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

[Grygorii Strashko <grygorii.strashko@xxxxxx>]

On 16/09/2020 11:35, Peter Ujfalusi wrote:
> On 15/09/2020 19.41, 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.
>
> This is how the DMAengine driver deals with the enable.
>
> Acked-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>

Sorry, but I'd need to resend v2 - based on wrong tree.
Worked too late yesterday :(

> > Fixes: d70241913413 ("dmaengine: ti: k3-udma: Add glue layer for non DMAengine users")
> > Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
> > ---
> >   drivers/dma/ti/k3-udma-glue.c | 15 +++------------
> >   1 file changed, 3 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/dma/ti/k3-udma-glue.c b/drivers/dma/ti/k3-udma-glue.c
> > index dc03880f021a..37d706cf3ba9 100644
> > --- a/drivers/dma/ti/k3-udma-glue.c
> > +++ b/drivers/dma/ti/k3-udma-glue.c
> > @@ -370,7 +370,6 @@ 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;
> >   	int ret;
> >   
> >   	ret = xudma_navss_psil_pair(tx_chn->common.udmax,
> > @@ -383,15 +382,11 @@ int k3_udma_glue_enable_tx_chn(struct k3_udma_glue_tx_channel *tx_chn)
> >   
> >   	tx_chn->psil_paired = true;
> >   
> > -	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;
> > @@ -1059,7 +1054,6 @@ 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;
> >   	int ret;
> >   
> >   	if (rx_chn->remote)
> > @@ -1078,11 +1072,8 @@ int k3_udma_glue_enable_rx_chn(struct k3_udma_glue_rx_channel *rx_chn)
> >   
> >   	rx_chn->psil_paired = true;
> >   
> > -	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);
>
> - Péter
>
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
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--
Best regards,
grygorii