS */
> >      _FDT((fdt_begin_node(fdt, "rtas")));
> >  
> > @@ -873,6 +840,68 @@ int spapr_h_cas_compose_response(sPAPRMachineState *spapr,
> >      return 0;
> >  }
> >  
> > +static void spapr_dt_chosen(sPAPRMachineState *spapr, void *fdt)
> > +{
> > +    MachineState *machine = MACHINE(spapr);
> > +    int chosen;
> > +    const char *boot_device = machine->boot_order;
> > +    char *stdout = spapr_vio_stdout_path(spapr->vio_bus);
> 
> Ah, by the way, calling a variable "stdout" like the FILE* from stdio.h
> feels somewhat wrong ... could you maybe use another name here instead?

Ah.. a very good idea.  Given the troubles I've seen with variables
called 'index' shadowing the standard library function, calling it
stdout is a terrible idea.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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