Re: writing an alsa driver

[Jarkko Nikula <jarkko.nikula@intel.com>]

Hi

On 06/04/2015 10:39 PM, Michele Curti wrote:
>                  Interrupt (ResourceConsumer, Level, ActiveLow, Exclusive, ,, )
>                  {
>                      0x0000001D,
>                  }
>                  Interrupt (ResourceConsumer, Level, ActiveLow, Exclusive, ,, )
>                  {
>                      0x00000018,
>                  }
>                  Interrupt (ResourceConsumer, Level, ActiveLow, Exclusive, ,, )
>                  {
>                      0x00000019,
>                  }
>                  Interrupt (ResourceConsumer, Level, ActiveLow, Exclusive, ,, )
>                  {
>                      0x0000001A,
>                  }
>                  Interrupt (ResourceConsumer, Level, ActiveLow, Exclusive, ,, )
>                  {
>                      0x0000001B,
>                  }
>                  Interrupt (ResourceConsumer, Level, ActiveLow, Exclusive, ,, )
>                  {
>                      0x0000001C,
>                  }
...
>
> So, 6 possible IRQs for the LPE core, from 0x18 to 0x1D?
>
2 for DMA, 3 for SSP ports and 1 for host IPC. I don't know does Windows 
use those others as BIOS is exposing them but Linux needs only the host 
IPC irq 0x1d and Linux DSP FW is managing itself the rest.

> Changed the code and tried all six
>
> diff --git a/sound/soc/intel/common/sst-acpi.c b/sound/soc/intel/common/sst-acpi.c
> index bb28e84..a306502 100644
> --- a/sound/soc/intel/common/sst-acpi.c
> +++ b/sound/soc/intel/common/sst-acpi.c
> @@ -149,8 +149,12 @@ static int sst_acpi_probe(struct platform_device *pdev)
>   		sst_pdata->dma_size = desc->dma_size;
>   	}
>
> -	if (desc->irqindex_host_ipc >= 0)
> -		sst_pdata->irq = platform_get_irq(pdev, desc->irqindex_host_ipc);
> +	if (desc->irqindex_host_ipc >= 0) {
> +		sst_pdata->irq = 0x1D; /* acpi-dump, from 0x18 to 0x1D */
> +		pr_info("audio dsp: IRQ # was %d, force to %d\n",
> +				platform_get_irq(pdev, desc->irqindex_host_ipc),
> +				sst_pdata->irq);
> +	}
>
>   	if (desc->resindex_lpe_base >= 0) {
>   		mmio = platform_get_resource(pdev, IORESOURCE_MEM,
>
> without success, I get always the "dsp boot timeout".
>
Above probably won't work as it doesn't set the trigger flags as 
platform_get_irq() does and the Linux irq number is not necessarily the 
same than the HW irq number through the IOAPIC routing.

Your earlier irqindex_host_ipc change should get the right interrupt for 
Linux on your machine.

-	.irqindex_host_ipc = 5,
+	.irqindex_host_ipc = 0,

Unfortunately this index is machine specific and when I looked a few 
DSDT tables earlier I didn't figure out a clean way at which index the 
interrupt should be used in runtime. Probably having quirks for index 5 
needs least amount of quirks as index 0 seems to be constantly used on 
newer machines.

-- 
Jarkko
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