Extend the rman(9) API to support altering an existing resource.

Specifically, these changes allow a resource to back a relocatable and
resizable resource such as the I/O window decoders in PCI-PCI bridges.
- rman_adjust_resource() can adjust the start and end address of an
  existing resource.  It only succeeds if the newly requested address
  space is already free.  It also supports shrinking a resource in
  which case the freed space will be marked unallocated in the rman.
- rman_first_free_region() and rman_last_free_region() return the
  start and end addresses for the first or last unallocated region in
  an rman, respectively.  This can be used to determine by how much
  the resource backing an rman must be adjusted to accomodate an
  allocation request that does not fit into the existing rman.

While here, document the rm_start and rm_end fields in struct rman,
rman_is_region_manager(), the bound argument to
rman_reserve_resource_bound(), and rman_init_from_resource().

2 files changed, 127 insertions, 5 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index bf2ceb3..93814c6 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -967,9 +967,11 @@ MLINKS+=refcount.9 refcount_acquire.9 \
 MLINKS+=resource_int_value.9 resource_long_value.9 \
 	resource_int_value.9 resource_string_value.9
 MLINKS+=rman.9 rman_activate_resource.9 \
+	rman.9 rman_adjust_resource.9 \
 	rman.9 rman_await_resource.9 \
 	rman.9 rman_deactivate_resource.9 \
 	rman.9 rman_fini.9 \
+	rman.9 rman_first_free_region.9 \
 	rman.9 rman_get_bushandle.9 \
 	rman.9 rman_get_bustag.9 \
 	rman.9 rman_get_device.9 \
@@ -980,6 +982,9 @@ MLINKS+=rman.9 rman_activate_resource.9 \
 	rman.9 rman_get_start.9 \
 	rman.9 rman_get_virtual.9 \
 	rman.9 rman_init.9 \
+	rman.9 rman_init_from_resource.9 \
+	rman.9 rman_is_region_manager.9 \
+	rman.9 rman_last_free_region.9 \
 	rman.9 rman_make_alignment_flags.9 \
 	rman.9 rman_manage_region.9 \
 	rman.9 rman_release_resource.9 \
diff --git a/share/man/man9/rman.9 b/share/man/man9/rman.9
index 113b608..7f8d889 100644
--- a/share/man/man9/rman.9
+++ b/share/man/man9/rman.9
@@ -25,17 +25,22 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 29, 2007
+.Dd April 29, 2011
 .Dt RMAN 9
 .Os
 .Sh NAME
 .Nm rman ,
 .Nm rman_activate_resource ,
+.Nm rman_adjust_resource ,
 .Nm rman_await_resource ,
 .Nm rman_deactivate_resource ,
 .Nm rman_fini ,
 .Nm rman_init ,
+.Nm rman_init_from_resource ,
+.Nm rman_is_region_manager ,
 .Nm rman_manage_region ,
+.Nm rman_first_free_region ,
+.Nm rman_last_free_region ,
 .Nm rman_release_resource ,
 .Nm rman_reserve_resource ,
 .Nm rman_reserve_resource_bound ,
@@ -60,6 +65,8 @@
 .Ft int
 .Fn rman_activate_resource "struct resource *r"
 .Ft int
+.Fn rman_adjust_resource "struct resource *r" "u_long start" "u_long end"
+.Ft int
 .Fn rman_await_resource "struct resource *r" "int pri2" "int timo"
 .Ft int
 .Fn rman_deactivate_resource "struct resource *r"
@@ -68,8 +75,16 @@
 .Ft int
 .Fn rman_init "struct rman *rm"
 .Ft int
+.Fn rman_init_from_resource "struct rman *rm" "struct resource *r"
+.Ft int
+.Fn rman_is_region_manager "struct resource *r" "struct rman *rm"
+.Ft int
 .Fn rman_manage_region "struct rman *rm" "u_long start" "u_long end"
 .Ft int
+.Fn rman_first_free_region "struct rman *rm" "u_long *start" "u_long *end"
+.Ft int
+.Fn rman_last_free_region "struct rman *rm" "u_long *start" "u_long *end"
+.Ft int
 .Fn rman_release_resource "struct resource *r"
 .Ft "struct resource *"
 .Fo rman_reserve_resource
@@ -155,6 +170,14 @@ shall be set to
 The field
 .Va rm_descr
 shall be set to a string that describes the resource to be managed.
+The
+.Va rm_start
+and
+.Va rm_end
+fields may be set to limit the range of acceptable resource addresses.
+If these fields are not set,
+.Fn rman_init
+will initialize them to allow the entire range of resource addresses.
 It also initializes any mutexes associated with the structure.
 If
 .Fn rman_init
@@ -194,12 +217,49 @@ If successful,
 will return 0.
 If the region overlaps with an existing region, it will return
 .Er EBUSY .
+If any part of the region falls outside of the valid address range for
+.Fa rm ,
+it will return
+.Er EINVAL .
 .Er ENOMEM
-will be return when
+will be returned when
 .Fn rman_manage_region
 failed to allocate memory for the region.
 .Pp
 The
+.Fn rman_init_from_resource
+function is a wrapper routine to create a resource manager backed by an
+existing resource.
+It initializes
+.Fa rm
+using
+.Fn rman_init
+and then adds a region to
+.Fa rm
+corresponding to the address range allocated to
+.Fa r
+via
+.Fn rman_manage_region .
+.Pp
+The
+.Fn rman_first_free_region
+and
+.Fn rman_last_free_region
+functions can be used to query a resource manager for its first
+.Pq or last
+unallocated region.
+If
+.Fa rm
+contains no free region,
+these functions will return
+.Er ENOENT .
+Otherwise,
+.Fa *start
+and
+.Fa *end
+are set to the bounds of the free region and zero is returned.
+.Pp
+The
 .Fn rman_reserve_resource_bound
 function is where the bulk of the
 .Nm
@@ -212,8 +272,9 @@ The caller can specify the
 .Fa start
 and
 .Fa end
-of an acceptable range, as well as
-alignment, and the code will attempt to find a free segment which fits.
+of an acceptable range,
+as well as a boundary restriction and required aligment,
+and the code will attempt to find a free segment which fits.
 The
 .Fa start
 argument is the lowest acceptable starting value of the resource.
@@ -225,6 +286,19 @@ Therefore,
 must be \[<=]
 .Fa end
 for any allocation to happen.
+The aligment requirement
+.Pq if any
+is specified in
+.Fa flags .
+The
+.Fa bound
+argument may be set to specify a boundary restriction such that an
+allocated region may cross an address that is a multiple of the
+boundary.
+The
+.Fa bound
+argument must be a power of two.
+It may be set to zero to specify no boundary restriction.
 The default behavior is to allocate an exclusive segment, unless the
 .Dv RF_SHAREABLE
 or
@@ -240,7 +314,7 @@ function is used to reserve resources within a previously established region.
 It is a simplified interface to
 .Fn rman_reserve_resource_bound
 which passes 0 for the
-.Fa flags
+.Fa bound
 argument.
 .Pp
 The
@@ -251,6 +325,49 @@ This should be used when calling
 .Fn rman_reserve_resource_bound .
 .Pp
 The
+.Fn rman_is_region_manager
+function returns true if the allocated resource
+.Fa r
+was allocated from
+.Fa rm .
+Otherwise,
+it returns false.
+.Pp
+The
+.Fn rman_adjust_resource
+function is used to adjust the reserved address range of an allocated resource
+to reserve
+.Fa start
+through
+.Fa end .
+It can be used to grow or shrink one or both ends of the resource range.
+The current implementation does not support entirely relocating the resource
+and will fail with
+.Er EINVAL
+if the new resource range does not overlap the old resource range.
+If either end of the resource range grows and the new resource range would
+conflict with another allocated resource,
+the function will fail with
+.Er EBUSY .
+The
+.Fn rman_adjust_resource
+function does not support adjusting the resource range for shared resources
+and will fail such attempts with
+.Er EINVAL .
+Upon success,
+the resource
+.Fa r
+will have a start address of
+.Fa start
+and an end address of
+.Fa end
+and the function will return zero.
+Note that none of the constraints of the original allocation request such
+as alignment or boundary restrictions are checked by
+.Fn rman_adjust_resource .
+It is the caller's responsibility to enforce any such requirements.
+.Pp
+The
 .Fn rman_release_resource
 function releases the reserved resource
 .Fa r .