From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C19D2C433F5 for ; Thu, 23 Sep 2021 14:58:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 95193610C9 for ; Thu, 23 Sep 2021 14:58:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241806AbhIWPAA (ORCPT ); Thu, 23 Sep 2021 11:00:00 -0400 Received: from foss.arm.com ([217.140.110.172]:35768 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241501AbhIWO76 (ORCPT ); Thu, 23 Sep 2021 10:59:58 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C5259D6E; Thu, 23 Sep 2021 07:58:26 -0700 (PDT) Received: from e120937-lin.home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DB23A3F718; Thu, 23 Sep 2021 07:58:24 -0700 (PDT) From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: sudeep.holla@arm.com, james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com, f.fainelli@gmail.com, etienne.carriere@linaro.org, vincent.guittot@linaro.org, souvik.chakravarty@arm.com, peter.hilber@opensynergy.com, igor.skalkin@opensynergy.com, cristian.marussi@arm.com Subject: [PATCH v5 0/13] Introduce atomic support for SCMI transports Date: Thu, 23 Sep 2021 15:57:49 +0100 Message-Id: <20210923145802.50938-1-cristian.marussi@arm.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, This series mainly aims to introduce atomic support for transports that can support it. At first in [02/13], as a closely related addition, it is introduced a common way for a transport to signal to the SCMI core that it does not offer completion interrupts, so that the usual polling behaviour based on .poll_done() will be required: this can be done enabling statically a global polling behaviour for the whole transport with flag scmi_desc.force_polling OR dynamically enabling at runtime such polling behaviour on a per-channel basis with scmi_chan_info.no_completion_irq, typically during .chan_setup(). The usual per-command polling selection behaviour based on hdr.poll_completion is preserved as before. In [03/13] a Kconfig is added to enable at build-time force_polling on SCMI Mailbox transport only. (VirtIO does not support polling, while it does not make sense to support global force_polling on SMC given the presence of sync_cmds_atomic_replies flag) Then in [04/13], a transport that supports atomic operations on its TX path can now declare itself as .atomic_capable and, if the platform has been also configured to use such atomic operation mode, the SCMI core will refrain itself too from sleeping on the correspondent RX-path even when using completion IRQs. In [07/13] a simple method is introduced so that an SCMI driver can easily query the core to check if the currently used transport is configured to behave in an atomic manner: in this way, interested SCMI driver users, like Clock framework [08/13], can optionally support atomic operations when operating on an atomically configured transport. In [09/13] virtio transport is declared atomic and a new Kconfig is added to be able to choose at build time if that specific platform should use the atomic operation mode or not; such new option is default N, so VirtIO will continue to operate in non-atomic mode unless otherwise specified. Finally there are 4 patches related to SMC transport. At first [10/13] ports SMC to use the common core completions when completion interrupt is available or otherwise revert to use common core polling mechanism above introduced: this avoids the improper call of scmi_rx_callback directly in smc_send_message. Then in [11/13] SMC is converted to be .atomic_capable by substituting the mutexes with busy-waiting to keep the channel 'locked' ONLY IF the SMC transport is configured to operate in atomic mode. (CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE=y) With [12/13] I introduce a flag to allow a transport to signal to the core that upon return of a .send_message() the requested command execution can be assumed by the core to have been fully completed by the platform, so that the response payload (if any) can be immediately fetched without the need to poll the channel. Finally in [13/13] I enable the above flag for SMC transport. Atomic support has been minimally tested against the virtio transport, while polling has been tested with mailbox transports. The series is based on sudeep/for-next/scmi[1] on top of: commit 1cd73200dad2 ("firmware: arm_scmi: Remove __exit annotation") Given I'm still gathering feedback on this, I still not have CCed any maintainer out of SCMI subsystem. Any feedback welcome. Thanks, Cristian [1]: https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git/log/?h=for-next/scmi --- V4 --> V5 - removed RFCs tags - added scmi_desc.atomic_enabled flags and a few Kconfig options to set atomic mode for SMC and VirtIO transports. Default disabled. - added Kconfig option to enable forced polling as a whole on the Mailbox transport - removed .poll_done callback from SMC transport since no real polling is needed once sync_cmds_atomic_replies is set - made atomic_capable changes on SMC transport dependent on Kconfig CONFIG_ARM_SCMI_TRANSPORT_SMC_ATOMIC_ENABLE: so no change and no busy waiting if atomic mode is NOT enabled in Kconfig. - made const: force_polling/atomic_capable/atomic_enabled/sync_cmds_atomic_replies V3 --> V4 - rebased on linux-next/master next-20210824 - renamed .needs_polling to .no_completion_irq - added .sync_cmds_atomic_replies - make SMC use .sync_cmd_atomic_replies V2 --> v3 - rebased on SCMI VirtIO V6 which in turn is based on v5.14-rc1 Cristian Marussi (13): firmware: arm_scmi: Perform earlier cinfo lookup call in do_xfer firmware: arm_scmi: Add configurable polling mode for transports firmware: arm_scmi: Add forced polling support to mailbox transport firmware: arm_scmi: Add support for atomic transports include: trace: Add new scmi_xfer_response_wait event firmware: arm_scmi: Use new trace event scmi_xfer_response_wait firmware: arm_scmi: Add is_transport_atomic() handle method clk: scmi: Support atomic enable/disable API firmware: arm_scmi: Add atomic mode support to virtio transport firmware: arm_scmi: Make smc transport use common completions firmware: arm_scmi: Add atomic mode support to smc transport firmware: arm_scmi: Add sync_cmds_atomic_replies transport flag firmware: arm_scmi: Make smc support atomic sync commands replies drivers/clk/clk-scmi.c | 44 ++++- drivers/firmware/arm_scmi/Kconfig | 38 +++++ drivers/firmware/arm_scmi/common.h | 25 +++ drivers/firmware/arm_scmi/driver.c | 251 +++++++++++++++++++++++----- drivers/firmware/arm_scmi/mailbox.c | 1 + drivers/firmware/arm_scmi/smc.c | 114 ++++++++++--- drivers/firmware/arm_scmi/virtio.c | 2 + include/linux/scmi_protocol.h | 8 + include/trace/events/scmi.h | 28 ++++ 9 files changed, 432 insertions(+), 79 deletions(-) -- 2.17.1