On Mon, 2014-02-24 at 14:44 +0800, Tang Yuantian-B29983 wrote:
On 2014/2/18 ζζδΊ 3:18, Scott Wood wrote:
On Sun, 2014-02-16 at 21:35 -0600, Tang Yuantian-B29983 wrote:
-----Original Message----- From: Wood Scott-B07421 To: Tang Yuantian-B29983 Cc: Sun York-R58495; Li Yang-Leo-R58472; u-boot@lists.denx.de; Kushwaha Prabhakar-B32579; Jin Zhengxiong-R64188 Subject: Re: [U-Boot,2/3] mpc85xx: Add deep sleep framework support
On Thu, 2014-02-13 at 02:12 -0600, Tang Yuantian-B29983 wrote:
Use an I/O accessor.
In_be64?? No such function.
Why do you need in_be64() rather than two in_be32()s?
Avoid ECC error. Although, according to my test, in_be32() works too.
Why would you get an ECC error?
-Scott
DDR operation is always in 64bits. if writing a 32bits to memory, you need to read a 32bits first, and combine it to form a 64bits. when the new 64bits is written to memory, ECC occurs. I was required to do so by hardware team.
U-Boot on PPC is a 32-bit binary (even on 64-bit hardware), so the compiler is already turning that into two 32-bit writes.
-Scott