sh: Document PTEL 31:29 use on PTEA-wielding parts.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/asm-sh/pgtable_32.h b/include/asm-sh/pgtable_32.h
index 7efc954..3e3557c 100644
--- a/include/asm-sh/pgtable_32.h
+++ b/include/asm-sh/pgtable_32.h
@@ -22,8 +22,9 @@
* - Bits 10 and 11 are low bits of the PPN that are reserved on >= 4K pages.
* Bit 10 is used for _PAGE_ACCESSED, bit 11 remains unused.
*
- * - Bits 31, 30, and 29 remain unused by everyone and can be used for future
- * software flags, although care must be taken to update _PAGE_CLEAR_FLAGS.
+ * - On 29 bit platforms, bits 31 to 29 are used for the space attributes
+ * and timing control which (together with bit 0) are moved into the
+ * old-style PTEA on the parts that support it.
*
* XXX: Leave the _PAGE_FILE and _PAGE_WT overhaul for a rainy day.
*