| Message ID | 20230912-spi-qup-dvfs-v1-0-3e38aa09c2bd@kernkonzept.com |
|---|---|
| Headers | show |
| Series | spi: qup: Allow scaling power domains and interconnect | expand |
On 12.09.2023 16:30, Stephan Gerhold wrote: > Parse the OPP table from the device tree and use dev_pm_opp_set_rate() > instead of clk_set_rate() to allow making performance state for power > domains specified in the OPP table. > > This is needed to guarantee correct behavior of the clock, especially > with the higher clock/SPI bus frequencies. > > Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com> > --- Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org> Konrad
On Tue, Sep 12, 2023 at 04:30:39PM +0200, Stephan Gerhold wrote: > When the SPI QUP controller is used together with a DMA engine it needs > to vote for the interconnect path to the DRAM. Otherwise it may be > unable to access the memory quickly enough. I realized that I argue here that the interconnect vote is for DMA to DRAM... > [...] > @@ -675,6 +698,12 @@ static int spi_qup_io_prep(struct spi_device *spi, struct spi_transfer *xfer) > return -EIO; > } > > + ret = spi_qup_vote_bw(controller, xfer->speed_hz); > + if (ret) { > + dev_err(controller->dev, "fail to vote for ICC bandwidth: %d\n", ret); > + return -EIO; > + } > + ... but here I vote for the bandwidth even if PIO is used instead of DMA. I think it would be more logical to only do the bandwidth vote in the DMA setup path. I'll fix this in v2. Thanks, Stephan
Make it possible to scale performance states of the power domain and interconnect of the SPI QUP controller in relation to the selected SPI speed / core clock. This is done separately by: - Parsing the OPP table from the device tree for performance state votes of the power domain - Voting for the necessary bandwidth on the interconnect path to DRAM Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com> --- Stephan Gerhold (4): spi: dt-bindings: qup: Document power-domains and OPP spi: qup: Parse OPP table for DVFS support spi: dt-bindings: qup: Document interconnects spi: qup: Vote for interconnect bandwidth to DRAM .../devicetree/bindings/spi/qcom,spi-qup.yaml | 13 ++++++ drivers/spi/spi-qup.c | 50 +++++++++++++++++++++- 2 files changed, 62 insertions(+), 1 deletion(-) --- base-commit: 678466ba68915d452c200b78d0385931e6f8e907 change-id: 20230912-spi-qup-dvfs-71fc8a5e0cb1 Best regards,