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 11:15:13 -0500 Message-ID: <124e9f09-fb60-071d-e2ba-ec6f7fb3955c@ti.com> 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> <5C59AEA3.1080400@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5C59AEA3.1080400@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 Roger, On 02/05/2019 10:41 AM, Roger Quadros wrote: > Murali, > > On 05/02/19 17:08, Murali Karicheri wrote: >> 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. > > PRU firmware accessing DRAM of other PRU is a design contract and that use case > requires both PRUs to be loaded with matching firmware. That should continue to work. > > What I'm suggesting here is that kernel remoteproc driver should have nothing to do > with the other PRU's data RAM. > > The application driver if needs both PRUs then it can obviously access both DRAMs > as it has a phandle to both PRUs. > That should be fine. Regards, Murali > cheers, > -roger > >> >> 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 >>> >