On Wed, Feb 8, 2012 at 3:44 AM, Hatim Ali hatim.rv@samsung.com wrote:
SMDK5250 development boards have different memory variants like DDR3, LPDDR2 and LPDDR3. This patch adds supports for DDR3. The DDR3 is configured for 667Mhz and is being enabled by default.
One other note: the SDRAM doesn't appear to be stable with the current CL as is. Specifically, I ran this test:
Load two copies of vmlinuz:
Hit any key to stop autoboot: 0 SMDK5250 # mmc rescan 0 SMDK5250 # fatload mmc 0:c 0x42000000 vmlinuz reading vmlinuz
3272888 bytes read SMDK5250 # fatload mmc 0:c 0x40008000 vmlinuz reading vmlinuz
3272888 bytes read
Now compare them:
SMDK5250 # cmp.l 0x40008000 0x42000000 3272888 word at 0x400097fc (0xe3160024) != word at 0x420017fc (0xe3160020) Total of 1535 words were the same
...but if you look at that memory, it's the same!
SMDK5250 # md.l 0x420017fc 1 420017fc: e3160020 ... SMDK5250 # md.l 0x400097fc 1 400097fc: e3160020 ...
...in this case, re-running the cmp.l still showed the difference (?)
Running RAM at 400MHz didn't show the same problem. NOTE: that doesn't prove the the problem is related to SDRAM stability, but it sure looks suspicious.
-Doug