diff options
Diffstat (limited to 'drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c')
| -rw-r--r-- | drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c b/drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c new file mode 100644 index 000000000000..de4169d0796b --- /dev/null +++ b/drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c @@ -0,0 +1,214 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Intel Speed Select Interface: Mbox via PCI Interface + * Copyright (c) 2019, Intel Corporation. + * All rights reserved. + * + * Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> + */ + +#include <linux/cpufeature.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/sched/signal.h> +#include <linux/uaccess.h> +#include <uapi/linux/isst_if.h> + +#include "isst_if_common.h" + +#define PUNIT_MAILBOX_DATA 0xA0 +#define PUNIT_MAILBOX_INTERFACE 0xA4 +#define PUNIT_MAILBOX_BUSY_BIT 31 + +/* + * Commands has variable amount of processing time. Most of the commands will + * be done in 0-3 tries, but some takes up to 50. + * The real processing time was observed as 25us for the most of the commands + * at 2GHz. It is possible to optimize this count taking samples on customer + * systems. + */ +#define OS_MAILBOX_RETRY_COUNT 50 + +struct isst_if_device { + struct mutex mutex; +}; + +static int isst_if_mbox_cmd(struct pci_dev *pdev, + struct isst_if_mbox_cmd *mbox_cmd) +{ + u32 retries, data; + int ret; + + /* Poll for rb bit == 0 */ + retries = OS_MAILBOX_RETRY_COUNT; + do { + ret = pci_read_config_dword(pdev, PUNIT_MAILBOX_INTERFACE, + &data); + if (ret) + return ret; + + if (data & BIT_ULL(PUNIT_MAILBOX_BUSY_BIT)) { + ret = -EBUSY; + continue; + } + ret = 0; + break; + } while (--retries); + + if (ret) + return ret; + + /* Write DATA register */ + ret = pci_write_config_dword(pdev, PUNIT_MAILBOX_DATA, + mbox_cmd->req_data); + if (ret) + return ret; + + /* Write command register */ + data = BIT_ULL(PUNIT_MAILBOX_BUSY_BIT) | + (mbox_cmd->parameter & GENMASK_ULL(13, 0)) << 16 | + (mbox_cmd->sub_command << 8) | + mbox_cmd->command; + + ret = pci_write_config_dword(pdev, PUNIT_MAILBOX_INTERFACE, data); + if (ret) + return ret; + + /* Poll for rb bit == 0 */ + retries = OS_MAILBOX_RETRY_COUNT; + do { + ret = pci_read_config_dword(pdev, PUNIT_MAILBOX_INTERFACE, + &data); + if (ret) + return ret; + + if (data & BIT_ULL(PUNIT_MAILBOX_BUSY_BIT)) { + ret = -EBUSY; + continue; + } + + if (data & 0xff) + return -ENXIO; + + ret = pci_read_config_dword(pdev, PUNIT_MAILBOX_DATA, &data); + if (ret) + return ret; + + mbox_cmd->resp_data = data; + ret = 0; + break; + } while (--retries); + + return ret; +} + +static long isst_if_mbox_proc_cmd(u8 *cmd_ptr, int *write_only, int resume) +{ + struct isst_if_mbox_cmd *mbox_cmd; + struct isst_if_device *punit_dev; + struct pci_dev *pdev; + int ret; + + mbox_cmd = (struct isst_if_mbox_cmd *)cmd_ptr; + + if (isst_if_mbox_cmd_invalid(mbox_cmd)) + return -EINVAL; + + if (isst_if_mbox_cmd_set_req(mbox_cmd) && !capable(CAP_SYS_ADMIN)) + return -EPERM; + + pdev = isst_if_get_pci_dev(mbox_cmd->logical_cpu, 1, 30, 1); + if (!pdev) + return -EINVAL; + + punit_dev = pci_get_drvdata(pdev); + if (!punit_dev) + return -EINVAL; + + /* + * Basically we are allowing one complete mailbox transaction on + * a mapped PCI device at a time. + */ + mutex_lock(&punit_dev->mutex); + ret = isst_if_mbox_cmd(pdev, mbox_cmd); + if (!ret && !resume && isst_if_mbox_cmd_set_req(mbox_cmd)) + ret = isst_store_cmd(mbox_cmd->command, + mbox_cmd->sub_command, + mbox_cmd->logical_cpu, 1, + mbox_cmd->parameter, + mbox_cmd->req_data); + mutex_unlock(&punit_dev->mutex); + if (ret) + return ret; + + *write_only = 0; + + return 0; +} + +static const struct pci_device_id isst_if_mbox_ids[] = { + { PCI_DEVICE(PCI_VENDOR_ID_INTEL, INTEL_CFG_MBOX_DEVID_0)}, + { 0 }, +}; +MODULE_DEVICE_TABLE(pci, isst_if_mbox_ids); + +static int isst_if_mbox_probe(struct pci_dev *pdev, + const struct pci_device_id *ent) +{ + struct isst_if_device *punit_dev; + struct isst_if_cmd_cb cb; + int ret; + + punit_dev = devm_kzalloc(&pdev->dev, sizeof(*punit_dev), GFP_KERNEL); + if (!punit_dev) + return -ENOMEM; + + ret = pcim_enable_device(pdev); + if (ret) + return ret; + + mutex_init(&punit_dev->mutex); + pci_set_drvdata(pdev, punit_dev); + + memset(&cb, 0, sizeof(cb)); + cb.cmd_size = sizeof(struct isst_if_mbox_cmd); + cb.offset = offsetof(struct isst_if_mbox_cmds, mbox_cmd); + cb.cmd_callback = isst_if_mbox_proc_cmd; + cb.owner = THIS_MODULE; + ret = isst_if_cdev_register(ISST_IF_DEV_MBOX, &cb); + + if (ret) + mutex_destroy(&punit_dev->mutex); + + return ret; +} + +static void isst_if_mbox_remove(struct pci_dev *pdev) +{ + struct isst_if_device *punit_dev; + + punit_dev = pci_get_drvdata(pdev); + isst_if_cdev_unregister(ISST_IF_DEV_MBOX); + mutex_destroy(&punit_dev->mutex); +} + +static int __maybe_unused isst_if_resume(struct device *device) +{ + isst_resume_common(); + return 0; +} + +static SIMPLE_DEV_PM_OPS(isst_if_pm_ops, NULL, isst_if_resume); + +static struct pci_driver isst_if_pci_driver = { + .name = "isst_if_mbox_pci", + .id_table = isst_if_mbox_ids, + .probe = isst_if_mbox_probe, + .remove = isst_if_mbox_remove, + .driver.pm = &isst_if_pm_ops, +}; + +module_pci_driver(isst_if_pci_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Intel speed select interface pci mailbox driver"); |