Hi Peter, On 11/5/22 20:49, Péter Ujfalusi wrote: > > > On 03/11/2022 22:30, Georgi Vlaev wrote: >> From: Vignesh Raghavendra <vigneshr@xxxxxx> >> >> The K3 platforms configure the DMA resources with the >> help of the TI's System Firmware's Device Manager(DM) >> over TISCI. The group of DMA related Resource Manager[1] >> TISCI messages includes: INTA, RINGACC, UDMAP, and PSI-L. >> This configuration however, does not persist in the DM >> after leaving from Suspend-to-RAM state. We have to restore >> the DMA channel configuration over TISCI for all configured >> channels when returning from suspend. >> >> The TISCI resource management calls for each DMA type (UDMA, >> PKTDMA, BCDMA) happen in device_free_chan_resources() and >> device_alloc_chan_resources(). In pm_suspend() we store >> the current udma_chan_config for channels that still have >> attached clients and call device_free_chan_resources(). >> In pm_resume() restore the udma_channel_config from backup >> and call device_alloc_chan_resources() for those channels. >> Drivers like CPSW can do their own DMA resource management, >> so use the late system suspend/resume hooks. > > It is wrong to push the DMA context store/restore task to a client driver (cpsw or icss), it has to be done by the glue layer. > > With this patch the DMAengine side of the UDMA/BCDMA/PKTDMA will support suspend/resume while the networking will remain broken, right? The CPSW suspend/resume patch [0] releases the DMA resources in suspend() and this one follows up in suspend_late() to deal with what's left. The order is reversed when we resume back from suspend. > > I can not test this atm since my setup relies solely on NFS rootfs via cpsw, I might be able to check with a USB-ethernet dongle.. > In this case you'll probably need CPSW suspend/resume patches [0] and apply this one on top of that sequence. > Please do a followup for the glue layer support. > Okay, will do. This may have some effect on the cpsw sequence though. > Acked-by: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxx> > Thanks. [0] https://lore.kernel.org/netdev/20221104132310.31577-1-rogerq@xxxxxxxxxx/ >> [1] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/index.html#resource-management-rm >> >> Signed-off-by: Vignesh Raghavendra <vigneshr@xxxxxx> >> [g-vlaev@xxxxxx: Add patch description and config backup] >> [g-vlaev@xxxxxx: Supend only channels with clients] >> Signed-off-by: Georgi Vlaev <g-vlaev@xxxxxx> >> --- >> Changes: >> >> v2: >> * Update the commit message >> * Use list_for_each_entry() to iterate over the channel list. >> >> drivers/dma/ti/k3-udma.c | 54 ++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 54 insertions(+) >> >> diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c >> index ce8b80bb34d7..29844044132c 100644 >> --- a/drivers/dma/ti/k3-udma.c >> +++ b/drivers/dma/ti/k3-udma.c >> @@ -304,6 +304,8 @@ struct udma_chan { >> /* Channel configuration parameters */ >> struct udma_chan_config config; >> + /* Channel configuration parameters (backup) */ >> + struct udma_chan_config backup_config; >> /* dmapool for packet mode descriptors */ >> bool use_dma_pool; >> @@ -5491,11 +5493,63 @@ static int udma_probe(struct platform_device *pdev) >> return ret; >> } >> +static int udma_pm_suspend(struct device *dev) >> +{ >> + struct udma_dev *ud = dev_get_drvdata(dev); >> + struct dma_device *dma_dev = &ud->ddev; >> + struct dma_chan *chan; >> + struct udma_chan *uc; >> + >> + list_for_each_entry(chan, &dma_dev->channels, device_node) { >> + if (chan->client_count) { >> + uc = to_udma_chan(chan); >> + /* backup the channel configuration */ >> + memcpy(&uc->backup_config, &uc->config, >> + sizeof(struct udma_chan_config)); >> + dev_dbg(dev, "Suspending channel %s\n", >> + dma_chan_name(chan)); >> + ud->ddev.device_free_chan_resources(chan); >> + } >> + } >> + >> + return 0; >> +} >> + >> +static int udma_pm_resume(struct device *dev) >> +{ >> + struct udma_dev *ud = dev_get_drvdata(dev); >> + struct dma_device *dma_dev = &ud->ddev; >> + struct dma_chan *chan; >> + struct udma_chan *uc; >> + int ret; >> + >> + list_for_each_entry(chan, &dma_dev->channels, device_node) { >> + if (chan->client_count) { >> + uc = to_udma_chan(chan); >> + /* restore the channel configuration */ >> + memcpy(&uc->config, &uc->backup_config, >> + sizeof(struct udma_chan_config)); >> + dev_dbg(dev, "Resuming channel %s\n", >> + dma_chan_name(chan)); >> + ret = ud->ddev.device_alloc_chan_resources(chan); >> + if (ret) >> + return ret; >> + } >> + } >> + >> + return 0; >> +} >> + >> +static const struct dev_pm_ops udma_pm_ops = { >> + SET_LATE_SYSTEM_SLEEP_PM_OPS(udma_pm_suspend, udma_pm_resume) >> +}; >> + >> static struct platform_driver udma_driver = { >> .driver = { >> .name = "ti-udma", >> .of_match_table = udma_of_match, >> .suppress_bind_attrs = true, >> + .pm = &udma_pm_ops, >> }, >> .probe = udma_probe, >> }; >> >> base-commit: 81214a573d19ae2fa5b528286ba23cd1cb17feec > -- Regards, Georgi
