On Fri, Jun 24, 2016 at 04:27:49PM +0200, Maxime Ripard wrote:

The libfdt overlay support introduces a bunch of new includes and functions.

Make sure we are able to build it by adding the needed glue.

Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

Is this intended only for downstream u-boot only, or also for upstream libfdt?

If it's u-boot only, you don't really need the #ifdef UBOOT. If it's for upstream, then it shouldn't have u-boot specific stuff.

In general the environment into which you're embedding libfdt (u-boot in this case) should provide libfdt_env.h. The one included in upstream libfdt is essentially just an example version designed to work with POSIX userspace.

---

include/libfdt_env.h | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/include/libfdt_env.h b/include/libfdt_env.h index 273b5d30f867..6c6845f76cf7 100644 --- a/include/libfdt_env.h +++ b/include/libfdt_env.h @@ -23,6 +23,12 @@ typedef __be64 fdt64_t; #define fdt64_to_cpu(x) be64_to_cpu(x) #define cpu_to_fdt64(x) cpu_to_be64(x)

+#ifdef __UBOOT__ +#include <vsprintf.h>

+#define strtoul(cp, endp, base) simple_strtoul(cp, endp, base) +#endif

/* adding a ramdisk needs 0x44 bytes in version 2008.10 */ #define FDT_RAMDISK_OVERHEAD 0x80

On Fri, Jun 24, 2016 at 04:27:52PM +0200, Maxime Ripard wrote:

Add a function to modify inplace a property starting from a given index.

This is especially useful when the property is an array of values, and you want to update one of them without changing the DT size.

Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

include/libfdt.h | 34 +++++++++++++++++++++++++++++++--- lib/libfdt/fdt_wip.c | 13 ++++++++----- 2 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/include/libfdt.h b/include/libfdt.h index 4643be5adf39..2c8a42bcb667 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -1032,6 +1032,27 @@ int fdt_size_cells(const void *fdt, int nodeoffset); /* Write-in-place functions */ /**********************************************************************/

+/**

• • fdt_setprop_inplace_namelen_by_index - change a property's value,

• •                                    but not its size
    

• • @fdt: pointer to the device tree blob
• • @nodeoffset: offset of the node whose property to change
• • @name: name of the property to change
• • @namelen: number of characters of name to consider
• • @index: index of the property to change in the array
• • @val: pointer to data to replace the property value with
• • @len: length of the property value
• • Identical to fdt_setprop_inplace(), but modifies the given property
• • starting from the given index, and using only the first characters
• • of the name. It is useful when you want to manipulate only one value of
• • an array and you have a string that doesn't end with \0.
• */

+int fdt_setprop_inplace_namelen_by_index(void *fdt, int nodeoffset,

• 			 const char *name, int namelen,
  

• 			 uint32_t index, const void *val,
  

• 			 int len);
  

This looks like a good addition to upstream, but I don't like the name. I'd suggest fdt_setprop_inplace_namelen_partial() because it only overwrite part of the existing property value.

/**

• fdt_setprop_inplace - change a property's value, but not its size
• @fdt: pointer to the device tree blob

@@ -1060,8 +1081,13 @@ int fdt_size_cells(const void *fdt, int nodeoffset);

• -FDT_ERR_BADSTRUCTURE,
• -FDT_ERR_TRUNCATED, standard meanings

*/ -int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,

• 	const void *val, int len);
  

+static inline int fdt_setprop_inplace(void *fdt, int nodeoffset,

• 		      const char *name, const void *val,
  

• 		      int len)
  

+{

• return fdt_setprop_inplace_namelen_by_index(fdt, nodeoffset, name,

• 				    strlen(name), 0, val, len);
  

This effectively removes the error if len is not equal to the existing property length, so that needs to be put back.

+}

/**

• fdt_setprop_inplace_u32 - change the value of a 32-bit integer property

@@ -1095,7 +1121,9 @@ static inline int fdt_setprop_inplace_u32(void *fdt, int nodeoffset, const char *name, uint32_t val) { fdt32_t tmp = cpu_to_fdt32(val);

• return fdt_setprop_inplace(fdt, nodeoffset, name, &tmp, sizeof(tmp));

• return fdt_setprop_inplace_namelen_by_index(fdt, nodeoffset,

• 				    name, strlen(name),
  

• 				    0, &tmp, sizeof(tmp));
  

}

/** diff --git a/lib/libfdt/fdt_wip.c b/lib/libfdt/fdt_wip.c index 9fe988655fe3..737769fa59e2 100644 --- a/lib/libfdt/fdt_wip.c +++ b/lib/libfdt/fdt_wip.c @@ -14,20 +14,23 @@

#include "libfdt_internal.h"

-int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,

• 	const void *val, int len)
  

+int fdt_setprop_inplace_namelen_by_index(void *fdt, int nodeoffset,

• 			 const char *name, int namelen,
  

• 			 uint32_t index, const void *val,
  

• 			 int len)
  

{ void *propval; int proplen;

• propval = fdt_getprop_w(fdt, nodeoffset, name, &proplen);

• propval = fdt_getprop_namelen_w(fdt, nodeoffset, name, namelen,

• 			&proplen);
  

  if (!propval) return proplen;

• if (proplen != len)

• if (proplen < (len + index)) return -FDT_ERR_NOSPACE;

• memcpy(propval, val, len);

• memcpy(propval + index, val, len); return 0;

}

On Mon, Jun 27, 2016 at 11:16:52AM +0200, Maxime Ripard wrote:

On Mon, Jun 27, 2016 at 01:45:11AM +1000, David Gibson wrote:

...

On Fri, Jun 24, 2016 at 04:27:52PM +0200, Maxime Ripard wrote:

...

Add a function to modify inplace a property starting from a given index.

This is especially useful when the property is an array of values, and you want to update one of them without changing the DT size.

Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

include/libfdt.h | 34 +++++++++++++++++++++++++++++++--- lib/libfdt/fdt_wip.c | 13 ++++++++----- 2 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/include/libfdt.h b/include/libfdt.h index 4643be5adf39..2c8a42bcb667 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -1032,6 +1032,27 @@ int fdt_size_cells(const void *fdt, int nodeoffset); /* Write-in-place functions */ /**********************************************************************/

+/**

• • fdt_setprop_inplace_namelen_by_index - change a property's value,

• •                                    but not its size
    

• • @fdt: pointer to the device tree blob
• • @nodeoffset: offset of the node whose property to change
• • @name: name of the property to change
• • @namelen: number of characters of name to consider
• • @index: index of the property to change in the array
• • @val: pointer to data to replace the property value with
• • @len: length of the property value
• • Identical to fdt_setprop_inplace(), but modifies the given property
• • starting from the given index, and using only the first characters
• • of the name. It is useful when you want to manipulate only one value of
• • an array and you have a string that doesn't end with \0.
• */

+int fdt_setprop_inplace_namelen_by_index(void *fdt, int nodeoffset,

• 			 const char *name, int namelen,
  

• 			 uint32_t index, const void *val,
  

• 			 int len);
  

This looks like a good addition to upstream, but I don't like the name. I'd suggest fdt_setprop_inplace_namelen_partial() because it only overwrite part of the existing property value.

Ack.

...

...

/**

• fdt_setprop_inplace - change a property's value, but not its size
• @fdt: pointer to the device tree blob

@@ -1060,8 +1081,13 @@ int fdt_size_cells(const void *fdt, int nodeoffset);

• -FDT_ERR_BADSTRUCTURE,
• -FDT_ERR_TRUNCATED, standard meanings

*/ -int fdt_setprop_inplace(void *fdt, int nodeoffset, const char *name,

• 	const void *val, int len);
  

+static inline int fdt_setprop_inplace(void *fdt, int nodeoffset,

• 		      const char *name, const void *val,
  

• 		      int len)
  

+{

• return fdt_setprop_inplace_namelen_by_index(fdt, nodeoffset, name,

• 				    strlen(name), 0, val, len);
  

This effectively removes the error if len is not equal to the existing property length, so that needs to be put back.

So I'm not really sure what you want me to do.

I can't check for the property length, since it would prevent that function from working, I can't check for the length + index, since we might update only a few bytes in the middle, and we want to keep that error case.

Or should I just forgive about merging the two functions and just duplicate the two?

No, what I'm suggesting is that fdt_setprop_inplace(), whether or not it is implemented using fdt_setprop_inplace_partial() *also* checks that the existing property length exactly matches the replacement length, and fails otherwise.

Doing this without too much code duplication might involve a private internal function, or maybe it's just simpler to duplicate. But those are the semantics they should have.

Hi Simon,

On Sat, Jun 25, 2016 at 08:53:55PM -0600, Simon Glass wrote:

Hi Maxime,

On 24 June 2016 at 08:27, Maxime Ripard maxime.ripard@free-electrons.com wrote:

...

Add a function to retrieve a writeable property only by the first characters of its name.

Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

include/libfdt.h | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/include/libfdt.h b/include/libfdt.h index dbe8a0efca87..b8758de3ae54 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -619,6 +619,13 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset, */ const void *fdt_getprop_namelen(const void *fdt, int nodeoffset, const char *name, int namelen, int *lenp); +static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,

•                                     const char *name, int namelen,
  

•                                     int *lenp)
  

+{

•   return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,
  

•                                                 namelen, lenp);
  

What are the casts for?

This is modelled after the already existing fdt_getprop_w.

The casts just remove the const qualifier in fdt_getprop return value so that you can modify it.

Maxime

On Mon, Jun 27, 2016 at 01:49:29AM +1000, David Gibson wrote:

On Fri, Jun 24, 2016 at 04:27:54PM +0200, Maxime Ripard wrote:

...

Add a function to retrieve a writeable property only by the first characters of its name.

Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

include/libfdt.h | 7 +++++++ 1 file changed, 7 insertions(+)

diff --git a/include/libfdt.h b/include/libfdt.h index dbe8a0efca87..b8758de3ae54 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -619,6 +619,13 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset, */ const void *fdt_getprop_namelen(const void *fdt, int nodeoffset, const char *name, int namelen, int *lenp); +static inline void *fdt_getprop_namelen_w(void *fdt, int nodeoffset,

• 			  const char *name, int namelen,
  

• 			  int *lenp)
  

+{

• return (void *)(uintptr_t)fdt_getprop_namelen(fdt, nodeoffset, name,

• 				      namelen, lenp);
  

+}

I believe you used this in your new setprop_inpace implementation. So the series needs to be re-ordered to avoid breaking bisection.

You're right, sorry for that.

Thanks! Maxime

Hi Maxime,

On 24 June 2016 at 08:27, Maxime Ripard maxime.ripard@free-electrons.com wrote:

The device tree overlays are a good way to deal with user-modifyable boards or boards with some kind of an expansion mechanism where we can easily plug new board in (like the BBB, the Raspberry Pi or the CHIP).

Add a new function to merge overlays with a base device tree.

Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

include/libfdt.h | 30 ++++ lib/Kconfig | 5 + lib/libfdt/Makefile | 2 + lib/libfdt/fdt_overlay.c | 381 +++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 418 insertions(+) create mode 100644 lib/libfdt/fdt_overlay.c

Is there a change log?

diff --git a/include/libfdt.h b/include/libfdt.h index b8758de3ae54..039ecb0c1ba7 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -1747,6 +1747,36 @@ int fdt_add_subnode(void *fdt, int parentoffset, const char *name); */ int fdt_del_node(void *fdt, int nodeoffset);

+/**

• • fdt_overlay_apply - Applies a DT overlay on a base DT
• • @fdt: pointer to the base device tree blob
• • @fdto: pointer to the device tree overlay blob
• • fdt_overlay_apply() will apply the given device tree overlay on the
• • given base device tree.
• • Expect the base device tree to be modified, even if the function
• • returns an error.
• • returns:

• • 0, on success
    

• • -FDT_ERR_NOSPACE, there's not enough space in the base device tree
    

• • -FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or
    

• •         properties in the base DT
    

• • -FDT_ERR_BADPHANDLE, the phandles in the overlay do not have the right
    

• •         magic
    

• • -FDT_ERR_INTERNAL,
    

• • -FDT_ERR_BADLAYOUT,
    

• • -FDT_ERR_BADMAGIC,
    

• • -FDT_ERR_BADOFFSET,
    

• • -FDT_ERR_BADPATH,
    

• • -FDT_ERR_BADVERSION,
    

• • -FDT_ERR_BADSTRUCTURE,
    

• • -FDT_ERR_BADSTATE,
    

• • -FDT_ERR_TRUNCATED, standard meanings
    

• */

+int fdt_overlay_apply(void *fdt, void *fdto);

/**********************************************************************/ /* Debugging / informational functions */ /**********************************************************************/ diff --git a/lib/Kconfig b/lib/Kconfig index 02ca4058d37e..16ff01a2cd37 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -139,6 +139,11 @@ config OF_LIBFDT particular compatible nodes. The library operates on a flattened version of the device tree.

+config OF_LIBFDT_OVERLAY

•   bool "Enable the FDT library overlay support"
  

•   help
  

•     This enables the FDT library (libfdt) overlay support.
  

config SPL_OF_LIBFDT bool "Enable the FDT library for SPL" default y if SPL_OF_CONTROL diff --git a/lib/libfdt/Makefile b/lib/libfdt/Makefile index 8b86c15904cb..6ef8290f4e09 100644 --- a/lib/libfdt/Makefile +++ b/lib/libfdt/Makefile @@ -15,3 +15,5 @@ obj-y += \ fdt_empty_tree.o \ fdt_addresses.o \ fdt_region.o

+obj-$(CONFIG_OF_LIBFDT_OVERLAY) += fdt_overlay.o diff --git a/lib/libfdt/fdt_overlay.c b/lib/libfdt/fdt_overlay.c new file mode 100644 index 000000000000..5835a90afafe --- /dev/null +++ b/lib/libfdt/fdt_overlay.c @@ -0,0 +1,381 @@ +#include "libfdt_env.h"

+#include <fdt.h> +#include <libfdt.h>

+#include "libfdt_internal.h"

+static uint32_t overlay_get_target_phandle(const void *fdto, int fragment) +{

•   const uint32_t *val;
  

•   int len;
  

•   val = fdt_getprop(fdto, fragment, "target", &len);
  

•   if (!val || (*val == 0xffffffff) || (len != sizeof(*val)))
  

•           return 0;
  

•   return fdt32_to_cpu(*val);
  

+}

+static int overlay_get_target(const void *fdt, const void *fdto,

•                         int fragment)
  

function comment please.

+{

•   uint32_t phandle;
  

•   const char *path;
  

•   /* Try first to do a phandle based lookup */
  

•   phandle = overlay_get_target_phandle(fdto, fragment);
  

•   if (phandle)
  

•           return fdt_node_offset_by_phandle(fdt, phandle);
  

•   /* And then a path based lookup */
  

•   path = fdt_getprop(fdto, fragment, "target-path", NULL);
  

•   if (!path)
  

•           return -FDT_ERR_NOTFOUND;
  

•   return fdt_path_offset(fdt, path);
  

+}

+static int overlay_phandle_add_offset(void *fdt, int node,

•                                 const char *name, uint32_t delta)
  

function comment please.

+{

•   const uint32_t *val;
  

•   uint32_t adj_val;
  

•   int len;
  

•   val = fdt_getprop(fdt, node, name, &len);
  

•   if (!val)
  

•           return len;
  

•   if (len != sizeof(*val))
  

•           return -FDT_ERR_BADSTRUCTURE;
  

•   adj_val = fdt32_to_cpu(*val);
  

•   adj_val += delta;
  

•   return fdt_setprop_inplace_u32(fdt, node, name, adj_val);
  

+}

+static int overlay_adjust_node_phandles(void *fdto, int node,

•                                   uint32_t delta)
  

function comment please.

+{

•   bool found = false;
  

•   int child;
  

•   int ret;
  

•   ret = overlay_phandle_add_offset(fdto, node, "phandle", delta);
  

•   if (ret && ret != -FDT_ERR_NOTFOUND)
  

•           return ret;
  

•   if (!ret)
  

•           found = true;
  

•   ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta);
  

•   if (ret && ret != -FDT_ERR_NOTFOUND)
  

•           return ret;
  

•   /*
  

•    * If neither phandle nor linux,phandle have been found return
  

•    * an error.
  

•    */
  

•   if (!found && !ret)
  

•           return ret;
  

•   fdt_for_each_subnode(fdto, child, node)
  

•           overlay_adjust_node_phandles(fdto, child, delta);
  

•   return 0;
  

+}

+static int overlay_adjust_local_phandles(void *fdto, uint32_t delta) +{

•   /*
  

•    * Start adjusting the phandles from the overlay root
  

•    */
  

•   return overlay_adjust_node_phandles(fdto, 0, delta);
  

+}

+static int overlay_update_local_node_references(void *fdto,

•                                           int tree_node,
  

•                                           int fixup_node,
  

•                                           uint32_t delta)
  

+{

Please add function comments for all of these.

•   int fixup_prop;
  

•   int fixup_child;
  

•   int ret;
  

•   fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {
  

•           const uint32_t *val = NULL;
  

•           uint32_t adj_val, index;
  

•           const char *name;
  

•           int fixup_len;
  

•           int tree_len;
  

•           val = fdt_getprop_by_offset(fdto, fixup_prop,
  

•                                       &name, &fixup_len);
  

•           if (!val)
  

•                   return fixup_len;
  

•           index = fdt32_to_cpu(*val);
  

•           val = fdt_getprop(fdto, tree_node, name, &tree_len);
  

•           if (!val)
  

•                   return tree_len;
  

•           adj_val = fdt32_to_cpu(*(val + (index / sizeof(uint32_t))));
  

•           adj_val += delta;
  

•           adj_val = cpu_to_fdt32(adj_val);
  

•           ret = fdt_setprop_inplace_namelen_by_index(fdto, tree_node,
  

•                                                      name, strlen(name),
  

•                                                      index, &adj_val,
  

•                                                      sizeof(adj_val));
  

•           if (ret)
  

•                   return ret;
  

•   }
  

•   fdt_for_each_subnode(fdto, fixup_child, fixup_node) {
  

•           const char *fixup_child_name = fdt_get_name(fdto, fixup_child,
  

•                                                       NULL);
  

•           int tree_child;
  

•           tree_child = fdt_subnode_offset(fdto, tree_node,
  

•                                           fixup_child_name);
  

•           if (tree_child < 0)
  

•                   return tree_child;
  

•           ret = overlay_update_local_node_references(fdto,
  

•                                                      tree_child,
  

•                                                      fixup_child,
  

•                                                      delta);
  

•           if (ret)
  

•                   return ret;
  

•   }
  

•   return 0;
  

+}

+static int overlay_update_local_references(void *dto, uint32_t delta) +{

•   int fixups;
  

•   fixups = fdt_path_offset(dto, "/__local_fixups__");
  

•   if (fixups < 0) {
  

•           /*
  

•            * There's no local phandles to adjust, bail out
  

On on line:

/* There's not local ... */

•            */
  

•           if (fixups == -FDT_ERR_NOTFOUND)
  

•                   return 0;
  

•           return fixups;
  

•   }
  

•   /*
  

•    * Update our local references from the root of the tree
  

•    */
  

•   return overlay_update_local_node_references(dto, 0, fixups,
  

•                                               delta);
  

+}

+static int overlay_fixup_one_phandle(void *fdt, void *fdto,

•                                int symbols_off,
  

•                                const char *path, uint32_t path_len,
  

•                                const char *name, uint32_t name_len,
  

•                                int index, const char *label)
  

+{

•   const char *symbol_path;
  

•   uint32_t phandle;
  

•   int symbol_off, fixup_off;
  

•   int prop_len;
  

•   symbol_path = fdt_getprop(fdt, symbols_off, label,
  

•                             &prop_len);
  

•   if (!symbol_path)
  

•           return -FDT_ERR_NOTFOUND;
  

•   symbol_off = fdt_path_offset(fdt, symbol_path);
  

•   if (symbol_off < 0)
  

•           return symbol_off;
  

•   phandle = fdt_get_phandle(fdt, symbol_off);
  

•   if (!phandle)
  

•           return -FDT_ERR_NOTFOUND;
  

•   fixup_off = fdt_path_offset_namelen(fdto, path, path_len);
  

•   if (fixup_off < 0)
  

•           return fixup_off;
  

•   phandle = cpu_to_fdt32(phandle);
  

•   return fdt_setprop_inplace_namelen_by_index(fdto, fixup_off,
  

•                                               name, name_len, index,
  

•                                               &phandle, sizeof(phandle));
  

+};

+static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,

•                            int property)
  

+{

•   const char *value;
  

•   const char *label;
  

•   int len;
  

•   value = fdt_getprop_by_offset(fdto, property,
  

•                                 &label, &len);
  

•   if (!value)
  

•           return len;
  

•   do {
  

•           const char *prop_string = value;
  

•           const char *path, *name;
  

•           uint32_t path_len, name_len;
  

•           char *sep, *endptr;
  

•           int index;
  

•           int ret;
  

•           path = prop_string;
  

•           sep = strchr(prop_string, ':');
  

•           path_len = sep - path;
  

•           name = sep + 1;
  

•           sep = strchr(name, ':');
  

•           name_len = sep - name;
  

•           index = strtoul(sep + 1, &endptr, 10);
  

•           if (endptr <= (sep + 1))
  

•                   return -FDT_ERR_BADSTRUCTURE;
  

•           index = strtoul(sep + 1, &endptr, 10);
  

•           if (endptr <= (sep + 1))
  

•                   return -FDT_ERR_BADSTRUCTURE;
  

•           len -= strlen(prop_string) + 1;
  

•           value += strlen(prop_string) + 1;
  

•           ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off,
  

•                                           path, path_len, name, name_len,
  

•                                           index, label);
  

•           if (ret)
  

•                   return ret;
  

•   } while (len > 0);
  

•   return 0;
  

+}

+static int overlay_fixup_phandles(void *dt, void *dto) +{

•   int fixups_off, symbols_off;
  

•   int property;
  

•   symbols_off = fdt_path_offset(dt, "/__symbols__");
  

•   fixups_off = fdt_path_offset(dto, "/__fixups__");
  

•   fdt_for_each_property_offset(property, dto, fixups_off)
  

•           overlay_fixup_phandle(dt, dto, symbols_off, property);
  

•   return 0;
  

+}

+static int apply_overlay_node(void *dt, int target,

•                         void *dto, int overlay)
  

+{

•   int property;
  

•   int node;
  

•   fdt_for_each_property_offset(property, dto, overlay) {
  

•           const char *name;
  

•           const void *prop;
  

•           int prop_len;
  

•           int ret;
  

•           prop = fdt_getprop_by_offset(dto, property, &name,
  

•                                        &prop_len);
  

•           if (!prop)
  

•                   return -FDT_ERR_INTERNAL;
  

•           ret = fdt_setprop(dt, target, name, prop, prop_len);
  

•           if (ret)
  

•                   return ret;
  

•   }
  

•   fdt_for_each_subnode(dto, node, overlay) {
  

•           const char *name = fdt_get_name(dto, node, NULL);
  

•           int nnode;
  

•           int ret;
  

•           nnode = fdt_add_subnode(dt, target, name);
  

•           if (nnode == -FDT_ERR_EXISTS)
  

•                   nnode = fdt_subnode_offset(dt, target, name);
  

•           if (nnode < 0)
  

•                   return nnode;
  

•           ret = apply_overlay_node(dt, nnode, dto, node);
  

•           if (ret)
  

•                   return ret;
  

•   }
  

•   return 0;
  

+}

+static int overlay_merge(void *dt, void *dto) +{

•   int fragment;
  

•   fdt_for_each_subnode(dto, fragment, 0) {
  

•           int overlay;
  

•           int target;
  

•           int ret;
  

•           target = overlay_get_target(dt, dto, fragment);
  

•           if (target < 0)
  

•                   continue;
  

•           overlay = fdt_subnode_offset(dto, fragment, "__overlay__");
  

•           if (overlay < 0)
  

•                   return overlay;
  

•           ret = apply_overlay_node(dt, target, dto, overlay);
  

•           if (ret)
  

•                   return ret;
  

•   }
  

•   return 0;
  

+}

+int fdt_overlay_apply(void *fdt, void *fdto) +{

•   uint32_t delta = fdt_get_max_phandle(fdt) + 1;
  

•   int ret;
  

•   FDT_CHECK_HEADER(fdt);
  

•   FDT_CHECK_HEADER(fdto);
  

•   ret = overlay_adjust_local_phandles(fdto, delta);
  

•   if (ret)
  

•           goto err;
  

•   ret = overlay_update_local_references(fdto, delta);
  

•   if (ret)
  

•           goto err;
  

•   ret = overlay_fixup_phandles(fdt, fdto);
  

•   if (ret)
  

•           goto err;
  

•   ret = overlay_merge(fdt, fdto);
  

•   if (!ret)
  

•           goto out;
  

+err:

•   /*
  

•    * The base device tree might have been damaged, erase its
  

•    * magic.
  

•    */
  

•   fdt_set_magic(fdt, ~0);
  

+out:

•   /*
  

•    * The overlay has been damaged, erase its magic.
  

•    */
  

•   fdt_set_magic(fdto, ~0);
  

•   return ret;
  

+}

2.9.0

Regards, Simon

On Fri, Jun 24, 2016 at 04:27:55PM +0200, Maxime Ripard wrote:

The device tree overlays are a good way to deal with user-modifyable boards or boards with some kind of an expansion mechanism where we can easily plug new board in (like the BBB, the Raspberry Pi or the CHIP).

Add a new function to merge overlays with a base device tree.

Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com

include/libfdt.h | 30 ++++ lib/Kconfig | 5 + lib/libfdt/Makefile | 2 + lib/libfdt/fdt_overlay.c | 381 +++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 418 insertions(+) create mode 100644 lib/libfdt/fdt_overlay.c

diff --git a/include/libfdt.h b/include/libfdt.h index b8758de3ae54..039ecb0c1ba7 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -1747,6 +1747,36 @@ int fdt_add_subnode(void *fdt, int parentoffset, const char *name); */ int fdt_del_node(void *fdt, int nodeoffset);

+/**

• • fdt_overlay_apply - Applies a DT overlay on a base DT
• • @fdt: pointer to the base device tree blob
• • @fdto: pointer to the device tree overlay blob
• • fdt_overlay_apply() will apply the given device tree overlay on the
• • given base device tree.
• • Expect the base device tree to be modified, even if the function
• • returns an error.
• • returns:
• • 0, on success
• • -FDT_ERR_NOSPACE, there's not enough space in the base device tree
• • -FDT_ERR_NOTFOUND, the overlay points to some inexistant nodes or

• • properties in the base DT
    

• • -FDT_ERR_BADPHANDLE, the phandles in the overlay do not have the right

• • magic
    

• • -FDT_ERR_INTERNAL,
• • -FDT_ERR_BADLAYOUT,
• • -FDT_ERR_BADMAGIC,
• • -FDT_ERR_BADOFFSET,
• • -FDT_ERR_BADPATH,
• • -FDT_ERR_BADVERSION,
• • -FDT_ERR_BADSTRUCTURE,
• • -FDT_ERR_BADSTATE,
• • -FDT_ERR_TRUNCATED, standard meanings
• */

+int fdt_overlay_apply(void *fdt, void *fdto);

/**********************************************************************/ /* Debugging / informational functions */ /**********************************************************************/ diff --git a/lib/Kconfig b/lib/Kconfig index 02ca4058d37e..16ff01a2cd37 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -139,6 +139,11 @@ config OF_LIBFDT particular compatible nodes. The library operates on a flattened version of the device tree.

+config OF_LIBFDT_OVERLAY

• bool "Enable the FDT library overlay support"
• help

•  This enables the FDT library (libfdt) overlay support.
  

config SPL_OF_LIBFDT bool "Enable the FDT library for SPL" default y if SPL_OF_CONTROL diff --git a/lib/libfdt/Makefile b/lib/libfdt/Makefile index 8b86c15904cb..6ef8290f4e09 100644 --- a/lib/libfdt/Makefile +++ b/lib/libfdt/Makefile @@ -15,3 +15,5 @@ obj-y += \ fdt_empty_tree.o \ fdt_addresses.o \ fdt_region.o

+obj-$(CONFIG_OF_LIBFDT_OVERLAY) += fdt_overlay.o diff --git a/lib/libfdt/fdt_overlay.c b/lib/libfdt/fdt_overlay.c new file mode 100644 index 000000000000..5835a90afafe --- /dev/null +++ b/lib/libfdt/fdt_overlay.c @@ -0,0 +1,381 @@ +#include "libfdt_env.h"

+#include <fdt.h> +#include <libfdt.h>

+#include "libfdt_internal.h"

+static uint32_t overlay_get_target_phandle(const void *fdto, int fragment) +{

• const uint32_t *val;
• int len;
• val = fdt_getprop(fdto, fragment, "target", &len);
• if (!val || (*val == 0xffffffff) || (len != sizeof(*val)))

• return 0;
  

This doesn't distinguish between a missing property (which may indicate a valid overlay using a target-path or some other method) and a badly formatted 'target' property, which is definitely an error in the overlay.

I think those should be treated differently.

• return fdt32_to_cpu(*val);

+}

+static int overlay_get_target(const void *fdt, const void *fdto,

• 	      int fragment)
  

+{

• uint32_t phandle;
• const char *path;
• /* Try first to do a phandle based lookup */
• phandle = overlay_get_target_phandle(fdto, fragment);
• if (phandle)

• return fdt_node_offset_by_phandle(fdt, phandle);
  

• /* And then a path based lookup */
• path = fdt_getprop(fdto, fragment, "target-path", NULL);
• if (!path)

• return -FDT_ERR_NOTFOUND;
  

• return fdt_path_offset(fdt, path);

+}

+static int overlay_phandle_add_offset(void *fdt, int node,

• 		      const char *name, uint32_t delta)
  

+{

• const uint32_t *val;
• uint32_t adj_val;
• int len;
• val = fdt_getprop(fdt, node, name, &len);
• if (!val)

• return len;
  

• if (len != sizeof(*val))

• return -FDT_ERR_BADSTRUCTURE;
  

• adj_val = fdt32_to_cpu(*val);
• adj_val += delta;

You should probably check for overflow here.

• return fdt_setprop_inplace_u32(fdt, node, name, adj_val);

+}

+static int overlay_adjust_node_phandles(void *fdto, int node,

• 			uint32_t delta)
  

+{

• bool found = false;
• int child;
• int ret;
• ret = overlay_phandle_add_offset(fdto, node, "phandle", delta);
• if (ret && ret != -FDT_ERR_NOTFOUND)

• return ret;
  

• if (!ret)

• found = true;
  

• ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta);
• if (ret && ret != -FDT_ERR_NOTFOUND)

• return ret;
  

I think the check for phandle vs. linux,phandle should be folded into overlay_phandle_add_offset().

• /*

• * If neither phandle nor linux,phandle have been found return
  

• * an error.
  

• */
  

• if (!found && !ret)

• return ret;
  

• fdt_for_each_subnode(fdto, child, node)

• overlay_adjust_node_phandles(fdto, child, delta);
  

• return 0;

+}

+static int overlay_adjust_local_phandles(void *fdto, uint32_t delta) +{

• /*

• * Start adjusting the phandles from the overlay root
  

• */
  

• return overlay_adjust_node_phandles(fdto, 0, delta);

+}

+static int overlay_update_local_node_references(void *fdto,

• 				int tree_node,
  

• 				int fixup_node,
  

• 				uint32_t delta)
  

+{

• int fixup_prop;
• int fixup_child;
• int ret;
• fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {

• const uint32_t *val = NULL;
  

• uint32_t adj_val, index;
  

• const char *name;
  

• int fixup_len;
  

• int tree_len;
  

• val = fdt_getprop_by_offset(fdto, fixup_prop,
  

• 			    &name, &fixup_len);
  

• if (!val)
  

• 	return fixup_len;
  

• index = fdt32_to_cpu(*val);
  

This still doesn't handle the case of multiple fixups within the same property. That would be entirely plausible for something like an interrupt-map property.

• val = fdt_getprop(fdto, tree_node, name, &tree_len);
  

• if (!val)
  

• 	return tree_len;
  

• adj_val = fdt32_to_cpu(*(val + (index / sizeof(uint32_t))));
  

phandle values need not be aligned within the property containint them (e.g. properties which mix strings and integer values). So you're going to need to work directly with a byte offset here.

• adj_val += delta;
  

• adj_val = cpu_to_fdt32(adj_val);
  

• ret = fdt_setprop_inplace_namelen_by_index(fdto, tree_node,
  

• 					   name, strlen(name),
  

• 					   index, &adj_val,
  

• 					   sizeof(adj_val));
  

• if (ret)
  

• 	return ret;
  

• }
• fdt_for_each_subnode(fdto, fixup_child, fixup_node) {

• const char *fixup_child_name = fdt_get_name(fdto, fixup_child,
  

• 					    NULL);
  

• int tree_child;
  

• tree_child = fdt_subnode_offset(fdto, tree_node,
  

• 				fixup_child_name);
  

• if (tree_child < 0)
  

• 	return tree_child;
  

• ret = overlay_update_local_node_references(fdto,
  

• 					   tree_child,
  

• 					   fixup_child,
  

• 					   delta);
  

• if (ret)
  

• 	return ret;
  

• }
• return 0;

+}

+static int overlay_update_local_references(void *dto, uint32_t delta) +{

• int fixups;
• fixups = fdt_path_offset(dto, "/__local_fixups__");
• if (fixups < 0) {

• /*
  

•  * There's no local phandles to adjust, bail out
  

•  */
  

• if (fixups == -FDT_ERR_NOTFOUND)
  

• 	return 0;
  

• return fixups;
  

• }
• /*

• * Update our local references from the root of the tree
  

• */
  

• return overlay_update_local_node_references(dto, 0, fixups,

• 				    delta);
  

+}

+static int overlay_fixup_one_phandle(void *fdt, void *fdto,

• 		     int symbols_off,
  

• 		     const char *path, uint32_t path_len,
  

• 		     const char *name, uint32_t name_len,
  

• 		     int index, const char *label)
  

+{

• const char *symbol_path;
• uint32_t phandle;
• int symbol_off, fixup_off;
• int prop_len;
• symbol_path = fdt_getprop(fdt, symbols_off, label,

• 		  &prop_len);
  

• if (!symbol_path)

• return -FDT_ERR_NOTFOUND;
  

• symbol_off = fdt_path_offset(fdt, symbol_path);
• if (symbol_off < 0)

• return symbol_off;
  

• phandle = fdt_get_phandle(fdt, symbol_off);
• if (!phandle)

• return -FDT_ERR_NOTFOUND;
  

• fixup_off = fdt_path_offset_namelen(fdto, path, path_len);
• if (fixup_off < 0)

• return fixup_off;
  

• phandle = cpu_to_fdt32(phandle);
• return fdt_setprop_inplace_namelen_by_index(fdto, fixup_off,

• 				    name, name_len, index,
  

• 				    &phandle, sizeof(phandle));
  

This will be broken on BE systems because fdt_get_phandle() byteswaps to native order, but setprop_inplace doesn't byteswap back (because it's input is a byte array, not a u32).

+};

+static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,

• 		 int property)
  

+{

• const char *value;
• const char *label;
• int len;
• value = fdt_getprop_by_offset(fdto, property,

• 		      &label, &len);
  

• if (!value)

• return len;
  

• do {

• const char *prop_string = value;
  

• const char *path, *name;
  

• uint32_t path_len, name_len;
  

• char *sep, *endptr;
  

• int index;
  

• int ret;
  

• path = prop_string;
  

• sep = strchr(prop_string, ':');
  

• path_len = sep - path;
  

You need to check for strchr() returning NULL (indicating a badly formatted fixup missing a separator).

Also... strchr() is not safe. Again, if the fixup string is badly formatted and doesn't have a terminating \0, this could overrun, so you want memchr() instead.

• name = sep + 1;
  

• sep = strchr(name, ':');
  

• name_len = sep - name;
  

And again.

• index = strtoul(sep + 1, &endptr, 10);
  

• if (endptr <= (sep + 1))
  

• 	return -FDT_ERR_BADSTRUCTURE;
  

IIRC the index value is supposed to go to the end of that portion of the fixup, so you should be able to check for *endptr == '\0'.

Except.. strtoul() could also overrun if the fixup property doesn't contain a \0 like it should.

So I think you'd be better off using a memchr() (or strnlen()) to search for the \0 before you attempt parsing the innards of a single fixup string.

Ugh. I hate that we're parsing text numbers in decimal here, but we're pretty much stuck with that format here. Doubly so that it's a gratuitously different way of encoding the (node, property, offset) tuple from local_fixups.

• index = strtoul(sep + 1, &endptr, 10);
  

• if (endptr <= (sep + 1))
  

• 	return -FDT_ERR_BADSTRUCTURE;
  

• len -= strlen(prop_string) + 1;
  

• value += strlen(prop_string) + 1;
  

Please don't double call strlen() on the same string - remember it's O(n) in C.

• ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off,
  

• 				path, path_len, name, name_len,
  

• 				index, label);
  

• if (ret)
  

• 	return ret;
  

• } while (len > 0);
• return 0;

+}

+static int overlay_fixup_phandles(void *dt, void *dto) +{

• int fixups_off, symbols_off;
• int property;
• symbols_off = fdt_path_offset(dt, "/__symbols__");
• fixups_off = fdt_path_offset(dto, "/__fixups__");
• fdt_for_each_property_offset(property, dto, fixups_off)

• overlay_fixup_phandle(dt, dto, symbols_off, property);
  

• return 0;

+}

+static int apply_overlay_node(void *dt, int target,

• 	      void *dto, int overlay)
  

I think 'overlay' should be 'fragment' here for consistency?

+{

• int property;
• int node;
• fdt_for_each_property_offset(property, dto, overlay) {

• const char *name;
  

• const void *prop;
  

• int prop_len;
  

• int ret;
  

• prop = fdt_getprop_by_offset(dto, property, &name,
  

• 			     &prop_len);
  

• if (!prop)
  

• 	return -FDT_ERR_INTERNAL;
  

Actually, you probably should check the error code returned in prop_len. Getting a NOTFOUND would indicate an internal error, but you could also get BADSTRUCTURE or similar errors which would indicate an error in input.

• ret = fdt_setprop(dt, target, name, prop, prop_len);
  

• if (ret)
  

• 	return ret;
  

• }
• fdt_for_each_subnode(dto, node, overlay) {

• const char *name = fdt_get_name(dto, node, NULL);
  

• int nnode;
  

• int ret;
  

• nnode = fdt_add_subnode(dt, target, name);
  

• if (nnode == -FDT_ERR_EXISTS)
  

• 	nnode = fdt_subnode_offset(dt, target, name);
  

• if (nnode < 0)
  

• 	return nnode;
  

• ret = apply_overlay_node(dt, nnode, dto, node);
  

• if (ret)
  

• 	return ret;
  

• }
• return 0;

+}

+static int overlay_merge(void *dt, void *dto) +{

• int fragment;
• fdt_for_each_subnode(dto, fragment, 0) {

• int overlay;
  

• int target;
  

• int ret;
  

• target = overlay_get_target(dt, dto, fragment);
  

• if (target < 0)
  

• 	continue;
  

• overlay = fdt_subnode_offset(dto, fragment, "__overlay__");
  

• if (overlay < 0)
  

• 	return overlay;
  

• ret = apply_overlay_node(dt, target, dto, overlay);
  

• if (ret)
  

• 	return ret;
  

• }
• return 0;

+}

+int fdt_overlay_apply(void *fdt, void *fdto) +{

• uint32_t delta = fdt_get_max_phandle(fdt) + 1;
• int ret;
• FDT_CHECK_HEADER(fdt);
• FDT_CHECK_HEADER(fdto);
• ret = overlay_adjust_local_phandles(fdto, delta);
• if (ret)

• goto err;
  

• ret = overlay_update_local_references(fdto, delta);
• if (ret)

• goto err;
  

• ret = overlay_fixup_phandles(fdt, fdto);
• if (ret)

• goto err;
  

• ret = overlay_merge(fdt, fdto);
• if (!ret)

• goto out;
  

+err:

This is a confusing use of gotos - this looks like it is in the exit path for both success and failure cases, but it's not due to the easy-to-miss goto out above.

• /*

• * The base device tree might have been damaged, erase its
  

• * magic.
  

• */
  

• fdt_set_magic(fdt, ~0);

+out:

• /*

• * The overlay has been damaged, erase its magic.
  

• */
  

• fdt_set_magic(fdto, ~0);
• return ret;

+}