From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933452AbcAKP1o (ORCPT ); Mon, 11 Jan 2016 10:27:44 -0500 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:57991 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932993AbcAKP1l (ORCPT ); Mon, 11 Jan 2016 10:27:41 -0500 Date: Mon, 11 Jan 2016 15:27:32 +0000 From: Russell King - ARM Linux To: Andy Shevchenko Cc: Aleksey Makarov , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , linux-arm Mailing List , Graeme Gregory , Greg Kroah-Hartman , "Rafael J . Wysocki" , Shannon Zhao , Vladimir Zapolskiy , Len Brown Subject: Re: [PATCH v5 2/2] ACPI: amba bus probing support Message-ID: <20160111152732.GU19062@n2100.arm.linux.org.uk> References: <1452518790-27053-1-git-send-email-aleksey.makarov@linaro.org> <1452518790-27053-3-git-send-email-aleksey.makarov@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 11, 2016 at 05:13:20PM +0200, Andy Shevchenko wrote: > On Mon, Jan 11, 2016 at 3:26 PM, Aleksey Makarov > wrote: > > From: Graeme Gregory > > > > On ARM64 some devices use the AMBA device and not the platform bus for > > probing so add support for this. Uses a dummy clock for apb_pclk as ACPI > > does not have a suitable clock representation and to keep the core > > AMBA bus code unchanged between probing methods. > > > > My comments below. > > > +++ b/drivers/acpi/acpi_amba.c > > @@ -0,0 +1,122 @@ > > + > > +/* > > + * ACPI support for platform bus type. > > + * > > + * Copyright (C) 2015, Linaro Ltd > > + * Author: Graeme Gregory > > + * > > + * This program is free software; you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License version 2 as > > + * published by the Free Software Foundation. > > + */ > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +#include "internal.h" > > + > > +static const struct acpi_device_id amba_id_list[] = { > > + {"ARMH0061", 0}, /* PL061 GPIO Device */ > > + {"", 0}, > > +}; > > + > > +static void amba_register_dummy_clk(void) > > +{ > > + static struct clk *amba_dummy_clk; > > + > > + /* If clock already registered */ > > + if (amba_dummy_clk) > > + return; > > + > > + amba_dummy_clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, > > + CLK_IS_ROOT, 0); > > + clk_register_clkdev(amba_dummy_clk, "apb_pclk", NULL); > > +} > > + > > +static int amba_handler_attach(struct acpi_device *adev, > > + const struct acpi_device_id *id) > > +{ > > + struct amba_device *dev; > > + struct resource_entry *rentry; > > + struct list_head resource_list; > > + bool address_found = false; > > + int irq_no = 0; > > + int ret; > > + > > + /* If the ACPI node already has a physical device attached, skip it. */ > > + if (adev->physical_node_count) > > + return 0; > > + > > + dev = amba_device_alloc(dev_name(&adev->dev), 0, 0); > > + if (!dev) { > > + dev_err(&adev->dev, "%s(): amba_device_alloc() failed\n", > > + __func__); > > + return -ENOMEM; > > + } > > + > > + INIT_LIST_HEAD(&resource_list); > > + ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL); > > + if (ret < 0) > > + goto err_free; > > + > > + list_for_each_entry(rentry, &resource_list, node) { > > + switch (resource_type(rentry->res)) { > > + case IORESOURCE_MEM: > > + if (!address_found) { > > + dev->res = *rentry->res; > > dev->res is 0 before this one, right? Could you use this fact instead > of address_found flag? amba_device_alloc() zero-initialises everything. However, dev->res is a struct resource, and I'd prefer _this_ method that the OT is using to testing some random part of struct resource. > > + address_found = true; > > + } > > + break; > > + case IORESOURCE_IRQ: > > + if (irq_no < AMBA_NR_IRQS) > > + dev->irq[irq_no++] = rentry->res->start; > > + break; > > + default: > > + dev_warn(&adev->dev, "Invalid resource\n"); > > Why? Isn't possible to have other resources for the devices? AMBA primecell devices have one memory region, and a number of interrupts. Other resource types don't make sense. > > + break; > > + } > > + } > > + > > + acpi_dev_free_resource_list(&resource_list); > > + > > + /* > > + * If the ACPI node has a parent and that parent has a physical device > > + * attached to it, that physical device should be the parent of > > + * the amba device we are about to create. > > + */ > > + if (adev->parent) > > + dev->dev.parent = acpi_get_first_physical_node(adev->parent); > > + > > + ACPI_COMPANION_SET(&dev->dev, adev); > > + > > + ret = amba_device_add(dev, &iomem_resource); > > + if (ret) { > > ret < 0? > > What to do if ret > 0? It will be considered as not error. Please, > check what function returns and adjust this. Non-zero is treated as an error by amba_device_add(). Doing otherwise here puts it at odds to the outcome of that function. This code is fine. -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.