On Monday, November 14, 2016 1:50:18 PM CET Russell King - ARM Linux wrote: > On Mon, Nov 14, 2016 at 01:03:09PM +0100, Arnd Bergmann wrote: > > On Monday, November 14, 2016 2:10:16 PM CET pankaj.dubey wrote: > > > >> + scu_base = of_iomap(np, 0); > > > >> + of_node_put(np); > > > >> + if (!scu_base) { > > > >> + pr_err("%s failed to map scu_base via DT\n", __func__); > > > > > > > > For non-ca5, non-ca9 based SoCs, we'll see this error msg. We understand > > > > what does it mean, but it may confuse normal users. In current version, > > > > berlin doesn't complain like this for non-ca9 SoCs > > > > > > > > > > OK, let me see other reviewer's comment on this. Then we will decide if > > > this error message is required or can be omitted. > > > > We need to look at all callers here, to see if the function ever gets > > called for a CPU that doesn't have an SCU. I'd say we should warn if > > we know there is an SCU but we cannot map it, but never warn on > > any of the CPU cores that don't support an SCU. > > Maybe there should be two helpers: > > of_scu_enable() which _only_ looks up the SCU address in DT and enables > it if it finds it, otherwise returning failure. > > a9_scu_enable() which tries to use the A9 provided SCU address and > enables it if it finds it, otherwise returning failure. > > Then callers can decide which of these to call, and what error messages > to print on their failures.
Splitting the function in two is probably simpler overall, but we may still have to look at all the callers: Any platform that currently tries to map it on any CPU and doesn't warn about the absence of the device node (or about scu_a9_has_base() == false) should really continue not to warn about that. If all platforms only call these on SMP machines with an ARM11MPcore, Cortex-A5 or Cortex-A9, everything should be fine here, otherwise we can leave the warning in the caller after checking the return code of the new APIs. Arnd