Re: [Qemu-devel] [PATCH 10/24] ide: add trigger_irq callback

[Kevin Wolf <kwolf@redhat.com>]

Am 28.10.2013 um 17:43 hat Paolo Bonzini geschrieben:
> AHCIDevice does not have a dma_status field.  The add_status callback thus
> does not make sense, start moving its functionality to new callbacks.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

This whole add_status(BM_STATUS_INT) is weird and doesn't seem to make
sense. For AHCI it triggers the actual IRQ, whereas for BMIDE it only
sets the status register bit and requires a separate call to trigger the
IRQ. This function is ide_set_irq(), which in turn ends up completely
ignored by AHCI (ahci_irq_set() is an empty function).

I think the right approach would be to let AHCI handle ide_set_irq() and
remove the add_status/trigger_irq calls completely.

>  hw/ide/ahci.c     | 12 ++++++++----
>  hw/ide/atapi.c    |  4 +++-
>  hw/ide/internal.h |  1 +
>  hw/ide/pci.c      |  7 +++++++
>  4 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
> index 23f3f22..7b47053 100644
> --- a/hw/ide/ahci.c
> +++ b/hw/ide/ahci.c
> @@ -1097,13 +1097,16 @@ static int ahci_dma_add_status(IDEDMA *dma, int status)
>      AHCIDevice *ad = DO_UPCAST(AHCIDevice, dma, dma);
>      DPRINTF(ad->port_no, "set status: %x\n", status);
>  
> -    if (status & BM_STATUS_INT) {
> -        ahci_trigger_irq(ad->hba, ad, PORT_IRQ_STAT_DSS);
> -    }
> -
>      return 0;
>  }
>  
> +static void ahci_dma_trigger_irq(IDEDMA *dma)
> +{
> +    AHCIDevice *ad = DO_UPCAST(AHCIDevice, dma, dma);
> +    DPRINTF(ad->port_no, "trigger irq\n");
> +    ahci_trigger_irq(ad->hba, ad, PORT_IRQ_STAT_DSS);
> +}
> +
>  static void ahci_async_cmd_done(IDEDMA *dma)
>  {
>      AHCIDevice *ad = DO_UPCAST(AHCIDevice, dma, dma);
> @@ -1134,6 +1137,7 @@ static const IDEDMAOps ahci_dma_ops = {
>      .prepare_buf = ahci_dma_prepare_buf,
>      .rw_buf = ahci_dma_rw_buf,
>      .set_unit = ahci_dma_set_unit,
> +    .trigger_irq = ahci_dma_trigger_irq,
>      .add_status = ahci_dma_add_status,
>      .async_cmd_done = ahci_async_cmd_done,
>      .restart_cb = ahci_dma_restart_cb,
> diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c
> index a7688bf..814cffb 100644
> --- a/hw/ide/atapi.c
> +++ b/hw/ide/atapi.c
> @@ -355,7 +355,9 @@ static void ide_atapi_cmd_read_dma_cb(void *opaque, int ret)
>  
>  eot:
>      bdrv_acct_done(s->bs, &s->acct);
> -    s->bus->dma->ops->add_status(s->bus->dma, BM_STATUS_INT);
> +    if (s->bus->dma->ops->trigger_irq) {
> +        s->bus->dma->ops->trigger_irq(s->bus->dma);
> +    }
>      ide_set_inactive(s);
>  }

This function looks suspicious as well, because there seems to be a path
where trigger_irq() can be called without actually triggering an IRQ.

Kevin