drivers/i2c/busses/i2c-amd-mp2-pci.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
  * AMD MP2 PCIe communication driver
  *
  * Authors: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
  *          Elie Morisse <syniurge@gmail.com>
  */

 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/slab.h>

 #include "i2c-amd-mp2.h"

 #include <linux/io-64-nonatomic-lo-hi.h>

 static void amd_mp2_c2p_mutex_lock(struct amd_i2c_common *i2c_common)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

 	/* there is only one data mailbox for two i2c adapters */
 	mutex_lock(&privdata->c2p_lock);
 	privdata->c2p_lock_busid = i2c_common->bus_id;
 }

 static void amd_mp2_c2p_mutex_unlock(struct amd_i2c_common *i2c_common)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

 	if (unlikely(privdata->c2p_lock_busid != i2c_common->bus_id)) {
 		pci_warn(privdata->pci_dev,
 			 "bus %d attempting to unlock C2P locked by bus %d\n",
 			 i2c_common->bus_id, privdata->c2p_lock_busid);
 		return;
 	}

 	mutex_unlock(&privdata->c2p_lock);
 }

 static int amd_mp2_cmd(struct amd_i2c_common *i2c_common,
 		       union i2c_cmd_base i2c_cmd_base)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 	void __iomem *reg;

 	i2c_common->reqcmd = i2c_cmd_base.s.i2c_cmd;

 	reg = privdata->mmio + ((i2c_cmd_base.s.bus_id == 1) ?
 				AMD_C2P_MSG1 : AMD_C2P_MSG0);
 	writel(i2c_cmd_base.ul, reg);

 	return 0;
 }

 int amd_mp2_bus_enable_set(struct amd_i2c_common *i2c_common, bool enable)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 	union i2c_cmd_base i2c_cmd_base;

 	pci_dbg(privdata->pci_dev, "id: %d\n", i2c_common->bus_id);

 	i2c_cmd_base.ul = 0;
 	i2c_cmd_base.s.i2c_cmd = enable ? i2c_enable : i2c_disable;
 	i2c_cmd_base.s.bus_id = i2c_common->bus_id;
 	i2c_cmd_base.s.i2c_speed = i2c_common->i2c_speed;

 	amd_mp2_c2p_mutex_lock(i2c_common);

 	return amd_mp2_cmd(i2c_common, i2c_cmd_base);
 }
 EXPORT_SYMBOL_GPL(amd_mp2_bus_enable_set);

 static void amd_mp2_cmd_rw_fill(struct amd_i2c_common *i2c_common,
 				union i2c_cmd_base *i2c_cmd_base,
 				enum i2c_cmd reqcmd)
 {
 	i2c_cmd_base->s.i2c_cmd = reqcmd;
 	i2c_cmd_base->s.bus_id = i2c_common->bus_id;
 	i2c_cmd_base->s.i2c_speed = i2c_common->i2c_speed;
 	i2c_cmd_base->s.slave_addr = i2c_common->msg->addr;
 	i2c_cmd_base->s.length = i2c_common->msg->len;
 }

 int amd_mp2_rw(struct amd_i2c_common *i2c_common, enum i2c_cmd reqcmd)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 	union i2c_cmd_base i2c_cmd_base;

 	amd_mp2_cmd_rw_fill(i2c_common, &i2c_cmd_base, reqcmd);
 	amd_mp2_c2p_mutex_lock(i2c_common);

 	if (i2c_common->msg->len <= 32) {
 		i2c_cmd_base.s.mem_type = use_c2pmsg;
 		if (reqcmd == i2c_write)
 			memcpy_toio(privdata->mmio + AMD_C2P_MSG2,
 				    i2c_common->msg->buf,
 				    i2c_common->msg->len);
 	} else {
 		i2c_cmd_base.s.mem_type = use_dram;
 		writeq((u64)i2c_common->dma_addr,
 		       privdata->mmio + AMD_C2P_MSG2);
 	}

 	return amd_mp2_cmd(i2c_common, i2c_cmd_base);
 }
 EXPORT_SYMBOL_GPL(amd_mp2_rw);

 static void amd_mp2_pci_check_rw_event(struct amd_i2c_common *i2c_common)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 	struct pci_dev *pdev = privdata->pci_dev;
 	int len = i2c_common->eventval.r.length;
 	u32 slave_addr = i2c_common->eventval.r.slave_addr;
 	bool err = false;

 	if (unlikely(len != i2c_common->msg->len)) {
 		pci_err(pdev, "length %d in event doesn't match buffer length %d!\n",
 			len, i2c_common->msg->len);
 		err = true;
 	}

 	if (unlikely(slave_addr != i2c_common->msg->addr)) {
 		pci_err(pdev, "unexpected slave address %x (expected: %x)!\n",
 			slave_addr, i2c_common->msg->addr);
 		err = true;
 	}

 	if (!err)
 		i2c_common->cmd_success = true;
 }

 static void __amd_mp2_process_event(struct amd_i2c_common *i2c_common)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 	struct pci_dev *pdev = privdata->pci_dev;
 	enum status_type sts = i2c_common->eventval.r.status;
 	enum response_type res = i2c_common->eventval.r.response;
 	int len = i2c_common->eventval.r.length;

 	if (res != command_success) {
 		if (res != command_failed)
 			pci_err(pdev, "invalid response to i2c command!\n");
 		return;
 	}

 	switch (i2c_common->reqcmd) {
 	case i2c_read:
 		if (sts == i2c_readcomplete_event) {
 			amd_mp2_pci_check_rw_event(i2c_common);
 			if (len <= 32)
 				memcpy_fromio(i2c_common->msg->buf,
 					      privdata->mmio + AMD_C2P_MSG2,
 					      len);
 		} else if (sts != i2c_readfail_event) {
 			pci_err(pdev, "invalid i2c status after read (%d)!\n", sts);
 		}
 		break;
 	case i2c_write:
 		if (sts == i2c_writecomplete_event)
 			amd_mp2_pci_check_rw_event(i2c_common);
 		else if (sts != i2c_writefail_event)
 			pci_err(pdev, "invalid i2c status after write (%d)!\n", sts);
 		break;
 	case i2c_enable:
 		if (sts == i2c_busenable_complete)
 			i2c_common->cmd_success = true;
 		else if (sts != i2c_busenable_failed)
 			pci_err(pdev, "invalid i2c status after bus enable (%d)!\n", sts);
 		break;
 	case i2c_disable:
 		if (sts == i2c_busdisable_complete)
 			i2c_common->cmd_success = true;
 		else if (sts != i2c_busdisable_failed)
 			pci_err(pdev, "invalid i2c status after bus disable (%d)!\n", sts);
 		break;
 	default:
 		break;
 	}
 }

 void amd_mp2_process_event(struct amd_i2c_common *i2c_common)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 	struct pci_dev *pdev = privdata->pci_dev;

 	if (unlikely(i2c_common->reqcmd == i2c_none)) {
 		pci_warn(pdev, "received msg but no cmd was sent (bus = %d)!\n",
 			 i2c_common->bus_id);
 		return;
 	}

 	__amd_mp2_process_event(i2c_common);

 	i2c_common->reqcmd = i2c_none;
 	amd_mp2_c2p_mutex_unlock(i2c_common);
 }
 EXPORT_SYMBOL_GPL(amd_mp2_process_event);

 static irqreturn_t amd_mp2_irq_isr(int irq, void *dev)
 {
 	struct amd_mp2_dev *privdata = dev;
 	struct pci_dev *pdev = privdata->pci_dev;
 	struct amd_i2c_common *i2c_common;
 	u32 val;
 	unsigned int bus_id;
 	void __iomem *reg;
 	enum irqreturn ret = IRQ_NONE;

 	for (bus_id = 0; bus_id < 2; bus_id++) {
 		i2c_common = privdata->busses[bus_id];
 		if (!i2c_common)
 			continue;

 		reg = privdata->mmio + ((bus_id == 0) ?
 					AMD_P2C_MSG1 : AMD_P2C_MSG2);
 		val = readl(reg);
 		if (val != 0) {
 			writel(0, reg);
 			writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
 			i2c_common->eventval.ul = val;
 			i2c_common->cmd_completion(i2c_common);

 			ret = IRQ_HANDLED;
 		}
 	}

 	if (ret != IRQ_HANDLED) {
 		val = readl(privdata->mmio + AMD_P2C_MSG_INTEN);
 		if (val != 0) {
 			writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
 			pci_warn(pdev, "received irq without message\n");
 			ret = IRQ_HANDLED;
 		}
 	}

 	return ret;
 }

 void amd_mp2_rw_timeout(struct amd_i2c_common *i2c_common)
 {
 	i2c_common->reqcmd = i2c_none;
 	amd_mp2_c2p_mutex_unlock(i2c_common);
 }
 EXPORT_SYMBOL_GPL(amd_mp2_rw_timeout);

 int amd_mp2_register_cb(struct amd_i2c_common *i2c_common)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 	struct pci_dev *pdev = privdata->pci_dev;

 	if (i2c_common->bus_id > 1)
 		return -EINVAL;

 	if (privdata->busses[i2c_common->bus_id]) {
 		pci_err(pdev, "Bus %d already taken!\n", i2c_common->bus_id);
 		return -EINVAL;
 	}

 	privdata->busses[i2c_common->bus_id] = i2c_common;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(amd_mp2_register_cb);

 int amd_mp2_unregister_cb(struct amd_i2c_common *i2c_common)
 {
 	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

 	privdata->busses[i2c_common->bus_id] = NULL;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(amd_mp2_unregister_cb);

 static void amd_mp2_clear_reg(struct amd_mp2_dev *privdata)
 {
 	int reg;

 	for (reg = AMD_C2P_MSG0; reg <= AMD_C2P_MSG9; reg += 4)
 		writel(0, privdata->mmio + reg);

 	for (reg = AMD_P2C_MSG1; reg <= AMD_P2C_MSG2; reg += 4)
 		writel(0, privdata->mmio + reg);
 }

 static int amd_mp2_pci_init(struct amd_mp2_dev *privdata,
 			    struct pci_dev *pci_dev)
 {
 	int rc;

 	pci_set_drvdata(pci_dev, privdata);

 	rc = pcim_enable_device(pci_dev);
 	if (rc) {
 		pci_err(pci_dev, "Failed to enable MP2 PCI device\n");
 		goto err_pci_enable;
 	}

 	rc = pcim_iomap_regions(pci_dev, 1 << 2, pci_name(pci_dev));
 	if (rc) {
 		pci_err(pci_dev, "I/O memory remapping failed\n");
 		goto err_pci_enable;
 	}
 	privdata->mmio = pcim_iomap_table(pci_dev)[2];

 	pci_set_master(pci_dev);

 	rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
 	if (rc)
 		goto err_dma_mask;

 	/* Set up intx irq */
 	writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
 	pci_intx(pci_dev, 1);
 	rc = devm_request_irq(&pci_dev->dev, pci_dev->irq, amd_mp2_irq_isr,
 			      IRQF_SHARED, dev_name(&pci_dev->dev), privdata);
 	if (rc)
 		pci_err(pci_dev, "Failure requesting irq %i: %d\n",
 			pci_dev->irq, rc);

 	return rc;

 err_dma_mask:
 	pci_clear_master(pci_dev);
 err_pci_enable:
 	pci_set_drvdata(pci_dev, NULL);
 	return rc;
 }

 static int amd_mp2_pci_probe(struct pci_dev *pci_dev,
 			     const struct pci_device_id *id)
 {
 	struct amd_mp2_dev *privdata;
 	int rc;

 	privdata = devm_kzalloc(&pci_dev->dev, sizeof(*privdata), GFP_KERNEL);
 	if (!privdata)
 		return -ENOMEM;

 	privdata->pci_dev = pci_dev;
 	rc = amd_mp2_pci_init(privdata, pci_dev);
 	if (rc)
 		return rc;

 	mutex_init(&privdata->c2p_lock);

 	pm_runtime_set_autosuspend_delay(&pci_dev->dev, 1000);
 	pm_runtime_use_autosuspend(&pci_dev->dev);
 	pm_runtime_put_autosuspend(&pci_dev->dev);
 	pm_runtime_allow(&pci_dev->dev);

 	privdata->probed = true;

 	pci_info(pci_dev, "MP2 device registered.\n");
 	return 0;
 }

 static void amd_mp2_pci_remove(struct pci_dev *pci_dev)
 {
 	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);

 	pm_runtime_forbid(&pci_dev->dev);
 	pm_runtime_get_noresume(&pci_dev->dev);

 	pci_intx(pci_dev, 0);
 	pci_clear_master(pci_dev);

 	amd_mp2_clear_reg(privdata);
 }

 #ifdef CONFIG_PM
 static int amd_mp2_pci_suspend(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
 	struct amd_i2c_common *i2c_common;
 	unsigned int bus_id;
 	int ret = 0;

 	for (bus_id = 0; bus_id < 2; bus_id++) {
 		i2c_common = privdata->busses[bus_id];
 		if (i2c_common)
 			i2c_common->suspend(i2c_common);
 	}

 	ret = pci_save_state(pci_dev);
 	if (ret) {
 		pci_err(pci_dev, "pci_save_state failed = %d\n", ret);
 		return ret;
 	}

 	pci_disable_device(pci_dev);
 	return ret;
 }

 static int amd_mp2_pci_resume(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
 	struct amd_i2c_common *i2c_common;
 	unsigned int bus_id;
 	int ret = 0;

 	pci_restore_state(pci_dev);
 	ret = pci_enable_device(pci_dev);
 	if (ret < 0) {
 		pci_err(pci_dev, "pci_enable_device failed = %d\n", ret);
 		return ret;
 	}

 	for (bus_id = 0; bus_id < 2; bus_id++) {
 		i2c_common = privdata->busses[bus_id];
 		if (i2c_common) {
 			ret = i2c_common->resume(i2c_common);
 			if (ret < 0)
 				return ret;
 		}
 	}

 	return ret;
 }

 static UNIVERSAL_DEV_PM_OPS(amd_mp2_pci_pm_ops, amd_mp2_pci_suspend,
 			    amd_mp2_pci_resume, NULL);
 #endif /* CONFIG_PM */

 static const struct pci_device_id amd_mp2_pci_tbl[] = {
 	{PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_MP2)},
 	{0}
 };
 MODULE_DEVICE_TABLE(pci, amd_mp2_pci_tbl);

 static struct pci_driver amd_mp2_pci_driver = {
 	.name		= "i2c_amd_mp2",
 	.id_table	= amd_mp2_pci_tbl,
 	.probe		= amd_mp2_pci_probe,
 	.remove		= amd_mp2_pci_remove,
 #ifdef CONFIG_PM
 	.driver = {
 		.pm	= &amd_mp2_pci_pm_ops,
 	},
 #endif
 };
 module_pci_driver(amd_mp2_pci_driver);

 struct amd_mp2_dev *amd_mp2_find_device(void)
 {
 	struct device *dev;
 	struct pci_dev *pci_dev;

 	dev = driver_find_next_device(&amd_mp2_pci_driver.driver, NULL);
 	if (!dev)
 		return NULL;

 	pci_dev = to_pci_dev(dev);
 	return (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
 }
 EXPORT_SYMBOL_GPL(amd_mp2_find_device);

 MODULE_DESCRIPTION("AMD(R) PCI-E MP2 I2C Controller Driver");
 MODULE_AUTHOR("Shyam Sundar S K <Shyam-sundar.S-k@amd.com>");
 MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
 MODULE_LICENSE("Dual BSD/GPL");
	// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
	/*
	* AMD MP2 PCIe communication driver
	*
	* Authors: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
	* Elie Morisse <syniurge@gmail.com>
	*/

	#include <linux/dma-mapping.h>
	#include <linux/interrupt.h>
	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/slab.h>

	#include "i2c-amd-mp2.h"

	#include <linux/io-64-nonatomic-lo-hi.h>

	static void amd_mp2_c2p_mutex_lock(struct amd_i2c_common *i2c_common)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

	/* there is only one data mailbox for two i2c adapters */
	mutex_lock(&privdata->c2p_lock);
	privdata->c2p_lock_busid = i2c_common->bus_id;
	}

	static void amd_mp2_c2p_mutex_unlock(struct amd_i2c_common *i2c_common)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

	if (unlikely(privdata->c2p_lock_busid != i2c_common->bus_id)) {
	pci_warn(privdata->pci_dev,
	"bus %d attempting to unlock C2P locked by bus %d\n",
	i2c_common->bus_id, privdata->c2p_lock_busid);
	return;
	}

	mutex_unlock(&privdata->c2p_lock);
	}

	static int amd_mp2_cmd(struct amd_i2c_common *i2c_common,
	union i2c_cmd_base i2c_cmd_base)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	void __iomem *reg;

	i2c_common->reqcmd = i2c_cmd_base.s.i2c_cmd;

	reg = privdata->mmio + ((i2c_cmd_base.s.bus_id == 1) ?
	AMD_C2P_MSG1 : AMD_C2P_MSG0);
	writel(i2c_cmd_base.ul, reg);

	return 0;
	}

	int amd_mp2_bus_enable_set(struct amd_i2c_common *i2c_common, bool enable)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	union i2c_cmd_base i2c_cmd_base;

	pci_dbg(privdata->pci_dev, "id: %d\n", i2c_common->bus_id);

	i2c_cmd_base.ul = 0;
	i2c_cmd_base.s.i2c_cmd = enable ? i2c_enable : i2c_disable;
	i2c_cmd_base.s.bus_id = i2c_common->bus_id;
	i2c_cmd_base.s.i2c_speed = i2c_common->i2c_speed;

	amd_mp2_c2p_mutex_lock(i2c_common);

	return amd_mp2_cmd(i2c_common, i2c_cmd_base);
	}
	EXPORT_SYMBOL_GPL(amd_mp2_bus_enable_set);

	static void amd_mp2_cmd_rw_fill(struct amd_i2c_common *i2c_common,
	union i2c_cmd_base *i2c_cmd_base,
	enum i2c_cmd reqcmd)
	{
	i2c_cmd_base->s.i2c_cmd = reqcmd;
	i2c_cmd_base->s.bus_id = i2c_common->bus_id;
	i2c_cmd_base->s.i2c_speed = i2c_common->i2c_speed;
	i2c_cmd_base->s.slave_addr = i2c_common->msg->addr;
	i2c_cmd_base->s.length = i2c_common->msg->len;
	}

	int amd_mp2_rw(struct amd_i2c_common *i2c_common, enum i2c_cmd reqcmd)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	union i2c_cmd_base i2c_cmd_base;

	amd_mp2_cmd_rw_fill(i2c_common, &i2c_cmd_base, reqcmd);
	amd_mp2_c2p_mutex_lock(i2c_common);

	if (i2c_common->msg->len <= 32) {
	i2c_cmd_base.s.mem_type = use_c2pmsg;
	if (reqcmd == i2c_write)
	memcpy_toio(privdata->mmio + AMD_C2P_MSG2,
	i2c_common->msg->buf,
	i2c_common->msg->len);
	} else {
	i2c_cmd_base.s.mem_type = use_dram;
	writeq((u64)i2c_common->dma_addr,
	privdata->mmio + AMD_C2P_MSG2);
	}

	return amd_mp2_cmd(i2c_common, i2c_cmd_base);
	}
	EXPORT_SYMBOL_GPL(amd_mp2_rw);

	static void amd_mp2_pci_check_rw_event(struct amd_i2c_common *i2c_common)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	struct pci_dev *pdev = privdata->pci_dev;
	int len = i2c_common->eventval.r.length;
	u32 slave_addr = i2c_common->eventval.r.slave_addr;
	bool err = false;

	if (unlikely(len != i2c_common->msg->len)) {
	pci_err(pdev, "length %d in event doesn't match buffer length %d!\n",
	len, i2c_common->msg->len);
	err = true;
	}

	if (unlikely(slave_addr != i2c_common->msg->addr)) {
	pci_err(pdev, "unexpected slave address %x (expected: %x)!\n",
	slave_addr, i2c_common->msg->addr);
	err = true;
	}

	if (!err)
	i2c_common->cmd_success = true;
	}

	static void __amd_mp2_process_event(struct amd_i2c_common *i2c_common)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	struct pci_dev *pdev = privdata->pci_dev;
	enum status_type sts = i2c_common->eventval.r.status;
	enum response_type res = i2c_common->eventval.r.response;
	int len = i2c_common->eventval.r.length;

	if (res != command_success) {
	if (res != command_failed)
	pci_err(pdev, "invalid response to i2c command!\n");
	return;
	}

	switch (i2c_common->reqcmd) {
	case i2c_read:
	if (sts == i2c_readcomplete_event) {
	amd_mp2_pci_check_rw_event(i2c_common);
	if (len <= 32)
	memcpy_fromio(i2c_common->msg->buf,
	privdata->mmio + AMD_C2P_MSG2,
	len);
	} else if (sts != i2c_readfail_event) {
	pci_err(pdev, "invalid i2c status after read (%d)!\n", sts);
	}
	break;
	case i2c_write:
	if (sts == i2c_writecomplete_event)
	amd_mp2_pci_check_rw_event(i2c_common);
	else if (sts != i2c_writefail_event)
	pci_err(pdev, "invalid i2c status after write (%d)!\n", sts);
	break;
	case i2c_enable:
	if (sts == i2c_busenable_complete)
	i2c_common->cmd_success = true;
	else if (sts != i2c_busenable_failed)
	pci_err(pdev, "invalid i2c status after bus enable (%d)!\n", sts);
	break;
	case i2c_disable:
	if (sts == i2c_busdisable_complete)
	i2c_common->cmd_success = true;
	else if (sts != i2c_busdisable_failed)
	pci_err(pdev, "invalid i2c status after bus disable (%d)!\n", sts);
	break;
	default:
	break;
	}
	}

	void amd_mp2_process_event(struct amd_i2c_common *i2c_common)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	struct pci_dev *pdev = privdata->pci_dev;

	if (unlikely(i2c_common->reqcmd == i2c_none)) {
	pci_warn(pdev, "received msg but no cmd was sent (bus = %d)!\n",
	i2c_common->bus_id);
	return;
	}

	__amd_mp2_process_event(i2c_common);

	i2c_common->reqcmd = i2c_none;
	amd_mp2_c2p_mutex_unlock(i2c_common);
	}
	EXPORT_SYMBOL_GPL(amd_mp2_process_event);

	static irqreturn_t amd_mp2_irq_isr(int irq, void *dev)
	{
	struct amd_mp2_dev *privdata = dev;
	struct pci_dev *pdev = privdata->pci_dev;
	struct amd_i2c_common *i2c_common;
	u32 val;
	unsigned int bus_id;
	void __iomem *reg;
	enum irqreturn ret = IRQ_NONE;

	for (bus_id = 0; bus_id < 2; bus_id++) {
	i2c_common = privdata->busses[bus_id];
	if (!i2c_common)
	continue;

	reg = privdata->mmio + ((bus_id == 0) ?
	AMD_P2C_MSG1 : AMD_P2C_MSG2);
	val = readl(reg);
	if (val != 0) {
	writel(0, reg);
	writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
	i2c_common->eventval.ul = val;
	i2c_common->cmd_completion(i2c_common);

	ret = IRQ_HANDLED;
	}
	}

	if (ret != IRQ_HANDLED) {
	val = readl(privdata->mmio + AMD_P2C_MSG_INTEN);
	if (val != 0) {
	writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
	pci_warn(pdev, "received irq without message\n");
	ret = IRQ_HANDLED;
	}
	}

	return ret;
	}

	void amd_mp2_rw_timeout(struct amd_i2c_common *i2c_common)
	{
	i2c_common->reqcmd = i2c_none;
	amd_mp2_c2p_mutex_unlock(i2c_common);
	}
	EXPORT_SYMBOL_GPL(amd_mp2_rw_timeout);

	int amd_mp2_register_cb(struct amd_i2c_common *i2c_common)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	struct pci_dev *pdev = privdata->pci_dev;

	if (i2c_common->bus_id > 1)
	return -EINVAL;

	if (privdata->busses[i2c_common->bus_id]) {
	pci_err(pdev, "Bus %d already taken!\n", i2c_common->bus_id);
	return -EINVAL;
	}

	privdata->busses[i2c_common->bus_id] = i2c_common;

	return 0;
	}
	EXPORT_SYMBOL_GPL(amd_mp2_register_cb);

	int amd_mp2_unregister_cb(struct amd_i2c_common *i2c_common)
	{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

	privdata->busses[i2c_common->bus_id] = NULL;

	return 0;
	}
	EXPORT_SYMBOL_GPL(amd_mp2_unregister_cb);

	static void amd_mp2_clear_reg(struct amd_mp2_dev *privdata)
	{
	int reg;

	for (reg = AMD_C2P_MSG0; reg <= AMD_C2P_MSG9; reg += 4)
	writel(0, privdata->mmio + reg);

	for (reg = AMD_P2C_MSG1; reg <= AMD_P2C_MSG2; reg += 4)
	writel(0, privdata->mmio + reg);
	}

	static int amd_mp2_pci_init(struct amd_mp2_dev *privdata,
	struct pci_dev *pci_dev)
	{
	int rc;

	pci_set_drvdata(pci_dev, privdata);

	rc = pcim_enable_device(pci_dev);
	if (rc) {
	pci_err(pci_dev, "Failed to enable MP2 PCI device\n");
	goto err_pci_enable;
	}

	rc = pcim_iomap_regions(pci_dev, 1 << 2, pci_name(pci_dev));
	if (rc) {
	pci_err(pci_dev, "I/O memory remapping failed\n");
	goto err_pci_enable;
	}
	privdata->mmio = pcim_iomap_table(pci_dev)[2];

	pci_set_master(pci_dev);

	rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
	if (rc)
	goto err_dma_mask;

	/* Set up intx irq */
	writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
	pci_intx(pci_dev, 1);
	rc = devm_request_irq(&pci_dev->dev, pci_dev->irq, amd_mp2_irq_isr,
	IRQF_SHARED, dev_name(&pci_dev->dev), privdata);
	if (rc)
	pci_err(pci_dev, "Failure requesting irq %i: %d\n",
	pci_dev->irq, rc);

	return rc;

	err_dma_mask:
	pci_clear_master(pci_dev);
	err_pci_enable:
	pci_set_drvdata(pci_dev, NULL);
	return rc;
	}

	static int amd_mp2_pci_probe(struct pci_dev *pci_dev,
	const struct pci_device_id *id)
	{
	struct amd_mp2_dev *privdata;
	int rc;

	privdata = devm_kzalloc(&pci_dev->dev, sizeof(*privdata), GFP_KERNEL);
	if (!privdata)
	return -ENOMEM;

	privdata->pci_dev = pci_dev;
	rc = amd_mp2_pci_init(privdata, pci_dev);
	if (rc)
	return rc;

	mutex_init(&privdata->c2p_lock);

	pm_runtime_set_autosuspend_delay(&pci_dev->dev, 1000);
	pm_runtime_use_autosuspend(&pci_dev->dev);
	pm_runtime_put_autosuspend(&pci_dev->dev);
	pm_runtime_allow(&pci_dev->dev);

	privdata->probed = true;

	pci_info(pci_dev, "MP2 device registered.\n");
	return 0;
	}

	static void amd_mp2_pci_remove(struct pci_dev *pci_dev)
	{
	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);

	pm_runtime_forbid(&pci_dev->dev);
	pm_runtime_get_noresume(&pci_dev->dev);

	pci_intx(pci_dev, 0);
	pci_clear_master(pci_dev);

	amd_mp2_clear_reg(privdata);
	}

	#ifdef CONFIG_PM
	static int amd_mp2_pci_suspend(struct device *dev)
	{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
	struct amd_i2c_common *i2c_common;
	unsigned int bus_id;
	int ret = 0;

	for (bus_id = 0; bus_id < 2; bus_id++) {
	i2c_common = privdata->busses[bus_id];
	if (i2c_common)
	i2c_common->suspend(i2c_common);
	}

	ret = pci_save_state(pci_dev);
	if (ret) {
	pci_err(pci_dev, "pci_save_state failed = %d\n", ret);
	return ret;
	}

	pci_disable_device(pci_dev);
	return ret;
	}

	static int amd_mp2_pci_resume(struct device *dev)
	{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
	struct amd_i2c_common *i2c_common;
	unsigned int bus_id;
	int ret = 0;

	pci_restore_state(pci_dev);
	ret = pci_enable_device(pci_dev);
	if (ret < 0) {
	pci_err(pci_dev, "pci_enable_device failed = %d\n", ret);
	return ret;
	}

	for (bus_id = 0; bus_id < 2; bus_id++) {
	i2c_common = privdata->busses[bus_id];
	if (i2c_common) {
	ret = i2c_common->resume(i2c_common);
	if (ret < 0)
	return ret;
	}
	}

	return ret;
	}

	static UNIVERSAL_DEV_PM_OPS(amd_mp2_pci_pm_ops, amd_mp2_pci_suspend,
	amd_mp2_pci_resume, NULL);
	#endif /* CONFIG_PM */

	static const struct pci_device_id amd_mp2_pci_tbl[] = {
	{PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_MP2)},
	{0}
	};
	MODULE_DEVICE_TABLE(pci, amd_mp2_pci_tbl);

	static struct pci_driver amd_mp2_pci_driver = {
	.name = "i2c_amd_mp2",
	.id_table = amd_mp2_pci_tbl,
	.probe = amd_mp2_pci_probe,
	.remove = amd_mp2_pci_remove,
	#ifdef CONFIG_PM
	.driver = {
	.pm = &amd_mp2_pci_pm_ops,
	},
	#endif
	};
	module_pci_driver(amd_mp2_pci_driver);

	struct amd_mp2_dev *amd_mp2_find_device(void)
	{
	struct device *dev;
	struct pci_dev *pci_dev;

	dev = driver_find_next_device(&amd_mp2_pci_driver.driver, NULL);
	if (!dev)
	return NULL;

	pci_dev = to_pci_dev(dev);
	return (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
	}
	EXPORT_SYMBOL_GPL(amd_mp2_find_device);

	MODULE_DESCRIPTION("AMD(R) PCI-E MP2 I2C Controller Driver");
	MODULE_AUTHOR("Shyam Sundar S K <Shyam-sundar.S-k@amd.com>");
	MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
	MODULE_LICENSE("Dual BSD/GPL");