cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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i2c-amd-mp2-pci.c (11785B)


      1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
      2/*
      3 * AMD MP2 PCIe communication driver
      4 *
      5 * Authors: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
      6 *          Elie Morisse <syniurge@gmail.com>
      7 */
      8
      9#include <linux/dma-mapping.h>
     10#include <linux/interrupt.h>
     11#include <linux/module.h>
     12#include <linux/pci.h>
     13#include <linux/slab.h>
     14
     15#include "i2c-amd-mp2.h"
     16
     17#include <linux/io-64-nonatomic-lo-hi.h>
     18
     19static void amd_mp2_c2p_mutex_lock(struct amd_i2c_common *i2c_common)
     20{
     21	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
     22
     23	/* there is only one data mailbox for two i2c adapters */
     24	mutex_lock(&privdata->c2p_lock);
     25	privdata->c2p_lock_busid = i2c_common->bus_id;
     26}
     27
     28static void amd_mp2_c2p_mutex_unlock(struct amd_i2c_common *i2c_common)
     29{
     30	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
     31
     32	if (unlikely(privdata->c2p_lock_busid != i2c_common->bus_id)) {
     33		pci_warn(privdata->pci_dev,
     34			 "bus %d attempting to unlock C2P locked by bus %d\n",
     35			 i2c_common->bus_id, privdata->c2p_lock_busid);
     36		return;
     37	}
     38
     39	mutex_unlock(&privdata->c2p_lock);
     40}
     41
     42static int amd_mp2_cmd(struct amd_i2c_common *i2c_common,
     43		       union i2c_cmd_base i2c_cmd_base)
     44{
     45	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
     46	void __iomem *reg;
     47
     48	i2c_common->reqcmd = i2c_cmd_base.s.i2c_cmd;
     49
     50	reg = privdata->mmio + ((i2c_cmd_base.s.bus_id == 1) ?
     51				AMD_C2P_MSG1 : AMD_C2P_MSG0);
     52	writel(i2c_cmd_base.ul, reg);
     53
     54	return 0;
     55}
     56
     57int amd_mp2_bus_enable_set(struct amd_i2c_common *i2c_common, bool enable)
     58{
     59	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
     60	union i2c_cmd_base i2c_cmd_base;
     61
     62	pci_dbg(privdata->pci_dev, "id: %d\n", i2c_common->bus_id);
     63
     64	i2c_cmd_base.ul = 0;
     65	i2c_cmd_base.s.i2c_cmd = enable ? i2c_enable : i2c_disable;
     66	i2c_cmd_base.s.bus_id = i2c_common->bus_id;
     67	i2c_cmd_base.s.i2c_speed = i2c_common->i2c_speed;
     68
     69	amd_mp2_c2p_mutex_lock(i2c_common);
     70
     71	return amd_mp2_cmd(i2c_common, i2c_cmd_base);
     72}
     73EXPORT_SYMBOL_GPL(amd_mp2_bus_enable_set);
     74
     75static void amd_mp2_cmd_rw_fill(struct amd_i2c_common *i2c_common,
     76				union i2c_cmd_base *i2c_cmd_base,
     77				enum i2c_cmd reqcmd)
     78{
     79	i2c_cmd_base->s.i2c_cmd = reqcmd;
     80	i2c_cmd_base->s.bus_id = i2c_common->bus_id;
     81	i2c_cmd_base->s.i2c_speed = i2c_common->i2c_speed;
     82	i2c_cmd_base->s.slave_addr = i2c_common->msg->addr;
     83	i2c_cmd_base->s.length = i2c_common->msg->len;
     84}
     85
     86int amd_mp2_rw(struct amd_i2c_common *i2c_common, enum i2c_cmd reqcmd)
     87{
     88	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
     89	union i2c_cmd_base i2c_cmd_base;
     90
     91	amd_mp2_cmd_rw_fill(i2c_common, &i2c_cmd_base, reqcmd);
     92	amd_mp2_c2p_mutex_lock(i2c_common);
     93
     94	if (i2c_common->msg->len <= 32) {
     95		i2c_cmd_base.s.mem_type = use_c2pmsg;
     96		if (reqcmd == i2c_write)
     97			memcpy_toio(privdata->mmio + AMD_C2P_MSG2,
     98				    i2c_common->msg->buf,
     99				    i2c_common->msg->len);
    100	} else {
    101		i2c_cmd_base.s.mem_type = use_dram;
    102		writeq((u64)i2c_common->dma_addr,
    103		       privdata->mmio + AMD_C2P_MSG2);
    104	}
    105
    106	return amd_mp2_cmd(i2c_common, i2c_cmd_base);
    107}
    108EXPORT_SYMBOL_GPL(amd_mp2_rw);
    109
    110static void amd_mp2_pci_check_rw_event(struct amd_i2c_common *i2c_common)
    111{
    112	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
    113	struct pci_dev *pdev = privdata->pci_dev;
    114	int len = i2c_common->eventval.r.length;
    115	u32 slave_addr = i2c_common->eventval.r.slave_addr;
    116	bool err = false;
    117
    118	if (unlikely(len != i2c_common->msg->len)) {
    119		pci_err(pdev, "length %d in event doesn't match buffer length %d!\n",
    120			len, i2c_common->msg->len);
    121		err = true;
    122	}
    123
    124	if (unlikely(slave_addr != i2c_common->msg->addr)) {
    125		pci_err(pdev, "unexpected slave address %x (expected: %x)!\n",
    126			slave_addr, i2c_common->msg->addr);
    127		err = true;
    128	}
    129
    130	if (!err)
    131		i2c_common->cmd_success = true;
    132}
    133
    134static void __amd_mp2_process_event(struct amd_i2c_common *i2c_common)
    135{
    136	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
    137	struct pci_dev *pdev = privdata->pci_dev;
    138	enum status_type sts = i2c_common->eventval.r.status;
    139	enum response_type res = i2c_common->eventval.r.response;
    140	int len = i2c_common->eventval.r.length;
    141
    142	if (res != command_success) {
    143		if (res != command_failed)
    144			pci_err(pdev, "invalid response to i2c command!\n");
    145		return;
    146	}
    147
    148	switch (i2c_common->reqcmd) {
    149	case i2c_read:
    150		if (sts == i2c_readcomplete_event) {
    151			amd_mp2_pci_check_rw_event(i2c_common);
    152			if (len <= 32)
    153				memcpy_fromio(i2c_common->msg->buf,
    154					      privdata->mmio + AMD_C2P_MSG2,
    155					      len);
    156		} else if (sts != i2c_readfail_event) {
    157			pci_err(pdev, "invalid i2c status after read (%d)!\n", sts);
    158		}
    159		break;
    160	case i2c_write:
    161		if (sts == i2c_writecomplete_event)
    162			amd_mp2_pci_check_rw_event(i2c_common);
    163		else if (sts != i2c_writefail_event)
    164			pci_err(pdev, "invalid i2c status after write (%d)!\n", sts);
    165		break;
    166	case i2c_enable:
    167		if (sts == i2c_busenable_complete)
    168			i2c_common->cmd_success = true;
    169		else if (sts != i2c_busenable_failed)
    170			pci_err(pdev, "invalid i2c status after bus enable (%d)!\n", sts);
    171		break;
    172	case i2c_disable:
    173		if (sts == i2c_busdisable_complete)
    174			i2c_common->cmd_success = true;
    175		else if (sts != i2c_busdisable_failed)
    176			pci_err(pdev, "invalid i2c status after bus disable (%d)!\n", sts);
    177		break;
    178	default:
    179		break;
    180	}
    181}
    182
    183void amd_mp2_process_event(struct amd_i2c_common *i2c_common)
    184{
    185	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
    186	struct pci_dev *pdev = privdata->pci_dev;
    187
    188	if (unlikely(i2c_common->reqcmd == i2c_none)) {
    189		pci_warn(pdev, "received msg but no cmd was sent (bus = %d)!\n",
    190			 i2c_common->bus_id);
    191		return;
    192	}
    193
    194	__amd_mp2_process_event(i2c_common);
    195
    196	i2c_common->reqcmd = i2c_none;
    197	amd_mp2_c2p_mutex_unlock(i2c_common);
    198}
    199EXPORT_SYMBOL_GPL(amd_mp2_process_event);
    200
    201static irqreturn_t amd_mp2_irq_isr(int irq, void *dev)
    202{
    203	struct amd_mp2_dev *privdata = dev;
    204	struct pci_dev *pdev = privdata->pci_dev;
    205	struct amd_i2c_common *i2c_common;
    206	u32 val;
    207	unsigned int bus_id;
    208	void __iomem *reg;
    209	enum irqreturn ret = IRQ_NONE;
    210
    211	for (bus_id = 0; bus_id < 2; bus_id++) {
    212		i2c_common = privdata->busses[bus_id];
    213		if (!i2c_common)
    214			continue;
    215
    216		reg = privdata->mmio + ((bus_id == 0) ?
    217					AMD_P2C_MSG1 : AMD_P2C_MSG2);
    218		val = readl(reg);
    219		if (val != 0) {
    220			writel(0, reg);
    221			writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
    222			i2c_common->eventval.ul = val;
    223			i2c_common->cmd_completion(i2c_common);
    224
    225			ret = IRQ_HANDLED;
    226		}
    227	}
    228
    229	if (ret != IRQ_HANDLED) {
    230		val = readl(privdata->mmio + AMD_P2C_MSG_INTEN);
    231		if (val != 0) {
    232			writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
    233			pci_warn(pdev, "received irq without message\n");
    234			ret = IRQ_HANDLED;
    235		}
    236	}
    237
    238	return ret;
    239}
    240
    241void amd_mp2_rw_timeout(struct amd_i2c_common *i2c_common)
    242{
    243	i2c_common->reqcmd = i2c_none;
    244	amd_mp2_c2p_mutex_unlock(i2c_common);
    245}
    246EXPORT_SYMBOL_GPL(amd_mp2_rw_timeout);
    247
    248int amd_mp2_register_cb(struct amd_i2c_common *i2c_common)
    249{
    250	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
    251	struct pci_dev *pdev = privdata->pci_dev;
    252
    253	if (i2c_common->bus_id > 1)
    254		return -EINVAL;
    255
    256	if (privdata->busses[i2c_common->bus_id]) {
    257		pci_err(pdev, "Bus %d already taken!\n", i2c_common->bus_id);
    258		return -EINVAL;
    259	}
    260
    261	privdata->busses[i2c_common->bus_id] = i2c_common;
    262
    263	return 0;
    264}
    265EXPORT_SYMBOL_GPL(amd_mp2_register_cb);
    266
    267int amd_mp2_unregister_cb(struct amd_i2c_common *i2c_common)
    268{
    269	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
    270
    271	privdata->busses[i2c_common->bus_id] = NULL;
    272
    273	return 0;
    274}
    275EXPORT_SYMBOL_GPL(amd_mp2_unregister_cb);
    276
    277static void amd_mp2_clear_reg(struct amd_mp2_dev *privdata)
    278{
    279	int reg;
    280
    281	for (reg = AMD_C2P_MSG0; reg <= AMD_C2P_MSG9; reg += 4)
    282		writel(0, privdata->mmio + reg);
    283
    284	for (reg = AMD_P2C_MSG1; reg <= AMD_P2C_MSG2; reg += 4)
    285		writel(0, privdata->mmio + reg);
    286}
    287
    288static int amd_mp2_pci_init(struct amd_mp2_dev *privdata,
    289			    struct pci_dev *pci_dev)
    290{
    291	int rc;
    292
    293	pci_set_drvdata(pci_dev, privdata);
    294
    295	rc = pcim_enable_device(pci_dev);
    296	if (rc) {
    297		pci_err(pci_dev, "Failed to enable MP2 PCI device\n");
    298		goto err_pci_enable;
    299	}
    300
    301	rc = pcim_iomap_regions(pci_dev, 1 << 2, pci_name(pci_dev));
    302	if (rc) {
    303		pci_err(pci_dev, "I/O memory remapping failed\n");
    304		goto err_pci_enable;
    305	}
    306	privdata->mmio = pcim_iomap_table(pci_dev)[2];
    307
    308	pci_set_master(pci_dev);
    309
    310	rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
    311	if (rc)
    312		goto err_dma_mask;
    313
    314	/* Set up intx irq */
    315	writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
    316	pci_intx(pci_dev, 1);
    317	rc = devm_request_irq(&pci_dev->dev, pci_dev->irq, amd_mp2_irq_isr,
    318			      IRQF_SHARED, dev_name(&pci_dev->dev), privdata);
    319	if (rc)
    320		pci_err(pci_dev, "Failure requesting irq %i: %d\n",
    321			pci_dev->irq, rc);
    322
    323	return rc;
    324
    325err_dma_mask:
    326	pci_clear_master(pci_dev);
    327err_pci_enable:
    328	pci_set_drvdata(pci_dev, NULL);
    329	return rc;
    330}
    331
    332static int amd_mp2_pci_probe(struct pci_dev *pci_dev,
    333			     const struct pci_device_id *id)
    334{
    335	struct amd_mp2_dev *privdata;
    336	int rc;
    337
    338	privdata = devm_kzalloc(&pci_dev->dev, sizeof(*privdata), GFP_KERNEL);
    339	if (!privdata)
    340		return -ENOMEM;
    341
    342	privdata->pci_dev = pci_dev;
    343	rc = amd_mp2_pci_init(privdata, pci_dev);
    344	if (rc)
    345		return rc;
    346
    347	mutex_init(&privdata->c2p_lock);
    348
    349	pm_runtime_set_autosuspend_delay(&pci_dev->dev, 1000);
    350	pm_runtime_use_autosuspend(&pci_dev->dev);
    351	pm_runtime_put_autosuspend(&pci_dev->dev);
    352	pm_runtime_allow(&pci_dev->dev);
    353
    354	privdata->probed = true;
    355
    356	pci_info(pci_dev, "MP2 device registered.\n");
    357	return 0;
    358}
    359
    360static void amd_mp2_pci_remove(struct pci_dev *pci_dev)
    361{
    362	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
    363
    364	pm_runtime_forbid(&pci_dev->dev);
    365	pm_runtime_get_noresume(&pci_dev->dev);
    366
    367	pci_intx(pci_dev, 0);
    368	pci_clear_master(pci_dev);
    369
    370	amd_mp2_clear_reg(privdata);
    371}
    372
    373#ifdef CONFIG_PM
    374static int amd_mp2_pci_suspend(struct device *dev)
    375{
    376	struct pci_dev *pci_dev = to_pci_dev(dev);
    377	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
    378	struct amd_i2c_common *i2c_common;
    379	unsigned int bus_id;
    380	int ret = 0;
    381
    382	for (bus_id = 0; bus_id < 2; bus_id++) {
    383		i2c_common = privdata->busses[bus_id];
    384		if (i2c_common)
    385			i2c_common->suspend(i2c_common);
    386	}
    387
    388	ret = pci_save_state(pci_dev);
    389	if (ret) {
    390		pci_err(pci_dev, "pci_save_state failed = %d\n", ret);
    391		return ret;
    392	}
    393
    394	pci_disable_device(pci_dev);
    395	return ret;
    396}
    397
    398static int amd_mp2_pci_resume(struct device *dev)
    399{
    400	struct pci_dev *pci_dev = to_pci_dev(dev);
    401	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
    402	struct amd_i2c_common *i2c_common;
    403	unsigned int bus_id;
    404	int ret = 0;
    405
    406	pci_restore_state(pci_dev);
    407	ret = pci_enable_device(pci_dev);
    408	if (ret < 0) {
    409		pci_err(pci_dev, "pci_enable_device failed = %d\n", ret);
    410		return ret;
    411	}
    412
    413	for (bus_id = 0; bus_id < 2; bus_id++) {
    414		i2c_common = privdata->busses[bus_id];
    415		if (i2c_common) {
    416			ret = i2c_common->resume(i2c_common);
    417			if (ret < 0)
    418				return ret;
    419		}
    420	}
    421
    422	return ret;
    423}
    424
    425static UNIVERSAL_DEV_PM_OPS(amd_mp2_pci_pm_ops, amd_mp2_pci_suspend,
    426			    amd_mp2_pci_resume, NULL);
    427#endif /* CONFIG_PM */
    428
    429static const struct pci_device_id amd_mp2_pci_tbl[] = {
    430	{PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_MP2)},
    431	{0}
    432};
    433MODULE_DEVICE_TABLE(pci, amd_mp2_pci_tbl);
    434
    435static struct pci_driver amd_mp2_pci_driver = {
    436	.name		= "i2c_amd_mp2",
    437	.id_table	= amd_mp2_pci_tbl,
    438	.probe		= amd_mp2_pci_probe,
    439	.remove		= amd_mp2_pci_remove,
    440#ifdef CONFIG_PM
    441	.driver = {
    442		.pm	= &amd_mp2_pci_pm_ops,
    443	},
    444#endif
    445};
    446module_pci_driver(amd_mp2_pci_driver);
    447
    448struct amd_mp2_dev *amd_mp2_find_device(void)
    449{
    450	struct device *dev;
    451	struct pci_dev *pci_dev;
    452
    453	dev = driver_find_next_device(&amd_mp2_pci_driver.driver, NULL);
    454	if (!dev)
    455		return NULL;
    456
    457	pci_dev = to_pci_dev(dev);
    458	return (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
    459}
    460EXPORT_SYMBOL_GPL(amd_mp2_find_device);
    461
    462MODULE_DESCRIPTION("AMD(R) PCI-E MP2 I2C Controller Driver");
    463MODULE_AUTHOR("Shyam Sundar S K <Shyam-sundar.S-k@amd.com>");
    464MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
    465MODULE_LICENSE("Dual BSD/GPL");