Re: [PATCH] dmaengine: ti: k3-udma-glue: do not create glue dma devices for udma channels

From: Péter Ujfalusi
Date: Tue Apr 04 2023 - 16:23:54 EST




On 04/04/2023 11:11, Siddharth Vadapalli wrote:
From: Grygorii Strashko <grygorii.strashko@xxxxxx>

In case K3 DMA glue layer is using UDMA channels (AM65/J721E/J7200) it
doesn't need to create own DMA devices per RX/TX channels as they are never
used and just waste resources. The UDMA based platforms are coherent and
UDMA device iteslf is used for DMA memory management.

Hence, update K3 DMA glue layer to create K3 DMA glue DMA devices per RX/TX
channels only in case of PKTDMA (AM64) where coherency configurable per DMA
channel.

Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@xxxxxx>
---
drivers/dma/ti/k3-udma-glue.c | 70 +++++++++++++++++------------------
1 file changed, 34 insertions(+), 36 deletions(-)

diff --git a/drivers/dma/ti/k3-udma-glue.c b/drivers/dma/ti/k3-udma-glue.c
index 789193ed0386..b0c9572b0d02 100644
--- a/drivers/dma/ti/k3-udma-glue.c
+++ b/drivers/dma/ti/k3-udma-glue.c
@@ -293,19 +293,18 @@ struct k3_udma_glue_tx_channel *k3_udma_glue_request_tx_chn(struct device *dev,
}
tx_chn->udma_tchan_id = xudma_tchan_get_id(tx_chn->udma_tchanx);
- tx_chn->common.chan_dev.class = &k3_udma_glue_devclass;
- tx_chn->common.chan_dev.parent = xudma_get_device(tx_chn->common.udmax);
- dev_set_name(&tx_chn->common.chan_dev, "tchan%d-0x%04x",
- tx_chn->udma_tchan_id, tx_chn->common.dst_thread);
- ret = device_register(&tx_chn->common.chan_dev);
- if (ret) {
- dev_err(dev, "Channel Device registration failed %d\n", ret);
- put_device(&tx_chn->common.chan_dev);
- tx_chn->common.chan_dev.parent = NULL;
- goto err;
- }
-
if (xudma_is_pktdma(tx_chn->common.udmax)) {

it might be possible to narrow it down to include a test for atype_asel 14 or 15, but then I would move that test to a helper (passing common as parameter) and re-use it in other places to avoid getting out o sync overtime.
Might not worth the effort, just an observation.

+ tx_chn->common.chan_dev.class = &k3_udma_glue_devclass;
+ tx_chn->common.chan_dev.parent = xudma_get_device(tx_chn->common.udmax);
+ dev_set_name(&tx_chn->common.chan_dev, "tchan%d-0x%04x",
+ tx_chn->udma_tchan_id, tx_chn->common.dst_thread);
+ ret = device_register(&tx_chn->common.chan_dev);
+ if (ret) {
+ dev_err(dev, "Channel Device registration failed %d\n", ret);

my guess is that the put_device() is still needed, no?

+ tx_chn->common.chan_dev.parent = NULL;
+ goto err;
+ }
+
/* prepare the channel device as coherent */
tx_chn->common.chan_dev.dma_coherent = true;
dma_coerce_mask_and_coherent(&tx_chn->common.chan_dev,
@@ -912,19 +911,18 @@ k3_udma_glue_request_rx_chn_priv(struct device *dev, const char *name,
}
rx_chn->udma_rchan_id = xudma_rchan_get_id(rx_chn->udma_rchanx);
- rx_chn->common.chan_dev.class = &k3_udma_glue_devclass;
- rx_chn->common.chan_dev.parent = xudma_get_device(rx_chn->common.udmax);
- dev_set_name(&rx_chn->common.chan_dev, "rchan%d-0x%04x",
- rx_chn->udma_rchan_id, rx_chn->common.src_thread);
- ret = device_register(&rx_chn->common.chan_dev);
- if (ret) {
- dev_err(dev, "Channel Device registration failed %d\n", ret);
- put_device(&rx_chn->common.chan_dev);
- rx_chn->common.chan_dev.parent = NULL;
- goto err;
- }
-
if (xudma_is_pktdma(rx_chn->common.udmax)) {
+ rx_chn->common.chan_dev.class = &k3_udma_glue_devclass;
+ rx_chn->common.chan_dev.parent = xudma_get_device(rx_chn->common.udmax);
+ dev_set_name(&rx_chn->common.chan_dev, "rchan%d-0x%04x",
+ rx_chn->udma_rchan_id, rx_chn->common.src_thread);
+ ret = device_register(&rx_chn->common.chan_dev);
+ if (ret) {
+ dev_err(dev, "Channel Device registration failed %d\n", ret);
+ rx_chn->common.chan_dev.parent = NULL;
+ goto err;
+ }
+
/* prepare the channel device as coherent */
rx_chn->common.chan_dev.dma_coherent = true;
dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,
@@ -1044,19 +1042,19 @@ k3_udma_glue_request_remote_rx_chn(struct device *dev, const char *name,
goto err;
}
- rx_chn->common.chan_dev.class = &k3_udma_glue_devclass;
- rx_chn->common.chan_dev.parent = xudma_get_device(rx_chn->common.udmax);
- dev_set_name(&rx_chn->common.chan_dev, "rchan_remote-0x%04x",
- rx_chn->common.src_thread);
- ret = device_register(&rx_chn->common.chan_dev);
- if (ret) {
- dev_err(dev, "Channel Device registration failed %d\n", ret);
- put_device(&rx_chn->common.chan_dev);
- rx_chn->common.chan_dev.parent = NULL;
- goto err;
- }
-
if (xudma_is_pktdma(rx_chn->common.udmax)) {
+ rx_chn->common.chan_dev.class = &k3_udma_glue_devclass;
+ rx_chn->common.chan_dev.parent = xudma_get_device(rx_chn->common.udmax);
+ dev_set_name(&rx_chn->common.chan_dev, "rchan_remote-0x%04x",
+ rx_chn->common.src_thread);
+
+ ret = device_register(&rx_chn->common.chan_dev);
+ if (ret) {
+ dev_err(dev, "Channel Device registration failed %d\n", ret);
+ rx_chn->common.chan_dev.parent = NULL;
+ goto err;
+ }
+
/* prepare the channel device as coherent */
rx_chn->common.chan_dev.dma_coherent = true;
dma_coerce_mask_and_coherent(&rx_chn->common.chan_dev,

--
Péter