From 9934075471dcc6de9bdce1f3c1e16f1afbd711a8 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Fri, 14 Oct 2016 10:30:47 +0530 Subject: dmaengine: omap-dma: add support for pause of non-cyclic transfers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. v3…v4: - update subject line. v2…v3: - rephrase the comment based on Russell's information / feedback. v1…v2: - move the drain loop into omap_dma_drain_chan() instead of having it twice. - allow pause only for DMA_DEV_TO_MEM transfers if non-cyclic. Add a comment why DMA_MEM_TO_DEV not allowed. - clear pause on terminate_all. Otherwise pause() + terminate_all() will keep the pause bit set and we can't pause the following transfer. Signed-off-by: Sebastian Andrzej Siewior [vigneshr@ti.com: drain channel only when buffering is on, rebase to v4.8] Signed-off-by: Vignesh R Acked-by: Peter Ujfalusi Signed-off-by: Vinod Koul --- drivers/dma/omap-dma.c | 124 +++++++++++++++++++++++++++++++++++-------------- 1 file changed, 89 insertions(+), 35 deletions(-) (limited to 'drivers/dma') diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c index 7ca27d4..fd6b9e6 100644 --- a/drivers/dma/omap-dma.c +++ b/drivers/dma/omap-dma.c @@ -422,7 +422,30 @@ static void omap_dma_start(struct omap_chan *c, struct omap_desc *d) c->running = true; } -static void omap_dma_stop(struct omap_chan *c) +static void omap_dma_drain_chan(struct omap_chan *c) +{ + int i; + u32 val; + + /* Wait for sDMA FIFO to drain */ + for (i = 0; ; i++) { + val = omap_dma_chan_read(c, CCR); + if (!(val & (CCR_RD_ACTIVE | CCR_WR_ACTIVE))) + break; + + if (i > 100) + break; + + udelay(5); + } + + if (val & (CCR_RD_ACTIVE | CCR_WR_ACTIVE)) + dev_err(c->vc.chan.device->dev, + "DMA drain did not complete on lch %d\n", + c->dma_ch); +} + +static int omap_dma_stop(struct omap_chan *c) { struct omap_dmadev *od = to_omap_dma_dev(c->vc.chan.device); uint32_t val; @@ -435,7 +458,6 @@ static void omap_dma_stop(struct omap_chan *c) val = omap_dma_chan_read(c, CCR); if (od->plat->errata & DMA_ERRATA_i541 && val & CCR_TRIGGER_SRC) { uint32_t sysconfig; - unsigned i; sysconfig = omap_dma_glbl_read(od, OCP_SYSCONFIG); val = sysconfig & ~DMA_SYSCONFIG_MIDLEMODE_MASK; @@ -446,27 +468,19 @@ static void omap_dma_stop(struct omap_chan *c) val &= ~CCR_ENABLE; omap_dma_chan_write(c, CCR, val); - /* Wait for sDMA FIFO to drain */ - for (i = 0; ; i++) { - val = omap_dma_chan_read(c, CCR); - if (!(val & (CCR_RD_ACTIVE | CCR_WR_ACTIVE))) - break; - - if (i > 100) - break; - - udelay(5); - } - - if (val & (CCR_RD_ACTIVE | CCR_WR_ACTIVE)) - dev_err(c->vc.chan.device->dev, - "DMA drain did not complete on lch %d\n", - c->dma_ch); + if (!(c->ccr & CCR_BUFFERING_DISABLE)) + omap_dma_drain_chan(c); omap_dma_glbl_write(od, OCP_SYSCONFIG, sysconfig); } else { + if (!(val & CCR_ENABLE)) + return -EINVAL; + val &= ~CCR_ENABLE; omap_dma_chan_write(c, CCR, val); + + if (!(c->ccr & CCR_BUFFERING_DISABLE)) + omap_dma_drain_chan(c); } mb(); @@ -481,8 +495,8 @@ static void omap_dma_stop(struct omap_chan *c) omap_dma_chan_write(c, CLNK_CTRL, val); } - c->running = false; + return 0; } static void omap_dma_start_sg(struct omap_chan *c, struct omap_desc *d) @@ -836,6 +850,8 @@ static enum dma_status omap_dma_tx_status(struct dma_chan *chan, } else { txstate->residue = 0; } + if (ret == DMA_IN_PROGRESS && c->paused) + ret = DMA_PAUSED; spin_unlock_irqrestore(&c->vc.lock, flags); return ret; @@ -1247,10 +1263,8 @@ static int omap_dma_terminate_all(struct dma_chan *chan) omap_dma_stop(c); } - if (c->cyclic) { - c->cyclic = false; - c->paused = false; - } + c->cyclic = false; + c->paused = false; vchan_get_all_descriptors(&c->vc, &head); spin_unlock_irqrestore(&c->vc.lock, flags); @@ -1269,28 +1283,66 @@ static void omap_dma_synchronize(struct dma_chan *chan) static int omap_dma_pause(struct dma_chan *chan) { struct omap_chan *c = to_omap_dma_chan(chan); + struct omap_dmadev *od = to_omap_dma_dev(chan->device); + unsigned long flags; + int ret = -EINVAL; + bool can_pause; - /* Pause/Resume only allowed with cyclic mode */ - if (!c->cyclic) - return -EINVAL; + spin_lock_irqsave(&od->irq_lock, flags); - if (!c->paused) { - omap_dma_stop(c); - c->paused = true; + if (!c->desc) + goto out; + + if (c->cyclic) + can_pause = true; + + /* + * We do not allow DMA_MEM_TO_DEV transfers to be paused. + * From the AM572x TRM, 16.1.4.18 Disabling a Channel During Transfer: + * "When a channel is disabled during a transfer, the channel undergoes + * an abort, unless it is hardware-source-synchronized …". + * A source-synchronised channel is one where the fetching of data is + * under control of the device. In other words, a device-to-memory + * transfer. So, a destination-synchronised channel (which would be a + * memory-to-device transfer) undergoes an abort if the the CCR_ENABLE + * bit is cleared. + * From 16.1.4.20.4.6.2 Abort: "If an abort trigger occurs, the channel + * aborts immediately after completion of current read/write + * transactions and then the FIFO is cleaned up." The term "cleaned up" + * is not defined. TI recommends to check that RD_ACTIVE and WR_ACTIVE + * are both clear _before_ disabling the channel, otherwise data loss + * will occur. + * The problem is that if the channel is active, then device activity + * can result in DMA activity starting between reading those as both + * clear and the write to DMA_CCR to clear the enable bit hitting the + * hardware. If the DMA hardware can't drain the data in its FIFO to the + * destination, then data loss "might" occur (say if we write to an UART + * and the UART is not accepting any further data). + */ + else if (c->desc->dir == DMA_DEV_TO_MEM) + can_pause = true; + + if (can_pause && !c->paused) { + ret = omap_dma_stop(c); + if (!ret) + c->paused = true; } +out: + spin_unlock_irqrestore(&od->irq_lock, flags); - return 0; + return ret; } static int omap_dma_resume(struct dma_chan *chan) { struct omap_chan *c = to_omap_dma_chan(chan); + struct omap_dmadev *od = to_omap_dma_dev(chan->device); + unsigned long flags; + int ret = -EINVAL; - /* Pause/Resume only allowed with cyclic mode */ - if (!c->cyclic) - return -EINVAL; + spin_lock_irqsave(&od->irq_lock, flags); - if (c->paused) { + if (c->paused && c->desc) { mb(); /* Restore channel link register */ @@ -1298,9 +1350,11 @@ static int omap_dma_resume(struct dma_chan *chan) omap_dma_start(c, c->desc); c->paused = false; + ret = 0; } + spin_unlock_irqrestore(&od->irq_lock, flags); - return 0; + return ret; } static int omap_dma_chan_init(struct omap_dmadev *od) -- cgit v1.1 From 0741b819246029a7e53b8edcc5693debd7c00c8f Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Wed, 19 Oct 2016 12:05:53 +0100 Subject: dmaengine: omap-dma: initialize can_pause to false can_pause is not initialized so it contains garbage. Fix this by setting it to false. Found using static analysis with cppcheck. Signed-off-by: Colin Ian King Signed-off-by: Vinod Koul --- drivers/dma/omap-dma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/dma') diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c index fd6b9e6..15eb802 100644 --- a/drivers/dma/omap-dma.c +++ b/drivers/dma/omap-dma.c @@ -1286,7 +1286,7 @@ static int omap_dma_pause(struct dma_chan *chan) struct omap_dmadev *od = to_omap_dma_dev(chan->device); unsigned long flags; int ret = -EINVAL; - bool can_pause; + bool can_pause = false; spin_lock_irqsave(&od->irq_lock, flags); -- cgit v1.1 From 201ac4861c1944ec3794364d6898b4ddfeb0faf8 Mon Sep 17 00:00:00 2001 From: Peter Ujfalusi Date: Tue, 29 Nov 2016 16:23:42 +0200 Subject: dmaengine: omap-dma: Support for slave devices with data port window Based on the src/dst_port_window_size - if it is set - configure the DMA channel to use double indexing in order to be able to loop within the address window. Signed-off-by: Peter Ujfalusi Signed-off-by: Vinod Koul --- drivers/dma/omap-dma.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 61 insertions(+), 2 deletions(-) (limited to 'drivers/dma') diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c index 15eb802..ac68666 100644 --- a/drivers/dma/omap-dma.c +++ b/drivers/dma/omap-dma.c @@ -166,6 +166,9 @@ enum { CSDP_DST_BURST_16 = 1 << 14, CSDP_DST_BURST_32 = 2 << 14, CSDP_DST_BURST_64 = 3 << 14, + CSDP_WRITE_NON_POSTED = 0 << 16, + CSDP_WRITE_POSTED = 1 << 16, + CSDP_WRITE_LAST_NON_POSTED = 2 << 16, CICR_TOUT_IE = BIT(0), /* OMAP1 only */ CICR_DROP_IE = BIT(1), @@ -881,15 +884,18 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg( unsigned i, es, en, frame_bytes; bool ll_failed = false; u32 burst; + u32 port_window, port_window_bytes; if (dir == DMA_DEV_TO_MEM) { dev_addr = c->cfg.src_addr; dev_width = c->cfg.src_addr_width; burst = c->cfg.src_maxburst; + port_window = c->cfg.src_port_window_size; } else if (dir == DMA_MEM_TO_DEV) { dev_addr = c->cfg.dst_addr; dev_width = c->cfg.dst_addr_width; burst = c->cfg.dst_maxburst; + port_window = c->cfg.dst_port_window_size; } else { dev_err(chan->device->dev, "%s: bad direction?\n", __func__); return NULL; @@ -910,6 +916,12 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg( return NULL; } + /* When the port_window is used, one frame must cover the window */ + if (port_window) { + burst = port_window; + port_window_bytes = port_window * es_bytes[es]; + } + /* Now allocate and setup the descriptor. */ d = kzalloc(sizeof(*d) + sglen * sizeof(d->sg[0]), GFP_ATOMIC); if (!d) @@ -921,11 +933,45 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg( d->ccr = c->ccr | CCR_SYNC_FRAME; if (dir == DMA_DEV_TO_MEM) { - d->ccr |= CCR_DST_AMODE_POSTINC | CCR_SRC_AMODE_CONSTANT; d->csdp = CSDP_DST_BURST_64 | CSDP_DST_PACKED; + + d->ccr |= CCR_DST_AMODE_POSTINC; + if (port_window) { + d->ccr |= CCR_SRC_AMODE_DBLIDX; + d->ei = 1; + /* + * One frame covers the port_window and by configure + * the source frame index to be -1 * (port_window - 1) + * we instruct the sDMA that after a frame is processed + * it should move back to the start of the window. + */ + d->fi = -(port_window_bytes - 1); + + if (port_window_bytes >= 64) + d->csdp = CSDP_SRC_BURST_64 | CSDP_SRC_PACKED; + else if (port_window_bytes >= 32) + d->csdp = CSDP_SRC_BURST_32 | CSDP_SRC_PACKED; + else if (port_window_bytes >= 16) + d->csdp = CSDP_SRC_BURST_16 | CSDP_SRC_PACKED; + } else { + d->ccr |= CCR_SRC_AMODE_CONSTANT; + } } else { - d->ccr |= CCR_DST_AMODE_CONSTANT | CCR_SRC_AMODE_POSTINC; d->csdp = CSDP_SRC_BURST_64 | CSDP_SRC_PACKED; + + d->ccr |= CCR_SRC_AMODE_POSTINC; + if (port_window) { + d->ccr |= CCR_DST_AMODE_DBLIDX; + + if (port_window_bytes >= 64) + d->csdp = CSDP_DST_BURST_64 | CSDP_DST_PACKED; + else if (port_window_bytes >= 32) + d->csdp = CSDP_DST_BURST_32 | CSDP_DST_PACKED; + else if (port_window_bytes >= 16) + d->csdp = CSDP_DST_BURST_16 | CSDP_DST_PACKED; + } else { + d->ccr |= CCR_DST_AMODE_CONSTANT; + } } d->cicr = CICR_DROP_IE | CICR_BLOCK_IE; @@ -943,6 +989,9 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg( d->ccr |= CCR_TRIGGER_SRC; d->cicr |= CICR_MISALIGNED_ERR_IE | CICR_TRANS_ERR_IE; + + if (port_window) + d->csdp |= CSDP_WRITE_LAST_NON_POSTED; } if (od->plat->errata & DMA_ERRATA_PARALLEL_CHANNELS) d->clnk_ctrl = c->dma_ch; @@ -968,6 +1017,16 @@ static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg( osg->addr = sg_dma_address(sgent); osg->en = en; osg->fn = sg_dma_len(sgent) / frame_bytes; + if (port_window && dir == DMA_MEM_TO_DEV) { + osg->ei = 1; + /* + * One frame covers the port_window and by configure + * the source frame index to be -1 * (port_window - 1) + * we instruct the sDMA that after a frame is processed + * it should move back to the start of the window. + */ + osg->fi = -(port_window_bytes - 1); + } if (d->using_ll) { osg->t2_desc = dma_pool_alloc(od->desc_pool, GFP_ATOMIC, -- cgit v1.1 From 08c824e87ea05f989a9768a365f0fc70bcd25298 Mon Sep 17 00:00:00 2001 From: Vignesh R Date: Wed, 23 Nov 2016 14:57:55 +0530 Subject: dmaengine: edma: re-initialize dummy slot during system resume The last param set in a transfer should always be pointing to dummy param set in non-cyclic mode. When system wakes from low power state EDMA PARAM slots may be reset to random values. Hence, re-initialize dummy slot to dummy param set on system resume. Signed-off-by: Vignesh R Acked-by: Peter Ujfalusi Signed-off-by: Vinod Koul --- drivers/dma/edma.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/dma') diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index e18a580..1d2be18 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -2450,6 +2450,9 @@ static int edma_pm_resume(struct device *dev) int i; s8 (*queue_priority_mapping)[2]; + /* re initialize dummy slot to dummy param set */ + edma_write_slot(ecc, ecc->dummy_slot, &dummy_paramset); + queue_priority_mapping = ecc->info->queue_priority_mapping; /* Event queue priority mapping */ -- cgit v1.1