[PATCH 3/8] of/fdt: Add unflatten_partial_device_tree
Grant Likely
grant.likely at secretlab.ca
Sat Jul 17 05:25:23 EST 2010
On Fri, Jul 16, 2010 at 12:13 PM, Stephen Neuendorffer
<stephen.neuendorffer at xilinx.com> wrote:
> This code allows a user to parse a partial device tree blob, which is
> structurally independent of any toplevel blob.
> Previously, this code assumed that the blob comes from initial_boot_params.
> Now, unflatten_partial_device_tree can take a blob from an arbitrary position,
> and the location of the blob gets passed around to the various support functions.
>
> Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer at xilinx.com>
> ---
> drivers/of/fdt.c | 169 +++++++++++++++++++++++++++++++++--------------
> include/linux/of_fdt.h | 11 ++-
> 2 files changed, 126 insertions(+), 54 deletions(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index d61fda8..89fb1f3 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -11,10 +11,12 @@
>
> #include <linux/kernel.h>
> #include <linux/initrd.h>
> +#include <linux/module.h>
> #include <linux/of.h>
> #include <linux/of_fdt.h>
> #include <linux/string.h>
> #include <linux/errno.h>
> +#include <linux/slab.h>
>
> #ifdef CONFIG_PPC
> #include <asm/machdep.h>
> @@ -22,15 +24,19 @@
>
> #include <asm/page.h>
>
> -int __initdata dt_root_addr_cells;
> -int __initdata dt_root_size_cells;
> +int dt_root_addr_cells;
> +int dt_root_size_cells;
The fact that these are still here looks wrong. The code cannot
depend on global symbols, particularly global symbols that it
modified, when it is changed to support processing non-rooted trees.
More rework will be needed here.
>
> struct boot_param_header *initial_boot_params;
>
> -char *find_flat_dt_string(u32 offset)
> +void __unflatten_device_tree(unsigned long *blob, struct device_node **mynodes,
> + unsigned long (*dt_alloc)(u64 size, u64 align));
> +
> +char *find_flat_dt_string(u32 offset,
> + struct boot_param_header *blob)
> {
> - return ((char *)initial_boot_params) +
> - be32_to_cpu(initial_boot_params->off_dt_strings) + offset;
> + return ((char *)blob) +
> + be32_to_cpu(blob->off_dt_strings) + offset;
> }
>
> /**
> @@ -118,8 +124,9 @@ unsigned long __init of_get_flat_dt_root(void)
> * This function can be used within scan_flattened_dt callback to get
> * access to properties
> */
> -void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
> - unsigned long *size)
> +void * __init of_get_flat_dt_prop(unsigned long node, const char *name,
> + unsigned long *size,
> + struct boot_param_header *blob)
> {
> unsigned long p = node;
>
> @@ -140,7 +147,7 @@ void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
> if (be32_to_cpu(initial_boot_params->version) < 0x10)
> p = ALIGN(p, sz >= 8 ? 8 : 4);
>
> - nstr = find_flat_dt_string(noff);
> + nstr = find_flat_dt_string(noff, blob);
> if (nstr == NULL) {
> pr_warning("Can't find property index name !\n");
> return NULL;
> @@ -160,12 +167,13 @@ void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
> * @node: node to test
> * @compat: compatible string to compare with compatible list.
> */
> -int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
> +int of_flat_dt_is_compatible(unsigned long node, const char *compat,
> + struct boot_param_header *blob)
> {
> const char *cp;
> unsigned long cplen, l;
>
> - cp = of_get_flat_dt_prop(node, "compatible", &cplen);
> + cp = of_get_flat_dt_prop(node, "compatible", &cplen, blob);
> if (cp == NULL)
> return 0;
> while (cplen > 0) {
> @@ -179,7 +187,7 @@ int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
> return 0;
> }
>
> -static void *__init unflatten_dt_alloc(unsigned long *mem, unsigned long size,
> +static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
> unsigned long align)
> {
> void *res;
> @@ -198,11 +206,12 @@ static void *__init unflatten_dt_alloc(unsigned long *mem, unsigned long size,
> * @allnextpp: pointer to ->allnext from last allocated device_node
> * @fpsize: Size of the node path up at the current depth.
> */
> -unsigned long __init unflatten_dt_node(unsigned long mem,
> - unsigned long *p,
> - struct device_node *dad,
> - struct device_node ***allnextpp,
> - unsigned long fpsize)
> +unsigned long unflatten_dt_node(unsigned long mem,
> + unsigned long *p,
> + struct device_node *dad,
> + struct device_node ***allnextpp,
> + unsigned long fpsize,
> + struct boot_param_header *blob)
> {
> struct device_node *np;
> struct property *pp, **prev_pp = NULL;
> @@ -298,10 +307,10 @@ unsigned long __init unflatten_dt_node(unsigned long mem,
> sz = be32_to_cpup((__be32 *)(*p));
> noff = be32_to_cpup((__be32 *)((*p) + 4));
> *p += 8;
> - if (be32_to_cpu(initial_boot_params->version) < 0x10)
> + if (be32_to_cpu(blob->version) < 0x10)
> *p = ALIGN(*p, sz >= 8 ? 8 : 4);
>
> - pname = find_flat_dt_string(noff);
> + pname = find_flat_dt_string(noff, blob);
> if (pname == NULL) {
> pr_info("Can't find property name in list !\n");
> break;
> @@ -380,7 +389,8 @@ unsigned long __init unflatten_dt_node(unsigned long mem,
> if (tag == OF_DT_NOP)
> *p += 4;
> else
> - mem = unflatten_dt_node(mem, p, np, allnextpp, fpsize);
> + mem = unflatten_dt_node(mem, p, np, allnextpp,
> + fpsize, blob);
> tag = be32_to_cpup((__be32 *)(*p));
> }
> if (tag != OF_DT_END_NODE) {
> @@ -391,6 +401,8 @@ unsigned long __init unflatten_dt_node(unsigned long mem,
> return mem;
> }
>
> +#if defined(CONFIG_MICROBLAZE) || defined(CONFIG_POWERPC) || defined(CONFIG_SPARC)
> +
Rather hacky.. There's got to be a better way. Might be better to add
a new Kconfig symbol.
Also, the test is wrong. ARM is going to want this. OLPC x86 might
want it. SPARC doesn't use it.
> #ifdef CONFIG_BLK_DEV_INITRD
> /**
> * early_init_dt_check_for_initrd - Decode initrd location from flat tree
> @@ -403,12 +415,14 @@ void __init early_init_dt_check_for_initrd(unsigned long node)
>
> pr_debug("Looking for initrd properties... ");
>
> - prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
> + prop = of_get_flat_dt_prop(node, "linux,initrd-start",
> + &len, initial_boot_params);
> if (!prop)
> return;
> start = of_read_ulong(prop, len/4);
>
> - prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
> + prop = of_get_flat_dt_prop(node, "linux,initrd-end",
> + &len, initial_boot_params);
> if (!prop)
> return;
> end = of_read_ulong(prop, len/4);
> @@ -436,12 +450,14 @@ int __init early_init_dt_scan_root(unsigned long node, const char *uname,
> dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
> dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
>
> - prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
> + prop = of_get_flat_dt_prop(node, "#size-cells",
> + NULL, initial_boot_params);
> if (prop)
> dt_root_size_cells = be32_to_cpup(prop);
> pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
>
> - prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
> + prop = of_get_flat_dt_prop(node, "#address-cells",
> + NULL, initial_boot_params);
> if (prop)
> dt_root_addr_cells = be32_to_cpup(prop);
> pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
This is the update to the static globals I was mentioning that must not be done.
> @@ -450,7 +466,7 @@ int __init early_init_dt_scan_root(unsigned long node, const char *uname,
> return 1;
> }
>
> -u64 __init dt_mem_next_cell(int s, __be32 **cellp)
> +u64 dt_mem_next_cell(int s, __be32 **cellp)
> {
> __be32 *p = *cellp;
>
> @@ -464,7 +480,8 @@ u64 __init dt_mem_next_cell(int s, __be32 **cellp)
> int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
> int depth, void *data)
> {
> - char *type = of_get_flat_dt_prop(node, "device_type", NULL);
> + char *type = of_get_flat_dt_prop(node, "device_type",
> + NULL, initial_boot_params);
> __be32 *reg, *endp;
> unsigned long l;
>
> @@ -479,9 +496,10 @@ int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
> } else if (strcmp(type, "memory") != 0)
> return 0;
>
> - reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
> + reg = of_get_flat_dt_prop(node, "linux,usable-memory",
> + &l, initial_boot_params);
> if (reg == NULL)
> - reg = of_get_flat_dt_prop(node, "reg", &l);
> + reg = of_get_flat_dt_prop(node, "reg", &l, initial_boot_params);
> if (reg == NULL)
> return 0;
>
> @@ -521,12 +539,12 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
>
> early_init_dt_check_for_initrd(node);
>
> +#ifdef CONFIG_CMDLINE
> /* Retreive command line */
> - p = of_get_flat_dt_prop(node, "bootargs", &l);
> + p = of_get_flat_dt_prop(node, "bootargs", &l, initial_boot_params);
> if (p != NULL && l > 0)
> strlcpy(cmd_line, p, min((int)l, COMMAND_LINE_SIZE));
>
> -#ifdef CONFIG_CMDLINE
Why is this being changed?
> #ifndef CONFIG_CMDLINE_FORCE
> if (p == NULL || l == 0 || (l == 1 && (*p) == 0))
> #endif
> @@ -535,12 +553,21 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
>
> early_init_dt_scan_chosen_arch(node);
>
> +#ifdef CONFIG_CMDLINE
> pr_debug("Command line is: %s\n", cmd_line);
> +#endif /* CONFIG_CMDLINE */
>
> /* break now */
> return 1;
> }
>
> +
> +static unsigned long early_device_tree_alloc(u64 size, u64 align)
> +{
> + unsigned long mem = early_init_dt_alloc_memory_arch(size, align);
> + return (unsigned long) __va(mem);
> +}
> +
> /**
> * unflatten_device_tree - create tree of device_nodes from flat blob
> *
> @@ -551,58 +578,98 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
> */
> void __init unflatten_device_tree(void)
> {
> + __unflatten_device_tree(initial_boot_params, &allnodes,
> + early_device_tree_alloc);
> +
> + /* Get pointer to OF "/chosen" node for use everywhere */
> + of_chosen = of_find_node_by_path("/chosen");
> + if (of_chosen == NULL)
> + of_chosen = of_find_node_by_path("/chosen at 0");
> +}
> +
> +#endif
> +
> +static unsigned long kernel_tree_alloc(u64 size, u64 align)
> +{
> + return (unsigned long) kzalloc(size, GFP_KERNEL);
> +}
> +
> +/**
> + * unflatten_partial_device_tree - create tree of device_nodes from flat blob
> + *
> + * unflattens the device-tree passed by the firmware, creating the
> + * tree of struct device_node. It also fills the "name" and "type"
> + * pointers of the nodes so the normal device-tree walking functions
> + * can be used.
> + */
> +void unflatten_partial_device_tree(unsigned long *blob,
> + struct device_node **mynodes)
> +{
> + __unflatten_device_tree(blob, mynodes, &kernel_tree_alloc);
> +}
> +EXPORT_SYMBOL(unflatten_partial_device_tree);
unflatten_partial_device_tree and unflatten_device_tree should be
defined *below* __unflatten_device_tree().
> +
> +/**
> + * __unflatten_device_tree - create tree of device_nodes from flat blob
> + *
> + * unflattens the device-tree passed by the firmware, creating the
> + * tree of struct device_node. It also fills the "name" and "type"
> + * pointers of the nodes so the normal device-tree walking functions
> + * can be used. Memory is allocated using the given function.
> + */
> +void __unflatten_device_tree(unsigned long *blob, struct device_node **mynodes,
> + unsigned long (*dt_alloc)(u64 size, u64 align))
> +{
> + struct boot_param_header *device_tree =
> + (struct boot_param_header *)blob;
> unsigned long start, mem, size;
> - struct device_node **allnextp = &allnodes;
> + struct device_node **allnextp = mynodes;
>
> pr_debug(" -> unflatten_device_tree()\n");
>
> - if (!initial_boot_params) {
> + if (!device_tree) {
> pr_debug("No device tree pointer\n");
> return;
> }
>
> pr_debug("Unflattening device tree:\n");
> - pr_debug("magic: %08x\n", be32_to_cpu(initial_boot_params->magic));
> - pr_debug("size: %08x\n", be32_to_cpu(initial_boot_params->totalsize));
> - pr_debug("version: %08x\n", be32_to_cpu(initial_boot_params->version));
> + pr_debug("magic: %08x\n", be32_to_cpu(device_tree->magic));
> + pr_debug("size: %08x\n", be32_to_cpu(device_tree->totalsize));
> + pr_debug("version: %08x\n", be32_to_cpu(device_tree->version));
>
> - if (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER) {
> - pr_err("Invalid device tree blob header\n");
> + if (be32_to_cpu(device_tree->magic) != OF_DT_HEADER) {
> + pr_err("Invalid device tree blob header %x\n",
> + be32_to_cpu(device_tree->magic));
> return;
> }
>
> /* First pass, scan for size */
> - start = ((unsigned long)initial_boot_params) +
> - be32_to_cpu(initial_boot_params->off_dt_struct);
> - size = unflatten_dt_node(0, &start, NULL, NULL, 0);
> + start = ((unsigned long)device_tree) +
> + be32_to_cpu(device_tree->off_dt_struct);
> + size = unflatten_dt_node(0, &start, NULL, NULL, 0, device_tree);
> size = (size | 3) + 1;
>
> pr_debug(" size is %lx, allocating...\n", size);
>
> /* Allocate memory for the expanded device tree */
> - mem = early_init_dt_alloc_memory_arch(size + 4,
> - __alignof__(struct device_node));
> - mem = (unsigned long) __va(mem);
> + mem = (unsigned long) dt_alloc(size + 4,
> + __alignof__(struct device_node));
>
> ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
>
> pr_debug(" unflattening %lx...\n", mem);
>
> /* Second pass, do actual unflattening */
> - start = ((unsigned long)initial_boot_params) +
> - be32_to_cpu(initial_boot_params->off_dt_struct);
> - unflatten_dt_node(mem, &start, NULL, &allnextp, 0);
> + start = ((unsigned long)device_tree) +
> + be32_to_cpu(device_tree->off_dt_struct);
> + unflatten_dt_node(mem, &start, NULL, &allnextp, 0, device_tree);
> if (be32_to_cpup((__be32 *)start) != OF_DT_END)
> - pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
> + pr_warning("Weird tag at end of tree: %08x\n",
> + *((u32 *)start));
> if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
> pr_warning("End of tree marker overwritten: %08x\n",
> be32_to_cpu(((__be32 *)mem)[size / 4]));
> *allnextp = NULL;
>
> - /* Get pointer to OF "/chosen" node for use everywhere */
> - of_chosen = of_find_node_by_path("/chosen");
> - if (of_chosen == NULL)
> - of_chosen = of_find_node_by_path("/chosen at 0");
> -
> pr_debug(" <- unflatten_device_tree()\n");
> }
> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> index 71e1a91..2bc0754 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -64,13 +64,16 @@ extern int __initdata dt_root_size_cells;
> extern struct boot_param_header *initial_boot_params;
>
> /* For scanning the flat device-tree at boot time */
> -extern char *find_flat_dt_string(u32 offset);
> +extern char *find_flat_dt_string(u32 offset,
> + struct boot_param_header *blob);
Well, fdt.c is the only user of this. I think this line can be removed.
> extern int of_scan_flat_dt(int (*it)(unsigned long node, const char *uname,
> int depth, void *data),
> void *data);
> extern void *of_get_flat_dt_prop(unsigned long node, const char *name,
> - unsigned long *size);
> -extern int of_flat_dt_is_compatible(unsigned long node, const char *name);
> + unsigned long *size,
> + struct boot_param_header *blob);
> +extern int of_flat_dt_is_compatible(unsigned long node, const char *name,
> + struct boot_param_header *blob);
Need to fix this. The prototypes for of_get_flat_dt_prop() and
of_flat_dt_is_compatible are changed, but there are users in the
microblaze and powerpc trees which are not updated.
> extern unsigned long of_get_flat_dt_root(void);
> extern void early_init_dt_scan_chosen_arch(unsigned long node);
> extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
> @@ -98,6 +101,8 @@ extern int early_init_dt_scan_root(unsigned long node, const char *uname,
>
> /* Other Prototypes */
> extern void unflatten_device_tree(void);
> +extern void unflatten_partial_device_tree(unsigned long *blob,
> + struct device_node **mynodes);
> extern void early_init_devtree(void *);
> #else /* CONFIG_OF_FLATTREE */
> static inline void unflatten_device_tree(void) {}
> --
> 1.5.6.6
>
>
>
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>
>
>
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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