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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 3/8] device tree: add device_tree_for_each_node()
On Tue, 2012-02-28 at 16:54 +0000, David Vrabel wrote:
> From: David Vrabel <david.vrabel@xxxxxxxxxx>
>
> Add device_tree_for_each_node() to iterate over all nodes in a flat
> device tree. Use this in device_tree_early_init().
>
> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
> ---
> xen/common/device_tree.c | 71
> ++++++++++++++++++++++++++---------------
> xen/include/xen/device_tree.h | 8 +++++
> 2 files changed, 53 insertions(+), 26 deletions(-)
>
> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
> index e5df748..e95ff3c 100644
> --- a/xen/common/device_tree.c
> +++ b/xen/common/device_tree.c
> @@ -66,7 +66,42 @@ static u32 __init prop_by_name_u32(const void *fdt, int
> node, const char *prop_n
> return fdt32_to_cpu(*(uint32_t*)prop->data);
> }
>
> -static void __init process_memory_node(const void *fdt, int node,
> +#define MAX_DEPTH 16
> +
> +/**
> + * device_tree_for_each_node - iterate over all device tree nodes
> + * @fdt: flat device tree.
> + * @func: function to call for each node.
> + * @data: data to pass to @func.
> + */
> +int device_tree_for_each_node(const void *fdt,
> + device_tree_node_func func, void *data)
> +{
> + int node;
> + int depth;
> + u32 address_cells[MAX_DEPTH];
> + u32 size_cells[MAX_DEPTH];
> + int ret;
> +
> + for (node = 0, depth = 0;
> + node >=0 && depth >= 0;
> + node = fdt_next_node(fdt, node, &depth))
Xen coding style has spaces both sides of the outermost "(" and ")" of a
for loop (similarly for if / while etc)
> + {
> + if (depth >= MAX_DEPTH)
Some sort of warning or error message would be useful here?
> + continue;
> +
> + address_cells[depth] = prop_by_name_u32(fdt, node, "#address-cells");
> + size_cells[depth] = prop_by_name_u32(fdt, node, "#size-cells");
> +
> + ret = func(fdt, node, fdt_get_name(fdt, node, NULL), depth,
> + address_cells[depth-1], size_cells[depth-1], data);
I suppose this function could have been written recursively and avoided
the arbitrary MAX_DEPTH, but actually in the hypervisor an iterative
version with explicit maximum stack usage seems like a reasonable idea.
> + if (ret < 0)
> + return ret;
> + }
> + return 0;
> +}
> +
> +static void __init process_memory_node(const void *fdt, int node, const char
> *name,
> u32 address_cells, u32 size_cells)
> {
> const struct fdt_property *prop;
> @@ -77,15 +112,13 @@ static void __init process_memory_node(const void *fdt,
> int node,
> paddr_t start, size;
>
> if (address_cells < 1 || size_cells < 1) {
I should have spotted this before, coding style needs a space inside the
() and { should be on the next line. There's a bunch of this in both the
context and the new code added by this patch. Obviously the new code
should be fixed, I don't mind if you deal with the existing bits by a
cleanup sweep or by picking it up as you go along.
> - early_printk("fdt: node `%s': invalid #address-cells or #size-cells",
> - fdt_get_name(fdt, node, NULL));
> + early_printk("fdt: node `%s': invalid #address-cells or
> #size-cells", name);
> return;
> }
>
> prop = fdt_get_property(fdt, node, "reg", NULL);
> if (!prop) {
> - early_printk("fdt: node `%s': missing `reg' property\n",
> - fdt_get_name(fdt, node, NULL));
> + early_printk("fdt: node `%s': missing `reg' property\n", name);
> return;
> }
>
> @@ -101,28 +134,14 @@ static void __init process_memory_node(const void *fdt,
> int node,
> }
> }
>
> -#define MAX_DEPTH 16
> -
> -static void __init early_scan(const void *fdt)
> +static int __init early_scan_node(const void *fdt,
> + int node, const char *name, int depth,
> + u32 address_cells, u32 size_cells, void
> *data)
> {
> - int node;
> - int depth;
> - u32 address_cells[MAX_DEPTH];
> - u32 size_cells[MAX_DEPTH];
> -
> - for (node = 0; depth >= 0; node = fdt_next_node(fdt, node, &depth)) {
> - if (depth >= MAX_DEPTH) {
> - early_printk("fdt: node '%s': nested too deep\n",
> - fdt_get_name(fdt, node, NULL));
> - continue;
> - }
> + if (node_matches(fdt, node, "memory"))
> + process_memory_node(fdt, node, name, address_cells, size_cells);
>
> - address_cells[depth] = prop_by_name_u32(fdt, node, "#address-cells");
> - size_cells[depth] = prop_by_name_u32(fdt, node, "#size-cells");
> -
> - if (node_matches(fdt, node, "memory"))
> - process_memory_node(fdt, node, address_cells[depth-1],
> size_cells[depth-1]);
> - }
> + return 0;
> }
>
> static void __init early_print_info(void)
> @@ -149,7 +168,7 @@ size_t __init device_tree_early_init(const void *fdt)
> if (ret < 0)
> early_panic("No valid device tree\n");
>
> - early_scan(fdt);
> + device_tree_for_each_node((void *)fdt, early_scan_node, NULL);
> early_print_info();
>
> return fdt_totalsize(fdt);
> diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
> index 28a3dee..505f3e3 100644
> --- a/xen/include/xen/device_tree.h
> +++ b/xen/include/xen/device_tree.h
> @@ -28,10 +28,18 @@ struct dt_early_info {
> struct dt_mem_info mem;
> };
>
> +typedef int (*device_tree_node_func)(const void *fdt,
> + int node, const char *name, int depth,
> + u32 address_cells, u32 size_cells,
> + void *data);
> +
> extern struct dt_early_info early_info;
> extern void *device_tree_flattened;
>
> size_t device_tree_early_init(const void *fdt);
> paddr_t device_tree_get_xen_paddr(void);
>
> +int device_tree_for_each_node(const void *fdt,
> + device_tree_node_func func, void *data);
> +
> #endif
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