[U-Boot] [PATCH v3] driver: spi: fsl-qspi: disable AHB buffer prefetch

[Yunhui Cui]

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

Errata: A-009282: QuadSPI data pre-fetch can result in incorrect data
We need this errata workaround when CONFIG_SYS_FSL_QSPI_AHB is enabled.

Signed-off-by: Yunhui Cui <yunhui.cui at nxp.com>
---
 drivers/spi/fsl_qspi.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c
index 75cbab2..0354e20 100644
--- a/drivers/spi/fsl_qspi.c
+++ b/drivers/spi/fsl_qspi.c
@@ -438,13 +438,23 @@ static void qspi_enable_ddr_mode(struct fsl_qspi_priv *priv)
 static void qspi_init_ahb_read(struct fsl_qspi_priv *priv)
 {
 	struct fsl_qspi_regs *regs = priv->regs;
+	int rx_size = 0x80;
 
 	/* AHB configuration for access buffer 0/1/2 .*/
 	qspi_write32(priv->flags, &regs->buf0cr, QSPI_BUFXCR_INVALID_MSTRID);
 	qspi_write32(priv->flags, &regs->buf1cr, QSPI_BUFXCR_INVALID_MSTRID);
 	qspi_write32(priv->flags, &regs->buf2cr, QSPI_BUFXCR_INVALID_MSTRID);
+
+#ifdef CONFIG_SYS_FSL_ERRATUM_A009282
+	/*A-009282: QuadSPI data pre-fetch can result in incorrect data
+	 *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.
+	*/
+	rx_size = 0x1;
+#endif
 	qspi_write32(priv->flags, &regs->buf3cr, QSPI_BUF3CR_ALLMST_MASK |
-		     (0x80 << QSPI_BUF3CR_ADATSZ_SHIFT));
+		     (rx_size << QSPI_BUF3CR_ADATSZ_SHIFT));
 
 	/* We only use the buffer3 */
 	qspi_write32(priv->flags, &regs->buf0ind, 0);
-- 
2.1.0.27.g96db324