[PATCH v2 0/3] Cleanup some unused functions in fdt.c

[PATCH v2 0/3] Cleanup some unused functions in fdt.c

[Stephen Boyd]

This series removes some unused functions, marks some more as __init,
marks the FDT as __ro_after_init for some more protections, and updates
the common properties binding to be less Linux specific.

Changes from v1:
 * New patch for dt-bindings and removal of that hunk from patch 2

Stephen Boyd (3):
  dt-bindings: Remove Linuxisms from common-properties binding
  of/fdt: Remove dead code and mark functions with __init
  of/fdt: Mark initial_boot_params as __ro_after_init

Cc: Hsin-Yi Wang <hsinyi@chromium.org>

 .../devicetree/bindings/common-properties.txt | 17 ++++----
 drivers/of/fdt.c                              | 39 +++----------------
 include/linux/of_fdt.h                        | 11 ------
 3 files changed, 14 insertions(+), 53 deletions(-)


base-commit: e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd
-- 
Sent by a computer through tubes

[PATCH v2 1/3] dt-bindings: Remove Linuxisms from common-properties binding

[Stephen Boyd]

We shouldn't reference Linux kernel functions or Linux itself in proper
bindings. It's OK to reference functions in the kernel when explaining
examples, but otherwise we shouldn't reference functions to describe
what the binding means.

Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 .../devicetree/bindings/common-properties.txt   | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/Documentation/devicetree/bindings/common-properties.txt b/Documentation/devicetree/bindings/common-properties.txt
index a3448bfa1c82..98a28130e100 100644
--- a/Documentation/devicetree/bindings/common-properties.txt
+++ b/Documentation/devicetree/bindings/common-properties.txt
@@ -5,30 +5,29 @@ Endianness
 ----------
 
 The Devicetree Specification does not define any properties related to hardware
-byteswapping, but endianness issues show up frequently in porting Linux to
+byte swapping, but endianness issues show up frequently in porting drivers to
 different machine types.  This document attempts to provide a consistent
-way of handling byteswapping across drivers.
+way of handling byte swapping across drivers.
 
 Optional properties:
  - big-endian: Boolean; force big endian register accesses
    unconditionally (e.g. ioread32be/iowrite32be).  Use this if you
-   know the peripheral always needs to be accessed in BE mode.
+   know the peripheral always needs to be accessed in big endian (BE) mode.
  - little-endian: Boolean; force little endian register accesses
    unconditionally (e.g. readl/writel).  Use this if you know the
-   peripheral always needs to be accessed in LE mode.
+   peripheral always needs to be accessed in little endian (LE) mode.
  - native-endian: Boolean; always use register accesses matched to the
    endianness of the kernel binary (e.g. LE vmlinux -> readl/writel,
-   BE vmlinux -> ioread32be/iowrite32be).  In this case no byteswaps
+   BE vmlinux -> ioread32be/iowrite32be).  In this case no byte swaps
    will ever be performed.  Use this if the hardware "self-adjusts"
    register endianness based on the CPU's configured endianness.
 
 If a binding supports these properties, then the binding should also
 specify the default behavior if none of these properties are present.
 In such cases, little-endian is the preferred default, but it is not
-a requirement.  The of_device_is_big_endian() and of_fdt_is_big_endian()
-helper functions do assume that little-endian is the default, because
-most existing (PCI-based) drivers implicitly default to LE by using
-readl/writel for MMIO accesses.
+a requirement.  Some implementations assume that little-endian is
+the default, because most existing (PCI-based) drivers implicitly
+default to LE for their MMIO accesses.
 
 Examples:
 Scenario 1 : CPU in LE mode & device in LE mode.
-- 
Sent by a computer through tubes

[PATCH v2 2/3] of/fdt: Remove dead code and mark functions with __init

[Stephen Boyd]

Some functions in here are never called, and others are only called
during __init. Remove the dead code and some dead exports for functions
that don't exist (I'm looking at you of_fdt_get_string!). Mark some
functions with __init so we can throw them away after we boot up and
poke at the FDT blob too.

Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/of/fdt.c       | 37 +++++--------------------------------
 include/linux/of_fdt.h | 11 -----------
 2 files changed, 5 insertions(+), 43 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 4734223ab702..93414b89735f 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -38,7 +38,7 @@
  * memory entries in the /memory node. This function may be called
  * any time after initial_boot_param is set.
  */
-void of_fdt_limit_memory(int limit)
+void __init of_fdt_limit_memory(int limit)
 {
 	int memory;
 	int len;
@@ -110,25 +110,6 @@ static int of_fdt_is_compatible(const void *blob,
 	return 0;
 }
 
-/**
- * of_fdt_is_big_endian - Return true if given node needs BE MMIO accesses
- * @blob: A device tree blob
- * @node: node to test
- *
- * Returns true if the node has a "big-endian" property, or if the kernel
- * was compiled for BE *and* the node has a "native-endian" property.
- * Returns false otherwise.
- */
-bool of_fdt_is_big_endian(const void *blob, unsigned long node)
-{
-	if (fdt_getprop(blob, node, "big-endian", NULL))
-		return true;
-	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
-	    fdt_getprop(blob, node, "native-endian", NULL))
-		return true;
-	return false;
-}
-
 static bool of_fdt_device_is_available(const void *blob, unsigned long node)
 {
 	const char *status = fdt_getprop(blob, node, "status", NULL);
@@ -145,8 +126,8 @@ static bool of_fdt_device_is_available(const void *blob, unsigned long node)
 /**
  * of_fdt_match - Return true if node matches a list of compatible values
  */
-int of_fdt_match(const void *blob, unsigned long node,
-                 const char *const *compat)
+static int __init of_fdt_match(const void *blob, unsigned long node,
+			       const char *const *compat)
 {
 	unsigned int tmp, score = 0;
 
@@ -758,7 +739,7 @@ int __init of_scan_flat_dt_subnodes(unsigned long parent,
  * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
  */
 
-int of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
+int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
 {
 	return fdt_subnode_offset(initial_boot_params, node, uname);
 }
@@ -771,14 +752,6 @@ unsigned long __init of_get_flat_dt_root(void)
 	return 0;
 }
 
-/**
- * of_get_flat_dt_size - Return the total size of the FDT
- */
-int __init of_get_flat_dt_size(void)
-{
-	return fdt_totalsize(initial_boot_params);
-}
-
 /**
  * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
  *
@@ -804,7 +777,7 @@ int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
 /**
  * of_flat_dt_match - Return true if node matches a list of compatible values
  */
-int __init of_flat_dt_match(unsigned long node, const char *const *compat)
+static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
 {
 	return of_fdt_match(initial_boot_params, node, compat);
 }
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index a713e5d156d8..acf820e88952 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -23,15 +23,6 @@
 struct device_node;
 
 /* For scanning an arbitrary device-tree at any time */
-extern char *of_fdt_get_string(const void *blob, u32 offset);
-extern void *of_fdt_get_property(const void *blob,
-				 unsigned long node,
-				 const char *name,
-				 int *size);
-extern bool of_fdt_is_big_endian(const void *blob,
-				 unsigned long node);
-extern int of_fdt_match(const void *blob, unsigned long node,
-			const char *const *compat);
 extern void *of_fdt_unflatten_tree(const unsigned long *blob,
 				   struct device_node *dad,
 				   struct device_node **mynodes);
@@ -64,9 +55,7 @@ extern int of_get_flat_dt_subnode_by_name(unsigned long node,
 extern const void *of_get_flat_dt_prop(unsigned long node, const char *name,
 				       int *size);
 extern int of_flat_dt_is_compatible(unsigned long node, const char *name);
-extern int of_flat_dt_match(unsigned long node, const char *const *matches);
 extern unsigned long of_get_flat_dt_root(void);
-extern int of_get_flat_dt_size(void);
 extern uint32_t of_get_flat_dt_phandle(unsigned long node);
 
 extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
-- 
Sent by a computer through tubes

[PATCH v2 3/3] of/fdt: Mark initial_boot_params as __ro_after_init

[Stephen Boyd]

The FDT pointer, i.e. initial_boot_params, shouldn't be changed after
init. It's only set by boot code and then the only user of the FDT is
the raw sysfs reading API. Mark this pointer with __ro_after_init so
that the pointer can't be changed after init.

Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/of/fdt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 93414b89735f..f131a1b8588b 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -516,7 +516,7 @@ EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
 int __initdata dt_root_addr_cells;
 int __initdata dt_root_size_cells;
 
-void *initial_boot_params;
+void *initial_boot_params __ro_after_init;
 
 #ifdef CONFIG_OF_EARLY_FLATTREE
 
-- 
Sent by a computer through tubes

Re: [PATCH v2 1/3] dt-bindings: Remove Linuxisms from common-properties binding

[Rob Herring]

On Tue, 14 May 2019 13:40:51 -0700, Stephen Boyd wrote:
> We shouldn't reference Linux kernel functions or Linux itself in proper
> bindings. It's OK to reference functions in the kernel when explaining
> examples, but otherwise we shouldn't reference functions to describe
> what the binding means.
> 
> Cc: Hsin-Yi Wang <hsinyi@chromium.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>  .../devicetree/bindings/common-properties.txt   | 17 ++++++++---------
>  1 file changed, 8 insertions(+), 9 deletions(-)
> 

Applied, thanks.

Rob

Re: [PATCH v2 2/3] of/fdt: Remove dead code and mark functions with __init

[Rob Herring]

On Tue, 14 May 2019 13:40:52 -0700, Stephen Boyd wrote:
> Some functions in here are never called, and others are only called
> during __init. Remove the dead code and some dead exports for functions
> that don't exist (I'm looking at you of_fdt_get_string!). Mark some
> functions with __init so we can throw them away after we boot up and
> poke at the FDT blob too.
> 
> Cc: Hsin-Yi Wang <hsinyi@chromium.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>  drivers/of/fdt.c       | 37 +++++--------------------------------
>  include/linux/of_fdt.h | 11 -----------
>  2 files changed, 5 insertions(+), 43 deletions(-)
> 

Applied, thanks.

Rob

Re: [PATCH v2 3/3] of/fdt: Mark initial_boot_params as __ro_after_init

[Rob Herring]

On Tue, 14 May 2019 13:40:53 -0700, Stephen Boyd wrote:
> The FDT pointer, i.e. initial_boot_params, shouldn't be changed after
> init. It's only set by boot code and then the only user of the FDT is
> the raw sysfs reading API. Mark this pointer with __ro_after_init so
> that the pointer can't be changed after init.
> 
> Cc: Hsin-Yi Wang <hsinyi@chromium.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>  drivers/of/fdt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

Applied, thanks.

Rob