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Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch

Started byHan Xu <han.xu@nxp.com>
First post2016-04-21 01:20 +0200
Last post2016-04-22 09:10 +0200
Articles 6 — 2 participants

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  Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch Han Xu <han.xu@nxp.com> - 2016-04-21 01:20 +0200
    RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch Yunhui Cui <yunhui.cui@nxp.com> - 2016-04-21 11:50 +0200
      Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch Han Xu <han.xu@nxp.com> - 2016-04-21 17:50 +0200
        RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch Yunhui Cui <yunhui.cui@nxp.com> - 2016-04-22 06:00 +0200
          Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch Han Xu <han.xu@nxp.com> - 2016-04-22 06:50 +0200
            RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch Yunhui Cui <yunhui.cui@nxp.com> - 2016-04-22 09:10 +0200

#1383793 — Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch

FromHan Xu <han.xu@nxp.com>
Date2016-04-21 01:20 +0200
SubjectRe: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
Message-ID<rq9zA-7El-7@gated-at.bofh.it>

________________________________________
From: Yunhui Cui <B56489@freescale.com>
Sent: Wednesday, April 13, 2016 9:50 PM
To: dwmw2@infradead.org; computersforpeace@gmail.com; han.xu@freescale.com
Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-arm-kernel@lists.infradead.org; Yao Yuan; Yunhui Cui
Subject: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch

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/mtd/spi-nor/fsl-quadspi.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-quadspi.c
index fea18b6..d9f3e50 100644
--- a/drivers/mtd/spi-nor/fsl-quadspi.c
+++ b/drivers/mtd/spi-nor/fsl-quadspi.c
@@ -752,19 +752,36 @@ static void fsl_qspi_init_abh_read(struct fsl_qspi *q)
 {
        void __iomem *base = q->iobase;
        int seqid;
+       const struct fsl_qspi_devtype_data *devtype_data = q->devtype_data;

        /* AHB configuration for access buffer 0/1/2 .*/
        qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base + QUADSPI_BUF0CR);
        qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base + QUADSPI_BUF1CR);
        qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base + QUADSPI_BUF2CR);
+
        /*
-        * Set ADATSZ with the maximum AHB buffer size to improve the
-        * read performance.
+        * Errata: A-009282: QuadSPI data prefetch may result in incorrect data
+        * Workaround: Keep the read data size to 64 bits (8 bytes).
+        * This disables the prefetch on the AHB buffer and
+        * prevents this issue from occurring.
         */
-       qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
-                       ((q->devtype_data->ahb_buf_size / 8)
-                       << QUADSPI_BUF3CR_ADATSZ_SHIFT),
-                       base + QUADSPI_BUF3CR);
+       if (devtype_data->devtype == FSL_QUADSPI_LS2080A ||
+           devtype_data->devtype == FSL_QUADSPI_LS1021A) {

Use QUIRK, not SoC name.
+
+               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
+                               (1 << QUADSPI_BUF3CR_ADATSZ_SHIFT),
+                               base + QUADSPI_BUF3CR);
+
+       } else {
+               /*
+                * Set ADATSZ with the maximum AHB buffer size to improve the
+                * read performance.
+               */
+               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
+                               ((q->devtype_data->ahb_buf_size / 8)
+                               << QUADSPI_BUF3CR_ADATSZ_SHIFT),
+                               base + QUADSPI_BUF3CR);
+       }

        /* We only use the buffer3 */
        qspi_writel(q, 0, base + QUADSPI_BUF0IND);
--
2.1.0.27.g96db324

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#1384020

FromYunhui Cui <yunhui.cui@nxp.com>
Date2016-04-21 11:50 +0200
Message-ID<rqjph-74z-15@gated-at.bofh.it>
In reply to#1383793
On Thu, Apr 24, 2016 at 06:37:01 AM +0800, Han Xu wrote:
> ________________________________________
> From: Yunhui Cui <B56489@freescale.com>
> Sent: Wednesday, April 13, 2016 9:50 PM
> To: dwmw2@infradead.org; computersforpeace@gmail.com;
> han.xu@freescale.com
> Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-
> arm-kernel@lists.infradead.org; Yao Yuan; Yunhui Cui
> Subject: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> 
> 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/mtd/spi-nor/fsl-quadspi.c | 29 +++++++++++++++++++++++------
>  1 file changed, 23 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-
> quadspi.c
> index fea18b6..d9f3e50 100644
> --- a/drivers/mtd/spi-nor/fsl-quadspi.c
> +++ b/drivers/mtd/spi-nor/fsl-quadspi.c
> @@ -752,19 +752,36 @@ static void fsl_qspi_init_abh_read(struct fsl_qspi
> *q)  {
>         void __iomem *base = q->iobase;
>         int seqid;
> +       const struct fsl_qspi_devtype_data *devtype_data =
> + q->devtype_data;
> 
>         /* AHB configuration for access buffer 0/1/2 .*/
>         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> QUADSPI_BUF0CR);
>         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> QUADSPI_BUF1CR);
>         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> QUADSPI_BUF2CR);
> +
>         /*
> -        * Set ADATSZ with the maximum AHB buffer size to improve the
> -        * read performance.
> +        * Errata: A-009282: QuadSPI data prefetch may result in
> incorrect data
> +        * Workaround: Keep the read data size to 64 bits (8 bytes).
> +        * This disables the prefetch on the AHB buffer and
> +        * prevents this issue from occurring.
>          */
> -       qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> -                       ((q->devtype_data->ahb_buf_size / 8)
> -                       << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> -                       base + QUADSPI_BUF3CR);
> +       if (devtype_data->devtype == FSL_QUADSPI_LS2080A ||
> +           devtype_data->devtype == FSL_QUADSPI_LS1021A) {
> 
> Use QUIRK, not SoC name.
[Yunhui] This is a SoC errata, we need distinguish according to the devtype_data->devtype
> +
> +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> +                               (1 << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> +                               base + QUADSPI_BUF3CR);
> +
> +       } else {
> +               /*
> +                * Set ADATSZ with the maximum AHB buffer size to improve
> the
> +                * read performance.
> +               */
> +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> +                               ((q->devtype_data->ahb_buf_size / 8)
> +                               << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> +                               base + QUADSPI_BUF3CR);
> +       }
> 
>         /* We only use the buffer3 */
>         qspi_writel(q, 0, base + QUADSPI_BUF0IND);
> --
> 2.1.0.27.g96db324

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#1384380

FromHan Xu <han.xu@nxp.com>
Date2016-04-21 17:50 +0200
Message-ID<rqp1E-316-13@gated-at.bofh.it>
In reply to#1384020

________________________________________
From: Yunhui Cui
Sent: Thursday, April 21, 2016 3:41 AM
To: Han Xu; Yunhui Cui; dwmw2@infradead.org; computersforpeace@gmail.com; han.xu@freescale.com
Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-arm-kernel@lists.infradead.org; Yao Yuan
Subject: RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch

On Thu, Apr 24, 2016 at 06:37:01 AM +0800, Han Xu wrote:
> ________________________________________
> From: Yunhui Cui <B56489@freescale.com>
> Sent: Wednesday, April 13, 2016 9:50 PM
> To: dwmw2@infradead.org; computersforpeace@gmail.com;
> han.xu@freescale.com
> Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-
> arm-kernel@lists.infradead.org; Yao Yuan; Yunhui Cui
> Subject: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
>
> 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/mtd/spi-nor/fsl-quadspi.c | 29 +++++++++++++++++++++++------
>  1 file changed, 23 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-
> quadspi.c
> index fea18b6..d9f3e50 100644
> --- a/drivers/mtd/spi-nor/fsl-quadspi.c
> +++ b/drivers/mtd/spi-nor/fsl-quadspi.c
> @@ -752,19 +752,36 @@ static void fsl_qspi_init_abh_read(struct fsl_qspi
> *q)  {
>         void __iomem *base = q->iobase;
>         int seqid;
> +       const struct fsl_qspi_devtype_data *devtype_data =
> + q->devtype_data;
>
>         /* AHB configuration for access buffer 0/1/2 .*/
>         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> QUADSPI_BUF0CR);
>         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> QUADSPI_BUF1CR);
>         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> QUADSPI_BUF2CR);
> +
>         /*
> -        * Set ADATSZ with the maximum AHB buffer size to improve the
> -        * read performance.
> +        * Errata: A-009282: QuadSPI data prefetch may result in
> incorrect data
> +        * Workaround: Keep the read data size to 64 bits (8 bytes).
> +        * This disables the prefetch on the AHB buffer and
> +        * prevents this issue from occurring.
>          */
> -       qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> -                       ((q->devtype_data->ahb_buf_size / 8)
> -                       << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> -                       base + QUADSPI_BUF3CR);
> +       if (devtype_data->devtype == FSL_QUADSPI_LS2080A ||
> +           devtype_data->devtype == FSL_QUADSPI_LS1021A) {
>
> Use QUIRK, not SoC name.
[Yunhui] This is a SoC errata, we need distinguish according to the devtype_data->devtype

It's the same thing and we have already done that before.

/*
 * TKT253890, Controller needs driver to fill txfifo till 16 byte to
 * trigger data transfer even though extra data will not transferred.
 */
#define QUADSPI_QUIRK_TKT253890         (1 << 2)
/* Controller cannot wake up from wait mode, TKT245618 */
#define QUADSPI_QUIRK_TKT245618         (1 << 3)


> +
> +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> +                               (1 << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> +                               base + QUADSPI_BUF3CR);
> +
> +       } else {
> +               /*
> +                * Set ADATSZ with the maximum AHB buffer size to improve
> the
> +                * read performance.
> +               */
> +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> +                               ((q->devtype_data->ahb_buf_size / 8)
> +                               << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> +                               base + QUADSPI_BUF3CR);
> +       }
>
>         /* We only use the buffer3 */
>         qspi_writel(q, 0, base + QUADSPI_BUF0IND);
> --
> 2.1.0.27.g96db324

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#1384681

FromYunhui Cui <yunhui.cui@nxp.com>
Date2016-04-22 06:00 +0200
Message-ID<rqAq5-3Ea-9@gated-at.bofh.it>
In reply to#1384380

> -----Original Message-----
> From: Han Xu
> Sent: Thursday, April 21, 2016 11:48 PM
> To: Yunhui Cui; Yunhui Cui; dwmw2@infradead.org;
> computersforpeace@gmail.com; han.xu@freescale.com
> Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-
> arm-kernel@lists.infradead.org; Yao Yuan
> Subject: Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> 
> 
> 
> ________________________________________
> From: Yunhui Cui
> Sent: Thursday, April 21, 2016 3:41 AM
> To: Han Xu; Yunhui Cui; dwmw2@infradead.org; computersforpeace@gmail.com;
> han.xu@freescale.com
> Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-
> arm-kernel@lists.infradead.org; Yao Yuan
> Subject: RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> 
> On Thu, Apr 24, 2016 at 06:37:01 AM +0800, Han Xu wrote:
> > ________________________________________
> > From: Yunhui Cui <B56489@freescale.com>
> > Sent: Wednesday, April 13, 2016 9:50 PM
> > To: dwmw2@infradead.org; computersforpeace@gmail.com;
> > han.xu@freescale.com
> > Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org;
> > linux- arm-kernel@lists.infradead.org; Yao Yuan; Yunhui Cui
> > Subject: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> >
> > 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/mtd/spi-nor/fsl-quadspi.c | 29 +++++++++++++++++++++++------
> >  1 file changed, 23 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c
> > b/drivers/mtd/spi-nor/fsl- quadspi.c index fea18b6..d9f3e50 100644
> > --- a/drivers/mtd/spi-nor/fsl-quadspi.c
> > +++ b/drivers/mtd/spi-nor/fsl-quadspi.c
> > @@ -752,19 +752,36 @@ static void fsl_qspi_init_abh_read(struct
> > fsl_qspi
> > *q)  {
> >         void __iomem *base = q->iobase;
> >         int seqid;
> > +       const struct fsl_qspi_devtype_data *devtype_data =
> > + q->devtype_data;
> >
> >         /* AHB configuration for access buffer 0/1/2 .*/
> >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > QUADSPI_BUF0CR);
> >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > QUADSPI_BUF1CR);
> >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > QUADSPI_BUF2CR);
> > +
> >         /*
> > -        * Set ADATSZ with the maximum AHB buffer size to improve the
> > -        * read performance.
> > +        * Errata: A-009282: QuadSPI data prefetch may result in
> > incorrect data
> > +        * Workaround: Keep the read data size to 64 bits (8 bytes).
> > +        * This disables the prefetch on the AHB buffer and
> > +        * prevents this issue from occurring.
> >          */
> > -       qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > -                       ((q->devtype_data->ahb_buf_size / 8)
> > -                       << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > -                       base + QUADSPI_BUF3CR);
> > +       if (devtype_data->devtype == FSL_QUADSPI_LS2080A ||
> > +           devtype_data->devtype == FSL_QUADSPI_LS1021A) {
> >
> > Use QUIRK, not SoC name.
> [Yunhui] This is a SoC errata, we need distinguish according to the
> devtype_data->devtype
> 
> It's the same thing and we have already done that before.

> [Yunhui] your mean that I should add such as the following code:
	#define QUADSPI_QUIRK_ERRATA_9282         (1 << 4)
	static inline int has_errata_num_a009282(struct fsl_qspi *q)
	{
        	 return q->devtype_data->driver_data & QUADSPI_QUIRK_ERRATA_9282;
	}

> /*
>  * TKT253890, Controller needs driver to fill txfifo till 16 byte to
>  * trigger data transfer even though extra data will not transferred.
>  */
> #define QUADSPI_QUIRK_TKT253890         (1 << 2)
> /* Controller cannot wake up from wait mode, TKT245618 */
> #define QUADSPI_QUIRK_TKT245618         (1 << 3)
> 
> 
> > +
> > +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > +                               (1 << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > +                               base + QUADSPI_BUF3CR);
> > +
> > +       } else {
> > +               /*
> > +                * Set ADATSZ with the maximum AHB buffer size to
> > + improve
> > the
> > +                * read performance.
> > +               */
> > +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > +                               ((q->devtype_data->ahb_buf_size / 8)
> > +                               << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > +                               base + QUADSPI_BUF3CR);
> > +       }
> >
> >         /* We only use the buffer3 */
> >         qspi_writel(q, 0, base + QUADSPI_BUF0IND);
> > --
> > 2.1.0.27.g96db324

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#1384693

FromHan Xu <han.xu@nxp.com>
Date2016-04-22 06:50 +0200
Message-ID<rqBcu-4nA-9@gated-at.bofh.it>
In reply to#1384681

________________________________________
From: Yunhui Cui
Sent: Thursday, April 21, 2016 9:52 PM
To: Han Xu; Yunhui Cui; dwmw2@infradead.org; computersforpeace@gmail.com; han.xu@freescale.com
Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-arm-kernel@lists.infradead.org; Yao Yuan
Subject: RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch

> -----Original Message-----
> From: Han Xu
> Sent: Thursday, April 21, 2016 11:48 PM
> To: Yunhui Cui; Yunhui Cui; dwmw2@infradead.org;
> computersforpeace@gmail.com; han.xu@freescale.com
> Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-
> arm-kernel@lists.infradead.org; Yao Yuan
> Subject: Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
>
>
>
> ________________________________________
> From: Yunhui Cui
> Sent: Thursday, April 21, 2016 3:41 AM
> To: Han Xu; Yunhui Cui; dwmw2@infradead.org; computersforpeace@gmail.com;
> han.xu@freescale.com
> Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-
> arm-kernel@lists.infradead.org; Yao Yuan
> Subject: RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
>
> On Thu, Apr 24, 2016 at 06:37:01 AM +0800, Han Xu wrote:
> > ________________________________________
> > From: Yunhui Cui <B56489@freescale.com>
> > Sent: Wednesday, April 13, 2016 9:50 PM
> > To: dwmw2@infradead.org; computersforpeace@gmail.com;
> > han.xu@freescale.com
> > Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org;
> > linux- arm-kernel@lists.infradead.org; Yao Yuan; Yunhui Cui
> > Subject: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> >
> > 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/mtd/spi-nor/fsl-quadspi.c | 29 +++++++++++++++++++++++------
> >  1 file changed, 23 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c
> > b/drivers/mtd/spi-nor/fsl- quadspi.c index fea18b6..d9f3e50 100644
> > --- a/drivers/mtd/spi-nor/fsl-quadspi.c
> > +++ b/drivers/mtd/spi-nor/fsl-quadspi.c
> > @@ -752,19 +752,36 @@ static void fsl_qspi_init_abh_read(struct
> > fsl_qspi
> > *q)  {
> >         void __iomem *base = q->iobase;
> >         int seqid;
> > +       const struct fsl_qspi_devtype_data *devtype_data =
> > + q->devtype_data;
> >
> >         /* AHB configuration for access buffer 0/1/2 .*/
> >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > QUADSPI_BUF0CR);
> >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > QUADSPI_BUF1CR);
> >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > QUADSPI_BUF2CR);
> > +
> >         /*
> > -        * Set ADATSZ with the maximum AHB buffer size to improve the
> > -        * read performance.
> > +        * Errata: A-009282: QuadSPI data prefetch may result in
> > incorrect data
> > +        * Workaround: Keep the read data size to 64 bits (8 bytes).
> > +        * This disables the prefetch on the AHB buffer and
> > +        * prevents this issue from occurring.
> >          */
> > -       qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > -                       ((q->devtype_data->ahb_buf_size / 8)
> > -                       << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > -                       base + QUADSPI_BUF3CR);
> > +       if (devtype_data->devtype == FSL_QUADSPI_LS2080A ||
> > +           devtype_data->devtype == FSL_QUADSPI_LS1021A) {
> >
> > Use QUIRK, not SoC name.
> [Yunhui] This is a SoC errata, we need distinguish according to the
> devtype_data->devtype
>
> It's the same thing and we have already done that before.

> [Yunhui] your mean that I should add such as the following code:
        #define QUADSPI_QUIRK_ERRATA_9282         (1 << 4)
        static inline int has_errata_num_a009282(struct fsl_qspi *q)
        {
                 return q->devtype_data->driver_data & QUADSPI_QUIRK_ERRATA_9282;
        }

I mean QUIRK can be used even for HW limitation, but it's not necessary to
use ERRATA number as QUIRK name, you can name it with natural language,
such as QUADSPI_QUIRK_ADASZ_8BYTE_LIMIT, and describe the reason in
comments.

> /*
>  * TKT253890, Controller needs driver to fill txfifo till 16 byte to
>  * trigger data transfer even though extra data will not transferred.
>  */
> #define QUADSPI_QUIRK_TKT253890         (1 << 2)
> /* Controller cannot wake up from wait mode, TKT245618 */
> #define QUADSPI_QUIRK_TKT245618         (1 << 3)
>
>
> > +
> > +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > +                               (1 << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > +                               base + QUADSPI_BUF3CR);
> > +
> > +       } else {
> > +               /*
> > +                * Set ADATSZ with the maximum AHB buffer size to
> > + improve
> > the
> > +                * read performance.
> > +               */
> > +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > +                               ((q->devtype_data->ahb_buf_size / 8)
> > +                               << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > +                               base + QUADSPI_BUF3CR);
> > +       }
> >
> >         /* We only use the buffer3 */
> >         qspi_writel(q, 0, base + QUADSPI_BUF0IND);
> > --
> > 2.1.0.27.g96db324

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#1384733

FromYunhui Cui <yunhui.cui@nxp.com>
Date2016-04-22 09:10 +0200
Message-ID<rqDnY-6vc-9@gated-at.bofh.it>
In reply to#1384693

> -----Original Message-----
> From: Han Xu
> Sent: Friday, April 22, 2016 12:49 PM
> To: Yunhui Cui; Yunhui Cui; dwmw2@infradead.org;
> computersforpeace@gmail.com; han.xu@freescale.com
> Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-
> arm-kernel@lists.infradead.org; Yao Yuan
> Subject: Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> 
> 
> 
> ________________________________________
> From: Yunhui Cui
> Sent: Thursday, April 21, 2016 9:52 PM
> To: Han Xu; Yunhui Cui; dwmw2@infradead.org; computersforpeace@gmail.com;
> han.xu@freescale.com
> Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org; linux-
> arm-kernel@lists.infradead.org; Yao Yuan
> Subject: RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> 
> > -----Original Message-----
> > From: Han Xu
> > Sent: Thursday, April 21, 2016 11:48 PM
> > To: Yunhui Cui; Yunhui Cui; dwmw2@infradead.org;
> > computersforpeace@gmail.com; han.xu@freescale.com
> > Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org;
> > linux- arm-kernel@lists.infradead.org; Yao Yuan
> > Subject: Re: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> >
> >
> >
> > ________________________________________
> > From: Yunhui Cui
> > Sent: Thursday, April 21, 2016 3:41 AM
> > To: Han Xu; Yunhui Cui; dwmw2@infradead.org;
> > computersforpeace@gmail.com; han.xu@freescale.com
> > Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org;
> > linux- arm-kernel@lists.infradead.org; Yao Yuan
> > Subject: RE: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> >
> > On Thu, Apr 24, 2016 at 06:37:01 AM +0800, Han Xu wrote:
> > > ________________________________________
> > > From: Yunhui Cui <B56489@freescale.com>
> > > Sent: Wednesday, April 13, 2016 9:50 PM
> > > To: dwmw2@infradead.org; computersforpeace@gmail.com;
> > > han.xu@freescale.com
> > > Cc: linux-kernel@vger.kernel.org; linux-mtd@lists.infradead.org;
> > > linux- arm-kernel@lists.infradead.org; Yao Yuan; Yunhui Cui
> > > Subject: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch
> > >
> > > 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/mtd/spi-nor/fsl-quadspi.c | 29
> > > +++++++++++++++++++++++------
> > >  1 file changed, 23 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c
> > > b/drivers/mtd/spi-nor/fsl- quadspi.c index fea18b6..d9f3e50 100644
> > > --- a/drivers/mtd/spi-nor/fsl-quadspi.c
> > > +++ b/drivers/mtd/spi-nor/fsl-quadspi.c
> > > @@ -752,19 +752,36 @@ static void fsl_qspi_init_abh_read(struct
> > > fsl_qspi
> > > *q)  {
> > >         void __iomem *base = q->iobase;
> > >         int seqid;
> > > +       const struct fsl_qspi_devtype_data *devtype_data =
> > > + q->devtype_data;
> > >
> > >         /* AHB configuration for access buffer 0/1/2 .*/
> > >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > > QUADSPI_BUF0CR);
> > >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > > QUADSPI_BUF1CR);
> > >         qspi_writel(q, QUADSPI_BUFXCR_INVALID_MSTRID, base +
> > > QUADSPI_BUF2CR);
> > > +
> > >         /*
> > > -        * Set ADATSZ with the maximum AHB buffer size to improve the
> > > -        * read performance.
> > > +        * Errata: A-009282: QuadSPI data prefetch may result in
> > > incorrect data
> > > +        * Workaround: Keep the read data size to 64 bits (8 bytes).
> > > +        * This disables the prefetch on the AHB buffer and
> > > +        * prevents this issue from occurring.
> > >          */
> > > -       qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > > -                       ((q->devtype_data->ahb_buf_size / 8)
> > > -                       << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > > -                       base + QUADSPI_BUF3CR);
> > > +       if (devtype_data->devtype == FSL_QUADSPI_LS2080A ||
> > > +           devtype_data->devtype == FSL_QUADSPI_LS1021A) {
> > >
> > > Use QUIRK, not SoC name.
> > [Yunhui] This is a SoC errata, we need distinguish according to the
> > devtype_data->devtype
> >
> > It's the same thing and we have already done that before.
> 
> > [Yunhui] your mean that I should add such as the following code:
>         #define QUADSPI_QUIRK_ERRATA_9282         (1 << 4)
>         static inline int has_errata_num_a009282(struct fsl_qspi *q)
>         {
>                  return q->devtype_data->driver_data &
> QUADSPI_QUIRK_ERRATA_9282;
>         }
> 
> I mean QUIRK can be used even for HW limitation, but it's not necessary
> to use ERRATA number as QUIRK name, you can name it with natural language,
> such as QUADSPI_QUIRK_ADASZ_8BYTE_LIMIT, and describe the reason in
> comments.
> [Yunhui] thanks, I will update it in v2.
> > /*
> >  * TKT253890, Controller needs driver to fill txfifo till 16 byte to
> >  * trigger data transfer even though extra data will not transferred.
> >  */
> > #define QUADSPI_QUIRK_TKT253890         (1 << 2)
> > /* Controller cannot wake up from wait mode, TKT245618 */
> > #define QUADSPI_QUIRK_TKT245618         (1 << 3)
> >
> >
> > > +
> > > +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > > +                               (1 << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > > +                               base + QUADSPI_BUF3CR);
> > > +
> > > +       } else {
> > > +               /*
> > > +                * Set ADATSZ with the maximum AHB buffer size to
> > > + improve
> > > the
> > > +                * read performance.
> > > +               */
> > > +               qspi_writel(q, QUADSPI_BUF3CR_ALLMST_MASK |
> > > +                               ((q->devtype_data->ahb_buf_size / 8)
> > > +                               << QUADSPI_BUF3CR_ADATSZ_SHIFT),
> > > +                               base + QUADSPI_BUF3CR);
> > > +       }
> > >
> > >         /* We only use the buffer3 */
> > >         qspi_writel(q, 0, base + QUADSPI_BUF0IND);
> > > --
> > > 2.1.0.27.g96db324

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