linux/drivers/hwmon/socfpga-hwmon.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Altera SoC FPGA hardware monitoring driver
 *
 * Copyright (c) 2026 Altera Corporation
 *
 * Authors:
 *	Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>
 *	Tze Yee Ng <tze.yee.ng@altera.com>
 */

#include <linux/bitops.h>
#include <linux/cleanup.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/firmware/intel/stratix10-svc-client.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#define HWMON_TIMEOUT			msecs_to_jiffies(SVC_HWMON_REQUEST_TIMEOUT_MS)
#define HWMON_RETRY_SLEEP_US		1000U
#define HWMON_ASYNC_MSG_RETRY		3U
#define SOCFPGA_HWMON_MAXSENSORS	16
#define SOCFPGA_HWMON_CHANNEL_MASK	GENMASK(15, 0)
#define SOCFPGA_HWMON_PAGE_SHIFT	16
#define SOCFPGA_HWMON_CHAN(page, channel) \
	(((page) << SOCFPGA_HWMON_PAGE_SHIFT) | \
	 ((channel) & SOCFPGA_HWMON_CHANNEL_MASK))
#define SOCFPGA_HWMON_ATTR_VISIBLE	0444
/* Temperature from SDM is signed Q8.8 degrees Celsius (8 fractional bits). */
#define SOCFPGA_HWMON_TEMP_FRAC_BITS	8
#define SOCFPGA_HWMON_TEMP_FRAC_DIV	BIT(SOCFPGA_HWMON_TEMP_FRAC_BITS)
#define SOCFPGA_HWMON_TEMP_MDEG_SCALE	1000
/* Voltage from SDM is unsigned Q16 volts (16 fractional bits). */
#define SOCFPGA_HWMON_VOLT_FRAC_BITS	16
#define SOCFPGA_HWMON_VOLT_FRAC_DIV	BIT(SOCFPGA_HWMON_VOLT_FRAC_BITS)
#define SOCFPGA_HWMON_VOLT_MV_SCALE	1000

#define ETEMP_INACTIVE			0x80000000U
#define ETEMP_TOO_OLD			0x80000001U
#define ETEMP_NOT_PRESENT		0x80000002U
#define ETEMP_TIMEOUT			0x80000003U
#define ETEMP_CORRUPT			0x80000004U
#define ETEMP_BUSY			0x80000005U
#define ETEMP_NOT_INITIALIZED		0x800000FFU

struct socfpga_hwmon_channel {
	u32 reg;
	const char *label;
};

struct socfpga_hwmon_board_data {
	const struct socfpga_hwmon_channel *temp;
	unsigned int num_temp;
	const struct socfpga_hwmon_channel *volt;
	unsigned int num_volt;
};

struct socfpga_hwmon_priv {
	struct stratix10_svc_chan *chan;
	struct stratix10_svc_client client;
	struct completion completion;
	struct mutex lock;	/* protect SVC calls */
	bool async;
	int last_err;		/* sync-mode SVC result; 0 on success */
	u32 temperature;
	u32 voltage;
	int temperature_channels;
	int voltage_channels;
	const char *temp_chan_names[SOCFPGA_HWMON_MAXSENSORS];
	const char *volt_chan_names[SOCFPGA_HWMON_MAXSENSORS];
	u32 temp_chan[SOCFPGA_HWMON_MAXSENSORS];
	u32 volt_chan[SOCFPGA_HWMON_MAXSENSORS];
};

static umode_t socfpga_hwmon_is_visible(const void *dev,
					enum hwmon_sensor_types type,
					u32 attr, int chan)
{
	const struct socfpga_hwmon_priv *priv = dev;

	switch (type) {
	case hwmon_temp:
		if (chan < priv->temperature_channels)
			return SOCFPGA_HWMON_ATTR_VISIBLE;
		return 0;
	case hwmon_in:
		if (chan < priv->voltage_channels)
			return SOCFPGA_HWMON_ATTR_VISIBLE;
		return 0;
	default:
		return 0;
	}
}

static void socfpga_hwmon_readtemp_cb(struct stratix10_svc_client *client,
				      struct stratix10_svc_cb_data *data)
{
	struct socfpga_hwmon_priv *priv = client->priv;

	priv->last_err = -EIO;
	if (data->status == BIT(SVC_STATUS_OK)) {
		priv->last_err = 0;
		priv->temperature = (u32)*(unsigned long *)data->kaddr1;
	} else if (data->kaddr1) {
		dev_err(client->dev, "%s failed with status 0x%x, value 0x%lx\n",
			__func__, data->status,
			*(unsigned long *)data->kaddr1);
	} else {
		dev_err(client->dev, "%s failed with status 0x%x\n",
			__func__, data->status);
	}

	complete(&priv->completion);
}

static void socfpga_hwmon_readvolt_cb(struct stratix10_svc_client *client,
				      struct stratix10_svc_cb_data *data)
{
	struct socfpga_hwmon_priv *priv = client->priv;

	priv->last_err = -EIO;
	if (data->status == BIT(SVC_STATUS_OK)) {
		priv->last_err = 0;
		priv->voltage = (u32)*(unsigned long *)data->kaddr1;
	} else if (data->kaddr1) {
		dev_err(client->dev, "%s failed with status 0x%x, value 0x%lx\n",
			__func__, data->status,
			*(unsigned long *)data->kaddr1);
	} else {
		dev_err(client->dev, "%s failed with status 0x%x\n",
			__func__, data->status);
	}

	complete(&priv->completion);
}

static int socfpga_hwmon_parse_temp(long *val, u32 temperature)
{
	switch (temperature) {
	case ETEMP_INACTIVE:
	case ETEMP_NOT_PRESENT:
	case ETEMP_CORRUPT:
	case ETEMP_NOT_INITIALIZED:
		return -EOPNOTSUPP;
	case ETEMP_TIMEOUT:
	case ETEMP_BUSY:
	case ETEMP_TOO_OLD:
		return -EAGAIN;
	default:
		/* SDM returns a 16-bit signed Q8.8 value in the low 16 bits. */
		*val = (long)(s16)(temperature & SOCFPGA_HWMON_CHANNEL_MASK) *
			SOCFPGA_HWMON_TEMP_MDEG_SCALE / SOCFPGA_HWMON_TEMP_FRAC_DIV;
		return 0;
	}
}

static int socfpga_hwmon_encode_temp_arg(u32 reg, u64 *arg)
{
	u32 page = (reg >> SOCFPGA_HWMON_PAGE_SHIFT) & SOCFPGA_HWMON_CHANNEL_MASK;
	u32 channel = reg & SOCFPGA_HWMON_CHANNEL_MASK;

	if (channel >= SOCFPGA_HWMON_MAXSENSORS)
		return -EINVAL;

	*arg = (1ULL << channel) | ((u64)page << SOCFPGA_HWMON_PAGE_SHIFT);
	return 0;
}

static int socfpga_hwmon_encode_volt_arg(u32 reg, u64 *arg)
{
	u32 channel = reg & SOCFPGA_HWMON_CHANNEL_MASK;

	if (channel >= SOCFPGA_HWMON_MAXSENSORS)
		return -EINVAL;

	*arg = 1ULL << channel;
	return 0;
}

static int socfpga_hwmon_async_read(struct device *dev,
				    enum hwmon_sensor_types type,
				    struct stratix10_svc_client_msg *msg)
{
	struct socfpga_hwmon_priv *priv = dev_get_drvdata(dev);
	struct stratix10_svc_cb_data data = {};
	unsigned long deadline = jiffies + HWMON_TIMEOUT;
	void *handle = NULL;
	int status, index, ret;

	for (index = 0; index < HWMON_ASYNC_MSG_RETRY; index++) {
		status = stratix10_svc_async_send(priv->chan, msg, &handle,
						  NULL, NULL);
		if (status == 0)
			break;
		dev_warn(dev, "Failed to send async message: %d\n", status);
		usleep_range(HWMON_RETRY_SLEEP_US, HWMON_RETRY_SLEEP_US * 2);
	}

	if (status && !handle) {
		dev_err(dev, "Failed to send async message after %u retries: %d\n",
			HWMON_ASYNC_MSG_RETRY, status);
		return status;
	}

	ret = -ETIMEDOUT;
	while (!time_after(jiffies, deadline)) {
		status = stratix10_svc_async_poll(priv->chan, handle, &data);
		if (status == -EAGAIN) {
			/* still in progress */
		} else if (status < 0) {
			ret = status;
			break;
		} else if (status == 0) {
			ret = 0;
			break;
		}
		usleep_range(HWMON_RETRY_SLEEP_US, HWMON_RETRY_SLEEP_US * 2);
	}

	if (ret) {
		dev_err(dev, "Failed to get async response\n");
		goto done;
	}

	if (data.status) {
		dev_err(dev, "%s returned 0x%x from SDM\n", __func__,
			data.status);
		ret = -EFAULT;
		goto done;
	}

	if (type == hwmon_temp)
		priv->temperature = (u32)*(unsigned long *)data.kaddr1;
	else
		priv->voltage = (u32)*(unsigned long *)data.kaddr1;

	ret = 0;

done:
	stratix10_svc_async_done(priv->chan, handle);
	return ret;
}

static int socfpga_hwmon_sync_read(struct device *dev,
				   enum hwmon_sensor_types type,
				   struct stratix10_svc_client_msg *msg)
{
	struct socfpga_hwmon_priv *priv = dev_get_drvdata(dev);
	int ret;

	reinit_completion(&priv->completion);

	if (type == hwmon_temp)
		priv->client.receive_cb = socfpga_hwmon_readtemp_cb;
	else
		priv->client.receive_cb = socfpga_hwmon_readvolt_cb;

	ret = stratix10_svc_send(priv->chan, msg);
	if (ret < 0)
		goto status_done;

	ret = wait_for_completion_timeout(&priv->completion, HWMON_TIMEOUT);
	if (!ret) {
		dev_err(priv->client.dev, "timeout waiting for SMC call\n");
		ret = -ETIMEDOUT;
		goto status_done;
	}

	ret = priv->last_err;

status_done:
	stratix10_svc_done(priv->chan);
	return ret;
}

static int socfpga_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
			      u32 attr, int chan, long *val)
{
	struct socfpga_hwmon_priv *priv = dev_get_drvdata(dev);
	struct stratix10_svc_client_msg msg = {0};
	int ret;

	if (chan >= SOCFPGA_HWMON_MAXSENSORS)
		return -EOPNOTSUPP;

	switch (type) {
	case hwmon_temp:
		ret = socfpga_hwmon_encode_temp_arg(priv->temp_chan[chan],
						    &msg.arg[0]);
		if (ret)
			return ret;
		msg.command = COMMAND_HWMON_READTEMP;
		break;
	case hwmon_in:
		ret = socfpga_hwmon_encode_volt_arg(priv->volt_chan[chan],
						    &msg.arg[0]);
		if (ret)
			return ret;
		msg.command = COMMAND_HWMON_READVOLT;
		break;
	default:
		return -EOPNOTSUPP;
	}

	guard(mutex)(&priv->lock);
	if (priv->async)
		ret = socfpga_hwmon_async_read(dev, type, &msg);
	else
		ret = socfpga_hwmon_sync_read(dev, type, &msg);
	if (ret)
		return ret;

	if (type == hwmon_temp)
		ret = socfpga_hwmon_parse_temp(val, priv->temperature);
	else
		/* SDM returns Q16 volts; convert to hwmon millivolts. */
		*val = (long)priv->voltage * SOCFPGA_HWMON_VOLT_MV_SCALE /
			SOCFPGA_HWMON_VOLT_FRAC_DIV;
	return ret;
}

static int socfpga_hwmon_read_string(struct device *dev,
				     enum hwmon_sensor_types type, u32 attr,
				     int chan, const char **str)
{
	struct socfpga_hwmon_priv *priv = dev_get_drvdata(dev);

	switch (type) {
	case hwmon_in:
		*str = priv->volt_chan_names[chan];
		return 0;
	case hwmon_temp:
		*str = priv->temp_chan_names[chan];
		return 0;
	default:
		return -EOPNOTSUPP;
	}
}

static const struct hwmon_ops socfpga_hwmon_ops = {
	.is_visible = socfpga_hwmon_is_visible,
	.read = socfpga_hwmon_read,
	.read_string = socfpga_hwmon_read_string,
};

static const struct hwmon_channel_info *socfpga_hwmon_info[] = {
	HWMON_CHANNEL_INFO(temp,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL,
			   HWMON_T_INPUT | HWMON_T_LABEL),
	HWMON_CHANNEL_INFO(in,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL,
			   HWMON_I_INPUT | HWMON_I_LABEL),
	NULL
};

static const struct hwmon_chip_info socfpga_hwmon_chip_info = {
	.ops = &socfpga_hwmon_ops,
	.info = socfpga_hwmon_info,
};

static const struct socfpga_hwmon_channel s10_hwmon_volt_channels[] = {
	{ SOCFPGA_HWMON_CHAN(0, 2), "0.8V VCC" },
	{ SOCFPGA_HWMON_CHAN(0, 3), "1.8V VCCIO_SDM" },
	{ SOCFPGA_HWMON_CHAN(0, 6), "0.9V VCCERAM" },
};

static const struct socfpga_hwmon_channel s10_hwmon_temp_channels[] = {
	{ SOCFPGA_HWMON_CHAN(0, 0), "Main Die SDM" },
};

static const struct socfpga_hwmon_board_data s10_hwmon_board = {
	.temp = s10_hwmon_temp_channels,
	.num_temp = ARRAY_SIZE(s10_hwmon_temp_channels),
	.volt = s10_hwmon_volt_channels,
	.num_volt = ARRAY_SIZE(s10_hwmon_volt_channels),
};

static const struct socfpga_hwmon_channel agilex_hwmon_volt_channels[] = {
	{ SOCFPGA_HWMON_CHAN(0, 2), "0.8V VCC" },
	{ SOCFPGA_HWMON_CHAN(0, 3), "1.8V VCCIO_SDM" },
	{ SOCFPGA_HWMON_CHAN(0, 4), "1.8V VCCPT" },
	{ SOCFPGA_HWMON_CHAN(0, 5), "1.2V VCCCRCORE" },
	{ SOCFPGA_HWMON_CHAN(0, 6), "0.9V VCCH" },
	{ SOCFPGA_HWMON_CHAN(0, 7), "0.8V VCCL" },
};

static const struct socfpga_hwmon_channel agilex_hwmon_temp_channels[] = {
	{ SOCFPGA_HWMON_CHAN(0, 0), "Main Die SDM" },
	{ SOCFPGA_HWMON_CHAN(1, 0), "Main Die corner bottom left max" },
	{ SOCFPGA_HWMON_CHAN(2, 0), "Main Die corner top left max" },
	{ SOCFPGA_HWMON_CHAN(3, 0), "Main Die corner bottom right max" },
	{ SOCFPGA_HWMON_CHAN(4, 0), "Main Die corner top right max" },
};

static const struct socfpga_hwmon_board_data agilex_hwmon_board = {
	.temp = agilex_hwmon_temp_channels,
	.num_temp = ARRAY_SIZE(agilex_hwmon_temp_channels),
	.volt = agilex_hwmon_volt_channels,
	.num_volt = ARRAY_SIZE(agilex_hwmon_volt_channels),
};

static const struct socfpga_hwmon_board_data *
socfpga_hwmon_get_board(struct device *dev)
{
	struct device_node *np = dev->of_node;

	if (!np)
		return NULL;

	if (of_device_is_compatible(np, "intel,stratix10-svc"))
		return &s10_hwmon_board;
	if (of_device_is_compatible(np, "intel,agilex-svc"))
		return &agilex_hwmon_board;

	return NULL;
}

static int socfpga_hwmon_init_channels(struct device *dev,
				       const struct socfpga_hwmon_board_data *board,
				       struct socfpga_hwmon_priv *priv)
{
	unsigned int i;

	if (board->num_temp > SOCFPGA_HWMON_MAXSENSORS ||
	    board->num_volt > SOCFPGA_HWMON_MAXSENSORS)
		return -EINVAL;

	for (i = 0; i < board->num_temp; i++) {
		priv->temp_chan_names[i] = board->temp[i].label;
		priv->temp_chan[i] = board->temp[i].reg;
	}
	priv->temperature_channels = board->num_temp;

	for (i = 0; i < board->num_volt; i++) {
		priv->volt_chan_names[i] = board->volt[i].label;
		priv->volt_chan[i] = board->volt[i].reg;
	}
	priv->voltage_channels = board->num_volt;

	return 0;
}

static void socfpga_hwmon_release_svc(void *data)
{
	struct socfpga_hwmon_priv *priv = data;

	if (priv->async)
		stratix10_svc_remove_async_client(priv->chan);
	stratix10_svc_free_channel(priv->chan);
}

static int socfpga_hwmon_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device *parent = dev->parent;
	const struct socfpga_hwmon_board_data *board;
	struct socfpga_hwmon_priv *priv;
	struct device *hwmon_dev;
	int ret;

	if (!parent || !parent->of_node) {
		dev_err(dev, "missing parent device node\n");
		return -ENODEV;
	}

	board = socfpga_hwmon_get_board(parent);
	if (!board) {
		dev_err(dev, "unsupported service layer compatible\n");
		return -ENODEV;
	}

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->client.dev = dev;
	priv->client.priv = priv;
	init_completion(&priv->completion);
	mutex_init(&priv->lock);

	ret = socfpga_hwmon_init_channels(dev, board, priv);
	if (ret)
		return ret;

	priv->chan = stratix10_svc_request_channel_byname(&priv->client,
							  SVC_CLIENT_HWMON);
	if (IS_ERR(priv->chan)) {
		ret = PTR_ERR(priv->chan);
		if (ret == -EPROBE_DEFER)
			dev_dbg(dev, "service channel %s not ready, deferring probe\n",
				SVC_CLIENT_HWMON);
		else
			dev_err(dev, "couldn't get service channel %s: %d\n",
				SVC_CLIENT_HWMON, ret);
		return ret;
	}

	ret = stratix10_svc_add_async_client(priv->chan, false);
	switch (ret) {
	case 0:
		priv->async = true;
		break;
	case -EINVAL:
	case -EOPNOTSUPP:
		/*
		 * stratix10_svc_add_async_client() returns -EINVAL when the
		 * async controller is not initialized; fall back to sync mode.
		 */
		dev_dbg(dev, "async operations not supported, using sync mode\n");
		priv->async = false;
		break;
	default:
		dev_err(dev, "failed to add async client: %d\n", ret);
		stratix10_svc_free_channel(priv->chan);
		return ret;
	}

	ret = devm_add_action_or_reset(dev, socfpga_hwmon_release_svc, priv);
	if (ret)
		return ret;

	hwmon_dev = devm_hwmon_device_register_with_info(dev, "socfpga_hwmon",
							 priv,
							 &socfpga_hwmon_chip_info,
							 NULL);
	if (IS_ERR(hwmon_dev))
		return PTR_ERR(hwmon_dev);

	platform_set_drvdata(pdev, priv);
	return 0;
}

static struct platform_driver socfpga_hwmon_driver = {
	.probe = socfpga_hwmon_probe,
	.driver = {
		.name = "socfpga-hwmon",
	},
};
module_platform_driver(socfpga_hwmon_driver);

MODULE_AUTHOR("Nazim Amirul <muhammad.nazim.amirul.nazle.asmade@altera.com>");
MODULE_AUTHOR("Tze Yee Ng <tze.yee.ng@altera.com>");
MODULE_DESCRIPTION("Altera SoC FPGA hardware monitoring driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:socfpga-hwmon");