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[7/9] spi: bcm2835aux: remove dangerous uncontrolled read of fifo

Message ID 20190224125440.16117-8-kernel@martin.sperl.org (mailing list archive)
State Superseded
Headers show
Series spi: bcm2835aux: bug fixes and improvements | expand

Commit Message

Martin Sperl Feb. 24, 2019, 12:54 p.m. UTC 
From: Martin Sperl <kernel@martin.sperl.org>

This read of the fifo is a potential candidate for a race condition
as the spi transfer is not necessarily finished and so can lead to
an early read of the fifo that still misses data.

So it has been removed - an additional loop will read the fifo
correctly.

Fixes: 1ea29b39f4c812ece2f936065a0a3d6fe44a263e
(Note: requires Patch 6)

Suggested-by: Hubert Denkmair <h.denkmair@intence.de>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>

---
 drivers/spi/spi-bcm2835aux.c | 7 -------
 1 file changed, 7 deletions(-)

--
2.11.0
diff mbox series

Patch

diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 9552f5343982..8821fc183ca0 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -246,13 +246,6 @@  static void bcm2835aux_spi_transfer_helper(struct bcm2835aux_spi *bs)
 		  BCM2835_AUX_SPI_STAT_TX_FULL))) {
 		bcm2835aux_wr_fifo(bs);
 	}
-
-	/* and check if we have reached "done" */
-	while (bs->rx_len &&
-	       (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
-		  BCM2835_AUX_SPI_STAT_BUSY))) {
-		bcm2835aux_rd_fifo(bs);
-	}
 }

 static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id)