From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9A9E4C433FE for ; Wed, 17 Nov 2021 16:01:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8052561BF9 for ; Wed, 17 Nov 2021 16:01:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238871AbhKQQED (ORCPT ); Wed, 17 Nov 2021 11:04:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:49644 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238861AbhKQQEA (ORCPT ); Wed, 17 Nov 2021 11:04:00 -0500 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 50F5E61B48; Wed, 17 Nov 2021 16:01:02 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=hot-poop.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mnNMq-0067Me-4W; Wed, 17 Nov 2021 16:01:00 +0000 From: Marc Zyngier To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org Cc: kernel-team@android.com, Alyssa Rosenzweig , Lorenzo Pieralisi , Bjorn Helgaas Subject: [PATCH] PCI: apple: Reset the port for 100ms on probe Date: Wed, 17 Nov 2021 16:00:53 +0000 Message-Id: <20211117160053.232158-1-maz@kernel.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, kernel-team@android.com, alyssa@rosenzweig.io, lorenzo.pieralisi@arm.com, bhelgaas@google.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While the Apple PCIe driver works correctly when directly booted from the firmware, it fails to initialise when the kernel is booted from a bootloader using PCIe such as u-boot. That's beacuse we're missing a proper reset of the port (we only clear the reset, but never assert it). Bring the port back to life by wiggling the #PERST pin for 100ms (as per the spec). Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up") Signed-off-by: Marc Zyngier Cc: Alyssa Rosenzweig Cc: Lorenzo Pieralisi Cc: Bjorn Helgaas --- drivers/pci/controller/pcie-apple.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c index 1bf4d75b61be..bbea5f6e0a68 100644 --- a/drivers/pci/controller/pcie-apple.c +++ b/drivers/pci/controller/pcie-apple.c @@ -543,6 +543,9 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie, if (ret < 0) return ret; + /* Hold #PERST for 100ms as per the spec */ + gpiod_set_value(reset, 0); + msleep(100); rmw_set(PORT_PERST_OFF, port->base + PORT_PERST); gpiod_set_value(reset, 1); -- 2.30.2