dmaengine: ti: k3-udma: Use ktime/usleep_range based TX completion check (1c83767c) · Commits · 戴 / test

drivers/dma/ti/k3-udma.c

+53 −27

Original line number	Diff line number	Diff line
		@@ -5,6 +5,7 @@
		*/

		#include <linux/kernel.h>
		#include <linux/delay.h>
		#include <linux/dmaengine.h>
		#include <linux/dma-mapping.h>
		#include <linux/dmapool.h>
		@@ -169,7 +170,7 @@ enum udma_chan_state {

		struct udma_tx_drain {
		struct delayed_work work;
		unsigned long jiffie;
		ktime_t tstamp;
		u32 residue;
		};

		@@ -946,9 +947,10 @@ static bool udma_is_desc_really_done(struct udma_chan uc, struct udma_desc d)
		peer_bcnt = udma_tchanrt_read(uc->tchan, UDMA_TCHAN_RT_PEER_BCNT_REG);
		bcnt = udma_tchanrt_read(uc->tchan, UDMA_TCHAN_RT_BCNT_REG);

		/* Transfer is incomplete, store current residue and time stamp */
		if (peer_bcnt < bcnt) {
		uc->tx_drain.residue = bcnt - peer_bcnt;
		uc->tx_drain.jiffie = jiffies;
		uc->tx_drain.tstamp = ktime_get();
		return false;
		}

		@@ -961,35 +963,59 @@ static void udma_check_tx_completion(struct work_struct *work)
		tx_drain.work.work);
		bool desc_done = true;
		u32 residue_diff;
		unsigned long jiffie_diff, delay;
		ktime_t time_diff;
		unsigned long delay;

		while (1) {
		if (uc->desc) {
		/* Get previous residue and time stamp */
		residue_diff = uc->tx_drain.residue;
		jiffie_diff = uc->tx_drain.jiffie;
		time_diff = uc->tx_drain.tstamp;
		/*
		* Get current residue and time stamp or see if
		* transfer is complete
		*/
		desc_done = udma_is_desc_really_done(uc, uc->desc);
		}

		if (!desc_done) {
		jiffie_diff = uc->tx_drain.jiffie - jiffie_diff;
		/*
		* Find the time delta and residue delta w.r.t
		* previous poll
		*/
		time_diff = ktime_sub(uc->tx_drain.tstamp,
		time_diff) + 1;
		residue_diff -= uc->tx_drain.residue;
		if (residue_diff) {
		/* Try to guess when we should check next time */
		residue_diff /= jiffie_diff;
		delay = uc->tx_drain.residue / residue_diff / 3;
		if (jiffies_to_msecs(delay) < 5)
		delay = 0;
		/*
		* Try to guess when we should check
		* next time by calculating rate at
		* which data is being drained at the
		* peer device
		*/
		delay = (time_diff / residue_diff) *
		uc->tx_drain.residue;
		} else {
		/* No progress, check again in 1 second */
		delay = HZ;
		schedule_delayed_work(&uc->tx_drain.work, HZ);
		break;
		}

		schedule_delayed_work(&uc->tx_drain.work, delay);
		} else if (uc->desc) {
		usleep_range(ktime_to_us(delay),
		ktime_to_us(delay) + 10);
		continue;
		}

		if (uc->desc) {
		struct udma_desc *d = uc->desc;

		uc->bcnt += d->residue;
		udma_start(uc);
		vchan_cookie_complete(&d->vd);
		break;
		}

		break;
		}
		}

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