[U-Boot] [PATCH] driver/ddr/fsl: Force enabling parity for A-009803
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 *
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
-----Original Message----- From: York Sun [mailto:york.sun@nxp.com] Sent: Friday, May 20, 2016 11:29 PM To: Shengzhou Liu shengzhou.liu@nxp.com; u-boot@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
On 05/23/2016 02:18 AM, Shengzhou Liu wrote:
-----Original Message----- From: York Sun [mailto:york.sun@nxp.com] Sent: Friday, May 20, 2016 11:29 PM To: Shengzhou Liu shengzhou.liu@nxp.com; u-boot@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
-----Original Message----- From: York Sun [mailto:york.sun@nxp.com] Sent: Monday, May 23, 2016 11:33 PM To: Shengzhou Liu shengzhou.liu@nxp.com; u-boot@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
On 05/23/2016 10:15 PM, Shengzhou Liu wrote:
-----Original Message----- From: York Sun [mailto:york.sun@nxp.com] Sent: Monday, May 23, 2016 11:33 PM To: Shengzhou Liu shengzhou.liu@nxp.com; u-boot@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
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