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platform/x86: ISST: Add Intel Speed Select mailbox interface via PCI
Add an IOCTL to send mailbox commands to PUNIT using PUNIT PCI device. A limited set of mailbox commands can be sent to PUNIT. This MMIO interface is used by the intel-speed-select tool under tools/x86/power to enumerate and control Intel Speed Select features. The MBOX commands ids and semantics of the message can be checked from the source code of the tool. Signed-off-by: Srinivas Pandruvada <[email protected]> Signed-off-by: Andy Shevchenko <[email protected]>
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199 changes: 199 additions & 0 deletions
199
drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,199 @@ | ||
| // 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 <[email protected]> | ||
| */ | ||
|
|
||
| #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); | ||
| 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 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, | ||
| }; | ||
|
|
||
| module_pci_driver(isst_if_pci_driver); | ||
|
|
||
| MODULE_LICENSE("GPL v2"); | ||
| MODULE_DESCRIPTION("Intel speed select interface pci mailbox driver"); |
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