Re: [Qemu-devel] [PATCH v4 03/18] spapr_pci: Introduce a liobn number generating macros

[Alexander Graf <agraf@suse.de>]

On 29.01.15 10:27, Alexey Kardashevskiy wrote:
> We are going to have multiple DMA windows per PHB and we want them to
> migrate so we need a predictable way of assigning LIOBNs.
> 
> This introduces a macro which makes up a LIOBN from fixed prefix,
> PHB index (unique PHB id) and window number.
> 
> This introduces a SPAPR_PCI_DMA_WINDOW_NUM() to know the window number
> from LIOBN. It is used to distinguish the default 32bit windows from
> dynamic windows and avoid picking default DMA window properties from
> a wrong TCE table.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  hw/ppc/spapr_pci.c     | 4 ++--
>  include/hw/ppc/spapr.h | 3 ++-
>  2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 4500849..64c7702 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -502,7 +502,7 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
>          }
>  
>          sphb->buid = SPAPR_PCI_BASE_BUID + sphb->index;
> -        sphb->dma_liobn = SPAPR_PCI_BASE_LIOBN + sphb->index;
> +        sphb->dma_liobn = SPAPR_PCI_LIOBN(sphb->index, 0);
>  
>          windows_base = SPAPR_PCI_WINDOW_BASE
>              + sphb->index * SPAPR_PCI_WINDOW_SPACING;
> @@ -843,7 +843,7 @@ static int spapr_phb_children_dt(Object *child, void *opaque)
>      sPAPRTCETable *tcet;
>  
>      tcet = (sPAPRTCETable *) object_dynamic_cast(child, TYPE_SPAPR_TCE_TABLE);
> -    if (!tcet) {
> +    if (!tcet || SPAPR_PCI_DMA_WINDOW_NUM(tcet->liobn)) {
>          return 0;
>      }
>  
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 642cdc3..a2c4bac 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -442,7 +442,8 @@ int spapr_rtas_device_tree_setup(void *fdt, hwaddr rtas_addr,
>  #define SPAPR_TCE_PAGE_MASK    (SPAPR_TCE_PAGE_SIZE - 1)
>  
>  #define SPAPR_VIO_BASE_LIOBN    0x00000000
> -#define SPAPR_PCI_BASE_LIOBN    0x80000000
> +#define SPAPR_PCI_LIOBN(i, n)   (0x80000000 | ((i) << 8) | (n))

It would be more readable if you called "i" "phb_id" and "n"
"window_num" instead ;).


Alex

> +#define SPAPR_PCI_DMA_WINDOW_NUM(liobn) ((liobn) & 0xff)
>  
>  #define RTAS_ERROR_LOG_MAX      2048
>  
>