| Message ID | 20230714130214.14552-2-johan+linaro@kernel.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | serial: qcom-geni: fix opp vote on shutdown | expand |
On 14.07.2023 15:02, Johan Hovold wrote: > The operating-performance-point vote needs to be dropped when shutting > down the port to avoid wasting power by keeping resources like power > domains in an unnecessarily high performance state (e.g. when a UART > connected Bluetooth controller is not in use). > > Fixes: a5819b548af0 ("tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state") > Cc: stable@vger.kernel.org # 5.9 > Cc: Rajendra Nayak <quic_rjendra@quicinc.com> > Cc: Matthias Kaehlcke <mka@chromium.org> > Signed-off-by: Johan Hovold <johan+linaro@kernel.org> > --- I don't know a whole lot about this subsystem, but the PM call has a pointer to uport which already contains this clock rate.. Is it zeroed out by the core before we reach it, which would prevent us from reusing it? Konrad > drivers/tty/serial/qcom_geni_serial.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c > index b825b05e6137..8be896dbaa88 100644 > --- a/drivers/tty/serial/qcom_geni_serial.c > +++ b/drivers/tty/serial/qcom_geni_serial.c > @@ -126,6 +126,7 @@ struct qcom_geni_serial_port { > dma_addr_t rx_dma_addr; > bool setup; > unsigned int baud; > + unsigned long clk_rate; > void *rx_buf; > u32 loopback; > bool brk; > @@ -1249,6 +1250,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport, > baud * sampling_rate, clk_rate, clk_div); > > uport->uartclk = clk_rate; > + port->clk_rate = clk_rate; > dev_pm_opp_set_rate(uport->dev, clk_rate); > ser_clk_cfg = SER_CLK_EN; > ser_clk_cfg |= clk_div << CLK_DIV_SHFT; > @@ -1513,10 +1515,13 @@ static void qcom_geni_serial_pm(struct uart_port *uport, > > if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF) { > geni_icc_enable(&port->se); > + if (port->clk_rate) > + dev_pm_opp_set_rate(uport->dev, port->clk_rate); > geni_se_resources_on(&port->se); > } else if (new_state == UART_PM_STATE_OFF && > old_state == UART_PM_STATE_ON) { > geni_se_resources_off(&port->se); > + dev_pm_opp_set_rate(uport->dev, 0); > geni_icc_disable(&port->se); > } > }
On Fri, Jul 14, 2023 at 04:29:08PM +0200, Konrad Dybcio wrote: > On 14.07.2023 15:02, Johan Hovold wrote: > > The operating-performance-point vote needs to be dropped when shutting > > down the port to avoid wasting power by keeping resources like power > > domains in an unnecessarily high performance state (e.g. when a UART > > connected Bluetooth controller is not in use). > > > > Fixes: a5819b548af0 ("tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state") > > Cc: stable@vger.kernel.org # 5.9 > > Cc: Rajendra Nayak <quic_rjendra@quicinc.com> > > Cc: Matthias Kaehlcke <mka@chromium.org> > > Signed-off-by: Johan Hovold <johan+linaro@kernel.org> > > --- > I don't know a whole lot about this subsystem, but the PM call has > a pointer to uport which already contains this clock rate.. Is it > zeroed out by the core before we reach it, which would prevent us > from reusing it? No, but this driver has other issues and I couldn't be arsed fixing them before addressing this bug. Specifically that uartclk variable can currently be set by userspace... I'll fix that up next week. Johan
On 14.07.2023 17:08, Johan Hovold wrote: > On Fri, Jul 14, 2023 at 04:29:08PM +0200, Konrad Dybcio wrote: >> On 14.07.2023 15:02, Johan Hovold wrote: >>> The operating-performance-point vote needs to be dropped when shutting >>> down the port to avoid wasting power by keeping resources like power >>> domains in an unnecessarily high performance state (e.g. when a UART >>> connected Bluetooth controller is not in use). >>> >>> Fixes: a5819b548af0 ("tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state") >>> Cc: stable@vger.kernel.org # 5.9 >>> Cc: Rajendra Nayak <quic_rjendra@quicinc.com> >>> Cc: Matthias Kaehlcke <mka@chromium.org> >>> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> >>> --- >> I don't know a whole lot about this subsystem, but the PM call has >> a pointer to uport which already contains this clock rate.. Is it >> zeroed out by the core before we reach it, which would prevent us >> from reusing it? > > No, but this driver has other issues and I couldn't be arsed fixing them > before addressing this bug. > > Specifically that uartclk variable can currently be set by userspace... > > I'll fix that up next week. OK sounds good Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org> Konrad > > Johan
diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index b825b05e6137..8be896dbaa88 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -126,6 +126,7 @@ struct qcom_geni_serial_port { dma_addr_t rx_dma_addr; bool setup; unsigned int baud; + unsigned long clk_rate; void *rx_buf; u32 loopback; bool brk; @@ -1249,6 +1250,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport, baud * sampling_rate, clk_rate, clk_div); uport->uartclk = clk_rate; + port->clk_rate = clk_rate; dev_pm_opp_set_rate(uport->dev, clk_rate); ser_clk_cfg = SER_CLK_EN; ser_clk_cfg |= clk_div << CLK_DIV_SHFT; @@ -1513,10 +1515,13 @@ static void qcom_geni_serial_pm(struct uart_port *uport, if (new_state == UART_PM_STATE_ON && old_state == UART_PM_STATE_OFF) { geni_icc_enable(&port->se); + if (port->clk_rate) + dev_pm_opp_set_rate(uport->dev, port->clk_rate); geni_se_resources_on(&port->se); } else if (new_state == UART_PM_STATE_OFF && old_state == UART_PM_STATE_ON) { geni_se_resources_off(&port->se); + dev_pm_opp_set_rate(uport->dev, 0); geni_icc_disable(&port->se); } }
The operating-performance-point vote needs to be dropped when shutting down the port to avoid wasting power by keeping resources like power domains in an unnecessarily high performance state (e.g. when a UART connected Bluetooth controller is not in use). Fixes: a5819b548af0 ("tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state") Cc: stable@vger.kernel.org # 5.9 Cc: Rajendra Nayak <quic_rjendra@quicinc.com> Cc: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Johan Hovold <johan+linaro@kernel.org> --- drivers/tty/serial/qcom_geni_serial.c | 5 +++++ 1 file changed, 5 insertions(+)