* [U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
@ 2016-05-20 8:05 Shengzhou Liu
2016-05-20 15:29 ` York Sun
0 siblings, 1 reply; 6+ messages in thread
From: Shengzhou Liu @ 2016-05-20 8:05 UTC (permalink / raw)
To: u-boot
Default address parity is disabled for DDR4 UDIMM for considing
performance, it needs to enable parity for A-009803 workaround.
Signed-off-by: Shengzhou Liu <Shengzhou.Liu@nxp.com>
---
drivers/ddr/fsl/options.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/ddr/fsl/options.c b/drivers/ddr/fsl/options.c
index d0075ff..dcef0bb 100644
--- a/drivers/ddr/fsl/options.c
+++ b/drivers/ddr/fsl/options.c
@@ -1016,6 +1016,9 @@ unsigned int populate_memctl_options(const common_timing_params_t *common_dimm,
}
}
+#ifdef CONFIG_SYS_FSL_ERRATUM_A009803
+ popts->ap_en = 1;
+#endif
/*
* BSTTOPRE precharge interval
*
--
2.1.0.27.g96db324
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
2016-05-20 8:05 [U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803 Shengzhou Liu
@ 2016-05-20 15:29 ` York Sun
2016-05-23 9:18 ` Shengzhou Liu
0 siblings, 1 reply; 6+ messages in thread
From: York Sun @ 2016-05-20 15:29 UTC (permalink / raw)
To: u-boot
On 05/20/2016 01:15 AM, Shengzhou Liu wrote:
> Default address parity is disabled for DDR4 UDIMM for considing
> performance, it needs to enable parity for A-009803 workaround.
>
> Signed-off-by: Shengzhou Liu <Shengzhou.Liu@nxp.com>
> ---
> drivers/ddr/fsl/options.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/ddr/fsl/options.c b/drivers/ddr/fsl/options.c
> index d0075ff..dcef0bb 100644
> --- a/drivers/ddr/fsl/options.c
> +++ b/drivers/ddr/fsl/options.c
> @@ -1016,6 +1016,9 @@ unsigned int populate_memctl_options(const common_timing_params_t *common_dimm,
> }
> }
>
> +#ifdef CONFIG_SYS_FSL_ERRATUM_A009803
> + popts->ap_en = 1;
> +#endif
> /*
> * BSTTOPRE precharge interval
> *
>
Shengzhou,
It looks backward. You should detect if the condition is right before applying
the workaround, not by forcing the condition.
York
^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
2016-05-20 15:29 ` York Sun
@ 2016-05-23 9:18 ` Shengzhou Liu
2016-05-23 15:33 ` York Sun
0 siblings, 1 reply; 6+ messages in thread
From: Shengzhou Liu @ 2016-05-23 9:18 UTC (permalink / raw)
To: u-boot
> -----Original Message-----
> From: York Sun [mailto:york.sun at nxp.com]
> Sent: Friday, May 20, 2016 11:29 PM
> To: Shengzhou Liu <shengzhou.liu@nxp.com>; u-boot at lists.denx.de
> Subject: Re: [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
> >
>
> Shengzhou,
>
> It looks backward. You should detect if the condition is right before
> applying the workaround, not by forcing the condition.
>
> York
If ERRATUM_A009803 is defined, ap_en should always be enabled whatever user configures parity=on in hwconfig.
As ERRATUM_A009803 is enabled only in arch-fsl-layerscape/config.h for LS2 SoC, I don't think we need to check anything other.
What condition do you mean?
-Shengzhou
^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
2016-05-23 9:18 ` Shengzhou Liu
@ 2016-05-23 15:33 ` York Sun
2016-05-24 5:15 ` Shengzhou Liu
0 siblings, 1 reply; 6+ messages in thread
From: York Sun @ 2016-05-23 15:33 UTC (permalink / raw)
To: u-boot
On 05/23/2016 02:18 AM, Shengzhou Liu wrote:
>> -----Original Message-----
>> From: York Sun [mailto:york.sun at nxp.com]
>> Sent: Friday, May 20, 2016 11:29 PM
>> To: Shengzhou Liu <shengzhou.liu@nxp.com>; u-boot at lists.denx.de
>> Subject: Re: [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
>>>
>>
>> Shengzhou,
>>
>> It looks backward. You should detect if the condition is right before
>> applying the workaround, not by forcing the condition.
>>
>> York
>
> If ERRATUM_A009803 is defined, ap_en should always be enabled whatever user configures parity=on in hwconfig.
> As ERRATUM_A009803 is enabled only in arch-fsl-layerscape/config.h for LS2 SoC, I don't think we need to check anything other.
> What condition do you mean?
>
Shengzhou,
My point is you should force ap=1. Do you mean if ERRATUM_A009803 is enabled,
users are forced to use address parity? That doesn't sound right. We have been
running UDIMM without address parity for a long time.
York
^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
2016-05-23 15:33 ` York Sun
@ 2016-05-24 5:15 ` Shengzhou Liu
2016-05-24 16:13 ` York Sun
0 siblings, 1 reply; 6+ messages in thread
From: Shengzhou Liu @ 2016-05-24 5:15 UTC (permalink / raw)
To: u-boot
> -----Original Message-----
> From: York Sun [mailto:york.sun at nxp.com]
> Sent: Monday, May 23, 2016 11:33 PM
> To: Shengzhou Liu <shengzhou.liu@nxp.com>; u-boot at lists.denx.de
> Subject: Re: [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
> Shengzhou,
>
> My point is you should force ap=1. Do you mean if ERRATUM_A009803 is
> enabled, users are forced to use address parity? That doesn't sound right.
> We have been running UDIMM without address parity for a long time.
>
> York
>
York,
My understanding is that ERRATUM_A009803 may still happen whatever ap_en is enabled or disabled.
To apply the workaround of A009803, it requires ap_en is enabled. Is your understanding that if we
disable ap_en, ERRATUM_A009803 will never happen? The CE document doesn't explain clearly this.
In last mail, did you mean we should force ap_en = 0 in case of A-009803?
Shengzhou
^ permalink raw reply [flat|nested] 6+ messages in thread
* [U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
2016-05-24 5:15 ` Shengzhou Liu
@ 2016-05-24 16:13 ` York Sun
0 siblings, 0 replies; 6+ messages in thread
From: York Sun @ 2016-05-24 16:13 UTC (permalink / raw)
To: u-boot
On 05/23/2016 10:15 PM, Shengzhou Liu wrote:
>
>> -----Original Message-----
>> From: York Sun [mailto:york.sun at nxp.com]
>> Sent: Monday, May 23, 2016 11:33 PM
>> To: Shengzhou Liu <shengzhou.liu@nxp.com>; u-boot at lists.denx.de
>> Subject: Re: [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
>> Shengzhou,
>>
>> My point is you should force ap=1. Do you mean if ERRATUM_A009803 is
>> enabled, users are forced to use address parity? That doesn't sound right.
>> We have been running UDIMM without address parity for a long time.
>>
>> York
>>
> York,
> My understanding is that ERRATUM_A009803 may still happen whatever ap_en is enabled or disabled.
> To apply the workaround of A009803, it requires ap_en is enabled. Is your understanding that if we
> disable ap_en, ERRATUM_A009803 will never happen? The CE document doesn't explain clearly this.
> In last mail, did you mean we should force ap_en = 0 in case of A-009803?
>
Sorry I had a typo. I meant you should NOT force ap=1. Let me explain.
The erratum tells you _if_ address parity is used, for either UDIMM or RDIMM,
you need to implement the workaround, as step 1, 2, 3, ... We understand users
don't have a choice for RDIMM, the address parity is always enabled. But for
UDIMM, users can choose not to enable it. Your _this_ patch forces the address
parity to be true, regardless of user's choice. I think this is wrong.
The erratum always applies to affected SoCs, but the address parity is not
always enabled. That's what I meant for "condition".
York
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-05-24 16:13 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-05-20 8:05 [U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803 Shengzhou Liu
2016-05-20 15:29 ` York Sun
2016-05-23 9:18 ` Shengzhou Liu
2016-05-23 15:33 ` York Sun
2016-05-24 5:15 ` Shengzhou Liu
2016-05-24 16:13 ` York Sun
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