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Commit 31a166fe authored by Srinivas Pandruvada's avatar Srinivas Pandruvada Committed by Andy Shevchenko
Browse files

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: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent d3a23584

drivers/platform/x86/intel_speed_select_if/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -6,3 +6,4 @@ 


obj-$(CONFIG_INTEL_SPEED_SELECT_INTERFACE) += isst_if_common.o

obj-$(CONFIG_INTEL_SPEED_SELECT_INTERFACE) += isst_if_mmio.o

obj-$(CONFIG_INTEL_SPEED_SELECT_INTERFACE) += isst_if_mbox_pci.o

drivers/platform/x86/intel_speed_select_if/isst_if_common.c

+85 −0
Original line number Diff line number Diff line
@@ -25,6 +25,86 @@ 


static struct isst_if_cmd_cb punit_callbacks[ISST_IF_DEV_MAX];



struct isst_valid_cmd_ranges {

	u16 cmd;

	u16 sub_cmd_beg;

	u16 sub_cmd_end;

};



struct isst_cmd_set_req_type {

	u16 cmd;

	u16 sub_cmd;

	u16 param;

};



static const struct isst_valid_cmd_ranges isst_valid_cmds[] = {

	{0xD0, 0x00, 0x03},

	{0x7F, 0x00, 0x0B},

	{0x7F, 0x10, 0x12},

	{0x7F, 0x20, 0x23},

};



static const struct isst_cmd_set_req_type isst_cmd_set_reqs[] = {

	{0xD0, 0x00, 0x08},

	{0xD0, 0x01, 0x08},

	{0xD0, 0x02, 0x08},

	{0xD0, 0x03, 0x08},

	{0x7F, 0x02, 0x00},

	{0x7F, 0x08, 0x00},

};



/**

 * isst_if_mbox_cmd_invalid() - Check invalid mailbox commands

 * @cmd: Pointer to the command structure to verify.

 *

 * Invalid command to PUNIT to may result in instability of the platform.

 * This function has a whitelist of commands, which are allowed.

 *

 * Return: Return true if the command is invalid, else false.

 */

bool isst_if_mbox_cmd_invalid(struct isst_if_mbox_cmd *cmd)

{

	int i;



	if (cmd->logical_cpu >= nr_cpu_ids)

		return true;



	for (i = 0; i < ARRAY_SIZE(isst_valid_cmds); ++i) {

		if (cmd->command == isst_valid_cmds[i].cmd &&

		    (cmd->sub_command >= isst_valid_cmds[i].sub_cmd_beg &&

		     cmd->sub_command <= isst_valid_cmds[i].sub_cmd_end)) {

			return false;

		}

	}



	return true;

}

EXPORT_SYMBOL_GPL(isst_if_mbox_cmd_invalid);



/**

 * isst_if_mbox_cmd_set_req() - Check mailbox command is a set request

 * @cmd: Pointer to the command structure to verify.

 *

 * Check if the given mail box level is set request and not a get request.

 *

 * Return: Return true if the command is set_req, else false.

 */

bool isst_if_mbox_cmd_set_req(struct isst_if_mbox_cmd *cmd)

{

	int i;



	for (i = 0; i < ARRAY_SIZE(isst_cmd_set_reqs); ++i) {

		if (cmd->command == isst_cmd_set_reqs[i].cmd &&

		    cmd->sub_command == isst_cmd_set_reqs[i].sub_cmd &&

		    cmd->parameter == isst_cmd_set_reqs[i].param) {

			return true;

		}

	}



	return false;

}

EXPORT_SYMBOL_GPL(isst_if_mbox_cmd_set_req);



static int isst_if_get_platform_info(void __user *argp)

{

	struct isst_if_platform_info info;
@@ -224,6 +304,11 @@ static long isst_if_def_ioctl(struct file *file, unsigned int cmd, 
		if (cb->registered)

			ret = isst_if_exec_multi_cmd(argp, cb);

		break;

	case ISST_IF_MBOX_COMMAND:

		cb = &punit_callbacks[ISST_IF_DEV_MBOX];

		if (cb->registered)

			ret = isst_if_exec_multi_cmd(argp, cb);

		break;

	default:

		break;

	}

drivers/platform/x86/intel_speed_select_if/isst_if_common.h

+3 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#define __ISST_IF_COMMON_H



#define INTEL_RAPL_PRIO_DEVID_0	0x3451

#define INTEL_CFG_MBOX_DEVID_0	0x3459



/*

 * Validate maximum commands in a single request.
@@ -60,4 +61,6 @@ struct isst_if_cmd_cb { 
int isst_if_cdev_register(int type, struct isst_if_cmd_cb *cb);

void isst_if_cdev_unregister(int type);

struct pci_dev *isst_if_get_pci_dev(int cpu, int bus, int dev, int fn);

bool isst_if_mbox_cmd_set_req(struct isst_if_mbox_cmd *mbox_cmd);

bool isst_if_mbox_cmd_invalid(struct isst_if_mbox_cmd *cmd);

#endif

drivers/platform/x86/intel_speed_select_if/isst_if_mbox_pci.c

0 → 100644
+199 −0
Original line number Diff line number Diff line 
// 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);

	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");

include/uapi/linux/isst_if.h

+38 −0
Original line number Diff line number Diff line
@@ -95,8 +95,46 @@ struct isst_if_io_regs { 
	struct isst_if_io_reg io_reg[1];

};



/**

 * struct isst_if_mbox_cmd - Structure to define mail box command

 * @logical_cpu:	Logical CPU number to get target PCI device

 * @parameter:		Mailbox parameter value

 * @req_data:		Request data for the mailbox

 * @resp_data:		Response data for mailbox command response

 * @command:		Mailbox command value

 * @sub_command:	Mailbox sub command value

 * @reserved:		Unused, set to 0

 *

 * Structure to specify mailbox command to be sent to PUNIT.

 */

struct isst_if_mbox_cmd {

	__u32 logical_cpu;

	__u32 parameter;

	__u32 req_data;

	__u32 resp_data;

	__u16 command;

	__u16 sub_command;

	__u32 reserved;

};



/**

 * struct isst_if_mbox_cmds - structure for mailbox commands

 * @cmd_count:	Number of mailbox commands in mbox_cmd[]

 * @mbox_cmd[]:	Holds one or more mbox commands

 *

 * This structure used with ioctl ISST_IF_MBOX_COMMAND to send

 * one or more mailbox commands to PUNIT. Here IOCTL return value

 * indicates number of commands sent or error number if no commands have

 * been sent.

 */

struct isst_if_mbox_cmds {

	__u32 cmd_count;

	struct isst_if_mbox_cmd mbox_cmd[1];

};



#define ISST_IF_MAGIC			0xFE

#define ISST_IF_GET_PLATFORM_INFO	_IOR(ISST_IF_MAGIC, 0, struct isst_if_platform_info *)

#define ISST_IF_GET_PHY_ID		_IOWR(ISST_IF_MAGIC, 1, struct isst_if_cpu_map *)

#define ISST_IF_IO_CMD		_IOW(ISST_IF_MAGIC, 2, struct isst_if_io_regs *)

#define ISST_IF_MBOX_COMMAND	_IOWR(ISST_IF_MAGIC, 3, struct isst_if_mbox_cmds *)

#endif