[U-Boot] [PATCH] armv8/ls1043a: Add the OCRAM initialization

From: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] armv8/ls1043a: Add the OCRAM initialization
Date: Sun, 23 Oct 2016 13:59:13 +0000	[thread overview]
Message-ID: <DB5PR0401MB195897BC072E3594516E530A97D60@DB5PR0401MB1958.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <AM4PR0401MB1732A6BEF7ACF9585727C53C9AD40@AM4PR0401MB1732.eurprd04.prod.outlook.com>

Hi York,

> -----Original Message-----
> From: york sun
> Sent: Saturday, October 22, 2016 1:39 AM
> To: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>; Pratiyush Srivastava
> <pratiyush.srivastava@nxp.com>; u-boot at lists.denx.de; Mingkai Hu
> <mingkai.hu@nxp.com>
> Cc: Hou Zhiqiang <Zhiqiang.Hou@freescale.com>
> Subject: Re: [PATCH] armv8/ls1043a: Add the OCRAM initialization
> 
> On 10/16/2016 10:35 PM, Prabhakar Kushwaha wrote:
> > Hi Mingkai,
> >
> >> -----Original Message-----
> >> From: Pratiyush Srivastava [mailto:pratiyush.srivastava at nxp.com]
> >> Sent: Wednesday, October 12, 2016 5:46 PM
> >> To: u-boot at lists.denx.de
> >> Cc: york sun <york.sun@nxp.com>; Prabhakar Kushwaha
> >> <prabhakar.kushwaha@nxp.com>; Pratiyush Srivastava
> >> <pratiyush.srivastava@nxp.com>; Hou Zhiqiang
> <Zhiqiang.Hou@freescale.com>
> >> Subject: [PATCH] armv8/ls1043a: Add the OCRAM initialization
> >>
> >> Clear the content to zero and the ECC error bit of OCRAM1/2.
> >>
> >> The OCRAM must be initialized to ZERO by the unit of 8-Byte before
> >> accessing it, or else it will generate ECC error. And the IBR has
> >> accessed the OCRAM before this initialization, so the ECC error
> >> status bit should to be cleared.
> >>
> >> Signed-off-by: Pratiyush Srivastava <pratiyush.srivastava@nxp.com>
> >> Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@freescale.com>
> >> Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
> >> ---
> >
> > This requirement is for both ls1043 and ls1088a.  was this patch taken care
> during ls1043a upstreaming
> > If not, how it is being taken care for ls1043a.  Same approach can be used for
> ls1088a
> >
> 
> I wonder why we don't see ECC errors before this patch. We have LS1043A
> boots on NAND, SD.
> 

OCRAM has a requirement of initializing before first time "read". 
If user reads OCRAM before **initializing**; ECC error will come.  (u-boot is not handling this error for now).

I can only guess the reason of not seeing this error as OCRAM never read before any write.
Even in case of Stack, data is first written and then read.

--prabhakar