@@ -1346,6 +1346,8 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
int rc = 0;
ata_scsi_sdev_config(sdev);
+ /* ATA slaves have specific SMART access methods */
+ sdev->smart = SCSI_SMART_ATA;
if (dev)
rc = ata_scsi_dev_config(sdev, dev);
@@ -59,6 +59,19 @@ config SCSI_MQ_DEFAULT
If unsure say N.
+config SCSI_HWMON
+ bool "S.M.A.R.T. HWMON support"
+ depends on (SCSI=m && HWMON) || HWMON=y
+ help
+ This options compiles in code to support temperature reading
+ from a SCSI device using the S.M.A.R.T. (Self-Monitoring,
+ Analysis and Reporting Technology) support for temperature
+ sensors found in some hard drives. The drive will be probed
+ to figure out if it has a temperature sensor, and if it does
+ the kernel hardware monitor framework will be utilized to
+ interact with the sensor. This work orthogonal to any userspace
+ S.M.A.R.T. access tools.
+
config SCSI_PROC_FS
bool "legacy /proc/scsi/ support"
depends on SCSI && PROC_FS
@@ -22,6 +22,7 @@ obj-$(CONFIG_PCMCIA) += pcmcia/
obj-$(CONFIG_SCSI) += scsi_mod.o
obj-$(CONFIG_BLK_SCSI_REQUEST) += scsi_common.o
+obj-$(CONFIG_SCSI_HWMON) += scsi_hwmon.o
obj-$(CONFIG_RAID_ATTRS) += raid_class.o
new file mode 100644
@@ -0,0 +1,464 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hwmon client for S.M.A.R.T. hard disk drives with temperature
+ * sensors.
+ * (C) 2018 Linus Walleij
+ *
+ * This code is based on know-how and examples from the
+ * smartmontools by Bruce Allen, Christian Franke et al.
+ * (C) 2002-2018
+ */
+
+#include <linux/ata.h>
+#include <linux/device.h>
+#include <linux/hwmon.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+
+#include "scsi_hwmon.h"
+
+#define ATA_MAX_SMART_ATTRS 30
+#define SMART_TEMP_PROP_194 194
+
+enum ata_temp_format {
+ ATA_TEMP_FMT_TT_XX_00_00_00_00,
+ ATA_TEMP_FMT_TT_XX_LL_HH_00_00,
+ ATA_TEMP_FMT_TT_LL_HH_00_00_00,
+ ATA_TEMP_FMT_TT_XX_LL_XX_HH_XX,
+ ATA_TEMP_FMT_TT_XX_HH_XX_LL_XX,
+ ATA_TEMP_FMT_TT_XX_LL_HH_CC_CC,
+ ATA_TEMP_FMT_UNKNOWN,
+};
+
+/**
+ * struct scsi_hwmon - device instance state
+ * @dev: parent device
+ * @sdev: associated SCSI device
+ * @tfmt: temperature format
+ * @smartdata: buffer for reading in the SMART "sector"
+ */
+struct scsi_hwmon {
+ struct device *dev;
+ struct scsi_device *sdev;
+ enum ata_temp_format tfmt;
+ u8 smartdata[ATA_SECT_SIZE];
+};
+
+static umode_t scsi_hwmon_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ const struct scsi_hwmon *shd = data;
+
+ /*
+ * If we detected a temperature format with min/max temperatures
+ * we make those attributes visible, else just the temperature
+ * input per se.
+ */
+ switch (type) {
+ case hwmon_temp:
+ switch (attr) {
+ case hwmon_temp_input:
+ return 00444;
+ case hwmon_temp_min:
+ case hwmon_temp_max:
+ if (shd->tfmt == ATA_TEMP_FMT_TT_XX_00_00_00_00)
+ return 0;
+ return 00444;
+ }
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+static int ata_check_temp_word(u16 word)
+{
+ if (word <= 0x7f)
+ return 0x11; /* >= 0, signed byte or word */
+ if (word <= 0xff)
+ return 0x01; /* < 0, signed byte */
+ if (word > 0xff80)
+ return 0x10; /* < 0, signed word */
+ return 0x00;
+}
+
+static bool ata_check_temp_range(int t, u8 t1, u8 t2)
+{
+ int lo = (s8)t1;
+ int hi = (s8)t2;
+
+ /* This is obviously wrong */
+ if (lo > hi)
+ return false;
+
+ /*
+ * If -60 <= lo <= t <= hi <= 120 and
+ * and lo != -1 and hi > 0, then we have valid lo and hi
+ */
+ if (-60 <= lo && lo <= t && t <= hi && hi <= 120
+ && (lo != -1 && hi > 0)) {
+ return true;
+ }
+ return false;
+}
+
+static void scsi_hwmon_convert_temperatures(struct scsi_hwmon *shd, u8 *raw,
+ int *t, int *lo, int *hi)
+{
+ *t = (s8)raw[0];
+
+ switch (shd->tfmt) {
+ case ATA_TEMP_FMT_TT_XX_00_00_00_00:
+ *lo = 0;
+ *hi = 0;
+ break;
+ case ATA_TEMP_FMT_TT_XX_LL_HH_00_00:
+ *lo = (s8)raw[2];
+ *hi = (s8)raw[3];
+ break;
+ case ATA_TEMP_FMT_TT_LL_HH_00_00_00:
+ *lo = (s8)raw[1];
+ *hi = (s8)raw[2];
+ break;
+ case ATA_TEMP_FMT_TT_XX_LL_XX_HH_XX:
+ *lo = (s8)raw[2];
+ *hi = (s8)raw[4];
+ break;
+ case ATA_TEMP_FMT_TT_XX_HH_XX_LL_XX:
+ *lo = (s8)raw[4];
+ *hi = (s8)raw[2];
+ break;
+ case ATA_TEMP_FMT_TT_XX_LL_HH_CC_CC:
+ *lo = (s8)raw[2];
+ *hi = (s8)raw[3];
+ break;
+ case ATA_TEMP_FMT_UNKNOWN:
+ *lo = 0;
+ *hi = 0;
+ break;
+ }
+}
+
+static int scsi_hwmon_parse_smartdata(struct scsi_hwmon *shd,
+ u8 *buf, u8 *raw)
+{
+ u8 id;
+ u16 flags;
+ u8 curr;
+ u8 worst;
+ int i;
+
+ /* Loop over SMART attributes */
+ for (i = 0; i < ATA_MAX_SMART_ATTRS; i++) {
+ int j;
+
+ id = buf[2 + i * 12];
+ if (!id)
+ continue;
+
+ /*
+ * The "current" and "worst" values represent a normalized
+ * value in the range 0..100 where 0 is "worst" and 100
+ * is "best". It does not represent actual temperatures.
+ * It is probably possible to use vendor-specific code per
+ * drive to convert this to proper temperatures but we leave
+ * it out for now.
+ */
+ flags = buf[3 + i * 12] | (buf[4 + i * 12] << 16);
+ /* Highest temperature since boot */
+ curr = buf[5 + i * 12];
+ /* Highest temperature ever */
+ worst = buf[6 + i * 12];
+ for (j = 0; j < 6; j++)
+ raw[j] = buf[7 + i * 12 + j];
+ dev_dbg(shd->dev, "ID: %d, FLAGS: %04x, current %d, worst %d, "
+ "RAW %02x %02x %02x %02x %02x %02x\n",
+ id, flags, curr, worst,
+ raw[0], raw[1], raw[2], raw[3], raw[4], raw[5]);
+
+ if (id == SMART_TEMP_PROP_194)
+ break;
+ }
+
+ if (id != SMART_TEMP_PROP_194)
+ return -ENOTSUPP;
+
+ return 0;
+}
+
+static int scsi_hwmon_read_raw(struct scsi_hwmon *shd, u8 *raw)
+{
+ u8 scsi_cmd[MAX_COMMAND_SIZE];
+ int cmd_result;
+ struct scsi_sense_hdr sshdr;
+ u8 *buf = shd->smartdata;
+ int ret;
+ u8 csum;
+ int i;
+
+ /* Send ATA command to read SMART values */
+ memset(scsi_cmd, 0, sizeof(scsi_cmd));
+ scsi_cmd[0] = ATA_16;
+ scsi_cmd[1] = (4 << 1); /* PIO Data-in */
+ /*
+ * No off.line or cc, read from dev, block count in sector count
+ * field.
+ */
+ scsi_cmd[2] = 0x0e;
+ scsi_cmd[4] = ATA_SMART_READ_VALUES;
+ scsi_cmd[6] = 1; /* Read 1 sector */
+ scsi_cmd[8] = 0; /* args[1]; */
+ scsi_cmd[10] = ATA_SMART_LBAM_PASS;
+ scsi_cmd[12] = ATA_SMART_LBAH_PASS;
+ scsi_cmd[14] = ATA_CMD_SMART;
+
+ cmd_result = scsi_execute(shd->sdev, scsi_cmd, DMA_FROM_DEVICE,
+ buf, ATA_SECT_SIZE,
+ NULL, &sshdr, 10 * HZ, 5, 0, 0, NULL);
+ if (cmd_result) {
+ dev_dbg(shd->dev, "error %d reading SMART values from device\n",
+ cmd_result);
+ return cmd_result;
+ }
+
+ /* Checksum the read value table */
+ csum = 0;
+ for (i = 0; i < ATA_SECT_SIZE; i++)
+ csum += buf[i];
+ if (csum) {
+ dev_dbg(shd->dev, "checksum error reading SMART values\n");
+ return -EIO;
+ }
+
+ /* This will fail with -ENOTSUPP if we don't have temperature */
+ ret = scsi_hwmon_parse_smartdata(shd, buf, raw);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int scsi_hwmon_detect_tempformat(struct scsi_hwmon *shd)
+{
+ u8 raw[6];
+ s8 t;
+ u16 w0, w1, w2;
+ int ctw0;
+ int ret;
+
+ shd->tfmt = ATA_TEMP_FMT_UNKNOWN;
+
+ /* First read in some raw temperature sensor data */
+ ret = scsi_hwmon_read_raw(shd, raw);
+ if (ret)
+ return ret;
+
+ /*
+ * Interpret the RAW temperature data:
+ * raw[0] is the temperature given as signed u8 on all known drives
+ *
+ * Search for possible min/max values
+ * This algorithm is a modified version from the smartmontools.
+ *
+ * [0][1][2][3][4][5] raw[]
+ * [ 0 ] [ 1 ] [ 2 ] word[]
+ * TT xx LL xx HH xx Hitachi/HGST
+ * TT xx HH xx LL xx Kingston SSDs
+ * TT xx LL HH 00 00 Maxtor, Samsung, Seagate, Toshiba
+ * TT LL HH 00 00 00 WDC
+ * TT xx LL HH CC CC WDC, CCCC=over temperature count
+ * (xx = 00/ff, possibly sign extension of lower byte)
+ *
+ * TODO: detect the 10x temperatures found on some Samsung
+ * drives. struct scsi_device contains manufacturer and model
+ * information.
+ */
+ w0 = raw[0] | raw[1] << 16;
+ w1 = raw[2] | raw[3] << 16;
+ w2 = raw[4] | raw[5] << 16;
+ t = (s8)raw[0];
+
+ /* If this is != 0, then w0 may contain something useful */
+ ctw0 = ata_check_temp_word(w0);
+
+ /* This checks variants with zero in [4] [5] */
+ if (!w2) {
+ /* TT xx 00 00 00 00 */
+ if (!w1 && ctw0)
+ shd->tfmt = ATA_TEMP_FMT_TT_XX_00_00_00_00;
+ /* TT xx LL HH 00 00 */
+ else if (ctw0 &&
+ ata_check_temp_range(t, raw[2], raw[3]))
+ shd->tfmt = ATA_TEMP_FMT_TT_XX_LL_HH_00_00;
+ /* TT LL HH 00 00 00 */
+ else if (!raw[3] &&
+ ata_check_temp_range(t, raw[1], raw[2]))
+ shd->tfmt = ATA_TEMP_FMT_TT_LL_HH_00_00_00;
+ else
+ return -ENOTSUPP;
+ } else if (ctw0) {
+ /*
+ * TT xx LL xx HH xx
+ * What the expression below does is to check that each word
+ * formed by [0][1], [2][3], and [4][5] is something little-
+ * endian s8 or s16 that could be meaningful.
+ */
+ if ((ctw0 & ata_check_temp_word(w1) & ata_check_temp_word(w2))
+ != 0x00)
+ if (ata_check_temp_range(t, raw[2], raw[4]))
+ shd->tfmt = ATA_TEMP_FMT_TT_XX_LL_XX_HH_XX;
+ else if (ata_check_temp_range(t, raw[4], raw[2]))
+ shd->tfmt = ATA_TEMP_FMT_TT_XX_HH_XX_LL_XX;
+ else
+ return -ENOTSUPP;
+ /*
+ * TT xx LL HH CC CC
+ * Make sure the CC CC word is at least not negative, and that
+ * the max temperature is something >= 40, then it is probably
+ * the right format.
+ */
+ else if (w2 < 0x7fff) {
+ if (ata_check_temp_range(t, raw[2], raw[3]) &&
+ raw[3] >= 40)
+ shd->tfmt = ATA_TEMP_FMT_TT_XX_LL_HH_CC_CC;
+ else
+ return -ENOTSUPP;
+ } else {
+ return -ENOTSUPP;
+ }
+ } else {
+ return -ENOTSUPP;
+ }
+
+ return 0;
+}
+
+static int scsi_hwmon_read_temp(struct scsi_hwmon *shd, int *temp,
+ int *min, int *max)
+{
+ u8 raw[6];
+ int ret;
+
+ ret = scsi_hwmon_read_raw(shd, raw);
+ if (ret)
+ return ret;
+
+ scsi_hwmon_convert_temperatures(shd, raw, temp, min, max);
+ dev_dbg(shd->dev, "temp = %d, min = %d, max = %d\n",
+ *temp, *min, *max);
+
+ return 0;
+}
+
+static int scsi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct scsi_hwmon *shd = dev_get_drvdata(dev);
+ int temp, min = 0, max = 0;
+ int ret;
+
+ ret = scsi_hwmon_read_temp(shd, &temp, &min, &max);
+ if (ret)
+ return ret;
+
+ /*
+ * Multiply return values by 1000 as hwmon expects millicentigrades
+ */
+ switch (attr) {
+ case hwmon_temp_input:
+ *val = temp * 1000;
+ break;
+ case hwmon_temp_min:
+ *val = min * 1000;
+ break;
+ case hwmon_temp_max:
+ *val = max * 1000;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static const struct hwmon_ops scsi_hwmon_ops = {
+ .is_visible = scsi_hwmon_is_visible,
+ .read = scsi_hwmon_read,
+};
+
+static const u32 scsi_hwmon_temp_config[] = {
+ HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX,
+ 0,
+};
+
+static const struct hwmon_channel_info scsi_hwmon_temp = {
+ .type = hwmon_temp,
+ .config = scsi_hwmon_temp_config,
+};
+
+static u32 scsi_hwmon_chip_config[] = {
+ HWMON_C_REGISTER_TZ,
+ 0
+};
+
+static const struct hwmon_channel_info scsi_hwmon_chip = {
+ .type = hwmon_chip,
+ .config = scsi_hwmon_chip_config,
+};
+
+static const struct hwmon_channel_info *scsi_hwmon_info[] = {
+ &scsi_hwmon_temp,
+ &scsi_hwmon_chip,
+ NULL,
+};
+
+static const struct hwmon_chip_info scsi_hwmon_devinfo = {
+ .ops = &scsi_hwmon_ops,
+ .info = scsi_hwmon_info,
+};
+
+int scsi_hwmon_probe(struct scsi_device *sdev)
+{
+ struct device *dev = &sdev->sdev_gendev;
+ struct device *hwmon_dev;
+ struct scsi_hwmon *shd;
+ int ret;
+
+ /*
+ * We currently only support SMART temperature readouts using
+ * ATA SMART propery 194.
+ *
+ * TODO: Add more SMART types for SCSI, SAS, USB etc.
+ */
+ if (sdev->smart != SCSI_SMART_ATA)
+ return 0;
+
+ shd = devm_kzalloc(dev, sizeof(*shd), GFP_KERNEL);
+ if (!shd)
+ return -ENOMEM;
+ shd->dev = dev;
+ shd->sdev = sdev;
+
+ /*
+ * If temperature reading is not supported in the SMART
+ * properties, we just bail out.
+ */
+ ret = scsi_hwmon_detect_tempformat(shd);
+ if (ret == -ENOTSUPP)
+ return 0;
+ /* Any other error, return upward */
+ if (ret)
+ return ret;
+
+ hwmon_dev =
+ devm_hwmon_device_register_with_info(dev, "sd", shd,
+ &scsi_hwmon_devinfo,
+ NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
new file mode 100644
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <scsi/scsi_device.h>
+
+#ifdef CONFIG_SCSI_HWMON
+
+int scsi_hwmon_probe(struct scsi_device *sdev);
+
+#else
+
+static inline int scsi_hwmon_probe(struct scsi_device *sdev)
+{
+ return 0;
+}
+
+#endif
@@ -49,6 +49,7 @@
#include "scsi_priv.h"
#include "scsi_logging.h"
+#include "scsi_hwmon.h"
#define ALLOC_FAILURE_MSG KERN_ERR "%s: Allocation failure during" \
" SCSI scanning, some SCSI devices might not be configured\n"
@@ -1495,6 +1496,7 @@ struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
*/
scsi_target_reap(starget);
put_device(&starget->dev);
+ scsi_hwmon_probe(sdev);
return sdev;
}
@@ -61,6 +61,11 @@ enum scsi_scan_mode {
SCSI_SCAN_MANUAL,
};
+enum scsi_smart_type {
+ SCSI_SMART_NONE = 0,
+ SCSI_SMART_ATA, /* Used to read temperatures */
+};
+
enum scsi_device_event {
SDEV_EVT_MEDIA_CHANGE = 1, /* media has changed */
SDEV_EVT_INQUIRY_CHANGE_REPORTED, /* 3F 03 UA reported */
@@ -226,6 +231,7 @@ struct scsi_device {
unsigned char access_state;
struct mutex state_mutex;
enum scsi_device_state sdev_state;
+ enum scsi_smart_type smart;
struct task_struct *quiesced_by;
unsigned long sdev_data[0];
} __attribute__((aligned(sizeof(unsigned long))));