Merge tag 'spi-fix-v6.6-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

Pull spi fixes from Mark Brown:
 "A couple of fixes for the sun6i driver. The patch to reduce DMA RX to
  single byte width all the time is *hopefully* excessively cautious but
  it's unclear which SoCs are affected so the fix just covers everything
  for safety"

* tag 'spi-fix-v6.6-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: sun6i: fix race between DMA RX transfer completion and RX FIFO drain
  spi: sun6i: reduce DMA RX transfer width to single byte

1 files changed, 29 insertions, 2 deletions

diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c
index 3f5b1556ece022..fddc633097736a 100644
--- a/drivers/spi/spi-sun6i.c
+++ b/drivers/spi/spi-sun6i.c
@@ -106,6 +106,7 @@ struct sun6i_spi {
 	struct reset_control	*rstc;
 
 	struct completion	done;
+	struct completion	dma_rx_done;
 
 	const u8		*tx_buf;
 	u8			*rx_buf;
@@ -200,6 +201,13 @@ static size_t sun6i_spi_max_transfer_size(struct spi_device *spi)
 	return SUN6I_MAX_XFER_SIZE - 1;
 }
 
+static void sun6i_spi_dma_rx_cb(void *param)
+{
+	struct sun6i_spi *sspi = param;
+
+	complete(&sspi->dma_rx_done);
+}
+
 static int sun6i_spi_prepare_dma(struct sun6i_spi *sspi,
 				 struct spi_transfer *tfr)
 {
@@ -211,7 +219,7 @@ static int sun6i_spi_prepare_dma(struct sun6i_spi *sspi,
 		struct dma_slave_config rxconf = {
 			.direction = DMA_DEV_TO_MEM,
 			.src_addr = sspi->dma_addr_rx,
-			.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
+			.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
 			.src_maxburst = 8,
 		};
 
@@ -224,6 +232,8 @@ static int sun6i_spi_prepare_dma(struct sun6i_spi *sspi,
 						 DMA_PREP_INTERRUPT);
 		if (!rxdesc)
 			return -EINVAL;
+		rxdesc->callback_param = sspi;
+		rxdesc->callback = sun6i_spi_dma_rx_cb;
 	}
 
 	txdesc = NULL;
@@ -279,6 +289,7 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
 		return -EINVAL;
 
 	reinit_completion(&sspi->done);
+	reinit_completion(&sspi->dma_rx_done);
 	sspi->tx_buf = tfr->tx_buf;
 	sspi->rx_buf = tfr->rx_buf;
 	sspi->len = tfr->len;
@@ -479,6 +490,22 @@ static int sun6i_spi_transfer_one(struct spi_master *master,
 	start = jiffies;
 	timeout = wait_for_completion_timeout(&sspi->done,
 					      msecs_to_jiffies(tx_time));
+
+	if (!use_dma) {
+		sun6i_spi_drain_fifo(sspi);
+	} else {
+		if (timeout && rx_len) {
+			/*
+			 * Even though RX on the peripheral side has finished
+			 * RX DMA might still be in flight
+			 */
+			timeout = wait_for_completion_timeout(&sspi->dma_rx_done,
+							      timeout);
+			if (!timeout)
+				dev_warn(&master->dev, "RX DMA timeout\n");
+		}
+	}
+
 	end = jiffies;
 	if (!timeout) {
 		dev_warn(&master->dev,
@@ -506,7 +533,6 @@ static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
 	/* Transfer complete */
 	if (status & SUN6I_INT_CTL_TC) {
 		sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC);
-		sun6i_spi_drain_fifo(sspi);
 		complete(&sspi->done);
 		return IRQ_HANDLED;
 	}
@@ -665,6 +691,7 @@ static int sun6i_spi_probe(struct platform_device *pdev)
 	}
 
 	init_completion(&sspi->done);
+	init_completion(&sspi->dma_rx_done);
 
 	sspi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 	if (IS_ERR(sspi->rstc)) {