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 DBAADC433F5 for ; Wed, 12 Jan 2022 23:07:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235375AbiALXHB (ORCPT ); Wed, 12 Jan 2022 18:07:01 -0500 Received: from mga17.intel.com ([192.55.52.151]:5672 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235185AbiALXGW (ORCPT ); Wed, 12 Jan 2022 18:06:22 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642028782; x=1673564782; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=UgZ+QsqPyJXG3NxK7ItmM8AuUepDhmYCaG7lwkR5rKU=; b=VGTvO9yRwNJbxlOSW+TXdYDsUj1GwNl4L3J6px6MceK0cQQbXhRLaR8T cKVBXqRIxw6LQYPRohcXum1PnUzKE2GcrvD0o73BsdRJr5Gpek1/xKRWm C1eqh582Gc9R4YUok+ZtV4naum5rnKqUBK8WsOHV1Zvz7A9ZGGdWBGys5 J/XCkJcLYqeAsVSlw/z9HrCNr17l/L0Z36h9YBcxPe1TWLy+hPkjEXjVa bC79H2zO7DH4uQwJjLdpZEtqmHYLwY6HmkgIDj5nXQVRjtjRJW49tirpv 7PiBb4pI8YU+5oaePoV4bMf1l23A1kCrgJeUqCk4TGOjvm4o5GPOAtuhp Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10225"; a="224564176" X-IronPort-AV: E=Sophos;i="5.88,284,1635231600"; d="scan'208";a="224564176" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 15:06:20 -0800 X-IronPort-AV: E=Sophos;i="5.88,284,1635231600"; d="scan'208";a="515691573" Received: from kstefans-mobl.ger.corp.intel.com (HELO localhost) ([10.249.154.174]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jan 2022 15:06:12 -0800 From: Iwona Winiarska To: linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org, Greg Kroah-Hartman Cc: devicetree@vger.kernel.org, linux-aspeed@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-hwmon@vger.kernel.org, linux-doc@vger.kernel.org, Rob Herring , Joel Stanley , Andrew Jeffery , Jean Delvare , Guenter Roeck , Arnd Bergmann , Olof Johansson , Jonathan Corbet , Borislav Petkov , Pierre-Louis Bossart , Tony Luck , Andy Shevchenko , Dan Williams , Randy Dunlap , Zev Weiss , David Muller , Dave Hansen , Billy Tsai , Iwona Winiarska Subject: [PATCH v5 06/13] peci: Add device detection Date: Thu, 13 Jan 2022 00:02:40 +0100 Message-Id: <20220112230247.982212-7-iwona.winiarska@intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220112230247.982212-1-iwona.winiarska@intel.com> References: <20220112230247.982212-1-iwona.winiarska@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since PECI devices are discoverable, we can dynamically detect devices that are actually available in the system. This change complements the earlier implementation by rescanning PECI bus to detect available devices. For this purpose, it also introduces the minimal API for PECI requests. Signed-off-by: Iwona Winiarska Reviewed-by: Pierre-Louis Bossart --- drivers/peci/Makefile | 2 +- drivers/peci/core.c | 33 +++++++++++ drivers/peci/device.c | 120 ++++++++++++++++++++++++++++++++++++++++ drivers/peci/internal.h | 14 +++++ drivers/peci/request.c | 55 ++++++++++++++++++ include/linux/peci.h | 2 + 6 files changed, 225 insertions(+), 1 deletion(-) create mode 100644 drivers/peci/device.c create mode 100644 drivers/peci/request.c diff --git a/drivers/peci/Makefile b/drivers/peci/Makefile index 926d8df15cbd..c5f9d3fe21bb 100644 --- a/drivers/peci/Makefile +++ b/drivers/peci/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-only # Core functionality -peci-y := core.o +peci-y := core.o request.o device.o obj-$(CONFIG_PECI) += peci.o # Hardware specific bus drivers diff --git a/drivers/peci/core.c b/drivers/peci/core.c index 73ad0a47fa9d..c3361e6e043a 100644 --- a/drivers/peci/core.c +++ b/drivers/peci/core.c @@ -29,6 +29,20 @@ struct device_type peci_controller_type = { .release = peci_controller_dev_release, }; +static int peci_controller_scan_devices(struct peci_controller *controller) +{ + int ret; + u8 addr; + + for (addr = PECI_BASE_ADDR; addr < PECI_BASE_ADDR + PECI_DEVICE_NUM_MAX; addr++) { + ret = peci_device_create(controller, addr); + if (ret) + return ret; + } + + return 0; +} + static struct peci_controller *peci_controller_alloc(struct device *dev, struct peci_controller_ops *ops) { @@ -64,10 +78,23 @@ static struct peci_controller *peci_controller_alloc(struct device *dev, return ERR_PTR(ret); } +static int unregister_child(struct device *dev, void *dummy) +{ + peci_device_destroy(to_peci_device(dev)); + + return 0; +} + static void unregister_controller(void *_controller) { struct peci_controller *controller = _controller; + /* + * Detach any active PECI devices. This can't fail, thus we do not + * check the returned value. + */ + device_for_each_child_reverse(&controller->dev, NULL, unregister_child); + device_unregister(&controller->dev); fwnode_handle_put(controller->dev.fwnode); @@ -113,6 +140,12 @@ struct peci_controller *devm_peci_controller_add(struct device *dev, if (ret) return ERR_PTR(ret); + /* + * Ignoring retval since failures during scan are non-critical for + * controller itself. + */ + peci_controller_scan_devices(controller); + return controller; err_fwnode: diff --git a/drivers/peci/device.c b/drivers/peci/device.c new file mode 100644 index 000000000000..2b3a2d893aaf --- /dev/null +++ b/drivers/peci/device.c @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (c) 2018-2021 Intel Corporation + +#include +#include + +#include "internal.h" + +/* + * PECI device can be removed using sysfs, but the removal can also happen as + * a result of controller being removed. + * Mutex is used to protect PECI device from being double-deleted. + */ +static DEFINE_MUTEX(peci_device_del_lock); + +static int peci_detect(struct peci_controller *controller, u8 addr) +{ + /* + * PECI Ping is a command encoded by tx_len = 0, rx_len = 0. + * We expect correct Write FCS if the device at the target address + * is able to respond. + */ + struct peci_request req = { 0 }; + int ret; + + mutex_lock(&controller->bus_lock); + ret = controller->ops->xfer(controller, addr, &req); + mutex_unlock(&controller->bus_lock); + + return ret; +} + +static bool peci_addr_valid(u8 addr) +{ + return addr >= PECI_BASE_ADDR && addr < PECI_BASE_ADDR + PECI_DEVICE_NUM_MAX; +} + +static int peci_dev_exists(struct device *dev, void *data) +{ + struct peci_device *device = to_peci_device(dev); + u8 *addr = data; + + if (device->addr == *addr) + return -EBUSY; + + return 0; +} + +int peci_device_create(struct peci_controller *controller, u8 addr) +{ + struct peci_device *device; + int ret; + + if (!peci_addr_valid(addr)) + return -EINVAL; + + /* Check if we have already detected this device before. */ + ret = device_for_each_child(&controller->dev, &addr, peci_dev_exists); + if (ret) + return 0; + + ret = peci_detect(controller, addr); + if (ret) { + /* + * Device not present or host state doesn't allow successful + * detection at this time. + */ + if (ret == -EIO || ret == -ETIMEDOUT) + return 0; + + return ret; + } + + device = kzalloc(sizeof(*device), GFP_KERNEL); + if (!device) + return -ENOMEM; + + device_initialize(&device->dev); + + device->addr = addr; + device->dev.parent = &controller->dev; + device->dev.bus = &peci_bus_type; + device->dev.type = &peci_device_type; + + ret = dev_set_name(&device->dev, "%d-%02x", controller->id, device->addr); + if (ret) + goto err_put; + + ret = device_add(&device->dev); + if (ret) + goto err_put; + + return 0; + +err_put: + put_device(&device->dev); + + return ret; +} + +void peci_device_destroy(struct peci_device *device) +{ + mutex_lock(&peci_device_del_lock); + if (!device->deleted) { + device_unregister(&device->dev); + device->deleted = true; + } + mutex_unlock(&peci_device_del_lock); +} + +static void peci_device_release(struct device *dev) +{ + struct peci_device *device = to_peci_device(dev); + + kfree(device); +} + +struct device_type peci_device_type = { + .release = peci_device_release, +}; diff --git a/drivers/peci/internal.h b/drivers/peci/internal.h index 918dea745a86..57d11a902c5d 100644 --- a/drivers/peci/internal.h +++ b/drivers/peci/internal.h @@ -8,6 +8,20 @@ #include struct peci_controller; +struct peci_device; +struct peci_request; + +/* PECI CPU address range 0x30-0x37 */ +#define PECI_BASE_ADDR 0x30 +#define PECI_DEVICE_NUM_MAX 8 + +struct peci_request *peci_request_alloc(struct peci_device *device, u8 tx_len, u8 rx_len); +void peci_request_free(struct peci_request *req); + +extern struct device_type peci_device_type; + +int peci_device_create(struct peci_controller *controller, u8 addr); +void peci_device_destroy(struct peci_device *device); extern struct bus_type peci_bus_type; diff --git a/drivers/peci/request.c b/drivers/peci/request.c new file mode 100644 index 000000000000..7dee51c50dd2 --- /dev/null +++ b/drivers/peci/request.c @@ -0,0 +1,55 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (c) 2021 Intel Corporation + +#include +#include +#include +#include + +#include "internal.h" + +/** + * peci_request_alloc() - allocate &struct peci_requests + * @device: PECI device to which request is going to be sent + * @tx_len: TX length + * @rx_len: RX length + * + * Return: A pointer to a newly allocated &struct peci_request on success or NULL otherwise. + */ +struct peci_request *peci_request_alloc(struct peci_device *device, u8 tx_len, u8 rx_len) +{ + struct peci_request *req; + + /* + * TX and RX buffers are fixed length members of peci_request, this is + * just a warn for developers to make sure to expand the buffers (or + * change the allocation method) if we go over the current limit. + */ + if (WARN_ON_ONCE(tx_len > PECI_REQUEST_MAX_BUF_SIZE || rx_len > PECI_REQUEST_MAX_BUF_SIZE)) + return NULL; + /* + * PECI controllers that we are using now don't support DMA, this + * should be converted to DMA API once support for controllers that do + * allow it is added to avoid an extra copy. + */ + req = kzalloc(sizeof(*req), GFP_KERNEL); + if (!req) + return NULL; + + req->device = device; + req->tx.len = tx_len; + req->rx.len = rx_len; + + return req; +} +EXPORT_SYMBOL_NS_GPL(peci_request_alloc, PECI); + +/** + * peci_request_free() - free peci_request + * @req: the PECI request to be freed + */ +void peci_request_free(struct peci_request *req) +{ + kfree(req); +} +EXPORT_SYMBOL_NS_GPL(peci_request_free, PECI); diff --git a/include/linux/peci.h b/include/linux/peci.h index 26e0a4e73b50..7e35673f3786 100644 --- a/include/linux/peci.h +++ b/include/linux/peci.h @@ -60,6 +60,7 @@ static inline struct peci_controller *to_peci_controller(void *d) * @dev: device object to register PECI device to the device model * @controller: manages the bus segment hosting this PECI device * @addr: address used on the PECI bus connected to the parent controller + * @deleted: indicates that PECI device was already deleted * * A peci_device identifies a single device (i.e. CPU) connected to a PECI bus. * The behaviour exposed to the rest of the system is defined by the PECI driver @@ -68,6 +69,7 @@ static inline struct peci_controller *to_peci_controller(void *d) struct peci_device { struct device dev; u8 addr; + bool deleted; }; static inline struct peci_device *to_peci_device(struct device *d) -- 2.31.1