Hi Peng, On 9/23/2019 6:14 PM, Peng Fan wrote: > From: Peng Fan <peng.fan@xxxxxxx> > > This mailbox driver implements a mailbox which signals transmitted data > via an ARM smc (secure monitor call) instruction. The mailbox receiver > is implemented in firmware and can synchronously return data when it > returns execution to the non-secure world again. > An asynchronous receive path is not implemented. > This allows the usage of a mailbox to trigger firmware actions on SoCs > which either don't have a separate management processor or on which such > a core is not available. A user of this mailbox could be the SCP > interface. > > Modified from Andre Przywara's v2 patch > https://lore.kernel.org/patchwork/patch/812999/ > > Cc: Andre Przywara <andre.przywara@xxxxxxx> > Signed-off-by: Peng Fan <peng.fan@xxxxxxx> > --- [snip] > +typedef unsigned long (smc_mbox_fn)(unsigned int, unsigned long, > + unsigned long, unsigned long, > + unsigned long, unsigned long, > + unsigned long); > +static smc_mbox_fn *invoke_smc_mbox_fn; Sorry for spotting this so late, the only thing that concerns me here with this singleton is if we happen to have both an arm,smc-mbox and arm,hvc-mbox configured in the system, this would not work. I do not believe this could be a functional use case, but we should probably guard against that or better yet, move that into the arm_smc_chan_data private structure? -- Florian
