[SLOF] [PATCH v3 14/22] virtio: add 64-bit virtio helpers for 1.0

[Thomas Huth]

On 22.01.2016 11:54, Nikunj A Dadhania wrote:
> 64-bit fields are to be treated as two 32-bit fields, with low 32 bit
> part followed by the high 32 bit part.
> 
> Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
> ---
>  lib/libvirtio/virtio.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c
> index 8c22e92..40bbd37 100644
> --- a/lib/libvirtio/virtio.c
> +++ b/lib/libvirtio/virtio.c
> @@ -51,6 +51,31 @@ struct virtio_dev_common {
>  	le64 q_used;
>  } __attribute__ ((packed));
>  
> +/* virtio 1.0 Spec: 4.1.3 PCI Device Layout
> + *
> + * Fields of different sizes are present in the device configuration regions.
> + * All 64-bit, 32-bit and 16-bit fields are little-endian. 64-bit fields are to
> + * be treated as two 32-bit fields, with low 32 bit part followed by the high 32
> + * bit part.
> + */
> +static void virtio_pci_write64(void *addr, uint64_t val)
> +{
> +	uint32_t hi = (val >> 32) & 0xFFFFFFFF;
> +	uint32_t lo = val & 0xFFFFFFFF;
> +
> +	ci_write_32(addr, cpu_to_le32(lo));
> +	ci_write_32(addr + 4, cpu_to_le32(hi));
> +}
> +
> +static uint64_t virtio_pci_read64(void *addr)
> +{
> +	uint64_t hi, lo;
> +
> +	lo = le32_to_cpu(ci_read_32(addr));
> +	hi = le32_to_cpu(ci_read_32(addr + 4));
> +	return (hi << 32) | lo;
> +}

So after the discussion with Alexey in the other mail thread, I'm a
little bit confused now ... are these functions here now only used for
PCI config space or also for MMIO?
If they are used for config space only, I think I'd rather agree with
Alexey and move them to slof/helpers.c, rename them to
SLOF_pci_config_read/write64 and use forth_eval("config-l!") etc. for
consistency ...

 Thomas