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* [U-Boot] [PATCH] driver: fsl_qspi: disable AHB buffer prefetch
@ 2016-07-04  3:16 Yunhui Cui
  2016-07-06 17:00 ` york sun
  0 siblings, 1 reply; 5+ messages in thread
From: Yunhui Cui @ 2016-07-04  3:16 UTC (permalink / raw)
  To: u-boot

From: Yunhui Cui <yunhui.cui@nxp.com>

A-009282: QuadSPI: QuadSPI data pre-fetch can result in incorrect data
Affects: QuadSPI
Description: With AHB buffer prefetch enabled, the QuadSPI may return
incorrect data on the AHB interface. The buffer pre-fetch is enabled
if the fetch size as configured either in the LUT or in the BUFxCR register
is greater than 8 bytes.
Impact: Only 64 bit read allowed.
Workaround: Keep the read data size to 64 bits (8 Bytes), which disables
the prefetch on the AHB buffer,
and prevents this issue from occurring.

Signed-off-by: Yunhui Cui <yunhui.cui@nxp.com>
---
 drivers/spi/fsl_qspi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c
index 75cbab2..e0a002d 100644
--- a/drivers/spi/fsl_qspi.c
+++ b/drivers/spi/fsl_qspi.c
@@ -444,7 +444,7 @@ static void qspi_init_ahb_read(struct fsl_qspi_priv *priv)
 	qspi_write32(priv->flags, &regs->buf1cr, QSPI_BUFXCR_INVALID_MSTRID);
 	qspi_write32(priv->flags, &regs->buf2cr, QSPI_BUFXCR_INVALID_MSTRID);
 	qspi_write32(priv->flags, &regs->buf3cr, QSPI_BUF3CR_ALLMST_MASK |
-		     (0x80 << QSPI_BUF3CR_ADATSZ_SHIFT));
+		     (0x1 << QSPI_BUF3CR_ADATSZ_SHIFT));
 
 	/* We only use the buffer3 */
 	qspi_write32(priv->flags, &regs->buf0ind, 0);
-- 
2.1.0.27.g96db324

^ permalink raw reply related	[flat|nested] 5+ messages in thread
* [U-Boot] [PATCH] driver: fsl_qspi: disable AHB buffer prefetch
  2016-07-04  3:16 [U-Boot] [PATCH] driver: fsl_qspi: disable AHB buffer prefetch Yunhui Cui
@ 2016-07-06 17:00 ` york sun
  2016-07-07  7:52   ` Yunhui Cui
  0 siblings, 1 reply; 5+ messages in thread
From: york sun @ 2016-07-06 17:00 UTC (permalink / raw)
  To: u-boot

On 07/03/2016 08:27 PM, Yunhui Cui wrote:
> From: Yunhui Cui <yunhui.cui@nxp.com>
>
> A-009282: QuadSPI: QuadSPI data pre-fetch can result in incorrect data
> Affects: QuadSPI
> Description: With AHB buffer prefetch enabled, the QuadSPI may return
> incorrect data on the AHB interface. The buffer pre-fetch is enabled
> if the fetch size as configured either in the LUT or in the BUFxCR register
> is greater than 8 bytes.
> Impact: Only 64 bit read allowed.
> Workaround: Keep the read data size to 64 bits (8 Bytes), which disables
> the prefetch on the AHB buffer,
> and prevents this issue from occurring.
>
> Signed-off-by: Yunhui Cui <yunhui.cui@nxp.com>
> ---
>   drivers/spi/fsl_qspi.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c
> index 75cbab2..e0a002d 100644
> --- a/drivers/spi/fsl_qspi.c
> +++ b/drivers/spi/fsl_qspi.c
> @@ -444,7 +444,7 @@ static void qspi_init_ahb_read(struct fsl_qspi_priv *priv)
>   	qspi_write32(priv->flags, &regs->buf1cr, QSPI_BUFXCR_INVALID_MSTRID);
>   	qspi_write32(priv->flags, &regs->buf2cr, QSPI_BUFXCR_INVALID_MSTRID);
>   	qspi_write32(priv->flags, &regs->buf3cr, QSPI_BUF3CR_ALLMST_MASK |
> -		     (0x80 << QSPI_BUF3CR_ADATSZ_SHIFT));
> +		     (0x1 << QSPI_BUF3CR_ADATSZ_SHIFT));
>
>   	/* We only use the buffer3 */
>   	qspi_write32(priv->flags, &regs->buf0ind, 0);
>

Yunhui,

We handle erratum workaround using macros in case the workaround has 
impact on other SoCs. We also put the erratum information either in a 
README file, or inline comment. It will be easier to read the code 
later. You don't have to put the whole erratum description in the commit 
message, as long as it explains what this patch does and refer the 
erratum number somewhere in the message so we can search the git log.

York

^ permalink raw reply	[flat|nested] 5+ messages in thread
* [U-Boot] [PATCH] driver: fsl_qspi: disable AHB buffer prefetch
  2016-07-06 17:00 ` york sun
@ 2016-07-07  7:52   ` Yunhui Cui
  2016-07-07 14:54     ` york sun
  0 siblings, 1 reply; 5+ messages in thread
From: Yunhui Cui @ 2016-07-07  7:52 UTC (permalink / raw)
  To: u-boot


>On 07/07/2016 1:01 AM, york sun wrote: 
> On 07/03/2016 08:27 PM, Yunhui Cui wrote:
> > From: Yunhui Cui <yunhui.cui@nxp.com>
> >
> > A-009282: QuadSPI: QuadSPI data pre-fetch can result in incorrect data
> > Affects: QuadSPI
> > Description: With AHB buffer prefetch enabled, the QuadSPI may return
> > incorrect data on the AHB interface. The buffer pre-fetch is enabled
> > if the fetch size as configured either in the LUT or in the BUFxCR
> > register is greater than 8 bytes.
> > Impact: Only 64 bit read allowed.
> > Workaround: Keep the read data size to 64 bits (8 Bytes), which
> > disables the prefetch on the AHB buffer, and prevents this issue from
> > occurring.
> >
> > Signed-off-by: Yunhui Cui <yunhui.cui@nxp.com>
> > ---
> >   drivers/spi/fsl_qspi.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c index
> > 75cbab2..e0a002d 100644
> > --- a/drivers/spi/fsl_qspi.c
> > +++ b/drivers/spi/fsl_qspi.c
> > @@ -444,7 +444,7 @@ static void qspi_init_ahb_read(struct fsl_qspi_priv
> *priv)
> >   	qspi_write32(priv->flags, &regs->buf1cr,
> QSPI_BUFXCR_INVALID_MSTRID);
> >   	qspi_write32(priv->flags, &regs->buf2cr,
> QSPI_BUFXCR_INVALID_MSTRID);
> >   	qspi_write32(priv->flags, &regs->buf3cr, QSPI_BUF3CR_ALLMST_MASK |
> > -		     (0x80 << QSPI_BUF3CR_ADATSZ_SHIFT));
> > +		     (0x1 << QSPI_BUF3CR_ADATSZ_SHIFT));
> >
> >   	/* We only use the buffer3 */
> >   	qspi_write32(priv->flags, &regs->buf0ind, 0);
> >
> 
> Yunhui,
> 
> We handle erratum workaround using macros in case the workaround has
> impact on other SoCs.

[Yunhui] For now, all SoCs with Qspi module need this errata.

> We also put the erratum information either in a
> README file, or inline comment. It will be easier to read the code later.

[Yunhui] ok, I will add inline comment in next version.

> You don't have to put the whole erratum description in the commit message,
> as long as it explains what this patch does and refer the erratum number
> somewhere in the message so we can search the git log.
> 
> York

[Yunhui] ok, I will update the commit message in next version.

Thanks
Yunhui

^ permalink raw reply	[flat|nested] 5+ messages in thread
* [U-Boot] [PATCH] driver: fsl_qspi: disable AHB buffer prefetch
  2016-07-07  7:52   ` Yunhui Cui
@ 2016-07-07 14:54     ` york sun
  2016-07-11  7:52       ` Yunhui Cui
  0 siblings, 1 reply; 5+ messages in thread
From: york sun @ 2016-07-07 14:54 UTC (permalink / raw)
  To: u-boot

On 07/07/2016 12:52 AM, Yunhui Cui wrote:
>
>> On 07/07/2016 1:01 AM, york sun wrote:
>> On 07/03/2016 08:27 PM, Yunhui Cui wrote:
>>> From: Yunhui Cui <yunhui.cui@nxp.com>
>>>
>>> A-009282: QuadSPI: QuadSPI data pre-fetch can result in incorrect data
>>> Affects: QuadSPI
>>> Description: With AHB buffer prefetch enabled, the QuadSPI may return
>>> incorrect data on the AHB interface. The buffer pre-fetch is enabled
>>> if the fetch size as configured either in the LUT or in the BUFxCR
>>> register is greater than 8 bytes.
>>> Impact: Only 64 bit read allowed.
>>> Workaround: Keep the read data size to 64 bits (8 Bytes), which
>>> disables the prefetch on the AHB buffer, and prevents this issue from
>>> occurring.
>>>
>>> Signed-off-by: Yunhui Cui <yunhui.cui@nxp.com>
>>> ---
>>>    drivers/spi/fsl_qspi.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c index
>>> 75cbab2..e0a002d 100644
>>> --- a/drivers/spi/fsl_qspi.c
>>> +++ b/drivers/spi/fsl_qspi.c
>>> @@ -444,7 +444,7 @@ static void qspi_init_ahb_read(struct fsl_qspi_priv
>> *priv)
>>>    	qspi_write32(priv->flags, &regs->buf1cr,
>> QSPI_BUFXCR_INVALID_MSTRID);
>>>    	qspi_write32(priv->flags, &regs->buf2cr,
>> QSPI_BUFXCR_INVALID_MSTRID);
>>>    	qspi_write32(priv->flags, &regs->buf3cr, QSPI_BUF3CR_ALLMST_MASK |
>>> -		     (0x80 << QSPI_BUF3CR_ADATSZ_SHIFT));
>>> +		     (0x1 << QSPI_BUF3CR_ADATSZ_SHIFT));
>>>
>>>    	/* We only use the buffer3 */
>>>    	qspi_write32(priv->flags, &regs->buf0ind, 0);
>>>
>>
>> Yunhui,
>>
>> We handle erratum workaround using macros in case the workaround has
>> impact on other SoCs.
>
> [Yunhui] For now, all SoCs with Qspi module need this errata.

I still think it is better to gate the workaround with #ifdef in case we 
need to disable it for future SoCs. It will also be easier to locate the 
workaround code.

>
>> We also put the erratum information either in a
>> README file, or inline comment. It will be easier to read the code later.
>
> [Yunhui] ok, I will add inline comment in next version.
>
>> You don't have to put the whole erratum description in the commit message,
>> as long as it explains what this patch does and refer the erratum number
>> somewhere in the message so we can search the git log.
>>
>> York
>
> [Yunhui] ok, I will update the commit message in next version.
>

Thanks.

York

^ permalink raw reply	[flat|nested] 5+ messages in thread
* [U-Boot] [PATCH] driver: fsl_qspi: disable AHB buffer prefetch
  2016-07-07 14:54     ` york sun
@ 2016-07-11  7:52       ` Yunhui Cui
  0 siblings, 0 replies; 5+ messages in thread
From: Yunhui Cui @ 2016-07-11  7:52 UTC (permalink / raw)
  To: u-boot



On 07/07/2016 10:55 PM, York wrote:
> On 07/07/2016 12:52 AM, Yunhui Cui wrote:
> >
> >> On 07/07/2016 1:01 AM, york sun wrote:
> >> On 07/03/2016 08:27 PM, Yunhui Cui wrote:
> >>> From: Yunhui Cui <yunhui.cui@nxp.com>
> >>>
> >>> A-009282: QuadSPI: QuadSPI data pre-fetch can result in incorrect
> >>> data
> >>> Affects: QuadSPI
> >>> Description: With AHB buffer prefetch enabled, the QuadSPI may
> >>> return incorrect data on the AHB interface. The buffer pre-fetch is
> >>> enabled if the fetch size as configured either in the LUT or in the
> >>> BUFxCR register is greater than 8 bytes.
> >>> Impact: Only 64 bit read allowed.
> >>> Workaround: Keep the read data size to 64 bits (8 Bytes), which
> >>> disables the prefetch on the AHB buffer, and prevents this issue
> >>> from occurring.
> >>>
> >>> Signed-off-by: Yunhui Cui <yunhui.cui@nxp.com>
> >>> ---
> >>>    drivers/spi/fsl_qspi.c | 2 +-
> >>>    1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c index
> >>> 75cbab2..e0a002d 100644
> >>> --- a/drivers/spi/fsl_qspi.c
> >>> +++ b/drivers/spi/fsl_qspi.c
> >>> @@ -444,7 +444,7 @@ static void qspi_init_ahb_read(struct
> >>> fsl_qspi_priv
> >> *priv)
> >>>    	qspi_write32(priv->flags, &regs->buf1cr,
> >> QSPI_BUFXCR_INVALID_MSTRID);
> >>>    	qspi_write32(priv->flags, &regs->buf2cr,
> >> QSPI_BUFXCR_INVALID_MSTRID);
> >>>    	qspi_write32(priv->flags, &regs->buf3cr,
> QSPI_BUF3CR_ALLMST_MASK |
> >>> -		     (0x80 << QSPI_BUF3CR_ADATSZ_SHIFT));
> >>> +		     (0x1 << QSPI_BUF3CR_ADATSZ_SHIFT));
> >>>
> >>>    	/* We only use the buffer3 */
> >>>    	qspi_write32(priv->flags, &regs->buf0ind, 0);
> >>>
> >>
> >> Yunhui,
> >>
> >> We handle erratum workaround using macros in case the workaround has
> >> impact on other SoCs.
> >
> > [Yunhui] For now, all SoCs with Qspi module need this errata.
> 
> I still think it is better to gate the workaround with #ifdef in case we
> need to disable it for future SoCs. It will also be easier to locate the
> workaround code.

[Yunhui] ok, I will update it in v2, thanks.

> 
> >
> >> We also put the erratum information either in a
> >> README file, or inline comment. It will be easier to read the code
> later.
> >
> > [Yunhui] ok, I will add inline comment in next version.
> >
> >> You don't have to put the whole erratum description in the commit
> message,
> >> as long as it explains what this patch does and refer the erratum
> number
> >> somewhere in the message so we can search the git log.
> >>
> >> York
> >
> > [Yunhui] ok, I will update the commit message in next version.
> >
> 
> Thanks.
> 
> York
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-07-11  7:52 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-07-04  3:16 [U-Boot] [PATCH] driver: fsl_qspi: disable AHB buffer prefetch Yunhui Cui
2016-07-06 17:00 ` york sun
2016-07-07  7:52   ` Yunhui Cui
2016-07-07 14:54     ` york sun
2016-07-11  7:52       ` Yunhui Cui

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