From patchwork Tue Nov 13 13:15:08 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 10680623 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D128C13BF for ; Tue, 13 Nov 2018 13:15:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C06982A385 for ; Tue, 13 Nov 2018 13:15:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B3E712A4DE; Tue, 13 Nov 2018 13:15:23 +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=ham 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 367F82A385 for ; Tue, 13 Nov 2018 13:15:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387475AbeKMXN0 (ORCPT ); Tue, 13 Nov 2018 18:13:26 -0500 Received: from albert.telenet-ops.be ([195.130.137.90]:57124 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733258AbeKMXN0 (ORCPT ); Tue, 13 Nov 2018 18:13:26 -0500 Received: from ramsan.of.borg ([84.194.111.163]) by albert.telenet-ops.be with bizsmtp id zRFK1y00L3XaVaC06RFKyX; Tue, 13 Nov 2018 14:15:19 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan.of.borg with esmtp (Exim 4.86_2) (envelope-from ) id 1gMYXH-00066m-Mm; Tue, 13 Nov 2018 14:15:19 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1gMYXH-0004l3-LD; Tue, 13 Nov 2018 14:15:19 +0100 From: Geert Uytterhoeven To: Eric Auger , Alex Williamson Cc: Philipp Zabel , kvm@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v5] vfio: platform: Add generic reset controller support Date: Tue, 13 Nov 2018 14:15:08 +0100 Message-Id: <20181113131508.18246-1-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 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 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, and devices have exactly one dedicated reset each, 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 Acked-by: Eric Auger --- This depends on "[PATCH] reset: Add reset_control_get_count()" (https://lore.kernel.org/lkml/20181113124744.7769-1-geert+renesas@glider.be/). v5: - Use reset_control_get_exclusive() instead of rejected reset_control_get_dedicated(), as exclusive already implies a dedicated reset line, - Ensure the device has exactly one reset, 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 | 29 +++++++++++++++++-- drivers/vfio/platform/vfio_platform_private.h | 1 + 2 files changed, 28 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c index c0cd824be2b767be..ce2aad8e0a8159f9 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 +114,14 @@ 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; + int count; + if (VFIO_PLATFORM_IS_ACPI(vdev)) return vfio_platform_acpi_has_reset(vdev) ? 0 : -ENOENT; @@ -128,8 +132,24 @@ 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; + + /* Generic reset handling needs a single, dedicated reset line */ + count = reset_control_get_count(vdev->device); + if (count < 0) + return count; + + if (count != 1) + return -EINVAL; - return vdev->of_reset ? 0 : -ENOENT; + rstc = reset_control_get_exclusive(vdev->device, NULL); + if (!IS_ERR(rstc)) { + vdev->reset_control = rstc; + return 0; + } + + return PTR_ERR(rstc); } static void vfio_platform_put_reset(struct vfio_platform_device *vdev) @@ -139,6 +159,8 @@ 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 +240,9 @@ 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; /*