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[209.85.222.176]) by smtp.gmail.com with ESMTPSA id m10-20020ad44a0a000000b006235e8fe94esm390054qvz.58.2023.05.31.06.16.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 31 May 2023 06:16:11 -0700 (PDT) Received: by mail-qk1-f176.google.com with SMTP id af79cd13be357-75b050b4fa0so602782885a.0; Wed, 31 May 2023 06:16:11 -0700 (PDT) X-Received: by 2002:a0d:f181:0:b0:568:fe3a:46b3 with SMTP id a123-20020a0df181000000b00568fe3a46b3mr1220876ywf.28.1685538581391; Wed, 31 May 2023 06:09:41 -0700 (PDT) MIME-Version: 1.0 References: <20230530220347.14049-1-blarson@amd.com> In-Reply-To: <20230530220347.14049-1-blarson@amd.com> From: Geert Uytterhoeven Date: Wed, 31 May 2023 15:09:28 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v14 6/8] arm64: dts: Add AMD Pensando Elba SoC support To: Brad Larson Cc: adrian.hunter@intel.com, alcooperx@gmail.com, andy.shevchenko@gmail.com, arnd@arndb.de, brendan.higgins@linux.dev, briannorris@chromium.org, broonie@kernel.org, catalin.marinas@arm.com, conor+dt@kernel.org, davidgow@google.com, devicetree@vger.kernel.org, fancer.lancer@gmail.com, gerg@linux-m68k.org, gsomlo@gmail.com, hal.feng@starfivetech.com, hasegawa-hitomi@fujitsu.com, j.neuschaefer@gmx.net, joel@jms.id.au, kernel@esmil.dk, krzk@kernel.org, krzysztof.kozlowski+dt@linaro.org, lee.jones@linaro.org, lee@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, linux-spi@vger.kernel.org, michal.simek@amd.com, p.zabel@pengutronix.de, rdunlap@infradead.org, robh+dt@kernel.org, samuel@sholland.org, skhan@linuxfoundation.org, suravee.suthikulpanit@amd.com, thomas.lendacky@amd.com, tonyhuang.sunplus@gmail.com, ulf.hansson@linaro.org, vaishnav.a@ti.com, walker.chen@starfivetech.com, will@kernel.org, zhuyinbo@loongson.cn Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org Hi Brad, On Wed, May 31, 2023 at 12:04 AM Brad Larson wrote: > On Wed, May 24, 2023 at 13:52 Geert Uytterhoeven wrote: > > On Tue, May 23, 2023 at 9:30 PM Brad Larson wrote: > >> On 5/16/23 09:54, Michal Simek wrote: > >> > On 5/15/23 20:16, Brad Larson wrote: > >> >> + */ > >> >> + > >> >> +/ { > >> >> + cpus { > >> >> + #address-cells = <2>; > >> >> + #size-cells = <0>; > >> >> + > >> >> + cpu-map { > >> >> + cluster0 { > >> >> + core0 { cpu = <&cpu0>; }; > >> >> + core1 { cpu = <&cpu1>; }; > >> >> + core2 { cpu = <&cpu2>; }; > >> >> + core3 { cpu = <&cpu3>; }; > >> >> + }; > >> >> + > >> >> + cluster1 { > >> >> + core0 { cpu = <&cpu4>; }; > >> >> + core1 { cpu = <&cpu5>; }; > >> >> + core2 { cpu = <&cpu6>; }; > >> >> + core3 { cpu = <&cpu7>; }; > >> >> + }; > >> >> + > >> >> + cluster2 { > >> >> + core0 { cpu = <&cpu8>; }; > >> >> + core1 { cpu = <&cpu9>; }; > >> >> + core2 { cpu = <&cpu10>; }; > >> >> + core3 { cpu = <&cpu11>; }; > >> >> + }; > >> >> + > >> >> + cluster3 { > >> >> + core0 { cpu = <&cpu12>; }; > >> >> + core1 { cpu = <&cpu13>; }; > >> >> + core2 { cpu = <&cpu14>; }; > >> >> + core3 { cpu = <&cpu15>; }; > >> >> + }; > >> >> + }; > >> >> + > >> >> + /* CLUSTER 0 */ > >> >> + cpu0: cpu@0 { > >> >> + device_type = "cpu"; > >> >> + compatible = "arm,cortex-a72"; > >> >> + reg = <0 0x0>; > >> > > >> > Do you really need 2/0 split here. The first cell is 0 anyway. > >> > >> Yes following 64-bit system definition > > > > You mean for the 64-bit main address space? > > The CPU address space under /cpus is unrelated. > > Yes, the reg prop for this node is CPU/threads per dt spec. Checked the history and > the Elba dt was derived from socionext for these nodes and this is how those device > trees are configured along with over a dozen other devices. I changed to > address-cells = <1> and dropped the leading zero from all cpu* reg<> and booting > the system I'm observing no change. Looking in drivers/of I'm not seeing where > cpu*/reg is read and used, any recommendation? drivers/of/cpu.c Looks like there are lots of DTS files that use #address-cells = <2> for CPU nodes :-( git grep -w -A1 cpus -- "*dts*" | grep address-cells | grep "<2>" I would use <1> is the first cell is always zero... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds