From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Date: Mon, 15 Dec 2014 16:27:45 +0100 Subject: [U-Boot] [PATCH 2/2] sun7i: Add PSCI v0.2 support In-Reply-To: <548EC9A2.1040108@redhat.com> References: <3801faf2e649b0908a93f12d1bca30de26392bd0.1418643457.git.jan.kiszka@siemens.com> <548EC9A2.1040108@redhat.com> Message-ID: <548EFDF1.9010404@siemens.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 2014-12-15 12:44, Hans de Goede wrote: > Hi, > > On 15-12-14 12:37, Jan Kiszka wrote: >> This extends the PSCI support for the A20 to a dual v0.2 and v0.1 >> interface. Recent OSes will prefer v0.2, olders will still find the >> original interface, just at v0.2 service IDs. >> >> In addition to the existing services, v0.2 requires us to implement both >> system off and reset. At least Linux will make use of them in favor of >> its own implementations and, thus, fail if they do not work. > > Ugh, that may be a problem, as at least power off is highly SoC specific > (different pmics, and newer pmics have a different bus) and somewhat board > specific. Yes, that was my first thought as well. > > I think we may avoid adding any board specific stuff for now, since we > only want PSCI support on A20 and later and the only boards I know > of which are not using the standard axp pmics are all A10 / A13 boards, > but this might come back to bite us in the future. Good - so this is a conceptual ack for this patch? > > Can't we just return -ENOTSUPPORTED or some such ? Unfortunately not. I don't know what was the intention of the designed of this spec regarding mandatory SYSTEM_OFF and SYSTEM_RESET support. Both functions are not supposed to return at all, and the kernel panics when you return from SYSTEM_OFF. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux