On Thu, Aug 17, 2023 at 2:18 PM Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote: > > Add a thermal cooling driver to provide path to access PCIe bandwidth > controller using the usual thermal interfaces. > > A cooling device is instantiated for controllable PCIe ports from the > bwctrl service driver. > > The thermal side state 0 means no throttling, i.e., maximum supported > PCIe speed. > > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> >From the cooling device interface perspective Acked-by: Rafael J. Wysocki <rafael@xxxxxxxxxx> > --- > MAINTAINERS | 1 + > drivers/pci/pcie/bwctrl.c | 11 ++++ > drivers/thermal/Kconfig | 10 +++ > drivers/thermal/Makefile | 2 + > drivers/thermal/pcie_cooling.c | 107 +++++++++++++++++++++++++++++++++ > include/linux/pci-bwctrl.h | 15 +++++ > 6 files changed, 146 insertions(+) > create mode 100644 drivers/thermal/pcie_cooling.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index d2eed2883a43..a0b40253fd5a 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -16421,6 +16421,7 @@ PCIE BANDWIDTH CONTROLLER > M: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> > S: Supported > F: drivers/pci/pcie/bwctrl.c > +F: drivers/thermal/pcie_cooling.c > F: include/linux/pci-bwctrl.h > > PCIE DRIVER FOR AMAZON ANNAPURNA LABS > diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c > index e3172d69476f..13c73546244e 100644 > --- a/drivers/pci/pcie/bwctrl.c > +++ b/drivers/pci/pcie/bwctrl.c > @@ -34,9 +34,11 @@ > /** > * struct bwctrl_service_data - PCIe Port Bandwidth Controller > * @set_speed_mutex: serializes link speed changes > + * @cdev: thermal cooling device associated with the port > */ > struct bwctrl_service_data { > struct mutex set_speed_mutex; > + struct thermal_cooling_device *cdev; > }; > > static bool bwctrl_valid_pcie_speed(enum pci_bus_speed speed) > @@ -253,8 +255,16 @@ static int pcie_bandwidth_notification_probe(struct pcie_device *srv) > pcie_enable_link_bandwidth_notification(port); > pci_info(port, "enabled with IRQ %d\n", srv->irq); > > + data->cdev = pcie_cooling_device_register(port, srv); > + if (IS_ERR(data->cdev)) { > + ret = PTR_ERR(data->cdev); > + goto disable_notifications; > + } > return 0; > > +disable_notifications: > + pcie_disable_link_bandwidth_notification(srv->port); > + kfree(data); > free_irq: > free_irq(srv->irq, srv); > return ret; > @@ -264,6 +274,7 @@ static void pcie_bandwidth_notification_remove(struct pcie_device *srv) > { > struct bwctrl_service_data *data = get_service_data(srv); > > + pcie_cooling_device_unregister(data->cdev); > pcie_disable_link_bandwidth_notification(srv->port); > free_irq(srv->irq, srv); > mutex_destroy(&data->set_speed_mutex); > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig > index 19a4b33cb564..7deda3a0237d 100644 > --- a/drivers/thermal/Kconfig > +++ b/drivers/thermal/Kconfig > @@ -219,6 +219,16 @@ config DEVFREQ_THERMAL > > If you want this support, you should say Y here. > > +config PCIE_THERMAL > + bool "PCIe cooling support" > + depends on PCIEPORTBUS > + select PCIE_BW > + help > + This implements PCIe cooling mechanism through bandwidth reduction > + for PCIe devices. > + > + If you want this support, you should say Y here. > + > config THERMAL_EMULATION > bool "Thermal emulation mode support" > help > diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile > index 058664bc3ec0..065972a08c84 100644 > --- a/drivers/thermal/Makefile > +++ b/drivers/thermal/Makefile > @@ -30,6 +30,8 @@ thermal_sys-$(CONFIG_CPU_IDLE_THERMAL) += cpuidle_cooling.o > # devfreq cooling > thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o > > +thermal_sys-$(CONFIG_PCIE_THERMAL) += pcie_cooling.o > + > obj-$(CONFIG_K3_THERMAL) += k3_bandgap.o k3_j72xx_bandgap.o > # platform thermal drivers > obj-y += broadcom/ > diff --git a/drivers/thermal/pcie_cooling.c b/drivers/thermal/pcie_cooling.c > new file mode 100644 > index 000000000000..d86265c03e80 > --- /dev/null > +++ b/drivers/thermal/pcie_cooling.c > @@ -0,0 +1,107 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * PCIe cooling device > + * > + * Copyright (C) 2023 Intel Corporation. > + */ > + > +#include <linux/build_bug.h> > +#include <linux/err.h> > +#include <linux/kernel.h> > +#include <linux/pci.h> > +#include <linux/pci-bwctrl.h> > +#include <linux/slab.h> > +#include <linux/string.h> > +#include <linux/thermal.h> > + > +#define COOLING_DEV_TYPE_PREFIX "PCIe_Port_" > + > +struct pcie_cooling_device { > + struct pci_dev *port; > + struct pcie_device *pdev; > +}; > + > +static int pcie_cooling_get_max_level(struct thermal_cooling_device *cdev, unsigned long *state) > +{ > + struct pcie_cooling_device *pcie_cdev = cdev->devdata; > + > + /* cooling state 0 is same as the maximum PCIe speed */ > + *state = pcie_cdev->port->subordinate->max_bus_speed - PCIE_SPEED_2_5GT; > + > + return 0; > +} > + > +static int pcie_cooling_get_cur_level(struct thermal_cooling_device *cdev, unsigned long *state) > +{ > + struct pcie_cooling_device *pcie_cdev = cdev->devdata; > + > + /* cooling state 0 is same as the maximum PCIe speed */ > + *state = cdev->max_state - > + (pcie_cdev->port->subordinate->cur_bus_speed - PCIE_SPEED_2_5GT); > + > + return 0; > +} > + > +static int pcie_cooling_set_cur_level(struct thermal_cooling_device *cdev, unsigned long state) > +{ > + struct pcie_cooling_device *pcie_cdev = cdev->devdata; > + enum pci_bus_speed speed; > + > + /* cooling state 0 is same as the maximum PCIe speed */ > + speed = (cdev->max_state - state) + PCIE_SPEED_2_5GT; > + > + return bwctrl_set_current_speed(pcie_cdev->pdev, speed); > +} > + > +static struct thermal_cooling_device_ops pcie_cooling_ops = { > + .get_max_state = pcie_cooling_get_max_level, > + .get_cur_state = pcie_cooling_get_cur_level, > + .set_cur_state = pcie_cooling_set_cur_level, > +}; > + > +struct thermal_cooling_device *pcie_cooling_device_register(struct pci_dev *port, > + struct pcie_device *pdev) > +{ > + struct pcie_cooling_device *pcie_cdev; > + struct thermal_cooling_device *cdev; > + size_t name_len; > + char *name; > + > + pcie_cdev = kzalloc(sizeof(*pcie_cdev), GFP_KERNEL); > + if (!pcie_cdev) > + return ERR_PTR(-ENOMEM); > + > + pcie_cdev->port = port; > + pcie_cdev->pdev = pdev; > + > + name_len = strlen(COOLING_DEV_TYPE_PREFIX) + strlen(pci_name(port)) + 1; > + name = kzalloc(name_len, GFP_KERNEL); > + if (!name) { > + kfree(pcie_cdev); > + return ERR_PTR(-ENOMEM); > + } > + > + snprintf(name, name_len, COOLING_DEV_TYPE_PREFIX "%s", pci_name(port)); > + cdev = thermal_cooling_device_register(name, pcie_cdev, &pcie_cooling_ops); > + kfree(name); > + > + return cdev; > +} > + > +void pcie_cooling_device_unregister(struct thermal_cooling_device *cdev) > +{ > + struct pcie_cooling_device *pcie_cdev = cdev->devdata; > + > + thermal_cooling_device_unregister(cdev); > + kfree(pcie_cdev); > +} > + > +/* For bus_speed <-> state arithmetic */ > +static_assert(PCIE_SPEED_2_5GT + 1 == PCIE_SPEED_5_0GT); > +static_assert(PCIE_SPEED_5_0GT + 1 == PCIE_SPEED_8_0GT); > +static_assert(PCIE_SPEED_8_0GT + 1 == PCIE_SPEED_16_0GT); > +static_assert(PCIE_SPEED_16_0GT + 1 == PCIE_SPEED_32_0GT); > +static_assert(PCIE_SPEED_32_0GT + 1 == PCIE_SPEED_64_0GT); > + > +MODULE_AUTHOR("Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("PCIe cooling driver"); > diff --git a/include/linux/pci-bwctrl.h b/include/linux/pci-bwctrl.h > index 46026fa25deb..366445517b72 100644 > --- a/include/linux/pci-bwctrl.h > +++ b/include/linux/pci-bwctrl.h > @@ -15,4 +15,19 @@ struct thermal_cooling_device; > > int bwctrl_set_current_speed(struct pcie_device *srv, enum pci_bus_speed speed); > > +#ifdef CONFIG_PCIE_THERMAL > +struct thermal_cooling_device *pcie_cooling_device_register(struct pci_dev *port, > + struct pcie_device *pdev); > +void pcie_cooling_device_unregister(struct thermal_cooling_device *cdev); > +#else > +static inline struct thermal_cooling_device *pcie_cooling_device_register(struct pci_dev *port, > + struct pcie_device *pdev) > +{ > + return NULL; > +} > +static inline void pcie_cooling_device_unregister(struct thermal_cooling_device *cdev) > +{ > +} > +#endif > + > #endif > -- > 2.30.2 >