| Message ID | 1683911265-3395-1-git-send-email-quic_vnivarth@quicinc.com |
|---|---|
| Headers | show |
| Series | spi: spi-geni-qcom: Add new interfaces and utilise them to do map/unmap in framework for SE DMA | expand |
Hi, On Fri, May 12, 2023 at 10:07 AM Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com> wrote: > > The geni_se_xx_dma_prep() interfaces necessarily do DMA mapping before > initiating DMA transfers. This is not suitable for spi where framework > is expected to handle map/unmap. > > Expose new interfaces geni_se_xx_init_dma() which do only DMA transfer. > > Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com> > --- > drivers/soc/qcom/qcom-geni-se.c | 67 +++++++++++++++++++++++++++++----------- > include/linux/soc/qcom/geni-se.h | 4 +++ > 2 files changed, 53 insertions(+), 18 deletions(-) > > diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c > index 795a2e1..adfcd6e 100644 > --- a/drivers/soc/qcom/qcom-geni-se.c > +++ b/drivers/soc/qcom/qcom-geni-se.c > @@ -682,6 +682,30 @@ EXPORT_SYMBOL(geni_se_clk_freq_match); > #define GENI_SE_DMA_EOT_EN BIT(1) > #define GENI_SE_DMA_AHB_ERR_EN BIT(2) > #define GENI_SE_DMA_EOT_BUF BIT(0) > + > +/** > + * geni_se_tx_init_dma() - Initiate TX DMA transfer on the serial engine > + * @se: Pointer to the concerned serial engine. > + * @iova: Pointer to store the mapped DMA address. We're not returning the "iova" from this function, so it shouldn't say "Pointer to store". > + * @len: Length of the TX buffer. > + * > + * This function is used to initiate DMA TX transfer. > + */ > +void geni_se_tx_init_dma(struct geni_se *se, dma_addr_t *iova, size_t len) There is no reason to pass iova as a pointer, right? Change it to just "dma_addr_t" Same comments on the RX side of things. -Doug
A "known issue" during implementation of SE DMA for spi geni driver was that it does DMA map/unmap internally instead of in spi framework. Current patches remove this hiccup and also clean up code a bit. Testing revealed no regressions and results with 1000 iterations of reading from EC showed no loss of performance. Results ======= Before - Iteration 999, min=5.10, max=5.17, avg=5.14, ints=25129 After - Iteration 999, min=5.10, max=5.20, avg=5.15, ints=25153 Vijaya Krishna Nivarthi (2): soc: qcom: geni-se: Add interfaces geni_se_tx_init_dma() and geni_se_rx_init_dma() spi: spi-geni-qcom: Do not do DMA map/unmap inside driver, use framework instead drivers/soc/qcom/qcom-geni-se.c | 67 +++++++++++++++++++------- drivers/spi/spi-geni-qcom.c | 101 ++++++++++++++++++++------------------- include/linux/soc/qcom/geni-se.h | 4 ++ 3 files changed, 105 insertions(+), 67 deletions(-)