From patchwork Sun Nov 17 23:06:01 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerhard Sittig X-Patchwork-Id: 3194981 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id E58139F3A0 for ; Sun, 17 Nov 2013 23:08:34 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E7AB8206AF for ; Sun, 17 Nov 2013 23:08:33 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9F868206AA for ; Sun, 17 Nov 2013 23:08:32 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ViBRX-0007Il-TC; 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Mon, 18 Nov 2013 00:06:57 +0100 (CET) X-Auth-Info: w7uRcW0T70UsT97WMlWPWJW+mTbhTm2s6wmvC7Jn3YY= Received: from localhost (host-82-135-33-74.customer.m-online.net [82.135.33.74]) by mail.mnet-online.de (Postfix) with ESMTPA; Mon, 18 Nov 2013 00:06:57 +0100 (CET) From: Gerhard Sittig To: linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, Anatolij Gustschin , Mike Turquette Subject: [PATCH v5 01/17] powerpc/fsl-pci: improve clock API use Date: Mon, 18 Nov 2013 00:06:01 +0100 Message-Id: <1384729577-7336-2-git-send-email-gsi@denx.de> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1384729577-7336-1-git-send-email-gsi@denx.de> References: <1384729577-7336-1-git-send-email-gsi@denx.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20131117_180720_062266_1E6BB45D X-CRM114-Status: GOOD ( 19.80 ) X-Spam-Score: -1.9 (-) Cc: Detlev Zundel , Benjamin Herrenschmidt , Gerhard Sittig , Kumar Gala , Paul Mackerras , Scott Wood X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP make the Freescale PCI driver get, prepare and enable the PCI clock during probe(); the clock gets put upon device shutdown by the devm approach clock lookup is non-fatal as not all platforms may provide clock specs in their device tree or implement a device tree based clock provider, but failure to enable clocks after successful lookup is fatal the driver appears to not have a remove() routine, so no reference to the clock is kept during use, and the clock isn't released (the devm approach will put the clock, but it won't get disabled or unprepared) the 85xx/86xx platforms go through the probe() routine, where clock lookup occurs and the clock gets acquired if one was specified; the 512x/83xx platforms don't pass through probe() but instead directly call the add_bridge() routine at a point in time where the clock provider has not been setup yet even if the platform implements one -- add comments to the code paths as a reminder for the potential need of a workaround in the platform's clock driver, and to keep awareness if code should get re-arranged or moved Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Kumar Gala Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Gerhard Sittig --- arch/powerpc/sysdev/fsl_pci.c | 52 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c index ccfb50ddfe38..efa0916f61b6 100644 --- a/arch/powerpc/sysdev/fsl_pci.c +++ b/arch/powerpc/sysdev/fsl_pci.c @@ -17,6 +17,8 @@ * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. */ + +#include #include #include #include @@ -755,6 +757,32 @@ int __init mpc83xx_add_bridge(struct device_node *dev) const int *bus_range; int primary; + /* + * 85xx/86xx platforms take the path through the probe() routine + * as one would expect, PCI related clocks get acquired there if + * specified + * + * 83xx/512x _don't_ pass through probe(), this add_bridge() + * routine instead is called from within .setup_arch() at a + * point in time where clock providers haven't been setup yet; + * so clocks cannot get acquired here -- lookup would always + * fail even on those platforms which implement the provider + * + * there is no counterpart for add_bridge() just like there is + * no remove() counterpart for probe(), so in either case the + * PCI related clock won't get released, and all of the + * 512x/83xx/85xx/86xx platforms behave in identical ways + * + * this comment is here to "keep the balance" against the + * probe() routine, and as a reminder to acquire clocks if the + * add_bridge() call should move to some later point in time + * + * until then clock providers are expected to work around the + * peripheral driver's not acquiring the PCI clock on those + * platforms where clock providers exist, while nothing needs to + * be done for those platforms without a clock provider + */ + is_mpc83xx_pci = 1; if (!of_device_is_available(dev)) { @@ -1086,9 +1114,33 @@ void fsl_pci_assign_primary(void) static int fsl_pci_probe(struct platform_device *pdev) { + struct clk *clk; int ret; struct device_node *node; + /* + * clock lookup is non-fatal since the driver is shared among + * platforms and not all of them provide clocks specs in their + * device tree, but failure to enable a specified clock is + * considered fatal + * + * note that only the 85xx and 86xx platforms pass through this + * probe() routine, while 83xx and 512x directly invoke the + * mpc83xx_add_bridge() routine from within .setup_arch() code + */ + clk = devm_clk_get(&pdev->dev, "ipg"); + if (!IS_ERR(clk)) { + ret = clk_prepare_enable(clk); + if (ret) { + dev_err(&pdev->dev, "Could not enable PCI clock\n"); + return ret; + } + /* + * TODO where to store the 'clk' reference? there appears + * to be no remove() routine which undoes what probe() does + */ + } + node = pdev->dev.of_node; ret = fsl_add_bridge(pdev, fsl_pci_primary == node);