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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 }; > + > + 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. > + 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(). > + > + 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. > +} > + > +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. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel