From patchwork Tue Apr 10 15:53:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 10333393 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A3DE96053B for ; Tue, 10 Apr 2018 15:54:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 96CDB1FF65 for ; Tue, 10 Apr 2018 15:54:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8B50C20856; Tue, 10 Apr 2018 15:54:22 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2EA241FF65 for ; Tue, 10 Apr 2018 15:54:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752033AbeDJPyH (ORCPT ); Tue, 10 Apr 2018 11:54:07 -0400 Received: from albert.telenet-ops.be ([195.130.137.90]:41816 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752037AbeDJPx7 (ORCPT ); Tue, 10 Apr 2018 11:53:59 -0400 Received: from ayla.of.borg ([84.194.111.163]) by albert.telenet-ops.be with bizsmtp id Yfty1x0073XaVaC06ftyGG; Tue, 10 Apr 2018 17:53:58 +0200 Received: from ramsan.of.borg ([192.168.97.29] helo=ramsan) by ayla.of.borg with esmtp (Exim 4.86_2) (envelope-from ) id 1f5vao-00071n-0u; Tue, 10 Apr 2018 17:53:58 +0200 Received: from geert by ramsan with local (Exim 4.86_2) (envelope-from ) id 1f5vao-0006CG-0B; Tue, 10 Apr 2018 17:53:58 +0200 From: Geert Uytterhoeven To: Baptiste Reynal , Alex Williamson Cc: Philipp Zabel , Rob Herring , Mark Rutland , kvm@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v2 2/2] vfio: platform: Add generic DT reset controller support Date: Tue, 10 Apr 2018 17:53:47 +0200 Message-Id: <1523375627-23746-3-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1523375627-23746-1-git-send-email-geert+renesas@glider.be> References: <1523375627-23746-1-git-send-email-geert+renesas@glider.be> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Vfio-platform requires 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, 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 --- 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 | 26 ++++++++++++++++++++++++-- drivers/vfio/platform/vfio_platform_private.h | 1 + 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c index b60bb5326668498c..3c13327b2777f8ec 100644 --- a/drivers/vfio/platform/vfio_platform_common.c +++ b/drivers/vfio/platform/vfio_platform_common.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include #include @@ -112,11 +113,19 @@ 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; + if (vdev->of_reset) + return true; + + if (vdev->reset_control) + return true; + + return false; } 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; @@ -127,8 +136,16 @@ 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 = of_reset_control_get_exclusive(vdev->device->of_node, 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) @@ -138,6 +155,8 @@ 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) @@ -217,6 +236,9 @@ 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; /*