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-tegra-bpmp.c (8643B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * drivers/i2c/busses/i2c-tegra-bpmp.c
      4 *
      5 * Copyright (c) 2016 NVIDIA Corporation.  All rights reserved.
      6 *
      7 * Author: Shardar Shariff Md <smohammed@nvidia.com>
      8 */
      9
     10#include <linux/err.h>
     11#include <linux/i2c.h>
     12#include <linux/init.h>
     13#include <linux/kernel.h>
     14#include <linux/module.h>
     15#include <linux/of_device.h>
     16#include <linux/platform_device.h>
     17#include <linux/pm_runtime.h>
     18
     19#include <soc/tegra/bpmp-abi.h>
     20#include <soc/tegra/bpmp.h>
     21
     22/*
     23 * Serialized I2C message header size is 6 bytes and includes address, flags
     24 * and length
     25 */
     26#define SERIALI2C_HDR_SIZE 6
     27
     28struct tegra_bpmp_i2c {
     29	struct i2c_adapter adapter;
     30	struct device *dev;
     31
     32	struct tegra_bpmp *bpmp;
     33	unsigned int bus;
     34};
     35
     36/*
     37 * Linux flags are translated to BPMP defined I2C flags that are used in BPMP
     38 * firmware I2C driver to avoid any issues in future if Linux I2C flags are
     39 * changed.
     40 */
     41static void tegra_bpmp_xlate_flags(u16 flags, u16 *out)
     42{
     43	if (flags & I2C_M_TEN)
     44		*out |= SERIALI2C_TEN;
     45
     46	if (flags & I2C_M_RD)
     47		*out |= SERIALI2C_RD;
     48
     49	if (flags & I2C_M_STOP)
     50		*out |= SERIALI2C_STOP;
     51
     52	if (flags & I2C_M_NOSTART)
     53		*out |= SERIALI2C_NOSTART;
     54
     55	if (flags & I2C_M_REV_DIR_ADDR)
     56		*out |= SERIALI2C_REV_DIR_ADDR;
     57
     58	if (flags & I2C_M_IGNORE_NAK)
     59		*out |= SERIALI2C_IGNORE_NAK;
     60
     61	if (flags & I2C_M_NO_RD_ACK)
     62		*out |= SERIALI2C_NO_RD_ACK;
     63
     64	if (flags & I2C_M_RECV_LEN)
     65		*out |= SERIALI2C_RECV_LEN;
     66}
     67
     68/*
     69 * The serialized I2C format is simply the following:
     70 * [addr little-endian][flags little-endian][len little-endian][data if write]
     71 * [addr little-endian][flags little-endian][len little-endian][data if write]
     72 *  ...
     73 *
     74 * The flags are translated from Linux kernel representation to seriali2c
     75 * representation. Any undefined flag being set causes an error.
     76 *
     77 * The data is there only for writes. Reads have the data transferred in the
     78 * other direction, and thus data is not present.
     79 *
     80 * See deserialize_i2c documentation for the data format in the other direction.
     81 */
     82static void tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c,
     83					struct mrq_i2c_request *request,
     84					struct i2c_msg *msgs,
     85					unsigned int num)
     86{
     87	char *buf = request->xfer.data_buf;
     88	unsigned int i, j, pos = 0;
     89
     90	for (i = 0; i < num; i++) {
     91		struct i2c_msg *msg = &msgs[i];
     92		u16 flags = 0;
     93
     94		tegra_bpmp_xlate_flags(msg->flags, &flags);
     95
     96		buf[pos++] = msg->addr & 0xff;
     97		buf[pos++] = (msg->addr & 0xff00) >> 8;
     98		buf[pos++] = flags & 0xff;
     99		buf[pos++] = (flags & 0xff00) >> 8;
    100		buf[pos++] = msg->len & 0xff;
    101		buf[pos++] = (msg->len & 0xff00) >> 8;
    102
    103		if ((flags & SERIALI2C_RD) == 0) {
    104			for (j = 0; j < msg->len; j++)
    105				buf[pos++] = msg->buf[j];
    106		}
    107	}
    108
    109	request->xfer.data_size = pos;
    110}
    111
    112/*
    113 * The data in the BPMP -> CPU direction is composed of sequential blocks for
    114 * those messages that have I2C_M_RD. So, for example, if you have:
    115 *
    116 * - !I2C_M_RD, len == 5, data == a0 01 02 03 04
    117 * - !I2C_M_RD, len == 1, data == a0
    118 * - I2C_M_RD, len == 2, data == [uninitialized buffer 1]
    119 * - !I2C_M_RD, len == 1, data == a2
    120 * - I2C_M_RD, len == 2, data == [uninitialized buffer 2]
    121 *
    122 * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and
    123 * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes
    124 * that will go to uninitialized buffer 2.
    125 */
    126static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c,
    127				      struct mrq_i2c_response *response,
    128				      struct i2c_msg *msgs,
    129				      unsigned int num)
    130{
    131	size_t size = response->xfer.data_size, len = 0, pos = 0;
    132	char *buf = response->xfer.data_buf;
    133	unsigned int i;
    134
    135	for (i = 0; i < num; i++)
    136		if (msgs[i].flags & I2C_M_RD)
    137			len += msgs[i].len;
    138
    139	if (len != size)
    140		return -EINVAL;
    141
    142	for (i = 0; i < num; i++) {
    143		if (msgs[i].flags & I2C_M_RD) {
    144			memcpy(msgs[i].buf, buf + pos, msgs[i].len);
    145			pos += msgs[i].len;
    146		}
    147	}
    148
    149	return 0;
    150}
    151
    152static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num)
    153{
    154	size_t tx_len = 0, rx_len = 0;
    155	unsigned int i;
    156
    157	for (i = 0; i < num; i++)
    158		if (!(msgs[i].flags & I2C_M_RD))
    159			tx_len += SERIALI2C_HDR_SIZE + msgs[i].len;
    160
    161	if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE)
    162		return -EINVAL;
    163
    164	for (i = 0; i < num; i++)
    165		if ((msgs[i].flags & I2C_M_RD))
    166			rx_len += msgs[i].len;
    167
    168	if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE)
    169		return -EINVAL;
    170
    171	return 0;
    172}
    173
    174static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c,
    175				   struct mrq_i2c_request *request,
    176				   struct mrq_i2c_response *response,
    177				   bool atomic)
    178{
    179	struct tegra_bpmp_message msg;
    180	int err;
    181
    182	request->cmd = CMD_I2C_XFER;
    183	request->xfer.bus_id = i2c->bus;
    184
    185	memset(&msg, 0, sizeof(msg));
    186	msg.mrq = MRQ_I2C;
    187	msg.tx.data = request;
    188	msg.tx.size = sizeof(*request);
    189	msg.rx.data = response;
    190	msg.rx.size = sizeof(*response);
    191
    192	if (atomic)
    193		err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg);
    194	else
    195		err = tegra_bpmp_transfer(i2c->bpmp, &msg);
    196
    197	if (err < 0) {
    198		dev_err(i2c->dev, "failed to transfer message: %d\n", err);
    199		return err;
    200	}
    201
    202	if (msg.rx.ret != 0) {
    203		if (msg.rx.ret == -BPMP_EAGAIN) {
    204			dev_dbg(i2c->dev, "arbitration lost\n");
    205			return -EAGAIN;
    206		}
    207
    208		if (msg.rx.ret == -BPMP_ETIMEDOUT) {
    209			dev_dbg(i2c->dev, "timeout\n");
    210			return -ETIMEDOUT;
    211		}
    212
    213		if (msg.rx.ret == -BPMP_ENXIO) {
    214			dev_dbg(i2c->dev, "NAK\n");
    215			return -ENXIO;
    216		}
    217
    218		dev_err(i2c->dev, "transaction failed: %d\n", msg.rx.ret);
    219		return -EIO;
    220	}
    221
    222	return 0;
    223}
    224
    225static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter,
    226				      struct i2c_msg *msgs, int num,
    227				      bool atomic)
    228{
    229	struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter);
    230	struct mrq_i2c_response response;
    231	struct mrq_i2c_request request;
    232	int err;
    233
    234	err = tegra_bpmp_i2c_msg_len_check(msgs, num);
    235	if (err < 0) {
    236		dev_err(i2c->dev, "unsupported message length\n");
    237		return err;
    238	}
    239
    240	memset(&request, 0, sizeof(request));
    241	memset(&response, 0, sizeof(response));
    242
    243	tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num);
    244	err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response, atomic);
    245	if (err < 0) {
    246		dev_err(i2c->dev, "failed to transfer message: %d\n", err);
    247		return err;
    248	}
    249
    250	err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num);
    251	if (err < 0) {
    252		dev_err(i2c->dev, "failed to deserialize message: %d\n", err);
    253		return err;
    254	}
    255
    256	return num;
    257}
    258
    259static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter,
    260			       struct i2c_msg *msgs, int num)
    261{
    262	return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, false);
    263}
    264
    265static int tegra_bpmp_i2c_xfer_atomic(struct i2c_adapter *adapter,
    266				      struct i2c_msg *msgs, int num)
    267{
    268	return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, true);
    269}
    270
    271static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter)
    272{
    273	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
    274	       I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART;
    275}
    276
    277static const struct i2c_algorithm tegra_bpmp_i2c_algo = {
    278	.master_xfer = tegra_bpmp_i2c_xfer,
    279	.master_xfer_atomic = tegra_bpmp_i2c_xfer_atomic,
    280	.functionality = tegra_bpmp_i2c_func,
    281};
    282
    283static int tegra_bpmp_i2c_probe(struct platform_device *pdev)
    284{
    285	struct tegra_bpmp_i2c *i2c;
    286	u32 value;
    287	int err;
    288
    289	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
    290	if (!i2c)
    291		return -ENOMEM;
    292
    293	i2c->dev = &pdev->dev;
    294
    295	i2c->bpmp = dev_get_drvdata(pdev->dev.parent);
    296	if (!i2c->bpmp)
    297		return -ENODEV;
    298
    299	err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id",
    300				   &value);
    301	if (err < 0)
    302		return err;
    303
    304	i2c->bus = value;
    305
    306	i2c_set_adapdata(&i2c->adapter, i2c);
    307	i2c->adapter.owner = THIS_MODULE;
    308	strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter",
    309		sizeof(i2c->adapter.name));
    310	i2c->adapter.algo = &tegra_bpmp_i2c_algo;
    311	i2c->adapter.dev.parent = &pdev->dev;
    312	i2c->adapter.dev.of_node = pdev->dev.of_node;
    313
    314	platform_set_drvdata(pdev, i2c);
    315
    316	return i2c_add_adapter(&i2c->adapter);
    317}
    318
    319static int tegra_bpmp_i2c_remove(struct platform_device *pdev)
    320{
    321	struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev);
    322
    323	i2c_del_adapter(&i2c->adapter);
    324
    325	return 0;
    326}
    327
    328static const struct of_device_id tegra_bpmp_i2c_of_match[] = {
    329	{ .compatible = "nvidia,tegra186-bpmp-i2c", },
    330	{ }
    331};
    332MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match);
    333
    334static struct platform_driver tegra_bpmp_i2c_driver = {
    335	.driver = {
    336		.name = "tegra-bpmp-i2c",
    337		.of_match_table = tegra_bpmp_i2c_of_match,
    338	},
    339	.probe = tegra_bpmp_i2c_probe,
    340	.remove = tegra_bpmp_i2c_remove,
    341};
    342module_platform_driver(tegra_bpmp_i2c_driver);
    343
    344MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver");
    345MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>");
    346MODULE_AUTHOR("Juha-Matti Tilli");
    347MODULE_LICENSE("GPL v2");