lkml.org 
[lkml]   [2021]   [Jul]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v6 00/17] Introduce SCMI transport based on VirtIO
Date
On 12.07.21 16:18, Cristian Marussi wrote:
> Hi all,
>

Hi Cristian,

thanks for your update. Please find some additional comments in this
reply and the following.

Best regards,

Peter

> While reworking this series starting from the work done up to V3 by
> OpenSynergy, I am keeping the original autorship and list distribution
> unchanged.
>
> The main aim of this rework, as said, is to simplify where possible the
> SCMI VirtIO support added in V3 by adding at first some new general
> mechanisms in the SCMI Transport layer.
>
> Indeed, after some initial small fixes, patches 05/06/07/08 add such new
> additional mechanisms to the SCMI core to ease implementation of more
> complex transports like virtio, while also addressing a few general issues
> already potentially affecting existing transports.
>
> In terms of rework I dropped original V3 patches 05/06/07/08/12 as no more
> needed, and modified where needed the remaining original patches to take
> advantage of the above mentioned new SCMI transport features.
>
> DT bindings patch has been ported on top of freshly YAML converted arm,scmi
> bindings.
>
> Moreover, since V5 I dropped support for polling mode from the virtio-scmi
> transport, since it is an optional general mechanism provided by the core
> to allow transports lacking a completion IRQ to work and it seemed a
> needless addition/complication in the context of virtio transport.
>

Just for correctness, in my understanding polling is not completely
optional ATM. Polling would be required by scmi_cpufreq_fast_switch().
But that requirement might be irrelevant for now.

> Additionally, in V5 I could also simplify a bit the virtio transport
> probing sequence starting from the observation that, by the VirtIO spec,
> in fact, only one single SCMI VirtIO device can possibly exist on a system.
>

I wouldn't say that the virtio spec restricts the # of virtio-scmi
devices to one. But I do think the one device limitation in the kernel
is acceptable.

> The series has been tested using an emulated fake SCMI device and also a
> proper SCP-fw stack running through QEMU vhost-users, with the SCMI stack
> compiled, in both cases, as builtin and as a loadable module, running tests
> against mocked SCMI Sensors using HWMON and IIO interfaces to check the
> functionality of notifications and sync/async commands.
>
> Virtio-scmi support has been exercised in the following testing scenario
> on a JUNO board:
>
> - normal sync/async command transfers
> - notifications
> - concurrent delivery of correlated response and delayed responses
> - out-of-order delivery of delayed responses before related responses
> - unexpected delayed response delivery for sync commands
> - late delivery of timed-out responses and delayed responses
>
> Some basic regression testing against mailbox transport has been performed
> for commands and notifications too.
>
> No sensible overhead in total handling time of commands and notifications
> has been observed, even though this series do indeed add a considerable
> amount of code to execute on TX path.
> More test and measurements could be needed in these regards.
>
> This series is based on top of v5.14-rc1.
>
> Any feedback/testing is welcome :D
>
> Thanks,
> Cristian
> ---
> V5 --> V6:
> - removed delegated xfers and its usage
> - add and use *priv optional parameter in scmi_rx_callback()
> - made .poll_done and .clear_channel ops optional
>
> V4 --> V5:
> - removed msg raw_payload helpers
> - reworked msg helpers to use xfer->priv reference
> - simplified SCMI device probe sequence (one static device)
> - added new SCMI Kconfig layout
> - removed SCMI virtio polling support
>
> V3 --> V4:
> - using new delegated xfers support and monotonically increasing tokens
> in virtio transport
> - ported SCMI virtio transport DT bindings to YAML format
> - added virtio-scmi polling support
> - added delegated xfers support
>
> Cristian Marussi (11):
> firmware: arm_scmi: Avoid padding in sensor message structure
> firmware: arm_scmi: Fix max pending messages boundary check
> firmware: arm_scmi: Add support for type handling in common functions
> firmware: arm_scmi: Remove scmi_dump_header_dbg() helper
> firmware: arm_scmi: Add transport optional init/exit support
> firmware: arm_scmi: Introduce monotonically increasing tokens
> firmware: arm_scmi: Handle concurrent and out-of-order messages
> firmware: arm_scmi: Add priv parameter to scmi_rx_callback
> firmware: arm_scmi: Make .clear_channel optional
> firmware: arm_scmi: Make polling mode optional
> firmware: arm_scmi: Make SCMI transports configurable
>
> Igor Skalkin (4):
> firmware: arm_scmi: Make shmem support optional for transports
> firmware: arm_scmi: Add method to override max message number
> dt-bindings: arm: Add virtio transport for SCMI
> firmware: arm_scmi: Add virtio transport
>
> Peter Hilber (2):
> firmware: arm_scmi: Add message passing abstractions for transports
> firmware: arm_scmi: Add optional link_supplier() transport op
>
> .../bindings/firmware/arm,scmi.yaml | 8 +-
> MAINTAINERS | 1 +
> drivers/firmware/Kconfig | 34 +-
> drivers/firmware/arm_scmi/Kconfig | 97 +++
> drivers/firmware/arm_scmi/Makefile | 8 +-
> drivers/firmware/arm_scmi/common.h | 94 ++-
> drivers/firmware/arm_scmi/driver.c | 651 +++++++++++++++---
> drivers/firmware/arm_scmi/mailbox.c | 2 +-
> drivers/firmware/arm_scmi/msg.c | 113 +++
> drivers/firmware/arm_scmi/sensors.c | 6 +-
> drivers/firmware/arm_scmi/smc.c | 3 +-
> drivers/firmware/arm_scmi/virtio.c | 491 +++++++++++++
> include/uapi/linux/virtio_ids.h | 1 +
> include/uapi/linux/virtio_scmi.h | 24 +
> 14 files changed, 1389 insertions(+), 144 deletions(-)
> create mode 100644 drivers/firmware/arm_scmi/Kconfig
> create mode 100644 drivers/firmware/arm_scmi/msg.c
> create mode 100644 drivers/firmware/arm_scmi/virtio.c
> create mode 100644 include/uapi/linux/virtio_scmi.h
>

\
 
 \ /
  Last update: 2021-07-15 18:38    [W:0.291 / U:0.604 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site