| Message ID | 20190412105320.2924-1-kernel@esmil.dk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | spi: rockchip: turn down tx dma bursts | expand |
Hi Mark On Wed, 8 May 2019 at 12:34, Mark Brown <broonie@kernel.org> wrote: > > The patch > > spi: rockchip: turn down tx dma bursts > > has been applied to the spi tree at > > https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git > > 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. I've tried looking in the for-next and for-5.x branches here, and I can't seem to find this patch. Am I missing something? It fixes a problem introduced in 4.19, so it'd be nice if it could make it to stable trees eventually. /Emil
On Wed, Jun 05, 2019 at 09:36:44PM +0200, Emil Renner Berthing wrote: > On Wed, 8 May 2019 at 12:34, Mark Brown <broonie@kernel.org> wrote: > > spi: rockchip: turn down tx dma bursts > I've tried looking in the for-next and for-5.x branches here, and I > can't seem to find this patch. > Am I missing something? > It fixes a problem introduced in 4.19, so it'd be nice if it could > make it to stable trees eventually. 47300728fb213486a830565d2af49da967c9d16a is in my tree. When it reaches Linus' tree send a request to Greg for it to be backported if none of the stable automation picks it up.
On Wed, 5 Jun 2019 at 21:55, Mark Brown <broonie@kernel.org> wrote: > > On Wed, Jun 05, 2019 at 09:36:44PM +0200, Emil Renner Berthing wrote: > > On Wed, 8 May 2019 at 12:34, Mark Brown <broonie@kernel.org> wrote: > > > > spi: rockchip: turn down tx dma bursts > > > I've tried looking in the for-next and for-5.x branches here, and I > > can't seem to find this patch. > > Am I missing something? > > > It fixes a problem introduced in 4.19, so it'd be nice if it could > > make it to stable trees eventually. > > 47300728fb213486a830565d2af49da967c9d16a is in my tree. When it reaches > Linus' tree send a request to Greg for it to be backported if none of > the stable automation picks it up. You're absolutely right, sorry about the noise. Thanks. /Emil
diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c index 3912526ead66..19f6a76f1c07 100644 --- a/drivers/spi/spi-rockchip.c +++ b/drivers/spi/spi-rockchip.c @@ -425,7 +425,7 @@ static int rockchip_spi_prepare_dma(struct rockchip_spi *rs, .direction = DMA_MEM_TO_DEV, .dst_addr = rs->dma_addr_tx, .dst_addr_width = rs->n_bytes, - .dst_maxburst = rs->fifo_len / 2, + .dst_maxburst = rs->fifo_len / 4, }; dmaengine_slave_config(master->dma_tx, &txconf); @@ -526,7 +526,7 @@ static void rockchip_spi_config(struct rockchip_spi *rs, else writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_RXFTLR); - writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_DMATDLR); + writel_relaxed(rs->fifo_len / 2, rs->regs + ROCKCHIP_SPI_DMATDLR); writel_relaxed(0, rs->regs + ROCKCHIP_SPI_DMARDLR); writel_relaxed(dmacr, rs->regs + ROCKCHIP_SPI_DMACR);
This fixes tx and bi-directional dma transfers on rk3399-gru-kevin. It seems the SPI fifo must have room for 2 bursts when the dma_tx_req signal is generated or it might skip some words. This in turn makes the rx dma channel never complete for bi-directional transfers. Fix it by setting tx burst length to fifo_len / 4 and the dma watermark to fifo_len / 2. However the rk3399 TRM says (sic): "DMAC support incrementing-address burst and fixed-address burst. But in the case of access SPI and UART at byte or halfword size, DMAC only support fixed-address burst and the address must be aligned to word." So this relies on fifo_len being a multiple of 16 such that the burst length (= fifo_len / 4) is a multiple of 4 and the addresses will be word-aligned. Fixes: dcfc861d24ec ("spi: rockchip: adjust dma watermark and burstlen") Signed-off-by: Emil Renner Berthing <kernel@esmil.dk> --- drivers/spi/spi-rockchip.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)