[PATCH] dmaengine: tegra: Return correct DMA status when paused

From: Kartik Rajput
Date: Thu Dec 12 2024 - 07:44:40 EST


From: Akhil R <akhilrajeev@xxxxxxxxxx>

Currently, the driver does not return the correct DMA status when a DMA
pause is issued by the client drivers. This causes GPCDMA users to
assume that DMA is still running, while in reality, the DMA is paused.

Return DMA_PAUSED for tx_status() if the channel is paused in the middle
of a transfer.

Fixes: ee17028009d4 ("dmaengine: tegra: Add tegra gpcdma driver")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Akhil R <akhilrajeev@xxxxxxxxxx>
Signed-off-by: Kartik Rajput <kkartik@xxxxxxxxxx>
---
drivers/dma/tegra186-gpc-dma.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
index cacf3757adc2..4d6fe0efa76e 100644
--- a/drivers/dma/tegra186-gpc-dma.c
+++ b/drivers/dma/tegra186-gpc-dma.c
@@ -231,6 +231,7 @@ struct tegra_dma_channel {
bool config_init;
char name[30];
enum dma_transfer_direction sid_dir;
+ enum dma_status status;
int id;
int irq;
int slave_id;
@@ -393,6 +394,8 @@ static int tegra_dma_pause(struct tegra_dma_channel *tdc)
tegra_dma_dump_chan_regs(tdc);
}

+ tdc->status = DMA_PAUSED;
+
return ret;
}

@@ -419,6 +422,8 @@ static void tegra_dma_resume(struct tegra_dma_channel *tdc)
val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
val &= ~TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
+
+ tdc->status = DMA_IN_PROGRESS;
}

static int tegra_dma_device_resume(struct dma_chan *dc)
@@ -544,6 +549,7 @@ static void tegra_dma_xfer_complete(struct tegra_dma_channel *tdc)

tegra_dma_sid_free(tdc);
tdc->dma_desc = NULL;
+ tdc->status = DMA_COMPLETE;
}

static void tegra_dma_chan_decode_error(struct tegra_dma_channel *tdc,
@@ -716,6 +722,7 @@ static int tegra_dma_terminate_all(struct dma_chan *dc)
tdc->dma_desc = NULL;
}

+ tdc->status = DMA_COMPLETE;
tegra_dma_sid_free(tdc);
vchan_get_all_descriptors(&tdc->vc, &head);
spin_unlock_irqrestore(&tdc->vc.lock, flags);
@@ -769,6 +776,9 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
if (ret == DMA_COMPLETE)
return ret;

+ if (tdc->status == DMA_PAUSED)
+ ret = DMA_PAUSED;
+
spin_lock_irqsave(&tdc->vc.lock, flags);
vd = vchan_find_desc(&tdc->vc, cookie);
if (vd) {
--
2.47.0