Hi Andre, > Subject: Re: [PATCH V7 0/2] mailbox: arm: introduce smc triggered mailbox > > On 23/09/2019 07:36, Peng Fan wrote: > > Hi Peng, > > thanks for the update! > > > From: Peng Fan <peng.fan@xxxxxxx> > > > > V7: > > Typo fix > > #mbox-cells changed to 0 > > Add a new header file arm-smccc-mbox.h Use ARM_SMCCC_IS_64 > > > > Andre, > > The function_id is still kept in arm_smccc_mbox_cmd, because > > arm,func-id property is optional, so clients could pass function_id to mbox > driver. > > Well, to be honest, this is the main thing I am opposing: > > It should *not* be optional. > > The controller driver DT node should *always* contain the function ID. > The reasons for that I explained in the other emails to Jassi: > We can't safely execute smc calls from the Linux kernel, unless we also > comply with the SMCCC standard. So we should not leave the choice of the > function ID to the mailbox client. > Also this much better separates the mailbox controller driver from the client. > > So I think we should reach an agreement here. I am ok to mark it as a required property in v9, but I am not sure Jassi accept it. Thanks, Peng. > > Cheers, > Andre > > > V6: > > Switch to per-channel a mbox controller Drop arm,num-chans, > > transports, method Add arm,hvc-mbox compatible Fix smc/hvc args, drop > > client id and use correct type. > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatc > > > hwork.kernel.org%2Fcover%2F11146641%2F&data=02%7C01%7Cpeng.f > an%40n > > > xp.com%7C52d7e331c222426852a508d740ae7d42%7C686ea1d3bc2b4c6fa9 > 2cd99c5c > > > 301635%7C0%7C0%7C637048990507177346&sdata=N%2BWdEXh9QXn > F4cn2DjCwHk > > qpD1JxtP%2BBfQwn3E3lzYs%3D&reserved=0 > > > > V5: > > yaml fix > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatc > > > hwork.kernel.org%2Fcover%2F11117741%2F&data=02%7C01%7Cpeng.f > an%40n > > > xp.com%7C52d7e331c222426852a508d740ae7d42%7C686ea1d3bc2b4c6fa9 > 2cd99c5c > > > 301635%7C0%7C0%7C637048990507177346&sdata=XcRM%2FH4ZQAU > QmT%2FDlGzq > > 93LjlVhUYuvEmdYSezivTog%3D&reserved=0 > > > > V4: > > yaml fix for num-chans in patch 1/2. > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatc > > > hwork.kernel.org%2Fcover%2F11116521%2F&data=02%7C01%7Cpeng.f > an%40n > > > xp.com%7C52d7e331c222426852a508d740ae7d42%7C686ea1d3bc2b4c6fa9 > 2cd99c5c > > > 301635%7C0%7C0%7C637048990507177346&sdata=8f0Etfnd29Q6LHx > bymLVyvEE > > 7ElGZzN3uVMcIL%2BmZNQ%3D&reserved=0 > > > > V3: > > Drop interrupt > > Introduce transports for mem/reg usage Add chan-id for mem usage > > Convert to yaml format > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatc > > > hwork.kernel.org%2Fcover%2F11043541%2F&data=02%7C01%7Cpeng.f > an%40n > > > xp.com%7C52d7e331c222426852a508d740ae7d42%7C686ea1d3bc2b4c6fa9 > 2cd99c5c > > > 301635%7C0%7C0%7C637048990507177346&sdata=U2%2BjaU06Iu0h > ULuCz0RT1r > > vhSfjsu%2BWuKzjTfY7MuNw%3D&reserved=0 > > > > V2: > > This is a modified version from Andre Przywara's patch series > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.ke > rnel.org%2Fpatchwork%2Fcover%2F812997%2F&data=02%7C01%7Cpe > ng.fan%40nxp.com%7C52d7e331c222426852a508d740ae7d42%7C686ea1d3 > bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637048990507177346&sda > ta=dku%2BfT%2BDLilVU5T0fdHMzuUi4DYCM7aV1FQB4vaKCVE%3D&re > served=0. > > The modification are mostly: > > Introduce arm,num-chans > > Introduce arm_smccc_mbox_cmd > > txdone_poll and txdone_irq are both set to false arm,func-ids are > > kept, but as an optional property. > > Rewords SCPI to SCMI, because I am trying SCMI over SMC, not SCPI. > > Introduce interrupts notification. > > > > [1] is a draft implementation of i.MX8MM SCMI ATF implementation that > > use smc as mailbox, power/clk is included, but only part of clk has > > been implemented to work with hardware, power domain only supports get > > name for now. > > > > The traditional Linux mailbox mechanism uses some kind of dedicated > > hardware IP to signal a condition to some other processing unit, > > typically a dedicated management processor. > > This mailbox feature is used for instance by the SCMI protocol to > > signal a request for some action to be taken by the management processor. > > However some SoCs does not have a dedicated management core to > provide > > those services. In order to service TEE and to avoid linux shutdown > > power and clock that used by TEE, need let firmware to handle power > > and clock, the firmware here is ARM Trusted Firmware that could also > > run SCMI service. > > > > The existing SCMI implementation uses a rather flexible shared memory > > region to communicate commands and their parameters, it still requires > > a mailbox to actually trigger the action. > > > > This patch series provides a Linux mailbox compatible service which > > uses smc calls to invoke firmware code, for instance taking care of SCMI > requests. > > The actual requests are still communicated using the standard SCMI way > > of shared memory regions, but a dedicated mailbox hardware IP can be > > replaced via this new driver. > > > > This simple driver uses the architected SMC calling convention to > > trigger firmware services, also allows for using "HVC" calls to call > > into hypervisors or firmware layers running in the EL2 exception level. > > > > Patch 1 contains the device tree binding documentation, patch 2 > > introduces the actual mailbox driver. > > > > Please note that this driver just provides a generic mailbox > > mechanism, It could support synchronous TX/RX, or synchronous TX with > > asynchronous RX. And while providing SCMI services was the reason for > > this exercise, this driver is in no way bound to this use case, but > > can be used generically where the OS wants to signal a mailbox > > condition to firmware or a hypervisor. > > Also the driver is in no way meant to replace any existing firmware > > interface, but actually to complement existing interfaces. > > > > [1] > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith > > > ub.com%2FMrVan%2Farm-trusted-firmware%2Ftree%2Fscmi&data=02 > %7C01%7 > > > Cpeng.fan%40nxp.com%7C52d7e331c222426852a508d740ae7d42%7C686ea > 1d3bc2b4 > > > c6fa92cd99c5c301635%7C0%7C0%7C637048990507177346&sdata=fFE > KK8jYap5 > > igpH6ESGTHYfnhBZMsL2zB%2BdykMdOPwg%3D&reserved=0 > > > > > > > > Peng Fan (2): > > dt-bindings: mailbox: add binding doc for the ARM SMC/HVC mailbox > > mailbox: introduce ARM SMC based mailbox > > > > .../devicetree/bindings/mailbox/arm-smc.yaml | 95 > ++++++++++++ > > drivers/mailbox/Kconfig | 7 + > > drivers/mailbox/Makefile | 2 + > > drivers/mailbox/arm-smc-mailbox.c | 168 > +++++++++++++++++++++ > > 4 files changed, 272 insertions(+) > > create mode 100644 > > Documentation/devicetree/bindings/mailbox/arm-smc.yaml > > create mode 100644 drivers/mailbox/arm-smc-mailbox.c > >
