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From 50aac689d5be0a086f076cd4bc8b14ee0b9ab995 Mon Sep 17 00:00:00 2001
From: Yunhui Cui <yunhui.cui@nxp.com>
Date: Tue, 8 Mar 2016 14:38:52 +0800
Subject: [PATCH 107/113] mtd: fsl-quadspi: disable AHB buffer prefetch
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(-)
--- a/drivers/mtd/spi-nor/fsl-quadspi.c
+++ b/drivers/mtd/spi-nor/fsl-quadspi.c
@@ -794,19 +794,36 @@ static void fsl_qspi_init_abh_read(struc
{
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) {
+
+ 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);
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