On 19 June 2014 23:52, Bjorn Andersson <bjorn@xxxxxxx> wrote: > On Wed, Jun 18, 2014 at 8:55 PM, Jassi Brar <jaswinder.singh@xxxxxxxxxx> wrote: >> On 18 June 2014 22:14, Kevin Hilman <khilman@xxxxxxxxxx> wrote: > [...] >>> Thinking more about what this RPM driver actually does, and since you >>> mentioned patterns across SoCs, it seems to me the RPM driver bascially >>> just doing the IPC. >>> >>> So, rather than MFD or drivers/soc, it seems to me that it should be >>> implmented as a controller in the new common mailbox framwork[1] being >>> worked on by Jassi Brar (added to Cc.) >>> >>> IIUC, RPM is actually only doing one-way IPC (it only exposes a write() >>> interface to clients) so it seems like a rather simple implementation of >>> a mailbox controller. >>> >> Yup, qcom_rpm.c is exactly what drivers/mailbox/ is meant for. >> > > The RPM provides a register file with 80ish registers of variable size, to > program the hardware you write to these registers. Then you write to a register > selector register and then signal an outgoing interrupt. > For mailbox_request_channel(), you have dev_get_qcom_rpm() and qcom_rpm_write() for mbox_send_message() Rest all is what you need to fire off a message to remote or register for interrupts. So nothing new to me. > That is, the interface exposed to the kernel by the SoC is not an mailbox like > interface. > I don't understand how having to program 80 registers makes it "not like mailbox"? I have used mailbox api to pass messages between CPUs (using PPI) under same instance of Linux and otoh I think it could also support IPC over gpio (if someone gets that desperate). Mailbox isn't about how you program the h/w. Do whatever is needed to send a message across. BTW I haven't looked closely, but probably you could push the data tables in DT? Cheers -Jassi -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
