This is a note to let you know that I've just added the patch titled
spi: sun4i: fix FIFO limit
to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
spi-sun4i-fix-fifo-limit.patch
and it can be found in the queue-4.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6d9fe44bd73d567d04d3a68a2d2fa521ab9532f2 Mon Sep 17 00:00:00 2001
From: Michal Suchanek <hramrach@xxxxxxxxx>
Date: Mon, 13 Jun 2016 17:46:49 +0000
Subject: spi: sun4i: fix FIFO limit
From: Michal Suchanek <hramrach@xxxxxxxxx>
commit 6d9fe44bd73d567d04d3a68a2d2fa521ab9532f2 upstream.
When testing SPI without DMA I noticed that filling the FIFO on the
spi controller causes timeout.
Always leave room for one byte in the FIFO.
Signed-off-by: Michal Suchanek <hramrach@xxxxxxxxx>
Acked-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/spi/spi-sun4i.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
--- a/drivers/spi/spi-sun4i.c
+++ b/drivers/spi/spi-sun4i.c
@@ -180,7 +180,10 @@ static int sun4i_spi_transfer_one(struct
/* We don't support transfer larger than the FIFO */
if (tfr->len > SUN4I_FIFO_DEPTH)
- return -EINVAL;
+ return -EMSGSIZE;
+
+ if (tfr->tx_buf && tfr->len >= SUN4I_FIFO_DEPTH)
+ return -EMSGSIZE;
reinit_completion(&sspi->done);
sspi->tx_buf = tfr->tx_buf;
@@ -270,8 +273,12 @@ static int sun4i_spi_transfer_one(struct
sun4i_spi_write(sspi, SUN4I_BURST_CNT_REG, SUN4I_BURST_CNT(tfr->len));
sun4i_spi_write(sspi, SUN4I_XMIT_CNT_REG, SUN4I_XMIT_CNT(tx_len));
- /* Fill the TX FIFO */
- sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH);
+ /*
+ * Fill the TX FIFO
+ * Filling the FIFO fully causes timeout for some reason
+ * at least on spi2 on A10s
+ */
+ sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH - 1);
/* Enable the interrupts */
sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, SUN4I_INT_CTL_TC);
Patches currently in stable-queue which might be from hramrach@xxxxxxxxx are
queue-4.6/spi-sun4i-fix-fifo-limit.patch
queue-4.6/spi-sunxi-fix-transfer-timeout.patch
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