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| author | Johan Hovold <johan+linaro@kernel.org> | 2023-03-07 17:44:04 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-03-09 17:27:50 +0100 |
| commit | 97820780b723197d1b472f2bd39fd8593b5d4edc (patch) | |
| tree | 3054ef886726dbe8561e302a3f50cc04c5047974 | |
| parent | 95fcfc08537763bff21ec8c450d3d3cb1a60ad09 (diff) | |
| download | linux-stable-97820780b723197d1b472f2bd39fd8593b5d4edc.tar.gz linux-stable-97820780b723197d1b472f2bd39fd8593b5d4edc.tar.bz2 linux-stable-97820780b723197d1b472f2bd39fd8593b5d4edc.zip | |
serial: qcom-geni: fix mapping of empty DMA buffer
Make sure that there is data in the ring buffer before trying to set up
a zero-length DMA transfer.
This specifically fixes the following warning when unmapping the empty
buffer on the sc8280xp-crd:
WARNING: CPU: 0 PID: 138 at drivers/iommu/dma-iommu.c:1046 iommu_dma_unmap_page+0xbc/0xd8
...
Call trace:
iommu_dma_unmap_page+0xbc/0xd8
dma_unmap_page_attrs+0x30/0x1c8
geni_se_tx_dma_unprep+0x28/0x38
qcom_geni_serial_isr+0x358/0x75c
Fixes: 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA")
Cc: stable <stable@kernel.org>
Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sa8540p-ride
Link: https://lore.kernel.org/r/20230307164405.14218-4-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/qcom_geni_serial.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2aa3872e6283..9871225b2f9b 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -631,6 +631,9 @@ static void qcom_geni_serial_start_tx_dma(struct uart_port *uport) if (port->tx_dma_addr) return; + if (uart_circ_empty(xmit)) + return; + xmit_size = uart_circ_chars_pending(xmit); if (xmit_size < WAKEUP_CHARS) uart_write_wakeup(uport); |