From: Peter Hilber <firstname.lastname@example.org> To: <email@example.com>, <firstname.lastname@example.org>, <email@example.com>, <firstname.lastname@example.org> Cc: email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, Rob Herring <firstname.lastname@example.org>, Peter Hilber <email@example.com>, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org Subject: [RFC PATCH v2 00/10] firmware: arm_scmi: Add virtio transport Date: Thu, 5 Nov 2020 22:21:06 +0100 [thread overview] Message-ID: <email@example.com> (raw) This series implements an SCMI virtio driver according to the virtio SCMI device spec patch v5 , after simple preparatory changes to the existing arm-scmi driver. The virtio transport differs in some respects from the existing shared-memory based SCMI transports. Message timeouts can be a problem if the virtio device (SCMI platform) does not have real-time properties. I set a high message rx timeout value which should work for non real-time virtio devices as well. There are other timeouts for delayed response and polling which were not addressed yet. Delayed responses are not really needed since, with the virtio transport, message responses may be transmitted out of order. Polling doesn't make sense at least for virtio devices without real-time behavior, in my understanding. There are some known issues which will be resolved before removing the RFC tag: - Further work is needed on the scmi_xfer management. Unlike shmem based transports, the virtio transport is actually exchanging messages with the SCMI agent through the scmi_xfer tx and rx buffers. In case of a message rx timeout, the arm-scmi driver could try to re-use the scmi_xfer, while that might still be used by the virtio device. I think part of the scmi_xfers_info bookkeeping could be optionally outsourced to the transport to remediate this. - After arm-scmi driver probe failure, or after remove, the scmi-virtio driver may still try to process and forward message responses from the virtio device. - We must be sure that the virtio transport option (such as virtio over MMIO) is available when the virtio SCMI device is probed. The series is based on for-next/scmi , on top of commit b9ceca6be432 ("firmware: arm_scmi: Fix duplicate workqueue name") The series was actually tested with a v5.4 based kernel, with the Base protocol and Sensor management protocol. The virtio SCMI device used was a proprietary implementation by OpenSynergy. Delayed responses were not tested. Changes in RFC v2: - Remove the DT virtio_transport phandle, since the SCMI virtio device may not be known in advance. Instead, use the first suitable probed device. Change due to Rob Herring's comment. Any comments are very welcome.  https://lists.oasis-open.org/archives/virtio-comment/202005/msg00096.html  https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git Igor Skalkin (7): firmware: arm_scmi, smccc, mailbox: Make shmem based transports optional firmware: arm_scmi: Document that max_msg is a per channel type limit firmware: arm_scmi: Add op to override max message # firmware: arm_scmi: Add per message transport data firmware: arm_scmi: Add xfer_init_buffers transport op dt-bindings: arm: Add virtio transport for SCMI firmware: arm_scmi: Add virtio transport Peter Hilber (3): firmware: arm_scmi: Add optional link_supplier() transport op firmware: arm_scmi: Add per-device transport private info firmware: arm_scmi: Add is_scmi_protocol_device() .../devicetree/bindings/arm/arm,scmi.txt | 35 +- MAINTAINERS | 1 + drivers/firmware/Kconfig | 19 +- drivers/firmware/arm_scmi/Makefile | 3 +- drivers/firmware/arm_scmi/bus.c | 5 + drivers/firmware/arm_scmi/common.h | 37 +- drivers/firmware/arm_scmi/driver.c | 124 ++++- drivers/firmware/arm_scmi/virtio.c | 493 ++++++++++++++++++ drivers/firmware/smccc/Kconfig | 1 + drivers/mailbox/Kconfig | 1 + include/uapi/linux/virtio_ids.h | 1 + include/uapi/linux/virtio_scmi.h | 41 ++ 12 files changed, 736 insertions(+), 25 deletions(-) create mode 100644 drivers/firmware/arm_scmi/virtio.c create mode 100644 include/uapi/linux/virtio_scmi.h base-commit: b9ceca6be43233845be70792be9b5ab315d2e010 -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list firstname.lastname@example.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2020-11-05 21:24 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-05 21:21 Peter Hilber [this message] 2020-11-05 21:21 ` [RFC PATCH v2 01/10] firmware: arm_scmi, smccc, mailbox: Make shmem based transports optional Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 02/10] firmware: arm_scmi: Document that max_msg is a per channel type limit Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 03/10] firmware: arm_scmi: Add op to override max message # Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 04/10] firmware: arm_scmi: Add per message transport data Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 05/10] firmware: arm_scmi: Add xfer_init_buffers transport op Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 06/10] firmware: arm_scmi: Add optional link_supplier() " Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 07/10] firmware: arm_scmi: Add per-device transport private info Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 08/10] firmware: arm_scmi: Add is_scmi_protocol_device() Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 09/10] dt-bindings: arm: Add virtio transport for SCMI Peter Hilber 2020-11-05 21:21 ` [RFC PATCH v2 10/10] firmware: arm_scmi: Add virtio transport Peter Hilber 2020-11-10 21:32 ` Cristian Marussi 2020-11-12 10:57 ` Peter Hilber 2020-11-17 21:20 ` Cristian Marussi 2021-04-08 3:45 ` Viresh Kumar
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