(I think this is okay to go on public here) +Cc: Pierre, Liam, DMA Engine ML, ASoC ML
On Mon, Jul 08, 2019 at 01:50:07PM -0700, Curtis Malainey wrote:
Hello Andy,
I am reaching out to you as you are the main author for drivers/dma/dw/core.c and we are seeing a failure in there on some of our samus devices. On certain device we are seeing the following failure (debugging enabled in this log.)
[ 3.587515] sst-acpi INT3438:00: DW_PARAMS: 0x00000000
AFAIK, when Synopsys DesignWare DMA IP is in use in Intel, we almost always (yes, I know couple of exceptions), enable auto configuration block. Thus, the *private* DMA controllers used in Broadwell are actually Intel iDMA 32-bit. Nowadays the differences can be seen in drivers/dma/dw/idma32.c.
Note, DMA in the driver is used solely for firmware load, simplest workaround is to disable DMA. Though, personally, for sake of test coverage, I would like to see how it works in DMA case.
[ 3.587519] haswell-pcm-audio haswell-pcm-audio: error: DMA device register failed [ 3.587524] haswell-pcm-audio haswell-pcm-audio: sst_dma_new failed -22 [ 3.598010] bdw-rt5677 bdw-rt5677: ASoC: failed to init link System PCM
I don't have the datasheets for this component but I am wondering if you could help us troubleshoot this bug it would be greatly appreciated if possible. I am not sure if we are seeing a hardware boot failure or a boot race. I was hoping you could shed some light on this and if it is a boot race help us recover from it. I know Intel relies on no defers typically but it would be nice to see if we can fix this. Below is where I have traced the error source to in core.c.
So, the correct fix is to provide a platform data, like it's done in drivers/dma/dw/pci.c::idma32_pdata, in the sst-firmware.c::dw_probe(), and call idma32_dma_probe() with idma32_dma_remove() respectively on removal stage.
(It will require latest patches to be applied, which are material for v5.x)
dw_params = dma_readl(dw, DW_PARAMS); dev_dbg(chip->dev, "DW_PARAMS: 0x%08x\n", dw_params); autocfg = dw_params >> DW_PARAMS_EN & 1; if (!autocfg) { err = -EINVAL; goto err_pdata; }Let me know if you have any ideas on how to mitigate this, thanks.