[PATCH 5.17 0067/1126] spi: mxic: Fix the transmit path

Greg Kroah-Hartman
2022-04-05T07:47:20Z

From: Miquel Raynal <miquel.raynal@bootlin.com>

commit 5fd6739e0df7e320bcac103dfb95fe75941fea17 upstream.

By working with external hardware ECC engines, we figured out that
Under certain circumstances, it is needed for the SPI controller to
check INT_TX_EMPTY and INT_RX_NOT_EMPTY in both receive and transmit
path (not only in the receive path). The delay penalty being
negligible, move this code in the common path.

Fixes: b942d80b0a39 ("spi: Add MXIC controller driver")
Cc: stable@vger.kernel.org
Suggested-by: Mason Yang <masonccyang@mxic.com.tw>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Zhengxun Li <zhengxunli@mxic.com.tw>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/linux-mtd/20220127091808.1043392-10-miquel.raynal@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/spi/spi-mxic.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)

--- a/drivers/spi/spi-mxic.c
+++ b/drivers/spi/spi-mxic.c
@@ -304,25 +304,21 @@ static int mxic_spi_data_xfer(struct mxi

writel(data, mxic->regs + TXD(nbytes % 4));

- if (rxbuf) {
- ret = readl_poll_timeout(mxic->regs + INT_STS, sts,
- sts & INT_TX_EMPTY, 0,
- USEC_PER_SEC);
- if (ret)
- return ret;
+ ret = readl_poll_timeout(mxic->regs + INT_STS, sts,
+ sts & INT_TX_EMPTY, 0, USEC_PER_SEC);
+ if (ret)
+ return ret;

- ret = readl_poll_timeout(mxic->regs + INT_STS, sts,
- sts & INT_RX_NOT_EMPTY, 0,
- USEC_PER_SEC);
- if (ret)
- return ret;
+ ret = readl_poll_timeout(mxic->regs + INT_STS, sts,
+ sts & INT_RX_NOT_EMPTY, 0,
+ USEC_PER_SEC);
+ if (ret)
+ return ret;

- data = readl(mxic->regs + RXD);
+ data = readl(mxic->regs + RXD);
+ if (rxbuf) {
data >>= (8 * (4 - nbytes));
memcpy(rxbuf + pos, &data, nbytes);
- WARN_ON(readl(mxic->regs + INT_STS) & INT_RX_NOT_EMPTY);
- } else {
- readl(mxic->regs + RXD);
}
WARN_ON(readl(mxic->regs + INT_STS) & INT_RX_NOT_EMPTY);