Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1500146
| From | Peter Ujfalusi <peter.ujfalusi@ti.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH RESEND v3] dma: omap-dma: add support for pause of non-cyclic transfers |
| Date | 2016-10-13 12:30 +0200 |
| Message-ID | <srLqW-2eM-55@gated-at.bofh.it> (permalink) |
| References | <sqHz4-16x-43@gated-at.bofh.it> <sqJAS-2hV-25@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 10/10/16 17:12, Peter Ujfalusi wrote: > On 10/10/16 15:07, Vignesh R wrote: >> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> >> >> This DMA driver is used by 8250-omap on DRA7-evm. There is one >> requirement that is to pause a transfer. This is currently used on the RX >> side. It is possible that the UART HW aborted the RX (UART's RX-timeout) >> but the DMA controller starts the transfer shortly after. >> Before we can manually purge the FIFO we need to pause the transfer, >> check how many bytes it already received and terminate the transfer >> without it making any progress. >> >> From testing on the TX side it seems that it is possible that we invoke >> pause once the transfer has completed which is indicated by the missing >> CCR_ENABLE bit but before the interrupt has been noticed. In that case the >> interrupt will come even after disabling it. >> >> The AM572x manual says that we have to wait for the CCR_RD_ACTIVE & >> CCR_WR_ACTIVE bits to be gone before programming it again here is the >> drain loop. Also it looks like without the drain the TX-transfer makes >> sometimes progress. >> >> One note: The pause + resume combo is broken because after resume the >> the complete transfer will be programmed again. That means the already >> transferred bytes (until the pause event) will be sent again. This is >> currently not important for my UART user because it does only pause + >> terminate. > > Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Can you resend the patch with corrected subject line? dmaengine: omap-dma: .... -- Péter
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH RESEND v3] dma: omap-dma: add support for pause of non-cyclic transfers Vignesh R <vigneshr@ti.com> - 2016-10-10 14:10 +0200
Re: [PATCH RESEND v3] dma: omap-dma: add support for pause of non-cyclic transfers Peter Ujfalusi <peter.ujfalusi@ti.com> - 2016-10-10 16:20 +0200
Re: [PATCH RESEND v3] dma: omap-dma: add support for pause of non-cyclic transfers Peter Ujfalusi <peter.ujfalusi@ti.com> - 2016-10-13 12:30 +0200
Re: [PATCH RESEND v3] dma: omap-dma: add support for pause of non-cyclic transfers Vignesh R <vigneshr@ti.com> - 2016-10-14 07:20 +0200
[PATCH v4] dmaengine: omap-dma: add support for pause of non-cyclic transfers Vignesh R <vigneshr@ti.com> - 2016-10-14 07:10 +0200
Re: [PATCH v4] dmaengine: omap-dma: add support for pause of non-cyclic transfers Vinod Koul <vinod.koul@intel.com> - 2016-10-18 16:50 +0200
csiph-web