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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: > > PECI devices may not be discoverable at the time when PECI controller is > being added (e.g. BMC can boot up when the Host system is still in S5). > Since we currently don't have the capabilities to figure out the Host > system state inside the PECI subsystem itself, we have to rely on > userspace to do it for us. > > In the future, PECI subsystem may be expanded with mechanisms that allow > us to avoid depending on userspace interaction (e.g. CPU presence could > be detected using GPIO, and the information on whether it's discoverable > could be obtained over IPMI). Thanks for this detail. > Unfortunately, those methods may ultimately not be available (support > will vary from platform to platform), which means that we still need > platform independent method triggered by userspace. > > Signed-off-by: Iwona Winiarska > --- > Documentation/ABI/testing/sysfs-bus-peci | 16 +++++ > drivers/peci/Makefile | 2 +- > drivers/peci/core.c | 3 +- > drivers/peci/device.c | 1 + > drivers/peci/internal.h | 5 ++ > drivers/peci/sysfs.c | 82 ++++++++++++++++++++++++ > 6 files changed, 107 insertions(+), 2 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-bus-peci > create mode 100644 drivers/peci/sysfs.c > > diff --git a/Documentation/ABI/testing/sysfs-bus-peci b/Documentation/ABI/testing/sysfs-bus-peci > new file mode 100644 > index 000000000000..56c2b2216bbd > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-bus-peci > @@ -0,0 +1,16 @@ > +What: /sys/bus/peci/rescan > +Date: July 2021 > +KernelVersion: 5.15 > +Contact: Iwona Winiarska > +Description: > + Writing a non-zero value to this attribute will > + initiate scan for PECI devices on all PECI controllers > + in the system. > + > +What: /sys/bus/peci/devices/-/remove > +Date: July 2021 > +KernelVersion: 5.15 > +Contact: Iwona Winiarska > +Description: > + Writing a non-zero value to this attribute will > + remove the PECI device and any of its children. > diff --git a/drivers/peci/Makefile b/drivers/peci/Makefile > index c5f9d3fe21bb..917f689e147a 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 request.o device.o > +peci-y := core.o request.o device.o sysfs.o > obj-$(CONFIG_PECI) += peci.o > > # Hardware specific bus drivers > diff --git a/drivers/peci/core.c b/drivers/peci/core.c > index d143f1a7fe98..c473acb3c2a0 100644 > --- a/drivers/peci/core.c > +++ b/drivers/peci/core.c > @@ -34,7 +34,7 @@ struct device_type peci_controller_type = { > .release = peci_controller_dev_release, > }; > > -static int peci_controller_scan_devices(struct peci_controller *controller) > +int peci_controller_scan_devices(struct peci_controller *controller) > { > int ret; > u8 addr; > @@ -159,6 +159,7 @@ EXPORT_SYMBOL_NS_GPL(devm_peci_controller_add, PECI); > > struct bus_type peci_bus_type = { > .name = "peci", > + .bus_groups = peci_bus_groups, > }; > > static int __init peci_init(void) > diff --git a/drivers/peci/device.c b/drivers/peci/device.c > index 32811248997b..d77d9dabd51e 100644 > --- a/drivers/peci/device.c > +++ b/drivers/peci/device.c > @@ -110,5 +110,6 @@ static void peci_device_release(struct device *dev) > } > > struct device_type peci_device_type = { > + .groups = peci_device_groups, > .release = peci_device_release, > }; > diff --git a/drivers/peci/internal.h b/drivers/peci/internal.h > index 57d11a902c5d..978e12c8e1d3 100644 > --- a/drivers/peci/internal.h > +++ b/drivers/peci/internal.h > @@ -8,6 +8,7 @@ > #include > > struct peci_controller; > +struct attribute_group; > struct peci_device; > struct peci_request; > > @@ -19,12 +20,16 @@ struct peci_request *peci_request_alloc(struct peci_device *device, u8 tx_len, u > void peci_request_free(struct peci_request *req); > > extern struct device_type peci_device_type; > +extern const struct attribute_group *peci_device_groups[]; > > 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; > +extern const struct attribute_group *peci_bus_groups[]; To me, sysfs.c is small enough to just fold into core.c, then no need to declare public attribute arrays like this, but up to you if you prefer the sysfs.c split. > > extern struct device_type peci_controller_type; > > +int peci_controller_scan_devices(struct peci_controller *controller); > + > #endif /* __PECI_INTERNAL_H */ > diff --git a/drivers/peci/sysfs.c b/drivers/peci/sysfs.c > new file mode 100644 > index 000000000000..db9ef05776e3 > --- /dev/null > +++ b/drivers/peci/sysfs.c > @@ -0,0 +1,82 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +// Copyright (c) 2021 Intel Corporation > + > +#include > +#include > +#include > + > +#include "internal.h" > + > +static int rescan_controller(struct device *dev, void *data) > +{ > + if (dev->type != &peci_controller_type) > + return 0; > + > + return peci_controller_scan_devices(to_peci_controller(dev)); > +} > + > +static ssize_t rescan_store(struct bus_type *bus, const char *buf, size_t count) > +{ > + bool res; > + int ret; > + > + ret = kstrtobool(buf, &res); > + if (ret) > + return ret; > + > + if (!res) > + return count; > + > + ret = bus_for_each_dev(&peci_bus_type, NULL, NULL, rescan_controller); > + if (ret) > + return ret; > + > + return count; > +} > +static BUS_ATTR_WO(rescan); > + > +static struct attribute *peci_bus_attrs[] = { > + &bus_attr_rescan.attr, > + NULL > +}; > + > +static const struct attribute_group peci_bus_group = { > + .attrs = peci_bus_attrs, > +}; > + > +const struct attribute_group *peci_bus_groups[] = { > + &peci_bus_group, > + NULL > +}; > + > +static ssize_t remove_store(struct device *dev, struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct peci_device *device = to_peci_device(dev); > + bool res; > + int ret; > + > + ret = kstrtobool(buf, &res); > + if (ret) > + return ret; > + > + if (res && device_remove_file_self(dev, attr)) > + peci_device_destroy(device); How do you solve races between sysfs device remove and controller device remove? Looks like double-free at first glance. Have a look at the kill_device() helper as one way to resolve this double-delete race.. > + > + return count; > +} > +static DEVICE_ATTR_IGNORE_LOCKDEP(remove, 0200, NULL, remove_store); > + > +static struct attribute *peci_device_attrs[] = { > + &dev_attr_remove.attr, > + NULL > +}; > + > +static const struct attribute_group peci_device_group = { > + .attrs = peci_device_attrs, > +}; > + > +const struct attribute_group *peci_device_groups[] = { > + &peci_device_group, > + NULL > +}; > -- > 2.31.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel