MIPS: Document the cca= command-line parameter

Commit 351336929ccf222ae38ff0cb7a8dd5fd5c6236a0 ("[MIPS] Allow setting
of the cache attribute at run time") introduced the 'cca=' kernel
command-line parameter which allows overriding the kernel pages
cacheable attributes, document that parameter.

[ralf@linux-mips.org: replace @mips.com email addresses with it's imgtec.com
equivalent in this commit message.  Rephrase slightly for a bit more
pedantic correctness.]

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: blogic@openwrt.org
Cc: anemo@mba.ocn.ne.jp
Cc: chris.dearman@imgtec.com
Patchwork: https://patchwork.linux-mips.org/patch/7182/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c1b9aa8c5a52e807e6458d40d96d4f1bc91f107b..ea4f2dfba19a66067527c37f3fde10190d20a7eb 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -566,6 +566,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        possible to determine what the correct size should be.
                        This option provides an override for these situations.
 
+       cca=            [MIPS] Override the kernel pages' cache coherency
+                       algorithm.  Accepted values range from 0 to 7
+                       inclusive. See arch/mips/include/asm/pgtable-bits.h
+                       for platform specific values (SB1, Loongson3 and
+                       others).
+
        ccw_timeout_log [S390]
                        See Documentation/s390/CommonIO for details.