2020-09-16 18:52:20

by Grygorii Strashko

Subject: [PATCH v2] dmaengine: ti: k3-udma-glue: fix channel enable functions

Now the K3 UDMA glue layer enable functions perform RMW operation on UDMA
RX/TX RT_CTL registers to set EN bit and enable channel, which is
incorrect, because only EN bit has to be set in those registers to enable
channel (all other bits should be cleared 0).
More over, this causes issues when bootloader leaves UDMA channel RX/TX
RT_CTL registers in incorrect state - TDOWN bit set, for example. As
result, UDMA channel will just perform teardown right after it's enabled.

Hence, fix it by writing correct values (EN=1) directly in UDMA channel
RX/TX RT_CTL registers in k3_udma_glue_enable_tx/rx_chn() functions.

Fixes: d70241913413 ("dmaengine: ti: k3-udma: Add glue layer for non DMAengine users")
Signed-off-by: Grygorii Strashko <[email protected]>
Acked-by: Peter Ujfalusi <[email protected]>
---
Changes in v2:
- properly rebased on top of -master
- add ack from Peter Ujfalusi

drivers/dma/ti/k3-udma-glue.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/dma/ti/k3-udma-glue.c b/drivers/dma/ti/k3-udma-glue.c
index 3a5d33ea5ebe..42c8ad10d75e 100644
--- a/drivers/dma/ti/k3-udma-glue.c
+++ b/drivers/dma/ti/k3-udma-glue.c
@@ -378,17 +378,11 @@ EXPORT_SYMBOL_GPL(k3_udma_glue_pop_tx_chn);

int k3_udma_glue_enable_tx_chn(struct k3_udma_glue_tx_channel *tx_chn)
{
- u32 txrt_ctl;
-
- txrt_ctl = UDMA_PEER_RT_EN_ENABLE;
xudma_tchanrt_write(tx_chn->udma_tchanx, UDMA_CHAN_RT_PEER_RT_EN_REG,
- txrt_ctl);
+ UDMA_PEER_RT_EN_ENABLE);

- txrt_ctl = xudma_tchanrt_read(tx_chn->udma_tchanx,
- UDMA_CHAN_RT_CTL_REG);
- txrt_ctl |= UDMA_CHAN_RT_CTL_EN;
xudma_tchanrt_write(tx_chn->udma_tchanx, UDMA_CHAN_RT_CTL_REG,
- txrt_ctl);
+ UDMA_CHAN_RT_CTL_EN);

k3_udma_glue_dump_tx_rt_chn(tx_chn, "txchn en");
return 0;
@@ -1058,19 +1052,14 @@ EXPORT_SYMBOL_GPL(k3_udma_glue_rx_flow_disable);

int k3_udma_glue_enable_rx_chn(struct k3_udma_glue_rx_channel *rx_chn)
{
- u32 rxrt_ctl;
-
if (rx_chn->remote)
return -EINVAL;

if (rx_chn->flows_ready < rx_chn->flow_num)
return -EINVAL;

- rxrt_ctl = xudma_rchanrt_read(rx_chn->udma_rchanx,
- UDMA_CHAN_RT_CTL_REG);
- rxrt_ctl |= UDMA_CHAN_RT_CTL_EN;
xudma_rchanrt_write(rx_chn->udma_rchanx, UDMA_CHAN_RT_CTL_REG,
- rxrt_ctl);
+ UDMA_CHAN_RT_CTL_EN);

xudma_rchanrt_write(rx_chn->udma_rchanx, UDMA_CHAN_RT_PEER_RT_EN_REG,
UDMA_PEER_RT_EN_ENABLE);
--
2.17.1

2020-09-18 08:17:17

by Vinod Koul

Subject: Re: [PATCH v2] dmaengine: ti: k3-udma-glue: fix channel enable functions

On 16-09-20, 15:09, Grygorii Strashko wrote:
> Now the K3 UDMA glue layer enable functions perform RMW operation on UDMA
> RX/TX RT_CTL registers to set EN bit and enable channel, which is
> incorrect, because only EN bit has to be set in those registers to enable
> channel (all other bits should be cleared 0).
> More over, this causes issues when bootloader leaves UDMA channel RX/TX
> RT_CTL registers in incorrect state - TDOWN bit set, for example. As
> result, UDMA channel will just perform teardown right after it's enabled.
>
> Hence, fix it by writing correct values (EN=1) directly in UDMA channel
> RX/TX RT_CTL registers in k3_udma_glue_enable_tx/rx_chn() functions.

Applied, thanks

--
~Vinod