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-rw-r--r--Documentation/core-api/printk-formats.rst63
1 files changed, 55 insertions, 8 deletions
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index 4451ef501936..4b7f3646ec6c 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -209,12 +209,17 @@ Struct Resources
::
%pr [mem 0x60000000-0x6fffffff flags 0x2200] or
+ [mem 0x60000000 flags 0x2200] or
[mem 0x0000000060000000-0x000000006fffffff flags 0x2200]
+ [mem 0x0000000060000000 flags 0x2200]
%pR [mem 0x60000000-0x6fffffff pref] or
+ [mem 0x60000000 pref] or
[mem 0x0000000060000000-0x000000006fffffff pref]
+ [mem 0x0000000060000000 pref]
For printing struct resources. The ``R`` and ``r`` specifiers result in a
-printed resource with (R) or without (r) a decoded flags member.
+printed resource with (R) or without (r) a decoded flags member. If start is
+equal to end only print the start value.
Passed by reference.
@@ -231,6 +236,19 @@ width of the CPU data path.
Passed by reference.
+Struct Range
+------------
+
+::
+
+ %pra [range 0x0000000060000000-0x000000006fffffff] or
+ [range 0x0000000060000000]
+
+For printing struct range. struct range holds an arbitrary range of u64
+values. If start is equal to end only print the start value.
+
+Passed by reference.
+
DMA address types dma_addr_t
----------------------------
@@ -553,9 +571,8 @@ struct clk
::
%pC pll1
- %pCn pll1
-For printing struct clk structures. %pC and %pCn print the name of the clock
+For printing struct clk structures. %pC prints the name of the clock
(Common Clock Framework) or a unique 32-bit ID (legacy clock framework).
Passed by reference.
@@ -576,13 +593,12 @@ The field width is passed by value, the bitmap is passed by reference.
Helper macros cpumask_pr_args() and nodemask_pr_args() are available to ease
printing cpumask and nodemask.
-Flags bitfields such as page flags, page_type, gfp_flags
+Flags bitfields such as page flags and gfp_flags
--------------------------------------------------------
::
%pGp 0x17ffffc0002036(referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff)
- %pGt 0xffffff7f(buddy)
%pGg GFP_USER|GFP_DMA32|GFP_NOWARN
%pGv read|exec|mayread|maywrite|mayexec|denywrite
@@ -591,7 +607,6 @@ would construct the value. The type of flags is given by the third
character. Currently supported are:
- p - [p]age flags, expects value of type (``unsigned long *``)
- - t - page [t]ype, expects value of type (``unsigned int *``)
- v - [v]ma_flags, expects value of type (``unsigned long *``)
- g - [g]fp_flags, expects value of type (``gfp_t *``)
@@ -632,6 +647,38 @@ Examples::
%p4cc Y10 little-endian (0x20303159)
%p4cc NV12 big-endian (0xb231564e)
+Generic FourCC code
+-------------------
+
+::
+ %p4c[h[R]lb] gP00 (0x67503030)
+
+Print a generic FourCC code, as both ASCII characters and its numerical
+value as hexadecimal.
+
+The generic FourCC code is always printed in the big-endian format,
+the most significant byte first. This is the opposite of V4L/DRM FourCCs.
+
+The additional ``h``, ``hR``, ``l``, and ``b`` specifiers define what
+endianness is used to load the stored bytes. The data might be interpreted
+using the host, reversed host byte order, little-endian, or big-endian.
+
+Passed by reference.
+
+Examples for a little-endian machine, given &(u32)0x67503030::
+
+ %p4ch gP00 (0x67503030)
+ %p4chR 00Pg (0x30305067)
+ %p4cl gP00 (0x67503030)
+ %p4cb 00Pg (0x30305067)
+
+Examples for a big-endian machine, given &(u32)0x67503030::
+
+ %p4ch gP00 (0x67503030)
+ %p4chR 00Pg (0x30305067)
+ %p4cl 00Pg (0x30305067)
+ %p4cb gP00 (0x67503030)
+
Rust
----
@@ -645,7 +692,7 @@ Do *not* use it from C.
Thanks
======
-If you add other %p extensions, please extend <lib/test_printf.c> with
-one or more test cases, if at all feasible.
+If you add other %p extensions, please extend <lib/tests/printf_kunit.c>
+with one or more test cases, if at all feasible.
Thank you for your cooperation and attention.