| Message ID | 20240902152451.862-8-johan+linaro@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | serial: qcom-geni: fix console corruption | expand |
Hi, On Mon, Sep 2, 2024 at 8:26 AM Johan Hovold <johan+linaro@kernel.org> wrote: > > Disable the GENI interrupts during console writes to reduce the risk of > having interrupt handlers spinning on the port lock on other cores for > extended periods of time. > > This can, for example, reduce the total amount of time spent in the > interrupt handler during boot of the x1e80100 CRD by up to a factor nine > (e.g. from 274 ms to 30 ms) while the worst case processing time drops > from 19 ms to 8 ms. > > Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") > Signed-off-by: Johan Hovold <johan+linaro@kernel.org> Reviewed-by: Douglas Anderson <dianders@chromium.org>
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index be620c5703f5..fbed143c90a3 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -488,6 +488,7 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, { struct uart_port *uport; struct qcom_geni_serial_port *port; + u32 m_irq_en, s_irq_en; bool locked = true; unsigned long flags; @@ -503,6 +504,11 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, else uart_port_lock_irqsave(uport, &flags); + m_irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); + s_irq_en = readl(uport->membase + SE_GENI_S_IRQ_EN); + writel(0, uport->membase + SE_GENI_M_IRQ_EN); + writel(0, uport->membase + SE_GENI_S_IRQ_EN); + if (qcom_geni_serial_main_active(uport)) { /* Wait for completion or drain FIFO */ if (!locked || port->tx_remaining == 0) @@ -515,6 +521,9 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, __qcom_geni_serial_console_write(uport, s, count); + writel(m_irq_en, uport->membase + SE_GENI_M_IRQ_EN); + writel(s_irq_en, uport->membase + SE_GENI_S_IRQ_EN); + if (locked) uart_port_unlock_irqrestore(uport, flags); }
Disable the GENI interrupts during console writes to reduce the risk of having interrupt handlers spinning on the port lock on other cores for extended periods of time. This can, for example, reduce the total amount of time spent in the interrupt handler during boot of the x1e80100 CRD by up to a factor nine (e.g. from 274 ms to 30 ms) while the worst case processing time drops from 19 ms to 8 ms. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Signed-off-by: Johan Hovold <johan+linaro@kernel.org> --- drivers/tty/serial/qcom_geni_serial.c | 9 +++++++++ 1 file changed, 9 insertions(+)