| Message ID | 20211220195646.44498-1-cristian.marussi@arm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Introduce atomic support for SCMI transports | expand |
On Mon, 20 Dec 2021 19:56:35 +0000, Cristian Marussi wrote: > This series mainly aims to introduce atomic support for SCMI transports > that can support it. > > In [01/11], 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 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 using > the flag 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. > > [...] Applied to sudeep.holla/linux (for-next/scmi), thanks! [01/11] firmware: arm_scmi: Add configurable polling mode for transports https://git.kernel.org/sudeep.holla/c/a690b7e6e7 [02/11] firmware: arm_scmi: Make smc transport use common completions https://git.kernel.org/sudeep.holla/c/f716cbd33f [03/11] firmware: arm_scmi: Add sync_cmds_completed_on_ret transport flag https://git.kernel.org/sudeep.holla/c/31d2f803c1 [04/11] firmware: arm_scmi: Make smc support sync_cmds_completed_on_ret https://git.kernel.org/sudeep.holla/c/117542b81f [05/11] firmware: arm_scmi: Make optee support sync_cmds_completed_on_ret https://git.kernel.org/sudeep.holla/c/bf322084fe [06/11] firmware: arm_scmi: Add support for atomic transports https://git.kernel.org/sudeep.holla/c/69255e7468 [07/11] firmware: arm_scmi: Add atomic mode support to smc transport https://git.kernel.org/sudeep.holla/c/0bfdca8a86 [08/11] firmware: arm_scmi: Add new parameter to mark_txdone https://git.kernel.org/sudeep.holla/c/94d0cd1da1 Deferring the last 3 for next release. We can see if we can include latest spec change for clock atomic support
On Mon, Dec 20, 2021 at 07:56:35PM +0000, Cristian Marussi wrote: > Hi all, > Hi this series has now been partially queued (01-->08), the remaining patches on virtio polling and SCMI CLK atomic support will be posted as a new small patchset in the next cycle. Thanks, Cristian
Hi all, This series mainly aims to introduce atomic support for SCMI transports that can support it. In [01/11], 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 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 using the flag 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. Patch [02/11], ports SMC transport 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. With [03/11] 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 effectively poll the channel. In [04/11] and [05/11] I enable such flag for SMC amd OPTEE transports. With [06/11] a transport that supports atomic operations on its TX path can now declare itself as .atomic_enabled and, if the platform has been also configured to use such atomic operation mode via Kconfig, the SCMI core will refrain itself too from sleeping on the RX path and instead rely on polling on the correspondent when such atomic behaviour is requested from the upper layers. (like the Clock framework) Then in [07/11] SMC is converted to be .atomic_enabled 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) In [08/11] a new parameter is added to mark_txdone transport operation; this will be needed to support polling/atomic support in SCMI virtio. [09/11] adds polling and configurable atomic mode support to SCMI virtio. (CONFIG_ARM_SCMI_TRANSPORT_VIRTIO_ATOMIC_ENABLE=y) Finally [10/11] adds support for atomic clock enable/disable requests to the SCMI Clock protocol layer, while in [11/11] the SCMI Clock driver is modified to gain optional support for atomic operations when operating on an atomically capable and configured SCMI transport. NOTE THAT once atomic mode is available and configured on the underlying SCMI transport, selected SCMI operations can be performed in atomic mode: in this series this is done only for Clock enable operations; moreover ALL the known clock devices are currently moved to atomic operations if supported by transport: later a more fine grained control to avoid atomic operations on 'slow' clock domains will be introduced, but this latter solution requires an SCMI Spec change which is still underway. Atomic support has been tested against the virtio transport in regards to the above mentioned Clock enable/disable operations. (echo 1 > /sys/kernel/debug/clk/myclock/clk_prepare_enable) Pure polling has been tested on mailbox transport. The series is based on sudeep/for-next/scmi [1] on top of: commit f872af09094c ("firmware: arm_scmi: Use new trace event scmi_xfer_response_wait") Any feedback welcome. Thanks, Cristian [1]: https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git/log/?h=for-next/scmi --- V7 --> V8 - rebased on top sudeep/for-next/scmi - removed clock prepare/unprepare for atomic transports - removed ifdeffery in SCMI virtio atomic/polling support - added SCMI virtio polling deferred worker - simplified SCMI virtio spinlocking around free list - removed ifdeffery in SMC atomic support - removed polling_capable/polling_enabled internal flags, using macros - renaming to sync_cmds_completed_on_ret V6 --> V7 - rebased on lates sudeep/for-next/scmi - fixed missing list_del() in vio_complete while processing pre-fetched buffers - added proper spilocking while accessing pending_cmds_list - reduced unneeded spinlocked region in virtio_poll_done - using __unused macro in optional mark_txdone param V5 --> V6 - changed default polling timeout - refactored SCMI RX path - added timeout_ms to traces in RX-path - added OPTEE support for sync_cmds_atomic_replies - reworked the whole atomic support in SCMI core removing any reliance on IRQs. (using pure polling) - added new parameter to mark_txdone - added new SCMI VirtIO polling/atomic support - reviewed Clock SCMI Driver atomic support: now supporting both clk_prepare and clk_enable when atomic transport is detected - added CCs 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 (11): firmware: arm_scmi: Add configurable polling mode for transports firmware: arm_scmi: Make smc transport use common completions firmware: arm_scmi: Add sync_cmds_completed_on_ret transport flag firmware: arm_scmi: Make smc support sync_cmds_completed_on_ret firmware: arm_scmi: Make optee support sync_cmds_completed_on_ret firmware: arm_scmi: Add support for atomic transports firmware: arm_scmi: Add atomic mode support to smc transport firmware: arm_scmi: Add new parameter to mark_txdone firmware: arm_scmi: Add atomic mode support to virtio transport firmware: arm_scmi: Add atomic support to clock protocol clk: scmi: Support atomic clock enable/disable API drivers/clk/clk-scmi.c | 54 +++++- drivers/firmware/arm_scmi/Kconfig | 29 +++ drivers/firmware/arm_scmi/clock.c | 22 ++- drivers/firmware/arm_scmi/common.h | 23 ++- drivers/firmware/arm_scmi/driver.c | 123 ++++++++++-- drivers/firmware/arm_scmi/mailbox.c | 3 +- drivers/firmware/arm_scmi/optee.c | 18 +- drivers/firmware/arm_scmi/smc.c | 98 +++++++--- drivers/firmware/arm_scmi/virtio.c | 291 +++++++++++++++++++++++++--- include/linux/scmi_protocol.h | 11 ++ 10 files changed, 586 insertions(+), 86 deletions(-)