From 3d7d916f9bc98ce88272b3e4405c7c685afbfcd6 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Thu, 17 Dec 2020 14:29:13 -0800 Subject: [PATCH] spi: spi-geni-qcom: Don't try to set CS if an xfer is pending If we get a timeout sending then this happens: spi_transfer_one_message() ->transfer_one() AKA spi_geni_transfer_one() setup_fifo_xfer() mas->cur_xfer = non-NULL spi_transfer_wait() => TIMES OUT if (msg->status != -EINPROGRESS) goto out if (ret != 0 ...) spi_set_cs() ->set_cs AKA spi_geni_set_cs() # mas->cur_xfer is non-NULL The above happens _before_ the SPI core calls ->handle_err() AKA handle_fifo_timeout(). Unfortunately that won't work so well on geni. If we got a timeout transferring then it's likely that our interrupt handler is blocked, but we need that same interrupt handler to run and the command channel to be unblocked in order to adjust the chip select. Trying to set the chip select doesn't crash us but ends up confusing our state machine and leads to messages like: Premature done. rx_rem = 32 bpw8 Let's just drop the chip select request in this case. We can detect the case because cur_xfer is non-NULL--it would have been set to NULL in the interrupt handler if the previous transfer had finished. Sure, we might leave the chip select in the wrong state but it's likely it was going to fail anyway and this avoids getting the driver even more confused about what it's doing. The SPI core in general assumes that setting chip select is a simple operation that doesn't fail. Yet another reason to just reconfigure the chip select line as GPIOs. Signed-off-by: Douglas Anderson Reviewed-by: Stephen Boyd Link: https://lore.kernel.org/r/20201217142842.v3.3.I07afdedcc49655c5d26880f8df9170aac5792378@changeid Signed-off-by: Mark Brown --- drivers/spi/spi-geni-qcom.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c index 32c053705dec..365565d3a998 100644 --- a/drivers/spi/spi-geni-qcom.c +++ b/drivers/spi/spi-geni-qcom.c @@ -207,9 +207,14 @@ static void spi_geni_set_cs(struct spi_device *slv, bool set_flag) goto exit; } - mas->cs_flag = set_flag; - spin_lock_irq(&mas->lock); + if (mas->cur_xfer) { + dev_err(mas->dev, "Can't set CS when prev xfer running\n"); + spin_unlock_irq(&mas->lock); + goto exit; + } + + mas->cs_flag = set_flag; reinit_completion(&mas->cs_done); if (set_flag) geni_se_setup_m_cmd(se, SPI_CS_ASSERT, 0);