Re: [PATCH] dmaengine: tegra210-adma: fix transfer failure

[Sameer Pujar]

On 6/20/2019 10:07 PM, Jon Hunter wrote:
> On 20/06/2019 17:15, Sameer Pujar wrote:
> >  From Tegra186 onwards OUTSTANDING_REQUESTS field is added in channel
> > configuration register (bits 7:4). ADMA allows a maximum of 8 reads
> > to source and that many writes to target memory be outstanding at any
> > given point of time. If this field is not programmed, DMA transfers
> > fail to happen.
> >
> > Thus added 'ch_pending_req' member in chip data structure and the
> > same is populated with maximum allowed pending requests. Since the
> > field is not applicable to Tegra210, mentioned bit fields are unused
> > and hence the member is initialized with 0.
> >
> > Fixes: 433de642a76c ("dmaengine: tegra210-adma: add support for Tegra186/Tegra194")
> >
> > Signed-off-by: Sameer Pujar <spujar@xxxxxxxxxx>
> > ---
> >   drivers/dma/tegra210-adma.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
> > index 17ea4dd99..8d291cf 100644
> > --- a/drivers/dma/tegra210-adma.c
> > +++ b/drivers/dma/tegra210-adma.c
> > @@ -96,6 +96,7 @@ struct tegra_adma;
> >    * @ch_req_tx_shift: Register offset for AHUB transmit channel select.
> >    * @ch_req_rx_shift: Register offset for AHUB receive channel select.
> >    * @ch_base_offset: Register offset of DMA channel registers.
> > + * @ch_pending_req: Outstaning DMA requests for a channel.
> >    * @ch_fifo_ctrl: Default value for channel FIFO CTRL register.
> >    * @ch_req_mask: Mask for Tx or Rx channel select.
> >    * @ch_req_max: Maximum number of Tx or Rx channels available.
> > @@ -109,6 +110,7 @@ struct tegra_adma_chip_data {
> >   	unsigned int ch_req_tx_shift;
> >   	unsigned int ch_req_rx_shift;
> >   	unsigned int ch_base_offset;
> > +	unsigned int ch_pending_req;
> >   	unsigned int ch_fifo_ctrl;
> >   	unsigned int ch_req_mask;
> >   	unsigned int ch_req_max;
> > @@ -613,6 +615,7 @@ static int tegra_adma_set_xfer_params(struct tegra_adma_chan *tdc,
> >   			 ADMA_CH_CTRL_FLOWCTRL_EN;
> >   	ch_regs->config |= cdata->adma_get_burst_config(burst_size);
> >   	ch_regs->config |= ADMA_CH_CONFIG_WEIGHT_FOR_WRR(1);
> > +	ch_regs->config |= cdata->ch_pending_req;
> >   	ch_regs->fifo_ctrl = cdata->ch_fifo_ctrl;
> >   	ch_regs->tc = desc->period_len & ADMA_CH_TC_COUNT_MASK;
> >   
> > @@ -797,6 +800,7 @@ static const struct tegra_adma_chip_data tegra210_chip_data = {
> >   	.ch_req_tx_shift	= 28,
> >   	.ch_req_rx_shift	= 24,
> >   	.ch_base_offset		= 0,
> > +	.ch_pending_req		= 0,
> >   	.ch_fifo_ctrl		= TEGRA210_FIFO_CTRL_DEFAULT,
> >   	.ch_req_mask		= 0xf,
> >   	.ch_req_max		= 10,
> > @@ -811,6 +815,7 @@ static const struct tegra_adma_chip_data tegra186_chip_data = {
> >   	.ch_req_tx_shift	= 27,
> >   	.ch_req_rx_shift	= 22,
> >   	.ch_base_offset		= 0x10000,
> > +	.ch_pending_req		= (8 << 4),
> So given that this is a value and a shift, I think that we should add a
> proper definition like we have for TEGRA186_FIFO_CTRL_DEFAULT below.
I can add.
> >   	.ch_fifo_ctrl		= TEGRA186_FIFO_CTRL_DEFAULT,
> >   	.ch_req_mask		= 0x1f,
> >   	.ch_req_max		= 20,
> Please group your patches into a series if you have more than one for a
> given driver.
The other ADMA related change is in Kconfig and a simple change. Current 
patch can go through some review
cycles. Hence didn't want to delay the other patch.
> Cheers
> Jon