From mboxrd@z Thu Jan 1 00:00:00 1970 From: Winiarska, Iwona Date: Mon, 15 Nov 2021 22:18:06 +0000 Subject: [PATCH v2 08/15] peci: Add device detection In-Reply-To: References: <20210803113134.2262882-1-iwona.winiarska@intel.com> <20210803113134.2262882-9-iwona.winiarska@intel.com> Message-ID: List-Id: To: linux-aspeed@lists.ozlabs.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Fri, 2021-08-27 at 12:01 -0700, Dan Williams wrote: > On Tue, Aug 3, 2021 at 4:35 AM Iwona Winiarska > wrote: > > > > 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?? | 114 ++++++++++++++++++++++++++++++++++++++++ > > ?drivers/peci/internal.h |? 14 +++++ > > ?drivers/peci/request.c? |? 50 ++++++++++++++++++ > > ?5 files changed, 212 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 7b3938af0396..d143f1a7fe98 100644 > > --- a/drivers/peci/core.c > > +++ b/drivers/peci/core.c > > @@ -34,6 +34,20 @@ 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) > > ?{ > > @@ -76,10 +90,23 @@ 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); > > ?} > > > > @@ -115,6 +142,12 @@ 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: > > diff --git a/drivers/peci/device.c b/drivers/peci/device.c > > new file mode 100644 > > index 000000000000..32811248997b > > --- /dev/null > > +++ b/drivers/peci/device.c > > @@ -0,0 +1,114 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +// Copyright (c) 2018-2021 Intel Corporation > > + > > +#include > > +#include > > + > > +#include "internal.h" > > + > > +static int peci_detect(struct peci_controller *controller, u8 addr) > > +{ > > +?????? struct peci_request *req; > > +?????? int ret; > > + > > +?????? /* > > +??????? * 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. > > +??????? */ > > +?????? req = peci_request_alloc(NULL, 0, 0); > > +?????? if (!req) > > +?????????????? return -ENOMEM; > > Seems a waste to do a heap allocation for this routine. Why not: > > ?????? /* > ??????? * 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 }; Done. > > > + > > +?????? mutex_lock(&controller->bus_lock); > > +?????? ret = controller->ops->xfer(controller, addr, req); > > +?????? mutex_unlock(&controller->bus_lock); > > + > > +?????? peci_request_free(req); > > + > > +?????? 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 (WARN_ON(!peci_addr_valid(addr))) > > The WARN_ON is overkill, especially as there is only one caller of > this and it loops through valid addresses. Done. > > > +?????????????? 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->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_free; > > It's cleaner to just have one unified error exit using put_device(). > Use the device_initialize() + device_add() pattern, not > device_register(). Done. > > > > + > > +?????? ret = device_register(&device->dev); > > +?????? if (ret) > > +?????????????? goto err_put; > > + > > +?????? return 0; > > + > > +err_put: > > +?????? put_device(&device->dev); > > +err_free: > > +?????? kfree(device); > > + > > +?????? return ret; > > +} > > + > > +void peci_device_destroy(struct peci_device *device) > > +{ > > +?????? device_unregister(&device->dev); > > No clear value for this wrapper, in fact in one caller it causes it to > do a to_peci_device() just this helper can undo that up-cast. It gains value after extending it with kill_device(). > > > +} > > + > > +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..81b567bc7b87 > > --- /dev/null > > +++ b/drivers/peci/request.c > > @@ -0,0 +1,50 @@ > > +// 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; > > + > > +?????? if (WARN_ON_ONCE(tx_len > PECI_REQUEST_MAX_BUF_SIZE || rx_len > > > PECI_REQUEST_MAX_BUF_SIZE)) > > WARN_ON_ONCE() should only be here to help other kernel developers not > make this mistake However, another way to enforce this is to stop > exporting peci_request_alloc() and instead export helpers for specific > command types, and keep this detail internal to the core. If you keep > this, it needs a comment that it is only here to warn other > peci-client developers of their bug before it goes upstream. Added comment. Thanks -Iwona