powerpc/mpc8xxx: Add DDR2 to unified DDR driver

DDR2 has different ODT table and values. Adding table according to Samsung
application note.

Fix additive latency calculation to avoid interger underflow.

Also converted typedef dynamic_odt_t to struct dynamic_odt.

Signed-off-by: York Sun <yorksun@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/doc/README.fsl-ddr b/doc/README.fsl-ddr
index c1ee0a68a8..abfb7f192d 100644
--- a/doc/README.fsl-ddr
+++ b/doc/README.fsl-ddr
@@ -170,3 +170,55 @@ Single slot system
 
 Reference http://www.xrosstalkmag.com/mag_issues/xrosstalk_oct08_final.pdf
 	  http://download.micron.com/pdf/technotes/ddr3/tn4108_ddr3_design_guide.pdf
+
+
+Table for ODT for DDR2
+======================
+Two slots system
++-----------------------+----------+---------------+-----------------------------+-----------------------------+
+|     Configuration     |          |DRAM controller|           Slot 1            |            Slot 2           |
++-----------+-----------+----------+-------+-------+--------------+--------------+--------------+--------------+
+|           |           |          |       |       |     Rank 1   |     Rank 2   |   Rank 1     |    Rank 2    |
++  Slot 1   |   Slot 2  |Write/Read| Write | Read  |-------+------+-------+------+-------+------+-------+------+
+|           |           |          |       |       | Write | Read | Write | Read | Write | Read | Write | Read |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|           |           |  Slot 1  |  off  | 150   | off   | off  | off   | off  | 75    | 75   | off   | off  |
+| Dual Rank | Dual Rank |----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|           |           |  Slot 2  |  off  | 150   | 75    | 75   | off   | off  | off   | off  | off   | off  |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|           |           |  Slot 1  |  off  | 150   | off   | off  | off   | off  | 75    | 75   |       |      |
+| Dual Rank |Single Rank|----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|           |           |  Slot 2  |  off  | 150   | 75    | 75   | off   | off  | off   | off  |       |      |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|           |           |  Slot 1  |  off  | 150   | off   | off  |       |      | 75    | 75   | off   | off  |
+|Single Rank| Dual Rank |----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|           |           |  Slot 2  |  off  | 150   | 75    | 75   |       |      | off   | off  | off   | off  |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|           |           |  Slot 1  |  off  | 150   | off   | off  |       |      | 75    | 75   |       |      |
+|Single Rank|Single Rank|----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|           |           |  Slot 2  |  off  | 150   | 75    | 75   |       |      | off   | off  |       |      |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+| Dual Rank |   Empty   |  Slot 1  |  off  | 75    | 150   | off  | off   | off  |       |      |       |      |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|   Empty   | Dual Rank |  Slot 2  |  off  | 75    |       |      |       |      | 150   | off  | off   | off  |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|Single Rank|   Empty   |  Slot 1  |  off  | 75    | 150   | off  |       |      |       |      |       |      |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+|   Empty   |Single Rank|  Slot 2  |  off  | 75    |       |      |       |      | 150   | off  |       |      |
++-----------+-----------+----------+-------+-------+-------+------+-------+------+-------+------+-------+------+
+
+Single slot system
++-------------+------------+---------------+-----------------------------+
+|             |            |DRAM controller|     Rank 1   |    Rank 2    |
+|Configuration| Write/Read |-------+-------+-------+------+-------+------+
+|             |            | Write | Read  | Write | Read | Write | Read |
++-------------+------------+-------+-------+-------+------+-------+------+
+|             |   R1       | off   | 75    | 150   | off  | off   | off  |
+|  Dual Rank  |------------+-------+-------+-------+------+-------+------+
+|             |   R2       | off   | 75    | 150   | off  | off   | off  |
++-------------+------------+-------+-------+-------+------+-------+------+
+| Single Rank |   R1       | off   | 75    | 150   | off  |
++-------------+------------+-------+-------+-------+------+
+
+Reference http://www.samsung.com/global/business/semiconductor/products/dram/downloads/applicationnote/ddr2_odt_control_200603.pdf
+