On 17. 04. 24, 12:15, Marek Szyprowski wrote:
Hi Jiri,
On 16.04.2024 12:23, Jiri Slaby wrote:
On 15. 04. 24, 23:17, Marek Szyprowski wrote:
On 05.04.2024 08:08, Jiri Slaby (SUSE) wrote:
This is a preparatory for the serial-to-kfifo switch. kfifo understands
only scatter-gatter approach, so switch to that.
No functional change intended, it's just dmaengine_prep_slave_single()
inline expanded.
And in this case, switch from dma_map_single() to dma_map_sg() too.
This
needs struct msm_dma changes. I split the rx and tx parts into an
union.
TX is now struct scatterlist, RX remains the old good phys-virt-count
triple.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx>
Cc: Bjorn Andersson <andersson@xxxxxxxxxx>
Cc: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
Cc: linux-arm-msm@xxxxxxxxxxxxxxx
I've just found that this patch broke UART operation on DragonBoard
410c. I briefly checked and didn't notice anything obviously wrong here,
but the board stops transmitting any data from its serial port after the
first message. I will try to analyze this issue a bit more tomorrow.
I double checked, but I see no immediate issues in the patch too. So
please, if you can analyze this more…
I've spent some time digging into this issue and frankly speaking I
still have no idea WHY it doesn't work (or I seriously mixed something
in the scatterlist principles). However I found a workaround to make it
working. Maybe it will help a bit guessing what happens there.
...
@@ -434,7 +436,7 @@ static void msm_start_tx(struct uart_port *port)
struct msm_dma *dma = &msm_port->tx_dma;
/* Already started in DMA mode */
- if (sg_dma_len(&dma->tx_sg))
+ if (dma->mapped)
Thanks for looking into this.
I was hesitant if I should use a flag. I should have, apparently.
Quick question:
What's value of CONFIG_NEED_SG_DMA_LENGTH in your .config?
thanks,
--
js
suse labs
