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 X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DFCC3ECE560 for ; Mon, 17 Sep 2018 16:40:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A3F742088F for ; Mon, 17 Sep 2018 16:40:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A3F742088F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=glider.be Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728828AbeIQWIY (ORCPT ); Mon, 17 Sep 2018 18:08:24 -0400 Received: from albert.telenet-ops.be ([195.130.137.90]:42694 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728429AbeIQWIO (ORCPT ); Mon, 17 Sep 2018 18:08:14 -0400 Received: from ramsan.of.borg ([84.194.111.163]) by albert.telenet-ops.be with bizsmtp id cgg41y00o3XaVaC06gg4sy; Mon, 17 Sep 2018 18:40:04 +0200 Received: from rox.of.borg ([192.168.97.57]) by ramsan.of.borg with esmtp (Exim 4.86_2) (envelope-from ) id 1g1wZA-0006bE-AL; Mon, 17 Sep 2018 18:40:04 +0200 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1g1wZA-0004xm-9N; Mon, 17 Sep 2018 18:40:04 +0200 From: Geert Uytterhoeven To: Philipp Zabel , Eric Auger , Alex Williamson Cc: kvm@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH/RFC v4 2/2] vfio: platform: Add generic reset controller support Date: Mon, 17 Sep 2018 18:39:55 +0200 Message-Id: <20180917163955.19023-3-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180917163955.19023-1-geert+renesas@glider.be> References: <20180917163955.19023-1-geert+renesas@glider.be> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Vfio-platform requires dedicated reset support, provided either by ACPI, or, on DT platforms, by a device-specific reset driver matching against the device's compatible value. On many SoCs, devices are connected to an SoC-internal reset controller. If the reset hierarchy is described in DT using "resets" properties, or in lookup tables in platform code, such devices can be reset in a generic way through the reset controller subsystem. Hence add support for this, avoiding the need to write device-specific reset drivers for each single device on affected SoCs. Devices that do require a more complex reset procedure can still provide a device-specific reset driver, as that takes precedence. Note that this functionality depends on CONFIG_RESET_CONTROLLER=y, and becomes a no-op (as in: "No reset function found for device") if reset controller support is disabled. Signed-off-by: Geert Uytterhoeven Reviewed-by: Philipp Zabel Reviewed-by: Simon Horman --- v4: - Add Reviewed-by, - Use new RFC reset_control_get_dedicated() instead of of_reset_control_get_exclusive(), to (a) make it more generic, and (b) make sure the reset returned is really a dedicated reset, and does not affect other devices, v3: - Add Reviewed-by, - Merge similar checks in vfio_platform_has_reset(), v2: - Don't store error values in vdev->reset_control, - Use of_reset_control_get_exclusive() instead of __of_reset_control_get(), - Improve description. --- drivers/vfio/platform/vfio_platform_common.c | 20 +++++++++++++++++-- drivers/vfio/platform/vfio_platform_private.h | 1 + 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c index c0cd824be2b767be..eb77fe87f3663e3e 100644 --- a/drivers/vfio/platform/vfio_platform_common.c +++ b/drivers/vfio/platform/vfio_platform_common.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -113,11 +114,13 @@ static bool vfio_platform_has_reset(struct vfio_platform_device *vdev) if (VFIO_PLATFORM_IS_ACPI(vdev)) return vfio_platform_acpi_has_reset(vdev); - return vdev->of_reset ? true : false; + return vdev->of_reset || vdev->reset_control; } static int vfio_platform_get_reset(struct vfio_platform_device *vdev) { + struct reset_control *rstc; + if (VFIO_PLATFORM_IS_ACPI(vdev)) return vfio_platform_acpi_has_reset(vdev) ? 0 : -ENOENT; @@ -128,8 +131,16 @@ static int vfio_platform_get_reset(struct vfio_platform_device *vdev) vdev->of_reset = vfio_platform_lookup_reset(vdev->compat, &vdev->reset_module); } + if (vdev->of_reset) + return 0; + + rstc = reset_control_get_dedicated(vdev->device, NULL); + if (!IS_ERR(rstc)) { + vdev->reset_control = rstc; + return 0; + } - return vdev->of_reset ? 0 : -ENOENT; + return PTR_ERR(rstc); } static void vfio_platform_put_reset(struct vfio_platform_device *vdev) @@ -139,6 +150,8 @@ static void vfio_platform_put_reset(struct vfio_platform_device *vdev) if (vdev->of_reset) module_put(vdev->reset_module); + + reset_control_put(vdev->reset_control); } static int vfio_platform_regions_init(struct vfio_platform_device *vdev) @@ -218,6 +231,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev, } else if (vdev->of_reset) { dev_info(vdev->device, "reset\n"); return vdev->of_reset(vdev); + } else if (vdev->reset_control) { + dev_info(vdev->device, "reset\n"); + return reset_control_reset(vdev->reset_control); } dev_warn(vdev->device, "no reset function found!\n"); diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h index 85ffe5d9d1abd94e..a56e80ae5986540b 100644 --- a/drivers/vfio/platform/vfio_platform_private.h +++ b/drivers/vfio/platform/vfio_platform_private.h @@ -60,6 +60,7 @@ struct vfio_platform_device { const char *compat; const char *acpihid; struct module *reset_module; + struct reset_control *reset_control; struct device *device; /* -- 2.17.1