[PATCH v3] spi: spi-rspi: Fix PIO fallback on RZ platforms

[PATCH v3] spi: spi-rspi: Fix PIO fallback on RZ platforms

[Biju Das]

RSPI IP on RZ/{A, G2L} SoC's has the same signal for both interrupt
and DMA transfer request. Setting DMARS register for DMA transfer
makes the signal to work as a DMA transfer request signal and
subsequent interrupt requests to the interrupt controller
are masked.

PIO fallback does not work as interrupt signal is disabled.

This patch fixes this issue by re-enabling the interrupts by
calling dmaengine_synchronize().

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v2->v3:
 * dmaengine_synchronize() called unconditionally and removed need_dmar_clr.
v1->v2:
 * Fixed the typo need_dmar_clr->rspi->ops->need_dmar_clr.
---
 drivers/spi/spi-rspi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 7a014eeec2d0..411b1307b7fd 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -613,6 +613,10 @@ static int rspi_dma_transfer(struct rspi_data *rspi, struct sg_table *tx,
 					       rspi->dma_callbacked, HZ);
 	if (ret > 0 && rspi->dma_callbacked) {
 		ret = 0;
+		if (tx)
+			dmaengine_synchronize(rspi->ctlr->dma_tx);
+		if (rx)
+			dmaengine_synchronize(rspi->ctlr->dma_rx);
 	} else {
 		if (!ret) {
 			dev_err(&rspi->ctlr->dev, "DMA timeout\n");
-- 
2.25.1

Re: [PATCH v3] spi: spi-rspi: Fix PIO fallback on RZ platforms

[Geert Uytterhoeven]

On Thu, Jul 21, 2022 at 4:35 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> RSPI IP on RZ/{A, G2L} SoC's has the same signal for both interrupt
> and DMA transfer request. Setting DMARS register for DMA transfer
> makes the signal to work as a DMA transfer request signal and
> subsequent interrupt requests to the interrupt controller
> are masked.
>
> PIO fallback does not work as interrupt signal is disabled.
>
> This patch fixes this issue by re-enabling the interrupts by
> calling dmaengine_synchronize().
>
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> v2->v3:
>  * dmaengine_synchronize() called unconditionally and removed need_dmar_clr.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v3] spi: spi-rspi: Fix PIO fallback on RZ platforms

[Mark Brown]

On Thu, 21 Jul 2022 15:34:49 +0100, Biju Das wrote:
> RSPI IP on RZ/{A, G2L} SoC's has the same signal for both interrupt
> and DMA transfer request. Setting DMARS register for DMA transfer
> makes the signal to work as a DMA transfer request signal and
> subsequent interrupt requests to the interrupt controller
> are masked.
> 
> PIO fallback does not work as interrupt signal is disabled.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: spi-rspi: Fix PIO fallback on RZ platforms
      commit: b620aa3a7be346f04ae7789b165937615c6ee8d3

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark