Re: [Xen-devel] [PATCH 2/4] xen: arm: parse modules from DT during early boot.

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Wed, 30 Jan 2013, Ian Campbell wrote:
> The bootloader should populate /chosen/modules/module@<N>/ for each
> module it wishes to pass to the hypervisor. The content of these nodes
> is described in docs/misc/arm/device-tree/booting.txt
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
> v6: Match based on compatibility instead of path
> v5: Moved later in the series
> v4: Use /chosen/modules/module@N
>     Identify module type by compatible property not number.
> v3: Use a reg = < > property for the module address/length.
> v2: Reserve the zeroeth module for Xen itself (not used yet)
>     Use a more idiomatic DT layout
>     Document said layout

Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>


>  docs/misc/arm/device-tree/booting.txt |   25 +++++++++++++++
>  xen/common/device_tree.c              |   54 
> ++++++++++++++++++++++++++++++++-
>  2 files changed, 78 insertions(+), 1 deletions(-)
>  create mode 100644 docs/misc/arm/device-tree/booting.txt
> 
> diff --git a/docs/misc/arm/device-tree/booting.txt 
> b/docs/misc/arm/device-tree/booting.txt
> new file mode 100644
> index 0000000..94cd3f1
> --- /dev/null
> +++ b/docs/misc/arm/device-tree/booting.txt
> @@ -0,0 +1,25 @@
> +Xen is passed the dom0 kernel and initrd via a reference in the /chosen
> +node of the device tree.
> +
> +Each node has the form /chosen/modules/module@<N> and contains the following
> +properties:
> +
> +- compatible
> +
> +     Must be:
> +
> +             "xen,<type>", "xen,multiboot-module"
> +
> +     where <type> must be one of:
> +
> +     - "linux-zimage" -- the dom0 kernel
> +     - "linux-initrd" -- the dom0 ramdisk
> +
> +- reg
> +
> +     Specifies the physical address of the module in RAM and the
> +     length of the module.
> +
> +- bootargs (optional)
> +
> +     Command line associated with this module
> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
> index f10ba1b..c92f8ca 100644
> --- a/xen/common/device_tree.c
> +++ b/xen/common/device_tree.c
> @@ -341,6 +341,48 @@ static void __init process_gic_node(const void *fdt, int 
> node,
>      early_info.gic.gic_vcpu_addr = start;
>  }
>  
> +static void __init process_multiboot_node(const void *fdt, int node,
> +                                          const char *name,
> +                                          u32 address_cells, u32 size_cells)
> +{
> +    const struct fdt_property *prop;
> +    const u32 *cell;
> +    int nr;
> +    struct dt_mb_module *mod;
> +    int len;
> +
> +    if ( fdt_node_check_compatible(fdt, node, "xen,linux-zimage") == 0 )
> +        nr = 1;
> +    else if ( fdt_node_check_compatible(fdt, node, "xen,linux-initrd") == 0)
> +        nr = 2;
> +    else
> +        early_panic("%s not a known xen multiboot type\n", name);
> +
> +    mod = &early_info.modules.module[nr];
> +
> +    prop = fdt_get_property(fdt, node, "reg", NULL);
> +    if ( !prop )
> +        early_panic("node %s missing `reg' property\n", name);
> +
> +    cell = (const u32 *)prop->data;
> +    device_tree_get_reg(&cell, address_cells, size_cells,
> +                        &mod->start, &mod->size);
> +
> +    prop = fdt_get_property(fdt, node, "bootargs", &len);
> +    if ( prop )
> +    {
> +        if ( len > sizeof(mod->cmdline) )
> +            early_panic("module %d command line too long\n", nr);
> +
> +        safe_strcpy(mod->cmdline, prop->data);
> +    }
> +    else
> +        mod->cmdline[0] = 0;
> +
> +    if ( nr > early_info.modules.nr_mods )
> +        early_info.modules.nr_mods = nr;
> +}
> +
>  static int __init early_scan_node(const void *fdt,
>                                    int node, const char *name, int depth,
>                                    u32 address_cells, u32 size_cells,
> @@ -352,6 +394,8 @@ static int __init early_scan_node(const void *fdt,
>          process_cpu_node(fdt, node, name, address_cells, size_cells);
>      else if ( device_tree_node_compatible(fdt, node, "arm,cortex-a15-gic") )
>          process_gic_node(fdt, node, name, address_cells, size_cells);
> +    else if ( device_tree_node_compatible(fdt, node, "xen,multiboot-module" 
> ) )
> +        process_multiboot_node(fdt, node, name, address_cells, size_cells);
>  
>      return 0;
>  }
> @@ -359,12 +403,20 @@ static int __init early_scan_node(const void *fdt,
>  static void __init early_print_info(void)
>  {
>      struct dt_mem_info *mi = &early_info.mem;
> +    struct dt_module_info *mods = &early_info.modules;
>      int i;
>  
>      for ( i = 0; i < mi->nr_banks; i++ )
> -        early_printk("RAM: %016llx - %016llx\n",
> +        early_printk("RAM: %"PRIpaddr" - %"PRIpaddr"\n",
>                       mi->bank[i].start,
>                       mi->bank[i].start + mi->bank[i].size - 1);
> +    early_printk("\n");
> +    for ( i = 1 ; i < mods->nr_mods + 1; i++ )
> +        early_printk("MODULE[%d]: %"PRIpaddr" - %"PRIpaddr" %s\n",
> +                     i,
> +                     mods->module[i].start,
> +                     mods->module[i].start + mods->module[i].size,
> +                     mods->module[i].cmdline);
>  }
>  
>  /**
> -- 
> 1.7.9.1
> 

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