[SeaBIOS] [PATCH v3 2/3] pci: add QEMU-specific PCI capability structure
Marcel Apfelbaum
marcel at redhat.com
Mon Jul 31 12:48:27 CEST 2017
On 29/07/2017 2:34, Aleksandr Bezzubikov wrote:
> On PCI init PCI bridge devices may need some
> extra info about bus number to reserve, IO, memory and
> prefetchable memory limits. QEMU can provide this
> with special vendor-specific PCI capability.
>
> This capability is intended to be used only
> for Red Hat PCI bridges, i.e. QEMU cooperation.
>
> Signed-off-by: Aleksandr Bezzubikov <zuban32s at gmail.com>
> ---
> src/fw/dev-pci.h | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 62 insertions(+)
> create mode 100644 src/fw/dev-pci.h
>
> diff --git a/src/fw/dev-pci.h b/src/fw/dev-pci.h
> new file mode 100644
> index 0000000..fbd49ed
> --- /dev/null
> +++ b/src/fw/dev-pci.h
> @@ -0,0 +1,62 @@
> +#ifndef _PCI_CAP_H
> +#define _PCI_CAP_H
> +
> +#include "types.h"
> +
> +/*
> +
Hi Aleksander,
> +QEMU-specific vendor(Red Hat)-specific capability.
> +It's intended to provide some hints for firmware to init PCI devices.
> +
> +Its is shown below:
> +
> +Header:
> +
> +u8 id; Standard PCI Capability Header field
> +u8 next; Standard PCI Capability Header field
> +u8 len; Standard PCI Capability Header field
> +u8 type; Red Hat vendor-specific capability type:
> + now only REDHAT_QEMU_CAP 1 exists
> +Data:
> +
> +u16 non_prefetchable_16; non-prefetchable memory limit
> +
Maybe we should name it "mem". And if I remember right Gerd
suggested keeping them all 32 bits:
u32 mem_res
> +u8 bus_res; minimum bus number to reserve;
> + this is necessary for PCI Express Root Ports
> + to support PCIE-to-PCI bridge hotplug
> +
> +u8 io_8; IO limit in case of 8-bit limit value
I must have missed it, but why do we need io_8 field?
> +u32 io_32; IO limit in case of 16-bit limit value
> + io_8 and io_16 are mutually exclusive, in other words,
> + they can't be non-zero simultaneously
I don't see any io_16 field.
Maybe only one field:
u32 io_res
> +
> +u32 prefetchable_32; non-prefetchable memory limit
> + in case of 32-bit limit value
Name and comment mismatch
> +u64 prefetchable_64; non-prefetchable memory limit
> + in case of 64-bit limit value
> + prefetachable_32 and prefetchable_64 are
> + mutually exclusive, in other words,
> + they can't be non-zero simultaneously
Name and comment mismatch
It should look like:
- u32 bus_res
- u32 io_res
- u32 mem_res,
- u32 mem_prefetchable_32,
- u64 mem_prefetchable_64, (mutually exclusive with the above)
Does it look right to all?
> +If any field in Data section is 0,
> +it means that such kind of reservation
> +is not needed.
> +
> +*/
> +
> +/* Offset of vendor-specific capability type field */
> +#define PCI_CAP_VNDR_SPEC_TYPE 3
> +
> +/* List of valid Red Hat vendor-specific capability types */
> +#define REDHAT_CAP_TYPE_QEMU 1
Maybe we should be more concrete:
REDHAT_CAP_TYPE_RES_RESERVE
> +
> +
> +/* Offsets of QEMU capability fields */
> +#define QEMU_PCI_CAP_NON_PREF 4
> +#define QEMU_PCI_CAP_BUS_RES 6
> +#define QEMU_PCI_CAP_IO_8 7
> +#define QEMU_PCI_CAP_IO_32 8
> +#define QEMU_PCI_CAP_PREF_32 12
> +#define QEMU_PCI_CAP_PREF_64 16
> +#define QEMU_PCI_CAP_SIZE 24
> +
> +#endif /* _PCI_CAP_H */
>
I know the exact layout is less important for your current
project, but is important to get it right the first time.
Thanks,
Marcel
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