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-rw-r--r--drivers/peci/device.c252
1 files changed, 252 insertions, 0 deletions
diff --git a/drivers/peci/device.c b/drivers/peci/device.c
new file mode 100644
index 000000000..e6b0bffb1
--- /dev/null
+++ b/drivers/peci/device.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2018-2021 Intel Corporation
+
+#include <linux/bitfield.h>
+#include <linux/peci.h>
+#include <linux/peci-cpu.h>
+#include <linux/slab.h>
+
+#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);
+
+#define REVISION_NUM_MASK GENMASK(15, 8)
+static int peci_get_revision(struct peci_device *device, u8 *revision)
+{
+ struct peci_request *req;
+ u64 dib;
+
+ req = peci_xfer_get_dib(device);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+
+ /*
+ * PECI device may be in a state where it is unable to return a proper
+ * DIB, in which case it returns 0 as DIB value.
+ * Let's treat this as an error to avoid carrying on with the detection
+ * using invalid revision.
+ */
+ dib = peci_request_dib_read(req);
+ if (dib == 0) {
+ peci_request_free(req);
+ return -EIO;
+ }
+
+ *revision = FIELD_GET(REVISION_NUM_MASK, dib);
+
+ peci_request_free(req);
+
+ return 0;
+}
+
+static int peci_get_cpu_id(struct peci_device *device, u32 *cpu_id)
+{
+ struct peci_request *req;
+ int ret;
+
+ req = peci_xfer_pkg_cfg_readl(device, PECI_PCS_PKG_ID, PECI_PKG_ID_CPU_ID);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+
+ ret = peci_request_status(req);
+ if (ret)
+ goto out_req_free;
+
+ *cpu_id = peci_request_data_readl(req);
+out_req_free:
+ peci_request_free(req);
+
+ return ret;
+}
+
+static unsigned int peci_x86_cpu_family(unsigned int sig)
+{
+ unsigned int x86;
+
+ x86 = (sig >> 8) & 0xf;
+
+ if (x86 == 0xf)
+ x86 += (sig >> 20) & 0xff;
+
+ return x86;
+}
+
+static unsigned int peci_x86_cpu_model(unsigned int sig)
+{
+ unsigned int fam, model;
+
+ fam = peci_x86_cpu_family(sig);
+
+ model = (sig >> 4) & 0xf;
+
+ if (fam >= 0x6)
+ model += ((sig >> 16) & 0xf) << 4;
+
+ return model;
+}
+
+static int peci_device_info_init(struct peci_device *device)
+{
+ u8 revision;
+ u32 cpu_id;
+ int ret;
+
+ ret = peci_get_cpu_id(device, &cpu_id);
+ if (ret)
+ return ret;
+
+ device->info.family = peci_x86_cpu_family(cpu_id);
+ device->info.model = peci_x86_cpu_model(cpu_id);
+
+ ret = peci_get_revision(device, &revision);
+ if (ret)
+ return ret;
+ device->info.peci_revision = revision;
+
+ device->info.socket_id = device->addr - PECI_BASE_ADDR;
+
+ return 0;
+}
+
+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 = peci_device_info_init(device);
+ if (ret)
+ goto err_put;
+
+ 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);
+}
+
+int __peci_driver_register(struct peci_driver *driver, struct module *owner,
+ const char *mod_name)
+{
+ driver->driver.bus = &peci_bus_type;
+ driver->driver.owner = owner;
+ driver->driver.mod_name = mod_name;
+
+ if (!driver->probe) {
+ pr_err("peci: trying to register driver without probe callback\n");
+ return -EINVAL;
+ }
+
+ if (!driver->id_table) {
+ pr_err("peci: trying to register driver without device id table\n");
+ return -EINVAL;
+ }
+
+ return driver_register(&driver->driver);
+}
+EXPORT_SYMBOL_NS_GPL(__peci_driver_register, PECI);
+
+void peci_driver_unregister(struct peci_driver *driver)
+{
+ driver_unregister(&driver->driver);
+}
+EXPORT_SYMBOL_NS_GPL(peci_driver_unregister, PECI);
+
+static void peci_device_release(struct device *dev)
+{
+ struct peci_device *device = to_peci_device(dev);
+
+ kfree(device);
+}
+
+struct device_type peci_device_type = {
+ .groups = peci_device_groups,
+ .release = peci_device_release,
+};