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

[Nikunj A Dadhania]

Thomas Huth <thuth at redhat.com> writes:

> 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?

It is used only for PCI config space.  

> 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 ...

config-l! is for 32-bit registers.

There is no config-x{!,@} (8bytes) version, we would need to add it in that
case.

Regards
Nikunj