From patchwork Thu Jun 9 11:27:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Whitchurch X-Patchwork-Id: 12875310 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 295DFCCA47B for ; Thu, 9 Jun 2022 11:27:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243752AbiFIL1t (ORCPT ); Thu, 9 Jun 2022 07:27:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243682AbiFIL1r (ORCPT ); Thu, 9 Jun 2022 07:27:47 -0400 Received: from smtp1.axis.com (smtp1.axis.com [195.60.68.17]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B80616A520; Thu, 9 Jun 2022 04:27:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1654774066; x=1686310066; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=LmOhtt+sTSzENhRVy269JX54eQelMXkrz6ZoDjQkje8=; b=DNfaqDHh+SjfmXNCXYlH9lmp7oKyjOizcJ+GX2O8Z9EsMOMqo62TQpXe lHz9EHlYHlVzKYk7alyLdQThEQ52gn0/k9dndOPJ5VsJ4ZvNOrXWtHC0v myoL9gH0TVf4eUC6XNi59dh5MLpceh42pnFJW5hH8TG59Fi+KpwhBZbtw usoyHs9bJz1eb5FMXMtu8Uif3pFkt28N2iJfKbMR4AJ/9P6ciqKV1q1+Q Um5XqXXFlqUEQcBiOEPQ7rlVislobos9IcJfZxLL+98OITyEM/9VmKRAG F8VeRBdD4u2hlKy37wMbQ/NKf1uZd2YcAn0tw1a+Vs4gc1FvJBXe7XGcu w==; From: Vincent Whitchurch To: , , CC: , Vincent Whitchurch , , , , , , Subject: [PATCH v4 1/4] dt-bindings: timer: exynos4210-mct: Add ARTPEC-8 MCT support Date: Thu, 9 Jun 2022 13:27:35 +0200 Message-ID: <20220609112738.359385-2-vincent.whitchurch@axis.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220609112738.359385-1-vincent.whitchurch@axis.com> References: <20220609112738.359385-1-vincent.whitchurch@axis.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org The ARTPEC-8 has an MCT with 4 global and 8 local timer interrupts. The SoC has a quad-core Cortex-A53 and a single-core Cortex-A5 which share one MCT with one global and eight local timers. The Cortex-A53 and Cortex-A5 do not have cache-coherency between them, and therefore run two separate kernels. The Cortex-A53 boots first and starts the global free-running counter and also registers a clock events device using the global timer. (This global timer clock events is usually replaced by arch timer clock events for each of the cores.) When the A5 boots (via the A53), it should not use the global timer interrupts or write to the global timer registers. This is because even if there are four global comparators, the control bits for all four are in the same registers, and we would need to synchronize between the cpus. Instead, the global timer FRC (already started by the A53) should be used as the clock source, and one of the local timers which are not used by the A53 can be used for clock events on the A5. To support this hardware, add a compatible for the MCT as well as two new properties to describe the hardware-mandated sharing of the FRC and dedicating local timers to specific processors. Reviewed-by: Krzysztof Kozlowski Signed-off-by: Vincent Whitchurch --- Notes: v4: - Add Krzysztof's Reviewed-by. v3: - Add all required bindings for ARTPEC-8 in one patch - Rename and split local-timer-only to samsung,local-timers and samsung,frc-shared - Restrict above properties to the ARTPEC-8 compatible. - Rewrite descriptions of properties to hopefully describe hardware. v2: - Use devicetree property instead of module parameter. .../timer/samsung,exynos4210-mct.yaml | 26 +++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.yaml b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.yaml index 9c81d00b12e0..829bd2227f7c 100644 --- a/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.yaml +++ b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.yaml @@ -25,6 +25,7 @@ properties: - samsung,exynos4412-mct - items: - enum: + - axis,artpec8-mct - samsung,exynos3250-mct - samsung,exynos5250-mct - samsung,exynos5260-mct @@ -45,6 +46,19 @@ properties: reg: maxItems: 1 + samsung,frc-shared: + type: boolean + description: | + Indicates that the hardware requires that this processor share the + free-running counter with a different (main) processor. + + samsung,local-timers: + $ref: /schemas/types.yaml#/definitions/uint32-array + minItems: 1 + maxItems: 16 + description: | + List of indices of local timers usable from this processor. + interrupts: description: | Interrupts should be put in specific order. This is, the local timer @@ -74,6 +88,17 @@ required: - reg allOf: + - if: + not: + properties: + compatible: + contains: + enum: + - axis,artpec8-mct + then: + properties: + samsung,local-timers: false + samsung,frc-shared: false - if: properties: compatible: @@ -101,6 +126,7 @@ allOf: compatible: contains: enum: + - axis,artpec8-mct - samsung,exynos5260-mct - samsung,exynos5420-mct - samsung,exynos5433-mct