[PATCH] spi: mediatek: Fix package division error

From: Zhichao Liu
Date: Fri Oct 21 2022 - 05:26:31 EST


From: "zhichao.liu" <zhichao.liu@xxxxxxxxxxxx>

Commit 7e963fb2a33ce ("spi: mediatek: add ipm design support
for MT7986") makes a mistake on package dividing operation
(one change is missing), need to fix it.

Background:
Ipm design is expanding the HW capability of dma (adjust package
length from 1KB to 64KB), and using "dev_comp->ipm_support" flag
to indicate it.

Issue description:
Ipm support patch (said above) is missing to handle remainder at
package dividing operation.
One case, a transmission length is 65KB, is will divide to 1K
(package length) * 65(package loop) in non-ipm desgin case, and
will divide to 64K(package length) * 1(package loop) + 1K(remainder)
in ipm design case. And the 1K remainder will be lost with the
current SW flow, and the transmission will be failure.
So, it should be fixed.

Solution:
Add "ipm_design" flag in function "mtk_spi_get_mult_delta()" to
indicate HW capability, and modify the parameters corespondingly.

fixes: 7e963fb2a33ce ("spi: mediatek: add ipm design support for MT7986")
Signed-off-by: zhichao.liu <zhichao.liu@xxxxxxxxxxxx>
---
drivers/spi/spi-mt65xx.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 11aeae7fe7fc..a33c9a3de395 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -551,14 +551,17 @@ static void mtk_spi_enable_transfer(struct spi_master *master)
writel(cmd, mdata->base + SPI_CMD_REG);
}

-static int mtk_spi_get_mult_delta(u32 xfer_len)
+static int mtk_spi_get_mult_delta(struct mtk_spi *mdata, u32 xfer_len)
{
- u32 mult_delta;
+ u32 mult_delta = 0;

- if (xfer_len > MTK_SPI_PACKET_SIZE)
- mult_delta = xfer_len % MTK_SPI_PACKET_SIZE;
- else
- mult_delta = 0;
+ if (mdata->dev_comp->ipm_design) {
+ if (xfer_len > MTK_SPI_IPM_PACKET_SIZE)
+ mult_delta = xfer_len % MTK_SPI_IPM_PACKET_SIZE;
+ } else {
+ if (xfer_len > MTK_SPI_PACKET_SIZE)
+ mult_delta = xfer_len % MTK_SPI_PACKET_SIZE;
+ }

return mult_delta;
}
@@ -570,22 +573,22 @@ static void mtk_spi_update_mdata_len(struct spi_master *master)

if (mdata->tx_sgl_len && mdata->rx_sgl_len) {
if (mdata->tx_sgl_len > mdata->rx_sgl_len) {
- mult_delta = mtk_spi_get_mult_delta(mdata->rx_sgl_len);
+ mult_delta = mtk_spi_get_mult_delta(mdata, mdata->rx_sgl_len);
mdata->xfer_len = mdata->rx_sgl_len - mult_delta;
mdata->rx_sgl_len = mult_delta;
mdata->tx_sgl_len -= mdata->xfer_len;
} else {
- mult_delta = mtk_spi_get_mult_delta(mdata->tx_sgl_len);
+ mult_delta = mtk_spi_get_mult_delta(mdata, mdata->tx_sgl_len);
mdata->xfer_len = mdata->tx_sgl_len - mult_delta;
mdata->tx_sgl_len = mult_delta;
mdata->rx_sgl_len -= mdata->xfer_len;
}
} else if (mdata->tx_sgl_len) {
- mult_delta = mtk_spi_get_mult_delta(mdata->tx_sgl_len);
+ mult_delta = mtk_spi_get_mult_delta(mdata, mdata->tx_sgl_len);
mdata->xfer_len = mdata->tx_sgl_len - mult_delta;
mdata->tx_sgl_len = mult_delta;
} else if (mdata->rx_sgl_len) {
- mult_delta = mtk_spi_get_mult_delta(mdata->rx_sgl_len);
+ mult_delta = mtk_spi_get_mult_delta(mdata, mdata->rx_sgl_len);
mdata->xfer_len = mdata->rx_sgl_len - mult_delta;
mdata->rx_sgl_len = mult_delta;
}
--
2.18.0