Merge tag 'hwmon-for-v5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:

 - Fix potential bufer overflow in pmbus/max20730 driver

 - Fix locking issue in pmbus core

 - Fix regression causing timeouts in applesmc driver

 - Fix RPM calculation in pwm-fan driver

 - Restrict counter visibility in amd_energy driver

* tag 'hwmon-for-v5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (amd_energy) modify the visibility of the counters
  hwmon: (applesmc) Re-work SMC comms
  hwmon: (pwm-fan) Fix RPM calculation
  hwmon: (pmbus) Add mutex locking for sysfs reads
  hwmon: (pmbus/max20730) use scnprintf() instead of snprintf()

5 files changed, 115 insertions, 72 deletions

diff --git a/drivers/hwmon/amd_energy.c b/drivers/hwmon/amd_energy.c
index d06597303d5a..3197cda7bcd9 100644
--- a/drivers/hwmon/amd_energy.c
+++ b/drivers/hwmon/amd_energy.c
@@ -171,7 +171,7 @@ static umode_t amd_energy_is_visible(const void *_data,
 				     enum hwmon_sensor_types type,
 				     u32 attr, int channel)
 {
-	return 0444;
+	return 0440;
 }
 
 static int energy_accumulator(void *p)
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index a18887990f4a..79b498f816fe 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -32,6 +32,7 @@
 #include <linux/hwmon.h>
 #include <linux/workqueue.h>
 #include <linux/err.h>
+#include <linux/bits.h>
 
 /* data port used by Apple SMC */
 #define APPLESMC_DATA_PORT	0x300
@@ -42,10 +43,13 @@
 
 #define APPLESMC_MAX_DATA_LENGTH 32
 
-/* wait up to 128 ms for a status change. */
-#define APPLESMC_MIN_WAIT	0x0010
-#define APPLESMC_RETRY_WAIT	0x0100
-#define APPLESMC_MAX_WAIT	0x20000
+/* Apple SMC status bits */
+#define SMC_STATUS_AWAITING_DATA  BIT(0) /* SMC has data waiting to be read */
+#define SMC_STATUS_IB_CLOSED      BIT(1) /* Will ignore any input */
+#define SMC_STATUS_BUSY           BIT(2) /* Command in progress */
+
+/* Initial wait is 8us */
+#define APPLESMC_MIN_WAIT      0x0008
 
 #define APPLESMC_READ_CMD	0x10
 #define APPLESMC_WRITE_CMD	0x11
@@ -151,65 +155,84 @@ static unsigned int key_at_index;
 static struct workqueue_struct *applesmc_led_wq;
 
 /*
- * wait_read - Wait for a byte to appear on SMC port. Callers must
- * hold applesmc_lock.
+ * Wait for specific status bits with a mask on the SMC.
+ * Used before all transactions.
+ * This does 10 fast loops of 8us then exponentially backs off for a
+ * minimum total wait of 262ms. Depending on usleep_range this could
+ * run out past 500ms.
  */
-static int wait_read(void)
+
+static int wait_status(u8 val, u8 mask)
 {
-	unsigned long end = jiffies + (APPLESMC_MAX_WAIT * HZ) / USEC_PER_SEC;
 	u8 status;
 	int us;
+	int i;
 
-	for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
-		usleep_range(us, us * 16);
+	us = APPLESMC_MIN_WAIT;
+	for (i = 0; i < 24 ; i++) {
 		status = inb(APPLESMC_CMD_PORT);
-		/* read: wait for smc to settle */
-		if (status & 0x01)
+		if ((status & mask) == val)
 			return 0;
-		/* timeout: give up */
-		if (time_after(jiffies, end))
-			break;
+		usleep_range(us, us * 2);
+		if (i > 9)
+			us <<= 1;
 	}
-
-	pr_warn("wait_read() fail: 0x%02x\n", status);
 	return -EIO;
 }
 
-/*
- * send_byte - Write to SMC port, retrying when necessary. Callers
- * must hold applesmc_lock.
- */
+/* send_byte - Write to SMC data port. Callers must hold applesmc_lock. */
+
 static int send_byte(u8 cmd, u16 port)
 {
-	u8 status;
-	int us;
-	unsigned long end = jiffies + (APPLESMC_MAX_WAIT * HZ) / USEC_PER_SEC;
+	int status;
+
+	status = wait_status(0, SMC_STATUS_IB_CLOSED);
+	if (status)
+		return status;
+	/*
+	 * This needs to be a separate read looking for bit 0x04
+	 * after bit 0x02 falls. If consolidated with the wait above
+	 * this extra read may not happen if status returns both
+	 * simultaneously and this would appear to be required.
+	 */
+	status = wait_status(SMC_STATUS_BUSY, SMC_STATUS_BUSY);
+	if (status)
+		return status;
 
 	outb(cmd, port);
-	for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
-		usleep_range(us, us * 16);
-		status = inb(APPLESMC_CMD_PORT);
-		/* write: wait for smc to settle */
-		if (status & 0x02)
-			continue;
-		/* ready: cmd accepted, return */
-		if (status & 0x04)
-			return 0;
-		/* timeout: give up */
-		if (time_after(jiffies, end))
-			break;
-		/* busy: long wait and resend */
-		udelay(APPLESMC_RETRY_WAIT);
-		outb(cmd, port);
-	}
-
-	pr_warn("send_byte(0x%02x, 0x%04x) fail: 0x%02x\n", cmd, port, status);
-	return -EIO;
+	return 0;
 }
 
+/* send_command - Write a command to the SMC. Callers must hold applesmc_lock. */
+
 static int send_command(u8 cmd)
 {
-	return send_byte(cmd, APPLESMC_CMD_PORT);
+	int ret;
+
+	ret = wait_status(0, SMC_STATUS_IB_CLOSED);
+	if (ret)
+		return ret;
+	outb(cmd, APPLESMC_CMD_PORT);
+	return 0;
+}
+
+/*
+ * Based on logic from the Apple driver. This is issued before any interaction
+ * If busy is stuck high, issue a read command to reset the SMC state machine.
+ * If busy is stuck high after the command then the SMC is jammed.
+ */
+
+static int smc_sane(void)
+{
+	int ret;
+
+	ret = wait_status(0, SMC_STATUS_BUSY);
+	if (!ret)
+		return ret;
+	ret = send_command(APPLESMC_READ_CMD);
+	if (ret)
+		return ret;
+	return wait_status(0, SMC_STATUS_BUSY);
 }
 
 static int send_argument(const char *key)
@@ -226,6 +249,11 @@ static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len)
 {
 	u8 status, data = 0;
 	int i;
+	int ret;
+
+	ret = smc_sane();
+	if (ret)
+		return ret;
 
 	if (send_command(cmd) || send_argument(key)) {
 		pr_warn("%.4s: read arg fail\n", key);
@@ -239,7 +267,8 @@ static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len)
 	}
 
 	for (i = 0; i < len; i++) {
-		if (wait_read()) {
+		if (wait_status(SMC_STATUS_AWAITING_DATA | SMC_STATUS_BUSY,
+				SMC_STATUS_AWAITING_DATA | SMC_STATUS_BUSY)) {
 			pr_warn("%.4s: read data[%d] fail\n", key, i);
 			return -EIO;
 		}
@@ -250,19 +279,24 @@ static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len)
 	for (i = 0; i < 16; i++) {
 		udelay(APPLESMC_MIN_WAIT);
 		status = inb(APPLESMC_CMD_PORT);
-		if (!(status & 0x01))
+		if (!(status & SMC_STATUS_AWAITING_DATA))
 			break;
 		data = inb(APPLESMC_DATA_PORT);
 	}
 	if (i)
 		pr_warn("flushed %d bytes, last value is: %d\n", i, data);
 
-	return 0;
+	return wait_status(0, SMC_STATUS_BUSY);
 }
 
 static int write_smc(u8 cmd, const char *key, const u8 *buffer, u8 len)
 {
 	int i;
+	int ret;
+
+	ret = smc_sane();
+	if (ret)
+		return ret;
 
 	if (send_command(cmd) || send_argument(key)) {
 		pr_warn("%s: write arg fail\n", key);
@@ -281,7 +315,7 @@ static int write_smc(u8 cmd, const char *key, const u8 *buffer, u8 len)
 		}
 	}
 
-	return 0;
+	return wait_status(0, SMC_STATUS_BUSY);
 }
 
 static int read_register_count(unsigned int *count)
diff --git a/drivers/hwmon/pmbus/max20730.c b/drivers/hwmon/pmbus/max20730.c
index 57923d72490c..be83b98411c7 100644
--- a/drivers/hwmon/pmbus/max20730.c
+++ b/drivers/hwmon/pmbus/max20730.c
@@ -122,8 +122,8 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 	switch (idx) {
 	case MAX20730_DEBUGFS_VOUT_MIN:
 		ret = VOLT_FROM_REG(data->mfr_voutmin * 10000);
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d.%d\n",
-			       ret / 10000, ret % 10000);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d.%d\n",
+				ret / 10000, ret % 10000);
 		break;
 	case MAX20730_DEBUGFS_FREQUENCY:
 		val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_FSW_MASK)
@@ -141,7 +141,7 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 			ret = 800;
 		else
 			ret = 900;
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
 		break;
 	case MAX20730_DEBUGFS_PG_DELAY:
 		val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_TSTAT_MASK)
@@ -223,7 +223,7 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 	case MAX20730_DEBUGFS_OC_PROTECT_MODE:
 		ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_OCPM_MASK)
 			>> MAX20730_MFR_DEVSET2_OCPM_BIT_POS;
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
 		break;
 	case MAX20730_DEBUGFS_SS_TIMING:
 		val = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_SS_MASK)
@@ -241,32 +241,32 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 	case MAX20730_DEBUGFS_IMAX:
 		ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_IMAX_MASK)
 			>> MAX20730_MFR_DEVSET2_IMAX_BIT_POS;
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
 		break;
 	case MAX20730_DEBUGFS_OPERATION:
 		ret = i2c_smbus_read_byte_data(psu->client, PMBUS_OPERATION);
 		if (ret < 0)
 			return ret;
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
 		break;
 	case MAX20730_DEBUGFS_ON_OFF_CONFIG:
 		ret = i2c_smbus_read_byte_data(psu->client, PMBUS_ON_OFF_CONFIG);
 		if (ret < 0)
 			return ret;
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
 		break;
 	case MAX20730_DEBUGFS_SMBALERT_MASK:
 		ret = i2c_smbus_read_word_data(psu->client,
 					       PMBUS_SMB_ALERT_MASK);
 		if (ret < 0)
 			return ret;
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
 		break;
 	case MAX20730_DEBUGFS_VOUT_MODE:
 		ret = i2c_smbus_read_byte_data(psu->client, PMBUS_VOUT_MODE);
 		if (ret < 0)
 			return ret;
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret);
 		break;
 	case MAX20730_DEBUGFS_VOUT_COMMAND:
 		ret = i2c_smbus_read_word_data(psu->client, PMBUS_VOUT_COMMAND);
@@ -274,8 +274,8 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 			return ret;
 
 		ret = VOLT_FROM_REG(ret * 10000);
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX,
-			       "%d.%d\n", ret / 10000, ret % 10000);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX,
+				"%d.%d\n", ret / 10000, ret % 10000);
 		break;
 	case MAX20730_DEBUGFS_VOUT_MAX:
 		ret = i2c_smbus_read_word_data(psu->client, PMBUS_VOUT_MAX);
@@ -283,8 +283,8 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf,
 			return ret;
 
 		ret = VOLT_FROM_REG(ret * 10000);
-		len = snprintf(tbuf, DEBUG_FS_DATA_MAX,
-			       "%d.%d\n", ret / 10000, ret % 10000);
+		len = scnprintf(tbuf, DEBUG_FS_DATA_MAX,
+				"%d.%d\n", ret / 10000, ret % 10000);
 		break;
 	default:
 		len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 170a9f82ca61..b0e2820a2d57 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -941,12 +941,16 @@ static ssize_t pmbus_show_sensor(struct device *dev,
 	struct i2c_client *client = to_i2c_client(dev->parent);
 	struct pmbus_sensor *sensor = to_pmbus_sensor(devattr);
 	struct pmbus_data *data = i2c_get_clientdata(client);
+	ssize_t ret;
 
+	mutex_lock(&data->update_lock);
 	pmbus_update_sensor_data(client, sensor);
 	if (sensor->data < 0)
-		return sensor->data;
-
-	return snprintf(buf, PAGE_SIZE, "%lld\n", pmbus_reg2data(data, sensor));
+		ret = sensor->data;
+	else
+		ret = snprintf(buf, PAGE_SIZE, "%lld\n", pmbus_reg2data(data, sensor));
+	mutex_unlock(&data->update_lock);
+	return ret;
 }
 
 static ssize_t pmbus_set_sensor(struct device *dev,
@@ -2012,8 +2016,11 @@ static ssize_t pmbus_show_samples(struct device *dev,
 	int val;
 	struct i2c_client *client = to_i2c_client(dev->parent);
 	struct pmbus_samples_reg *reg = to_samples_reg(devattr);
+	struct pmbus_data *data = i2c_get_clientdata(client);
 
+	mutex_lock(&data->update_lock);
 	val = _pmbus_read_word_data(client, reg->page, 0xff, reg->attr->reg);
+	mutex_unlock(&data->update_lock);
 	if (val < 0)
 		return val;
 
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index bdba2143021a..1f63807c0399 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -54,16 +54,18 @@ static irqreturn_t pulse_handler(int irq, void *dev_id)
 static void sample_timer(struct timer_list *t)
 {
 	struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
+	unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
 	int pulses;
-	u64 tmp;
 
-	pulses = atomic_read(&ctx->pulses);
-	atomic_sub(pulses, &ctx->pulses);
-	tmp = (u64)pulses * ktime_ms_delta(ktime_get(), ctx->sample_start) * 60;
-	do_div(tmp, ctx->pulses_per_revolution * 1000);
-	ctx->rpm = tmp;
+	if (delta) {
+		pulses = atomic_read(&ctx->pulses);
+		atomic_sub(pulses, &ctx->pulses);
+		ctx->rpm = (unsigned int)(pulses * 1000 * 60) /
+			(ctx->pulses_per_revolution * delta);
+
+		ctx->sample_start = ktime_get();
+	}
 
-	ctx->sample_start = ktime_get();
 	mod_timer(&ctx->rpm_timer, jiffies + HZ);
 }