From owner-freebsd-arm@freebsd.org Wed Jul 29 19:26:33 2020 Return-Path: Delivered-To: freebsd-arm@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id A6A28369D32 for ; Wed, 29 Jul 2020 19:26:33 +0000 (UTC) (envelope-from kamalpr@gmail.com) Received: from mail-io1-xd32.google.com (mail-io1-xd32.google.com [IPv6:2607:f8b0:4864:20::d32]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4BH3SS5RMwz497v for ; Wed, 29 Jul 2020 19:26:32 +0000 (UTC) (envelope-from kamalpr@gmail.com) Received: by mail-io1-xd32.google.com with SMTP id e64so25724457iof.12 for ; Wed, 29 Jul 2020 12:26:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:reply-to:from:date:message-id:subject:to; bh=MB4y466r5d9/3uevyF6jqE09R49N3fGBQ86HXvcJRXU=; b=InjpklUk9n6lzuR8RDsSQ9H6Scb0diBEcjnNPspRoIOHtuzaz+71AaG3g6dSEiaVa0 BCgmvGMueW83BCD+q80TW7CwnEdEbzqDvidshcVDucHo44UVpqSTQvbXY9ASFtADARdR uKpqi1FyVUByjxrPGAY8+1ATTtII+aPGr1WDX0JMp35MBxZKBWlvC1u7qUqJB0bIc053 Ziey/D9O5JO0hRJPNr6I4hW21nPSSyD5kd1wvAngaX9agFTgHIgxUfpjGBpSBnrrkeFB wuY4OvUOq4f9B7IOhmOeceairiEMa3bqZAwAka0DpACoTGKd+5FMEIuQaQZ5ZAunsShx IIRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:reply-to:from:date:message-id :subject:to; bh=MB4y466r5d9/3uevyF6jqE09R49N3fGBQ86HXvcJRXU=; b=Jh36fohKHu4EpPxM5NmjgWLJaTfEWBnYmHnrMDqXyrQmFCYkpiloxNW9VO5do/4eET DwZXitzh+lWxQxFpgvWfoKrSrjb1eKuY2zruJgYuvUGSL2JTFwHyzZJm6MgCTMr06MD/ qmwv+lWVyxpVVMVt06DCbzgn5VP1/WdAuodMMHpoYEJj2cNYnhXW6TUcInmzDGGDbl2Q hdgF7vUMenxf2dNJEtkRH/J12m6ALl7LRGQWExOkWoKJH0ftuvSbJBFhD851jVvYeumd LC7Q37MfkbgBQQbcH1b4Bl/it30HBAWBQnaGFrD50luSETmIWukJtFHVJD6b973eqD5Z GDQg== X-Gm-Message-State: AOAM530Nr8ZothlB5Eso5Tdc+4Cc3kLUoi2CzkKS6sKMwqg1NFvp+KgA f0nkUFZ2fcX6e+A+hS4LltB+8dwVkfgqz28pCkREQ3J1+Q== X-Google-Smtp-Source: ABdhPJyM5e7wUa86a5BXpLxmAfFniGgZxNnmgVzzL4QG4qanh4oF6xXfHE2g59HiZMpGgWZOINKfNC5yaoHbyySkh+M= X-Received: by 2002:a5e:dd02:: with SMTP id t2mr21794854iop.90.1596050790970; Wed, 29 Jul 2020 12:26:30 -0700 (PDT) MIME-Version: 1.0 Reply-To: kamalp@acm.org From: "Kamal R. Prasad" Date: Thu, 30 Jul 2020 00:56:20 +0530 Message-ID: Subject: mutexes To: freebsd-arm@freebsd.org X-Rspamd-Queue-Id: 4BH3SS5RMwz497v X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=InjpklUk; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of kamalpr@gmail.com designates 2607:f8b0:4864:20::d32 as permitted sender) smtp.mailfrom=kamalpr@gmail.com X-Spamd-Result: default: False [-2.62 / 15.00]; ARC_NA(0.00)[]; HAS_REPLYTO(0.00)[kamalp@acm.org]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; NEURAL_HAM_MEDIUM(-0.90)[-0.904]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2607:f8b0:4000::/36:c]; FREEMAIL_FROM(0.00)[gmail.com]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; REPLYTO_DOM_NEQ_FROM_DOM(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[freebsd-arm@freebsd.org]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.03)[-1.030]; TO_DN_NONE(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; RCVD_IN_DNSWL_NONE(0.00)[2607:f8b0:4864:20::d32:from]; NEURAL_SPAM_SHORT(0.31)[0.313]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.33 X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Jul 2020 19:26:33 -0000 hello, i have 2 instances of an spi controller (pl022) on my setup. can someone tell me :- 1. is there any danger if we interleave spi io transfers between these 2 controllers i.e spi transfer starts on controller 0 and before it can finish, controller 1 starts spi transfer. the 2 controllers have different spi slave devices. 2. assuming there is an issue with that, how to setup a mutex in the code path so that it is common to both instances of pl022 driver? thanks -kamal