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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD081C2BB41 for ; Tue, 16 Aug 2022 09:08:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233079AbiHPJIQ (ORCPT ); Tue, 16 Aug 2022 05:08:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233403AbiHPJHf (ORCPT ); Tue, 16 Aug 2022 05:07:35 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 3DF38BCC3D for ; Tue, 16 Aug 2022 00:25:12 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1FCBA1D34; Tue, 16 Aug 2022 00:25:12 -0700 (PDT) Received: from e120937-lin.home (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 83A1B3F70D; Tue, 16 Aug 2022 00:25:09 -0700 (PDT) From: Cristian Marussi To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: sudeep.holla@arm.com, james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com, f.fainelli@gmail.com, etienne.carriere@linaro.org, vincent.guittot@linaro.org, souvik.chakravarty@arm.com, wleavitt@marvell.com, peter.hilber@opensynergy.com, nicola.mazzucato@arm.com, tarek.el-sherbiny@arm.com, cristian.marussi@arm.com Subject: [RFC PATCH 2/6] firmware: arm_scmi: Add bus helpers to enter raw mode Date: Tue, 16 Aug 2022 08:24:46 +0100 Message-Id: <20220816072450.3120959-3-cristian.marussi@arm.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220816072450.3120959-1-cristian.marussi@arm.com> References: <20220816072450.3120959-1-cristian.marussi@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a couple of helpers to be able to trigger the un-registration and the re-registration of the whole stack of SCMI drivers from/to the SCMI bus. Once this mode is enabled any new SCMI driver registration is inhibited and delayed till the this new mode is disabled. Signed-off-by: Cristian Marussi --- drivers/firmware/arm_scmi/bus.c | 69 +++++++++++++++++++++++++++++- drivers/firmware/arm_scmi/common.h | 2 + include/linux/scmi_protocol.h | 1 + 3 files changed, 71 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c index d4e23101448a..c4b3371dcb1b 100644 --- a/drivers/firmware/arm_scmi/bus.c +++ b/drivers/firmware/arm_scmi/bus.c @@ -19,6 +19,10 @@ static DEFINE_IDA(scmi_bus_id); static DEFINE_IDR(scmi_protocols); static DEFINE_SPINLOCK(protocol_lock); +static bool scmi_raw_mode_enabled; +static LIST_HEAD(scmi_registered_drivers); +static DEFINE_MUTEX(scmi_raw_mode_mtx); + static const struct scmi_device_id * scmi_dev_match_id(struct scmi_device *scmi_dev, struct scmi_driver *scmi_drv) { @@ -144,6 +148,18 @@ int scmi_driver_register(struct scmi_driver *driver, struct module *owner, driver->driver.owner = owner; driver->driver.mod_name = mod_name; + mutex_lock(&scmi_raw_mode_mtx); + list_add_tail(&driver->node, &scmi_registered_drivers); + /* + * If RAW mode is enabled here, the driver will be registered fully + * only later, when RAW will be (if ever) disabled. + */ + if (scmi_raw_mode_enabled) { + mutex_unlock(&scmi_raw_mode_mtx); + return 0; + } + mutex_unlock(&scmi_raw_mode_mtx); + retval = driver_register(&driver->driver); if (!retval) pr_debug("registered new scmi driver %s\n", driver->name); @@ -154,7 +170,18 @@ EXPORT_SYMBOL_GPL(scmi_driver_register); void scmi_driver_unregister(struct scmi_driver *driver) { - driver_unregister(&driver->driver); + mutex_lock(&scmi_raw_mode_mtx); + list_del_init(&driver->node); + /* + * No need to unregister a driver when RAW mode is enabled, it would + * have been already unregistered when RAW was enabled. + */ + if (!scmi_raw_mode_enabled) { + mutex_unlock(&scmi_raw_mode_mtx); + driver_unregister(&driver->driver); + mutex_lock(&scmi_raw_mode_mtx); + } + mutex_unlock(&scmi_raw_mode_mtx); scmi_protocol_device_unrequest(driver->id_table); } EXPORT_SYMBOL_GPL(scmi_driver_unregister); @@ -276,6 +303,46 @@ static void scmi_devices_unregister(void) bus_for_each_dev(&scmi_bus_type, NULL, NULL, __scmi_devices_unregister); } +void scmi_bus_raw_mode_enable(void) +{ + struct scmi_driver *driver; + + /* On enable any known SCMI driver is unregistered */ + mutex_lock(&scmi_raw_mode_mtx); + list_for_each_entry_reverse(driver, &scmi_registered_drivers, node) { + mutex_unlock(&scmi_raw_mode_mtx); + + driver_unregister(&driver->driver); + + mutex_lock(&scmi_raw_mode_mtx); + } + scmi_raw_mode_enabled = true; + mutex_unlock(&scmi_raw_mode_mtx); +} + +void scmi_bus_raw_mode_disable(void) +{ + int retval; + struct scmi_driver *driver; + + /* + * On disable any known SCMI driver is registered again unless it was + * removed already as a module. + */ + mutex_lock(&scmi_raw_mode_mtx); + list_for_each_entry(driver, &scmi_registered_drivers, node) { + mutex_unlock(&scmi_raw_mode_mtx); + + retval = driver_register(&driver->driver); + if (retval) + pr_warn("Failed to rebind driver %s\n", driver->name); + + mutex_lock(&scmi_raw_mode_mtx); + } + scmi_raw_mode_enabled = false; + mutex_unlock(&scmi_raw_mode_mtx); +} + int __init scmi_bus_init(void) { int retval; diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h index 61aba7447c32..bbaac20544a5 100644 --- a/drivers/firmware/arm_scmi/common.h +++ b/drivers/firmware/arm_scmi/common.h @@ -171,6 +171,8 @@ int scmi_protocol_device_request(const struct scmi_device_id *id_table); void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table); struct scmi_device *scmi_child_dev_find(struct device *parent, int prot_id, const char *name); +void scmi_bus_raw_mode_enable(void); +void scmi_bus_raw_mode_disable(void); /** * struct scmi_desc - Description of SoC integration diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h index 4f765bc788ff..39e64ec72984 100644 --- a/include/linux/scmi_protocol.h +++ b/include/linux/scmi_protocol.h @@ -820,6 +820,7 @@ struct scmi_driver { void (*remove)(struct scmi_device *sdev); const struct scmi_device_id *id_table; + struct list_head node; struct device_driver driver; }; -- 2.32.0