From: Eric Blake <eblake@redhat.com>
To: sfeldma@gmail.com, qemu-devel@nongnu.org, jiri@resnulli.us,
roopa@cumulusnetworks.com, john.fastabend@gmail.com,
pbonzini@redhat.com, stefanha@gmail.com, dsahern@gmail.com,
jasowang@redhat.com
Subject: Re: [Qemu-devel] [PATCH v5 03/10] rocker: add register programming guide
Date: Tue, 03 Feb 2015 09:40:32 -0700 [thread overview]
Message-ID: <54D0FA00.4090303@redhat.com> (raw)
In-Reply-To: <1421913839-22448-4-git-send-email-sfeldma@gmail.com>
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On 01/22/2015 01:03 AM, sfeldma@gmail.com wrote:
> From: Scott Feldman <sfeldma@gmail.com>
>
> This is the register programming guide for the Rocker device. It's intended
> for driver writers and device writers. It covers the device's PCI space,
> the register set, DMA interface, and interrupts.
>
In addition to typos already pointed out by Stefan,
> +
> +Writing BASE_ADDR or SIZE will reset HEAD and TAIL to zero. HEAD cannot be
> +written passed TAIL. To do so would wrap the ring. An empty ring is when HEAD
s/passed/past/
> +
> +To support forward- and backward-compatibility, descriptor and completion
> +payloads are specified in TLV format. Fields are packed with Type=field name,
> +Length=field length, and Value=field value. Software will ignore unknown fields
> +filled in by the switch. Likewise, the switch will ignore unknown fields
> +filled in by software.
Is ignoring unknown fields always the wisest action? If the unknown
fields are supposed to have an impact according the to writer, but get
ignored by the reader, then the two can get out of sync with what they
assume the other end is doing.
> +MSI-X vectors used for descriptor ring completions use a credit mechanism for
> +efficient device, PCIe bus, OS and driver operations. Each descriptor ring has
> +a credit count which represent the number of outstanding descriptors to be
s/represent/represents/
> +
> + port mapping
> + -------------------------------------------------------
> + 0 CPU port (for packets to/from host CPU)
> + 1-62 front-panel physical ports
> + 63 loopback port
> + 64-0x0000ffff RSVD
> + 0x00010000-0x0001ffff logical tunnel ports
> + 0x00020000-0xffffffff RSVD
Alignment looks off.
> +Port Settings
> +-------------
> +
> +Links status for all front-panel ports is available via PORT_PHYS_LINK_STATUS:
s/Links/Link/
> +
> + DESC_COMP_ERR reason
> + --------------------------------------------------------------------
> + 0 OK
> + -ROCKER_ENXIO address or data read err on desc buf
> + -ROCKER_ENOMEM no memory for internal staging desc buf
> + -ROCKER_EMSGSIZE Rx descriptor buffer wasn't big enough to contain
> + pactet data TLV and other TLVs.
s/pactet/packet/
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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next prev parent reply other threads:[~2015-02-03 16:40 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-22 8:03 [Qemu-devel] [PATCH v5 00/10] rocker: add new rocker ethernet switch device sfeldma
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 01/10] net: add MAC address string printer sfeldma
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 02/10] virtio-net: use qemu_mac_strdup_printf sfeldma
2015-02-03 16:19 ` Eric Blake
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 03/10] rocker: add register programming guide sfeldma
2015-02-02 16:16 ` Stefan Hajnoczi
2015-02-02 16:19 ` Stefan Hajnoczi
2015-02-03 11:08 ` Paolo Bonzini
2015-02-05 10:45 ` Stefan Hajnoczi
2015-02-05 6:29 ` Scott Feldman
2015-02-03 16:40 ` Eric Blake [this message]
2015-02-05 6:25 ` Scott Feldman
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 04/10] pci: add rocker device ID sfeldma
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 05/10] pci: add network device class 'other' for network switches sfeldma
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 06/10] rocker: add new rocker switch device sfeldma
2015-02-02 17:12 ` Stefan Hajnoczi
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 07/10] qmp: add rocker device support sfeldma
2015-02-03 15:10 ` Eric Blake
2015-02-05 6:10 ` Scott Feldman
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 08/10] rocker: add tests sfeldma
2015-02-02 16:36 ` Stefan Hajnoczi
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 09/10] MAINTAINERS: add rocker sfeldma
2015-01-22 8:03 ` [Qemu-devel] [PATCH v5 10/10] rocker: timestamp on the debug logs helps correlate with events in the VM sfeldma
2015-01-22 8:21 ` Jiri Pirko
2015-02-02 17:13 ` [Qemu-devel] [PATCH v5 00/10] rocker: add new rocker ethernet switch device Stefan Hajnoczi
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