Merge tag 'xtensa-20121218' of git://github.com/czankel/xtensa-linux

Pull Xtensa patchset from Chris Zankel:
 "This contains support of device trees, many fixes, and code clean-ups"

* tag 'xtensa-20121218' of git://github.com/czankel/xtensa-linux: (33 commits)
  xtensa: don't try to build DTB when OF is disabled
  xtensa: set the correct ethernet address for xtfpga
  xtensa: clean up files to make them code-style compliant
  xtensa: provide endianness macro for sparse
  xtensa: fix RASID SR initialization
  xtensa: initialize CPENABLE SR when core has one
  xtensa: reset all timers on initialization
  Use for_each_compatible_node() macro.
  xtensa: add XTFPGA DTS
  xtensa: add support for the XTFPGA boards
  xtensa: add device trees support
  xtensa: add IRQ domains support
  xtensa: add U-Boot image support (uImage).
  xtensa: clean up boot make rules
  xtensa: fix mb and wmb definitions
  xtensa: add s32c1i-based spinlock implementations
  xtensa: add s32c1i-based bitops implementations
  xtensa: add s32c1i-based atomic ops implementations
  xtensa: add s32c1i sanity check
  xtensa: add trap_set_handler function
  ...

1 files changed, 44 insertions, 0 deletions

diff --git a/Documentation/xtensa/atomctl.txt b/Documentation/xtensa/atomctl.txt
new file mode 100644
index 000000000000..10a8d1ff35ec
--- /dev/null
+++ b/Documentation/xtensa/atomctl.txt
@@ -0,0 +1,44 @@
+We Have Atomic Operation Control (ATOMCTL) Register.
+This register determines the effect of using a S32C1I instruction
+with various combinations of:
+
+     1. With and without an Coherent Cache Controller which
+        can do Atomic Transactions to the memory internally.
+
+     2. With and without An Intelligent Memory Controller which
+        can do Atomic Transactions itself.
+
+The Core comes up with a default value of for the three types of cache ops:
+
+      0x28: (WB: Internal, WT: Internal, BY:Exception)
+
+On the FPGA Cards we typically simulate an Intelligent Memory controller
+which can implement  RCW transactions. For FPGA cards with an External
+Memory controller we let it to the atomic operations internally while
+doing a Cached (WB) transaction and use the Memory RCW for un-cached
+operations.
+
+For systems without an coherent cache controller, non-MX, we always
+use the memory controllers RCW, thought non-MX controlers likely
+support the Internal Operation.
+
+CUSTOMER-WARNING:
+   Virtually all customers buy their memory controllers from vendors that
+   don't support atomic RCW memory transactions and will likely want to
+   configure this register to not use RCW.
+
+Developers might find using RCW in Bypass mode convenient when testing
+with the cache being bypassed; for example studying cache alias problems.
+
+See Section 4.3.12.4 of ISA; Bits:
+
+                             WB     WT      BY
+                           5   4 | 3   2 | 1   0
+  2 Bit
+  Field
+  Values     WB - Write Back         WT - Write Thru         BY - Bypass
+---------    ---------------         -----------------     ----------------
+    0        Exception               Exception               Exception
+    1        RCW Transaction         RCW Transaction         RCW Transaction
+    2        Internal Operation      Exception               Reserved
+    3        Reserved                Reserved                Reserved