Applied "spi: imx: correct wml as the last sg length" to the spi tree

[Mark Brown <broonie@xxxxxxxxxx>]

The patch

   spi: imx: correct wml as the last sg length

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 5ba5a3730639caddf42af11c60f3f3d99d9a5f00 Mon Sep 17 00:00:00 2001
From: Robin Gong <yibin.gong@xxxxxxx>
Date: Wed, 10 Oct 2018 10:32:45 +0000
Subject: [PATCH] spi: imx: correct wml as the last sg length

Correct wml as the last rx sg length instead of the whole transfer
length. Otherwise, mtd_stresstest will be failed as below:

insmod mtd_stresstest.ko dev=0
=================================================
mtd_stresstest: MTD device: 0
mtd_stresstest: not NAND flash, assume page size is 512 bytes.
mtd_stresstest: MTD device size 4194304, eraseblock size 65536, page size 512, count of eraseblocks 64, pa0
mtd_stresstest: doing operations
mtd_stresstest: 0 operations done
mtd_test: mtd_read from 1ff532, size 880
mtd_test: mtd_read from 20c267, size 64998
spi_master spi0: I/O Error in DMA RX
m25p80 spi0.0: SPI transfer failed: -110
spi_master spi0: failed to transfer one message from queue
mtd_test: error: read failed at 0x20c267
mtd_stresstest: error -110 occurred
=================================================
insmod: ERROR: could not insert module mtd_stresstest.ko: Connection timed out

Signed-off-by: Robin Gong <yibin.gong@xxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 drivers/spi/spi-imx.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index e861157e3459..037abbb852a4 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -217,7 +217,6 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
 			 struct spi_transfer *transfer)
 {
 	struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
-	unsigned int bytes_per_word, i;
 
 	if (!master->dma_rx)
 		return false;
@@ -225,14 +224,6 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
 	if (spi_imx->slave_mode)
 		return false;
 
-	bytes_per_word = spi_imx_bytes_per_word(transfer->bits_per_word);
-
-	for (i = spi_imx->devtype_data->fifo_size / 2; i > 0; i--) {
-		if (!(transfer->len % (i * bytes_per_word)))
-			break;
-	}
-
-	spi_imx->wml = i;
 	spi_imx->dynamic_burst = 0;
 
 	return true;
@@ -594,7 +585,7 @@ static void mx51_setup_wml(struct spi_imx_data *spi_imx)
 	 * and enable DMA request.
 	 */
 
-	writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml) |
+	writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml - 1) |
 		MX51_ECSPI_DMA_TX_WML(spi_imx->wml) |
 		MX51_ECSPI_DMA_RXT_WML(spi_imx->wml) |
 		MX51_ECSPI_DMA_TEDEN | MX51_ECSPI_DMA_RXDEN |
@@ -1287,12 +1278,30 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 	unsigned long timeout;
 	struct spi_master *master = spi_imx->bitbang.master;
 	struct sg_table *tx = &transfer->tx_sg, *rx = &transfer->rx_sg;
+	struct scatterlist *last_sg = sg_last(rx->sgl, rx->nents);
+	unsigned int bytes_per_word, i;
 	int ret;
 
+	/* Get the right burst length from the last sg to ensure no tail data */
+	bytes_per_word = spi_imx_bytes_per_word(transfer->bits_per_word);
+	for (i = spi_imx->devtype_data->fifo_size / 2; i > 0; i--) {
+		if (!(sg_dma_len(last_sg) % (i * bytes_per_word)))
+			break;
+	}
+	/* Use 1 as wml in case no available burst length got */
+	if (i == 0)
+		i = 1;
+
+	spi_imx->wml =  i;
+
 	ret = spi_imx_dma_configure(master);
 	if (ret)
 		return ret;
 
+	if (!spi_imx->devtype_data->setup_wml) {
+		dev_err(spi_imx->dev, "No setup_wml()?\n");
+		return -EINVAL;
+	}
 	spi_imx->devtype_data->setup_wml(spi_imx);
 
 	/*
-- 
2.19.0