From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH v5 1/2] dt-bindings: mailbox: add binding doc for the ARM SMC/HVC mailbox Date: Fri, 30 Aug 2019 10:30:05 +0100 Message-ID: <20190830093005.GA31297@bogus> References: <1567004515-3567-1-git-send-email-peng.fan@nxp.com> <1567004515-3567-2-git-send-email-peng.fan@nxp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Peng Fan Cc: Jassi Brar , "robh+dt@kernel.org" , "mark.rutland@arm.com" , "andre.przywara@arm.com" , "f.fainelli@gmail.com" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , dl-linux-imx , Sudeep Holla List-Id: devicetree@vger.kernel.org On Fri, Aug 30, 2019 at 07:37:41AM +0000, Peng Fan wrote: > Hi Jassi, > > > I think there could be channel for TEE, and channel for Linux. > > > For virtualization case, there could be dedicated channel for each VM. > > > > > I am talking from Linux pov. Functions 0xfe and 0xff above, can't both be > > active at the same time, right? > > If I get your point correctly, > On UP, both could not be active. On SMP, tx/rx could be both active, anyway > this depends on secure firmware and Linux firmware design. > Just to confirm, we can't have SMC/HVC based Rx channel as there's no *architectural* way to achieve it. So it can be based on some interrupt from secure side and hence will be a *different* type of channel/controller. Sorry to make this point repeatedly, but juts to be absolutely clear: as it stands, SMC/HVC can be used only for Tx today. -- Regards, Sudeep