[U-Boot-Users] [PATCH] Enable the isdram command on the MPC8360EMDS board

[Jon Loeliger <jdl@freescale.com>]

On Sat, 2008-01-12 at 12:24, Jerry Van Baren wrote:

> Hi Kim,
> 
> The isdram command is controlled separately from the rest of the i2c
> commands (CONFIG_CMD_I2C + CONFIG_CMD_SDRAM).  I did this originally
> because the isdram command was arguably a memory consuming luxury.
> Luxuries tend to become necessities over time...
> 
> Larry Johnson submitted a patch yesterday to extend the decoding and
> printout to include DDR2 fields, making this even more useful (and jdl
> is claiming a share of the credit ;-).
> 
> gvb

I'm not claiming any credit for it, but if I do the
following command:

    $ git show d9b94f28a442b001 -- cpu/mpc85xx/spd_sdram.c

Someone who impersonated me quite well appears to have
checked in whole bunch of DDR2 decode stuff way back in
July of 2005.

For example:

+/*
+ * Convert a two-nibble BCD value into a cycle time.
+ * While the spec calls for nano-seconds, picos are returned.
+ *
+ * This implements the tables for bytes 9, 23 and 25 for both
+ * DDR I and II.  No allowance for distinguishing the invalid
+ * fields absent for DDR I yet present in DDR II is made.
+ * (That is, cycle times of .25, .33, .66 and .75 ns are
+ * allowed for both DDR II and I.)
+ */
+
 unsigned int
-banksize(unsigned char row_dens)
+convert_bcd_tenths_to_cycle_time_ps(unsigned int spd_val)
 {
-       return ((row_dens >> 2) | ((row_dens & 3) << 6)) << 24;
+       /*
+        * Table look up the lower nibble, allow DDR I & II.
+        */
+       unsigned int tenths_ps[16] = {
+               0,
+               100,
+               200,
+               300,
+               400,
+               500,
+               600,
+               700,
+               800,
+               900,
+               250,
+               330,    /* FIXME: Is 333 better/valid? */
+               660,    /* FIXME: Is 667 better/valid? */
+               750,
+               0,      /* undefined */
+               0       /* undefined */
+       };
+

Weird, huh?

jdl