[U-Boot] [PATCHv6 2/6] ARMv8: add the secure monitor firmware framework

[Zhiqiang Hou <zhiqiang.hou@nxp.com>]

Hi York,

Thanks for your comments!

> -----Original Message-----
> From: york sun
> Sent: 2016?6?23? 0:20
> To: Zhiqiang Hou <zhiqiang.hou@nxp.com>; u-boot at lists.denx.de;
> albert.u.boot at aribaud.net; scottwood at freescale.com;
> Mingkai.hu at freescale.com; yorksun at freescale.com; leoli at freescale.com;
> prabhakar at freescale.com; bhupesh.sharma at freescale.com
> Subject: Re: [PATCHv6 2/6] ARMv8: add the secure monitor firmware framework
> 
> On 06/21/2016 08:42 PM, Zhiqiang Hou wrote:
> 
> <snip>
> 
> > +
> > +#ifdef CONFIG_ARMV8_PSCI
> > +/*
> > + * The PSCI_VERSION function is added from PSCI v0.2. When the PSCI
> > + * v0.1 received this function, the NOT_SUPPORTED (0xffff_ffff) error
> > + * number will be returned according to SMC Calling Conventions. But
> > + * when getting the NOT_SUPPORTED error number, we cannot ensure if
> > + * the PSCI version is v0.1 or other error occurred. So, PSCI v0.1
> > + * won't be supported by this framework.
> > + * And if the secure firmware isn't running, return NOT_SUPPORTED.
> > + *
> > + * The return value on success is PSCI version in format
> > + * major[31:16]:minor[15:0].
> > + */
> > +unsigned int sec_firmware_support_psci_version(void)
> > +{
> > +	if (gd->sec_firmware & SEC_FIRMWARE_RUNNING)
> > +		return _sec_firmware_support_psci_version();
> > +
> > +	return 0xffffffff;
> > +}
> > +#endif
> 
> Does _sec_firmware_support_psci_version() always return version numbers?
> Any chance it returns an error code?

If the PSCI_VERSION was supported in current PSCI version, it will return the version,
otherwise, the SMC will return the value 0xffff_ffff to indicate the PSCI_VERSION isn't
supported.
There isn't any description for returning error code in the PSCI spec.

Thanks,
Zhiqiang