nb/via/cx700: Implement raminit

This brings the old raminit implementation for CX700 back. It was
removed in commit e99f0390b9b8 (Remove VIA CX700 northbridge sup-
port). The code is mostly unchanged, three minor issues are fixed:

* A shift (>>= 2) was missing when reading tRRD from SPD byte 28.
  The fixed value matches  what the vendor BIOS of a VIA EPIA-EX
  board programs. The code also suggests that we are looking for
  a small value (<= 19 for DDR2-533).

* We allow the board port to specify which clock outputs should
  be enabled now.  This is necessary for the VIA EPIA-EX, which
  needs the ALL_MCLKO setting  (instead of the previously hard-
  coded MCLKO2.

* When programming the DQS output delays, we considered the 1~2
  rank values only for single-rank configurations. Changing the
  `< 2` to `<= 2`  brings us closer to the vendor values on the
  VIA EPIA-EX.

Otherwise a lot of cosmetics changed. Partly because the original
code was to be #included into another C file, but also to satisfy
checkpatch. Also, all the #if'd code was removed (32-bit width
option, ECC, etc.).

Change-Id: Ibc36b4f314cdf47f18c8be0fcb98218c50938e94
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82770
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/northbridge/via/cx700/raminit.h b/src/northbridge/via/cx700/raminit.h
new file mode 100644
index 0000000000..811e3e1690
--- /dev/null
+++ b/src/northbridge/via/cx700/raminit.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __VIA_CX700_RAMINIT_H__
+#define __VIA_CX700_RAMINIT_H__
+
+struct dram_cfg;
+void sdram_enable(const struct dram_cfg *);
+
+#endif