From f9143be0531fd361b66260ea4168e0e60368d45b Mon Sep 17 00:00:00 2001
From: Guenter Roeck <linux@roeck-us.net>
Date: Sun, 1 Aug 2021 20:00:23 -0700
Subject: [PATCH] spi: mediatek: Fix fifo transfer
commit 0d5c3954b35eddff0da0436c31e8d721eceb7dc2 upstream.
Commit 3a70dd2d0503 ("spi: mediatek: fix fifo rx mode") claims that
fifo RX mode was never handled, and adds the presumably missing code
to the FIFO transfer function. However, the claim that receive data
was not handled is incorrect. It was handled as part of interrupt
handling after the transfer was complete. The code added with the above
mentioned commit reads data from the receive FIFO before the transfer
is started, which is wrong. This results in an actual transfer error
on a Hayato Chromebook.
Remove the code trying to handle receive data before the transfer is
started to fix the problem.
Fixes: 3a70dd2d0503 ("spi: mediatek: fix fifo rx mode")
Cc: Peter Hess <peter.hess@ph-home.de>
Cc: Frank Wunderlich <frank-w@public-files.de>
Cc: Tzung-Bi Shih <tzungbi@google.com>
Cc: Hsin-Yi Wang <hsinyi@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Hsin-Yi Wang <hsinyi@google.com>
Tested-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20210802030023.1748777-1-linux@roeck-us.net
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/spi/spi-mt65xx.c | 19 +++++--------------
1 file changed, 5 insertions(+), 14 deletions(-)
diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index e2b171057b3b3..690e8ddf5f6b8 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -391,24 +391,15 @@ static int mtk_spi_fifo_transfer(struct spi_master *master,
mtk_spi_prepare_transfer(master, xfer);
mtk_spi_setup_packet(master);
- cnt = xfer->len / 4;
- if (xfer->tx_buf)
+ if (xfer->tx_buf) {
+ cnt = xfer->len / 4;
iowrite32_rep(mdata->base + SPI_TX_DATA_REG, xfer->tx_buf, cnt);
-
- if (xfer->rx_buf)
- ioread32_rep(mdata->base + SPI_RX_DATA_REG, xfer->rx_buf, cnt);
-
- remainder = xfer->len % 4;
- if (remainder > 0) {
- reg_val = 0;
- if (xfer->tx_buf) {
+ remainder = xfer->len % 4;
+ if (remainder > 0) {
+ reg_val = 0;
memcpy(®_val, xfer->tx_buf + (cnt * 4), remainder);
writel(reg_val, mdata->base + SPI_TX_DATA_REG);
}
- if (xfer->rx_buf) {
- reg_val = readl(mdata->base + SPI_RX_DATA_REG);
- memcpy(xfer->rx_buf + (cnt * 4), ®_val, remainder);
- }
}
mtk_spi_enable_transfer(master);