| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20220511192724.51845-1-eajames@linux.ibm.com>
Date: Wed, 11 May 2022 14:27:24 -0500
From: Eddie James <eajames@...ux.ibm.com>
To: linux-iio@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, jic23@...nel.org, lars@...afoo.de,
joel@....id.au
Subject: [PATCH] iio: pressure: dps310: Reset chip if MEAS_CFG is corrupt
Corruption of the MEAS_CFG register has been observed soon after
system boot. In order to recover this scenario, check MEAS_CFG if
measurement isn't ready, and if it's incorrect, reset the DPS310
and write all the necessary registers.
Signed-off-by: Eddie James <eajames@...ux.ibm.com>
---
drivers/iio/pressure/dps310.c | 280 +++++++++++++++++++++-------------
1 file changed, 173 insertions(+), 107 deletions(-)
diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c
index 36fb7ae0d0a9..39f84614f44e 100644
--- a/drivers/iio/pressure/dps310.c
+++ b/drivers/iio/pressure/dps310.c
@@ -159,6 +159,106 @@ static int dps310_get_coefs(struct dps310_data *data)
return 0;
}
+/*
+ * Some verions of chip will read temperatures in the ~60C range when
+ * its actually ~20C. This is the manufacturer recommended workaround
+ * to correct the issue. The registers used below are undocumented.
+ */
+static int dps310_temp_workaround(struct dps310_data *data)
+{
+ int rc;
+ int reg;
+
+ rc = regmap_read(data->regmap, 0x32, ®);
+ if (rc < 0)
+ return rc;
+
+ /*
+ * If bit 1 is set then the device is okay, and the workaround does not
+ * need to be applied
+ */
+ if (reg & BIT(1))
+ return 0;
+
+ rc = regmap_write(data->regmap, 0x0e, 0xA5);
+ if (rc < 0)
+ return rc;
+
+ rc = regmap_write(data->regmap, 0x0f, 0x96);
+ if (rc < 0)
+ return rc;
+
+ rc = regmap_write(data->regmap, 0x62, 0x02);
+ if (rc < 0)
+ return rc;
+
+ rc = regmap_write(data->regmap, 0x0e, 0x00);
+ if (rc < 0)
+ return rc;
+
+ return regmap_write(data->regmap, 0x0f, 0x00);
+}
+
+static int dps310_startup(struct dps310_data *data)
+{
+ int rc;
+ int ready;
+
+ /*
+ * Set up pressure sensor in single sample, one measurement per second
+ * mode
+ */
+ rc = regmap_write(data->regmap, DPS310_PRS_CFG, 0);
+ if (rc < 0)
+ return rc;
+
+ /*
+ * Set up external (MEMS) temperature sensor in single sample, one
+ * measurement per second mode
+ */
+ rc = regmap_write(data->regmap, DPS310_TMP_CFG, DPS310_TMP_EXT);
+ if (rc < 0)
+ return rc;
+
+ /* Temp and pressure shifts are disabled when PRC <= 8 */
+ rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
+ DPS310_PRS_SHIFT_EN | DPS310_TMP_SHIFT_EN, 0);
+ if (rc < 0)
+ return rc;
+
+ /* MEAS_CFG doesn't update correctly unless first written with 0 */
+ rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
+ DPS310_MEAS_CTRL_BITS, 0);
+ if (rc < 0)
+ return rc;
+
+ /* Turn on temperature and pressure measurement in the background */
+ rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
+ DPS310_MEAS_CTRL_BITS, DPS310_PRS_EN |
+ DPS310_TEMP_EN | DPS310_BACKGROUND);
+ if (rc < 0)
+ return rc;
+
+ /*
+ * Calibration coefficients required for reporting temperature.
+ * They are available 40ms after the device has started
+ */
+ rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
+ ready & DPS310_COEF_RDY, 10000, 40000);
+ if (rc < 0)
+ return rc;
+
+ rc = dps310_get_coefs(data);
+ if (rc < 0)
+ return rc;
+
+ rc = dps310_temp_workaround(data);
+ if (rc < 0)
+ return rc;
+
+ return 0;
+}
+
static int dps310_get_pres_precision(struct dps310_data *data)
{
int rc;
@@ -297,6 +397,38 @@ static int dps310_get_temp_k(struct dps310_data *data)
return scale_factors[ilog2(rc)];
}
+/* Called with lock held */
+static int dps310_verify_meas_cfg(struct dps310_data *data, int ready_bit)
+{
+ int en = DPS310_PRS_EN | DPS310_TEMP_EN | DPS310_BACKGROUND;
+ int meas_cfg;
+ int rc = regmap_read(data->regmap, DPS310_MEAS_CFG, &meas_cfg);
+
+ if (rc < 0)
+ return rc;
+
+ if (meas_cfg & ready_bit)
+ return 0;
+
+ if ((meas_cfg & en) != en) {
+ /* DPS310 register state corrupt, better start from scratch */
+ rc = regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC);
+ if (rc < 0)
+ return rc;
+
+ /* Wait for device chip access: 2.5ms in specification */
+ usleep_range(2500, 12000);
+ rc = dps310_startup(data);
+ if (rc)
+ return rc;
+
+ dev_info(&data->client->dev,
+ "recovered from corrupted MEAS_CFG=%02x\n", meas_cfg);
+ }
+
+ return 1;
+}
+
static int dps310_read_pres_raw(struct dps310_data *data)
{
int rc;
@@ -309,15 +441,25 @@ static int dps310_read_pres_raw(struct dps310_data *data)
if (mutex_lock_interruptible(&data->lock))
return -EINTR;
- rate = dps310_get_pres_samp_freq(data);
- timeout = DPS310_POLL_TIMEOUT_US(rate);
-
- /* Poll for sensor readiness; base the timeout upon the sample rate. */
- rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
- ready & DPS310_PRS_RDY,
- DPS310_POLL_SLEEP_US(timeout), timeout);
- if (rc)
- goto done;
+ rc = dps310_verify_meas_cfg(data, DPS310_PRS_RDY);
+ if (rc) {
+ if (rc < 0)
+ goto done;
+
+ rate = dps310_get_pres_samp_freq(data);
+ timeout = DPS310_POLL_TIMEOUT_US(rate);
+
+ /*
+ * Poll for sensor readiness; base the timeout upon the sample
+ * rate.
+ */
+ rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG,
+ ready, ready & DPS310_PRS_RDY,
+ DPS310_POLL_SLEEP_US(timeout),
+ timeout);
+ if (rc)
+ goto done;
+ }
rc = regmap_bulk_read(data->regmap, DPS310_PRS_BASE, val, sizeof(val));
if (rc < 0)
@@ -358,15 +500,25 @@ static int dps310_read_temp_raw(struct dps310_data *data)
if (mutex_lock_interruptible(&data->lock))
return -EINTR;
- rate = dps310_get_temp_samp_freq(data);
- timeout = DPS310_POLL_TIMEOUT_US(rate);
-
- /* Poll for sensor readiness; base the timeout upon the sample rate. */
- rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
- ready & DPS310_TMP_RDY,
- DPS310_POLL_SLEEP_US(timeout), timeout);
- if (rc < 0)
- goto done;
+ rc = dps310_verify_meas_cfg(data, DPS310_TMP_RDY);
+ if (rc) {
+ if (rc < 0)
+ goto done;
+
+ rate = dps310_get_temp_samp_freq(data);
+ timeout = DPS310_POLL_TIMEOUT_US(rate);
+
+ /*
+ * Poll for sensor readiness; base the timeout upon the sample
+ * rate.
+ */
+ rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG,
+ ready, ready & DPS310_TMP_RDY,
+ DPS310_POLL_SLEEP_US(timeout),
+ timeout);
+ if (rc < 0)
+ goto done;
+ }
rc = dps310_read_temp_ready(data);
@@ -677,52 +829,12 @@ static const struct iio_info dps310_info = {
.write_raw = dps310_write_raw,
};
-/*
- * Some verions of chip will read temperatures in the ~60C range when
- * its actually ~20C. This is the manufacturer recommended workaround
- * to correct the issue. The registers used below are undocumented.
- */
-static int dps310_temp_workaround(struct dps310_data *data)
-{
- int rc;
- int reg;
-
- rc = regmap_read(data->regmap, 0x32, ®);
- if (rc < 0)
- return rc;
-
- /*
- * If bit 1 is set then the device is okay, and the workaround does not
- * need to be applied
- */
- if (reg & BIT(1))
- return 0;
-
- rc = regmap_write(data->regmap, 0x0e, 0xA5);
- if (rc < 0)
- return rc;
-
- rc = regmap_write(data->regmap, 0x0f, 0x96);
- if (rc < 0)
- return rc;
-
- rc = regmap_write(data->regmap, 0x62, 0x02);
- if (rc < 0)
- return rc;
-
- rc = regmap_write(data->regmap, 0x0e, 0x00);
- if (rc < 0)
- return rc;
-
- return regmap_write(data->regmap, 0x0f, 0x00);
-}
-
static int dps310_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct dps310_data *data;
struct iio_dev *iio;
- int rc, ready;
+ int rc;
iio = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!iio)
@@ -747,54 +859,8 @@ static int dps310_probe(struct i2c_client *client,
if (rc)
return rc;
- /*
- * Set up pressure sensor in single sample, one measurement per second
- * mode
- */
- rc = regmap_write(data->regmap, DPS310_PRS_CFG, 0);
-
- /*
- * Set up external (MEMS) temperature sensor in single sample, one
- * measurement per second mode
- */
- rc = regmap_write(data->regmap, DPS310_TMP_CFG, DPS310_TMP_EXT);
- if (rc < 0)
- return rc;
-
- /* Temp and pressure shifts are disabled when PRC <= 8 */
- rc = regmap_write_bits(data->regmap, DPS310_CFG_REG,
- DPS310_PRS_SHIFT_EN | DPS310_TMP_SHIFT_EN, 0);
- if (rc < 0)
- return rc;
-
- /* MEAS_CFG doesn't update correctly unless first written with 0 */
- rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
- DPS310_MEAS_CTRL_BITS, 0);
- if (rc < 0)
- return rc;
-
- /* Turn on temperature and pressure measurement in the background */
- rc = regmap_write_bits(data->regmap, DPS310_MEAS_CFG,
- DPS310_MEAS_CTRL_BITS, DPS310_PRS_EN |
- DPS310_TEMP_EN | DPS310_BACKGROUND);
- if (rc < 0)
- return rc;
-
- /*
- * Calibration coefficients required for reporting temperature.
- * They are available 40ms after the device has started
- */
- rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
- ready & DPS310_COEF_RDY, 10000, 40000);
- if (rc < 0)
- return rc;
-
- rc = dps310_get_coefs(data);
- if (rc < 0)
- return rc;
-
- rc = dps310_temp_workaround(data);
- if (rc < 0)
+ rc = dps310_startup(data);
+ if (rc)
return rc;
rc = devm_iio_device_register(&client->dev, iio);
--
2.27.0
Powered by blists - more mailing lists