From mboxrd@z Thu Jan 1 00:00:00 1970 From: Murali Karicheri Subject: Re: [PATCH v2 01/14] dt-bindings: remoteproc: Add TI PRUSS bindings Date: Tue, 5 Feb 2019 10:08:11 -0500 Message-ID: References: <1549290167-876-1-git-send-email-rogerq@ti.com> <1549290167-876-2-git-send-email-rogerq@ti.com> <20190204163312.GI5720@atomide.com> <5C5959DB.2090608@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5C5959DB.2090608@ti.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Roger Quadros , Tony Lindgren , s-anna@ti.com Cc: ohad@wizery.com, bjorn.andersson@linaro.org, david@lechnology.com, nsekhar@ti.com, t-kristo@ti.com, nsaulnier@ti.com, jreeder@ti.com, woods.technical@gmail.com, linux-omap@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org Hi Roger, On 02/05/2019 04:39 AM, Roger Quadros wrote: > Hi Tony & Suman, > > On 04/02/19 18:33, Tony Lindgren wrote: >> Hi, >> >> * Roger Quadros [190204 14:23]: >>> From: Suman Anna >> ... >>> +Example: >>> +======== >>> +1. /* AM33xx PRU-ICSS */ >>> + >>> + pruss: pruss@0 { >>> + compatible = "ti,am3356-pruss"; >>> + reg = <0x0 0x2000>, >>> + <0x2000 0x2000>, >>> + <0x10000 0x3000>; >>> + reg-names = "dram0", "dram1", >>> + "shrdram2"; >>> + #address-cells = <1>; >>> + #size-cells = <1>; >>> + ranges; >> >> Thanks for fixing up the reg ranges for the top level node. >> >> Ideally there would not even be a top level node here as >> AFAIK the whole PRUSS is a collection of devices on a PRU >> internal interconnect. So following that path a bit further.. >> How about just get rid of the top level node and just do: >> >> pruss: pruss@0 { >> dram0: memory@0 { >> device_type = "memory"; >> reg = <0x0 0x2000>; >> }; >> >> dram1: memory@2000 { >> device_type = "memory"; >> reg = <0x2000 0x2000>; >> }; > > Actually dram0 and dram1 are data memories for PRU0 and PRU1 respectively. > Isn't it better if they are moved to the pru node? > e.g. > > pru0: pru@34000 { > compatible = "ti,am3356-pru"; > reg = <0x34000 0x2000>, > <0x22000 0x400>, > <0x22400 0x100>, > <0x0 0x2000>; > reg-names = "iram", "control", "debug", "dram"; > ... > }; > > pru1: pru@38000 { > compatible = "ti,am3356-pru"; > reg = <0x38000 0x2000>, > <0x24000 0x400>, > <0x24400 0x100>, > <0x2000 0x2000>; > reg-names = "iram", "control", "debug", "dram"; > ... > }; > > I think it is better to place a restriction that firmware on PRU0 cannot use data > memory of PRU1 and vice versa. > That will not work as there are switch firmware cases where PRU access DRAM of other PRU and is a valid case to support in the future. So let us not do that. Murali > Application drivers do sometimes need to read/write to data memory. The pru_rproc > driver could provide a API for the application drivers to get virtual address of > the respective PRU's data memory. > >> >> shrdram2: memory@10000 { >> device_type = "memory"; >> reg = <0x10000 0x3000>; >> }; > > Shared RAM is not so straight forward. Both PRU firmwares and both application drivers > might need to read/write here. The area split is decided by firmware design and there > is no hardware protection to prevent from stomping on each others toes. > > We need a carveout based memory allocator at least I think that can do a > allocate(base_offset, size); into shared RAM. > > This could be used by pru_rproc driver at firmware load time and by application drivers > at initialization time. > > Thoughts? > >> >> pruss_cfg: cfg@26000 { >> ... >> }; >> ... >> }; >> >> If the device_type = "memory" cannot be used here for >> being specific to the top level properties, then >> there's probably some other generic property usable >> here :) >> >>> + pruss_mii_rt: mii_rt@32000 { >>> + reg = <0x32000 0x58>; >>> + }; >> >> The node name should not have underscores so >> pruss_mii_rt: mii-rt@32000. Please check the others >> too, like app_node. >> > > OK. > >>> + app_node: app_node { >>> + prus = <&pru0>, <&pru1>; >>> + firmware-name = "pruss-app-fw", "pruss-app-fw-2"; >>> + ti,pruss-gp-mux-sel = <2>, <1>; >>> + /* setup interrupts for prus: >>> + prus[0] => pru1_0: ev=16, chnl=2, host-irq=7, >>> + prus[1] => pru1_1: ev=19, chnl=1, host-irq=3 */ >>> + ti,pru-interrupt-map = <0 16 2 7 >, <1 19 1 3>; >>> + } >> >> If the ti,pruss-gp-mux-sel and ti,pru-interrupt-map are >> firmware configuration options, maybe leave them out of >> the dts completely and make the app-node optional. > > Yes the app-node is optional. I will mention it. > > No, ti,pruss-gp-mux-sel and ti,pru-interrupt-map are not firmware options. > But these settings are application/firmware specific. > > ti,pru-interrupt-map specifies the configuration to be used for the INTC interrupt > controller. > > ti,pruss-gp-mux-sel is used to configure this register. > "Table 30-20. PRUSS_GPCFG0" in http://www.tij.co.jp/jp/lit/ug/spruhz7h/spruhz7h.pdf > "29:26 PR1_PRU0_GP_MUX_SEL" > > It configures how the pins from the PRUSS module are routed internally > to the various modules. > > see "30.2.1 PRU-ICSS I/O Interface" > and "Table 30-1. PRU-ICSS1 I/O Signals" > >> >> And have a proper compatible for this node such as >> "ti,pruss-app-xyz". And this should be only set if the the >> hardware is wired up in such way that things need to be >> configured in the dts rather than by the firmware. > > Yes, compatible is a required property as we need to load > the appropriate application (kernel space) driver for it. > I will fix the example. > >> >> And then you can just hide mux-sel and interrupt-map >> behind the compatible property for that hardware. And >> leave them out from the dts and have the handling driver >> would set mux-sel and interrupt-map based on the >> match->data during probe. > > To summarize: > > I'll mark the app node as optional. Only required if a kernel > driver is required for the application. > Compatible is mandatory for app node. > ti,pruss-gp-mux-sel and ti,pru-interrupt-map are optional > for app node. > > cheers, > -roger >