> -----Original Message----- > From: Han Xu > Sent: Thursday, April 21, 2016 11:48 PM > To: Yunhui Cui; Yunhui Cui; dw...@infradead.org; > computersforpe...@gmail.com; han...@freescale.com > Cc: linux-kernel@vger.kernel.org; linux-...@lists.infradead.org; linux- > arm-ker...@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; dw...@infradead.org; computersforpe...@gmail.com; > han...@freescale.com > Cc: linux-kernel@vger.kernel.org; linux-...@lists.infradead.org; linux- > arm-ker...@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 <b56...@freescale.com> > > Sent: Wednesday, April 13, 2016 9:50 PM > > To: dw...@infradead.org; computersforpe...@gmail.com; > > han...@freescale.com > > Cc: linux-kernel@vger.kernel.org; linux-...@lists.infradead.org; > > linux- arm-ker...@lists.infradead.org; Yao Yuan; Yunhui Cui > > Subject: [PATCH 8/9] mtd: fsl-quadspi: disable AHB buffer prefetch > > > > From: Yunhui Cui <yunhui....@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....@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