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Date: Sat, 23 Jul 2022 19:39:10 +0200
From: Angel Iglesias <ang.iglesiasg@...il.com>
To: linux-iio@...r.kernel.org
Cc: Angel Iglesias <ang.iglesiasg@...il.com>,
Jonathan Cameron <jic23@...nel.org>,
Lars-Peter Clausen <lars@...afoo.de>,
Paul Cercueil <paul@...pouillou.net>,
Ulf Hansson <ulf.hansson@...aro.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH v4 3/5] iio: pressure: bmp280: Fix alignment for DMA safety
Adds a DMA-safe buffer to driver data struct to store raw data from sensor
Updated calibration read functions to use DMA-safe buffers as well.
In this case, as calibration data is only read at sensor initialization,
the buffers are allocated with kmalloc and freed after being processed.
Suggested-by: Jonathan Cameron <jic23@...nel.org>
Signed-off-by: Angel Iglesias <ang.iglesiasg@...il.com>
---
drivers/iio/pressure/bmp280-core.c | 164 ++++++++++++++++++-----------
1 file changed, 103 insertions(+), 61 deletions(-)
diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index 60fba199c7a0..9311eeec8473 100644
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -29,6 +29,7 @@
#include <linux/completion.h>
#include <linux/pm_runtime.h>
#include <linux/random.h>
+#include <asm/unaligned.h>
#include "bmp280.h"
@@ -36,7 +37,19 @@
* These enums are used for indexing into the array of calibration
* coefficients for BMP180.
*/
-enum { AC1, AC2, AC3, AC4, AC5, AC6, B1, B2, MB, MC, MD };
+enum {
+ AC1 = 0,
+ AC2 = 2,
+ AC3 = 4,
+ AC4 = 6,
+ AC5 = 8,
+ AC6 = 10,
+ B1 = 12,
+ B2 = 14,
+ MB = 16,
+ MC = 18,
+ MD = 20,
+};
struct bmp180_calib {
s16 AC1;
@@ -104,6 +117,12 @@ struct bmp280_data {
* calculation.
*/
s32 t_fine;
+
+ /*
+ * DMA (thus cache coherency maintenance) may require the
+ * transfer buffers to live in their own cache lines.
+ */
+ u8 buf[3] __aligned(IIO_DMA_MINALIGN);
};
struct bmp280_chip_info {
@@ -135,8 +154,18 @@ struct bmp280_chip_info {
* These enums are used for indexing into the array of compensation
* parameters for BMP280.
*/
-enum { T1, T2, T3 };
-enum { P1, P2, P3, P4, P5, P6, P7, P8, P9 };
+enum { T1 = 0, T2 = 2, T3 = 4 };
+enum {
+ P1 = 0,
+ P2 = 2,
+ P3 = 4,
+ P4 = 6,
+ P5 = 8,
+ P6 = 10,
+ P7 = 12,
+ P8 = 14,
+ P9 = 16,
+};
static const struct iio_chan_spec bmp280_channels[] = {
{
@@ -159,51 +188,59 @@ static const struct iio_chan_spec bmp280_channels[] = {
static int bmp280_read_calib(struct bmp280_data *data, unsigned int chip)
{
int ret;
+ u8 *t_buf;
+ u8 *p_buf;
unsigned int tmp;
- __le16 l16;
- __be16 b16;
struct device *dev = data->dev;
struct bmp280_calib *calib = &data->calib.bmp280;
- __le16 t_buf[BMP280_COMP_TEMP_REG_COUNT / 2];
- __le16 p_buf[BMP280_COMP_PRESS_REG_COUNT / 2];
+ t_buf = kmalloc(BMP280_COMP_TEMP_REG_COUNT, GFP_KERNEL);
+ if (!t_buf)
+ return -ENOMEM;
/* Read temperature calibration values. */
ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START,
t_buf, BMP280_COMP_TEMP_REG_COUNT);
if (ret < 0) {
dev_err(data->dev,
"failed to read temperature calibration parameters\n");
+ kfree(t_buf);
return ret;
}
/* Toss the temperature calibration data into the entropy pool */
add_device_randomness(t_buf, sizeof(t_buf));
- calib->T1 = le16_to_cpu(t_buf[T1]);
- calib->T2 = le16_to_cpu(t_buf[T2]);
- calib->T3 = le16_to_cpu(t_buf[T3]);
+ calib->T1 = get_unaligned_le16(&t_buf[T1]);
+ calib->T2 = get_unaligned_le16(&t_buf[T2]);
+ calib->T3 = get_unaligned_le16(&t_buf[T3]);
+ kfree(t_buf);
+ p_buf = kmalloc(BMP280_COMP_PRESS_REG_COUNT, GFP_KERNEL);
+ if (!p_buf)
+ return -ENOMEM;
/* Read pressure calibration values. */
ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_PRESS_START,
p_buf, BMP280_COMP_PRESS_REG_COUNT);
if (ret < 0) {
dev_err(data->dev,
"failed to read pressure calibration parameters\n");
+ kfree(p_buf);
return ret;
}
/* Toss the pressure calibration data into the entropy pool */
add_device_randomness(p_buf, sizeof(p_buf));
- calib->P1 = le16_to_cpu(p_buf[P1]);
- calib->P2 = le16_to_cpu(p_buf[P2]);
- calib->P3 = le16_to_cpu(p_buf[P3]);
- calib->P4 = le16_to_cpu(p_buf[P4]);
- calib->P5 = le16_to_cpu(p_buf[P5]);
- calib->P6 = le16_to_cpu(p_buf[P6]);
- calib->P7 = le16_to_cpu(p_buf[P7]);
- calib->P8 = le16_to_cpu(p_buf[P8]);
- calib->P9 = le16_to_cpu(p_buf[P9]);
+ calib->P1 = get_unaligned_le16(&p_buf[P1]);
+ calib->P2 = get_unaligned_le16(&p_buf[P2]);
+ calib->P3 = get_unaligned_le16(&p_buf[P3]);
+ calib->P4 = get_unaligned_le16(&p_buf[P4]);
+ calib->P5 = get_unaligned_le16(&p_buf[P5]);
+ calib->P6 = get_unaligned_le16(&p_buf[P6]);
+ calib->P7 = get_unaligned_le16(&p_buf[P7]);
+ calib->P8 = get_unaligned_le16(&p_buf[P8]);
+ calib->P9 = get_unaligned_le16(&p_buf[P9]);
+ kfree(p_buf);
/*
* Read humidity calibration values.
@@ -222,12 +259,12 @@ static int bmp280_read_calib(struct bmp280_data *data, unsigned int chip)
}
calib->H1 = tmp;
- ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H2, &l16, 2);
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H2, data->buf, 2);
if (ret < 0) {
dev_err(dev, "failed to read H2 comp value\n");
return ret;
}
- calib->H2 = sign_extend32(le16_to_cpu(l16), 15);
+ calib->H2 = get_unaligned_le16(data->buf);
ret = regmap_read(data->regmap, BMP280_REG_COMP_H3, &tmp);
if (ret < 0) {
@@ -236,20 +273,20 @@ static int bmp280_read_calib(struct bmp280_data *data, unsigned int chip)
}
calib->H3 = tmp;
- ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H4, &b16, 2);
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H4, data->buf, 2);
if (ret < 0) {
dev_err(dev, "failed to read H4 comp value\n");
return ret;
}
- calib->H4 = sign_extend32(((be16_to_cpu(b16) >> 4) & 0xff0) |
- (be16_to_cpu(b16) & 0xf), 11);
+ calib->H4 = sign_extend32(((get_unaligned_be16(data->buf) >> 4) & 0xff0) |
+ (get_unaligned_be16(data->buf) & 0xf), 11);
- ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H5, &l16, 2);
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H5, data->buf, 2);
if (ret < 0) {
dev_err(dev, "failed to read H5 comp value\n");
return ret;
}
- calib->H5 = sign_extend32(((le16_to_cpu(l16) >> 4) & 0xfff), 11);
+ calib->H5 = sign_extend32(((get_unaligned_le16(data->buf) >> 4) & 0xfff), 11);
ret = regmap_read(data->regmap, BMP280_REG_COMP_H6, &tmp);
if (ret < 0) {
@@ -344,16 +381,15 @@ static int bmp280_read_temp(struct bmp280_data *data,
int *val)
{
int ret;
- __be32 tmp = 0;
s32 adc_temp, comp_temp;
- ret = regmap_bulk_read(data->regmap, BMP280_REG_TEMP_MSB, &tmp, 3);
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_TEMP_MSB, data->buf, 3);
if (ret < 0) {
dev_err(data->dev, "failed to read temperature\n");
return ret;
}
- adc_temp = be32_to_cpu(tmp) >> 12;
+ adc_temp = get_unaligned_be24(data->buf) >> 4;
if (adc_temp == BMP280_TEMP_SKIPPED) {
/* reading was skipped */
dev_err(data->dev, "reading temperature skipped\n");
@@ -377,7 +413,6 @@ static int bmp280_read_press(struct bmp280_data *data,
int *val, int *val2)
{
int ret;
- __be32 tmp = 0;
s32 adc_press;
u32 comp_press;
@@ -386,13 +421,13 @@ static int bmp280_read_press(struct bmp280_data *data,
if (ret < 0)
return ret;
- ret = regmap_bulk_read(data->regmap, BMP280_REG_PRESS_MSB, &tmp, 3);
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_PRESS_MSB, data->buf, 3);
if (ret < 0) {
dev_err(data->dev, "failed to read pressure\n");
return ret;
}
- adc_press = be32_to_cpu(tmp) >> 12;
+ adc_press = get_unaligned_be24(data->buf) >> 4;
if (adc_press == BMP280_PRESS_SKIPPED) {
/* reading was skipped */
dev_err(data->dev, "reading pressure skipped\n");
@@ -408,7 +443,6 @@ static int bmp280_read_press(struct bmp280_data *data,
static int bmp280_read_humid(struct bmp280_data *data, int *val, int *val2)
{
- __be16 tmp;
int ret;
s32 adc_humidity;
u32 comp_humidity;
@@ -418,13 +452,13 @@ static int bmp280_read_humid(struct bmp280_data *data, int *val, int *val2)
if (ret < 0)
return ret;
- ret = regmap_bulk_read(data->regmap, BMP280_REG_HUMIDITY_MSB, &tmp, 2);
+ ret = regmap_bulk_read(data->regmap, BMP280_REG_HUMIDITY_MSB, data->buf, 2);
if (ret < 0) {
dev_err(data->dev, "failed to read humidity\n");
return ret;
}
- adc_humidity = be16_to_cpu(tmp);
+ adc_humidity = get_unaligned_be16(data->buf);
if (adc_humidity == BMP280_HUMIDITY_SKIPPED) {
/* reading was skipped */
dev_err(data->dev, "reading humidity skipped\n");
@@ -755,56 +789,65 @@ static int bmp180_measure(struct bmp280_data *data, u8 ctrl_meas)
static int bmp180_read_adc_temp(struct bmp280_data *data, int *val)
{
- __be16 tmp;
int ret;
ret = bmp180_measure(data, BMP180_MEAS_TEMP);
if (ret)
return ret;
- ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, &tmp, 2);
+ ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, data->buf, 2);
if (ret)
return ret;
- *val = be16_to_cpu(tmp);
+ *val = get_unaligned_be16(data->buf);
return 0;
}
static int bmp180_read_calib(struct bmp280_data *data, unsigned int chip)
{
+ struct bmp180_calib *calib = &data->calib.bmp180;
+ u8 *buf;
int ret;
int i;
- struct bmp180_calib *calib = &data->calib.bmp180;
- __be16 buf[BMP180_REG_CALIB_COUNT / 2];
+
+ buf = kmalloc(BMP180_REG_CALIB_COUNT, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
ret = regmap_bulk_read(data->regmap, BMP180_REG_CALIB_START, buf,
- sizeof(buf));
+ BMP180_REG_CALIB_COUNT);
- if (ret < 0)
+ if (ret < 0) {
+ kfree(buf);
return ret;
+ }
/* None of the words has the value 0 or 0xFFFF */
- for (i = 0; i < ARRAY_SIZE(buf); i++) {
- if (buf[i] == cpu_to_be16(0) || buf[i] == cpu_to_be16(0xffff))
+ for (i = 0; i < BMP180_REG_CALIB_COUNT; i += 2) {
+ if (get_unaligned_be16(&buf[i]) == cpu_to_be16(0) ||
+ get_unaligned_be16(&buf[i]) == cpu_to_be16(0xffff)) {
+ kfree(buf);
return -EIO;
+ }
}
/* Toss the calibration data into the entropy pool */
- add_device_randomness(buf, sizeof(buf));
-
- calib->AC1 = be16_to_cpu(buf[AC1]);
- calib->AC2 = be16_to_cpu(buf[AC2]);
- calib->AC3 = be16_to_cpu(buf[AC3]);
- calib->AC4 = be16_to_cpu(buf[AC4]);
- calib->AC5 = be16_to_cpu(buf[AC5]);
- calib->AC6 = be16_to_cpu(buf[AC6]);
- calib->B1 = be16_to_cpu(buf[B1]);
- calib->B2 = be16_to_cpu(buf[B2]);
- calib->MB = be16_to_cpu(buf[MB]);
- calib->MC = be16_to_cpu(buf[MC]);
- calib->MD = be16_to_cpu(buf[MD]);
-
+ add_device_randomness(buf, BMP180_REG_CALIB_COUNT);
+
+ calib->AC1 = get_unaligned_be16(&buf[AC1]);
+ calib->AC2 = get_unaligned_be16(&buf[AC2]);
+ calib->AC3 = get_unaligned_be16(&buf[AC3]);
+ calib->AC4 = get_unaligned_be16(&buf[AC4]);
+ calib->AC5 = get_unaligned_be16(&buf[AC5]);
+ calib->AC6 = get_unaligned_be16(&buf[AC6]);
+ calib->B1 = get_unaligned_be16(&buf[B1]);
+ calib->B2 = get_unaligned_be16(&buf[B2]);
+ calib->MB = get_unaligned_be16(&buf[MB]);
+ calib->MC = get_unaligned_be16(&buf[MC]);
+ calib->MD = get_unaligned_be16(&buf[MD]);
+
+ kfree(buf);
return 0;
}
@@ -852,18 +895,17 @@ static int bmp180_read_temp(struct bmp280_data *data, int *val)
static int bmp180_read_adc_press(struct bmp280_data *data, int *val)
{
int ret;
- __be32 tmp = 0;
u8 oss = data->oversampling_press;
ret = bmp180_measure(data, BMP180_MEAS_PRESS_X(oss));
if (ret)
return ret;
- ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, &tmp, 3);
+ ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, data->buf, 3);
if (ret)
return ret;
- *val = (be32_to_cpu(tmp) >> 8) >> (8 - oss);
+ *val = get_unaligned_be24(data->buf) >> (8 - oss);
return 0;
}
--
2.37.1
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