6.6-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan+linaro@kernel.org
commit 23ee4a25661c33e6381d41e848a9060ed6d72845 upstream.
Make sure to wait for the DMA transfer to complete when cancelling the rx command on stop_rx(). This specifically prevents the DMA completion interrupt from firing after rx has been restarted, something which can lead to an IOMMU fault and hosed rx when the interrupt handler unmaps the DMA buffer for the new command:
qcom_geni_serial 988000.serial: serial engine reports 0 RX bytes in! arm-smmu 15000000.iommu: FSR = 00000402 [Format=2 TF], SID=0x563 arm-smmu 15000000.iommu: FSYNR0 = 00210013 [S1CBNDX=33 WNR PLVL=3] Bluetooth: hci0: command 0xfc00 tx timeout Bluetooth: hci0: Reading QCA version information failed (-110)
Also add the missing state machine reset which is needed in case cancellation fails.
Fixes: 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") Cc: stable@vger.kernel.org # 6.3 Cc: Bartosz Golaszewski bartosz.golaszewski@linaro.org Signed-off-by: Johan Hovold johan+linaro@kernel.org Link: https://lore.kernel.org/r/20241009145110.16847-5-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/qcom_geni_serial.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
--- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -775,17 +775,27 @@ static void qcom_geni_serial_start_rx_fi static void qcom_geni_serial_stop_rx_dma(struct uart_port *uport) { struct qcom_geni_serial_port *port = to_dev_port(uport); + bool done;
if (!qcom_geni_serial_secondary_active(uport)) return;
geni_se_cancel_s_cmd(&port->se); - qcom_geni_serial_poll_bit(uport, SE_GENI_S_IRQ_STATUS, - S_CMD_CANCEL_EN, true); - - if (qcom_geni_serial_secondary_active(uport)) + done = qcom_geni_serial_poll_bit(uport, SE_DMA_RX_IRQ_STAT, + RX_EOT, true); + if (done) { + writel(RX_EOT | RX_DMA_DONE, + uport->membase + SE_DMA_RX_IRQ_CLR); + } else { qcom_geni_serial_abort_rx(uport);
+ writel(1, uport->membase + SE_DMA_RX_FSM_RST); + qcom_geni_serial_poll_bit(uport, SE_DMA_RX_IRQ_STAT, + RX_RESET_DONE, true); + writel(RX_RESET_DONE | RX_DMA_DONE, + uport->membase + SE_DMA_RX_IRQ_CLR); + } + if (port->rx_dma_addr) { geni_se_rx_dma_unprep(&port->se, port->rx_dma_addr, DMA_RX_BUF_SIZE);