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([2409:40d4:1248:1816:fcb7:1765:17f9:b9a5]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-320ea2fcfb8sm17305163eec.21.2026.08.15.10.57.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 15 Aug 2026 10:57:47 -0700 (PDT) From: Yash Suthar To: jic23@kernel.org Cc: dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org, andriy.shevchenko@intel.com, yashsuthar983@gmail.com, grondon@gmail.com, linusw@kernel.org, hexlabsecurity@proton.me, sakari.ailus@linux.intel.com, srinivas.pandruvada@linux.intel.com, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/3] iio: accel: bmc150: use DMA-safe buffers for regmap bulk reads Date: Sat, 15 Aug 2026 23:27:27 +0530 Message-ID: <20260815175728.99541-3-yashsuthar983@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260815175728.99541-1-yashsuthar983@gmail.com> References: <20260815175728.99541-1-yashsuthar983@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The FIFO and read_raw buffers are passed to regmap bulk/raw reads ,which is not DMA-safe.Moved them into struct bmc150_accel_data after scan, each aligned to IIO_DMA_MINALIGN. Suggested-by: Jonathan Cameron Signed-off-by: Yash Suthar --- drivers/iio/accel/bmc150-accel-core.c | 14 ++++++-------- drivers/iio/accel/bmc150-accel.h | 5 +++++ 2 files changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/iio/accel/bmc150-accel-core.c b/drivers/iio/accel/bmc150-accel-core.c index 89a475ef9a9b..e8d27fd1be3f 100644 --- a/drivers/iio/accel/bmc150-accel-core.c +++ b/drivers/iio/accel/bmc150-accel-core.c @@ -125,7 +125,6 @@ #define BMC150_ACCEL_REG_FIFO_CONFIG0 0x30 #define BMC150_ACCEL_REG_FIFO_CONFIG1 0x3E #define BMC150_ACCEL_REG_FIFO_DATA 0x3F -#define BMC150_ACCEL_FIFO_LENGTH 32 enum bmc150_accel_axis { AXIS_X, @@ -622,7 +621,6 @@ static int bmc150_accel_get_axis(struct bmc150_accel_data *data, struct device *dev = regmap_get_device(data->regmap); int ret; int axis = chan->scan_index; - __le16 raw_val; mutex_lock(&data->mutex); ret = bmc150_accel_set_power_state(data, true); @@ -632,14 +630,14 @@ static int bmc150_accel_get_axis(struct bmc150_accel_data *data, } ret = regmap_bulk_read(data->regmap, BMC150_ACCEL_AXIS_TO_REG(axis), - &raw_val, sizeof(raw_val)); + &data->regval, sizeof(data->regval)); if (ret < 0) { dev_err(dev, "Error reading axis %d\n", axis); bmc150_accel_set_power_state(data, false); mutex_unlock(&data->mutex); return ret; } - *val = sign_extend32(le16_to_cpu(raw_val) >> chan->scan_type.shift, + *val = sign_extend32(le16_to_cpu(data->regval) >> chan->scan_type.shift, chan->scan_type.realbits - 1); ret = bmc150_accel_set_power_state(data, false); mutex_unlock(&data->mutex); @@ -918,7 +916,7 @@ static int bmc150_accel_set_watermark(struct iio_dev *indio_dev, unsigned val) * frame data is discarded. */ static int bmc150_accel_fifo_transfer(struct bmc150_accel_data *data, - char *buffer, int samples) + void *buffer, int samples) { struct device *dev = regmap_get_device(data->regmap); int sample_length = 3 * 2; @@ -941,7 +939,6 @@ static int __bmc150_accel_fifo_flush(struct iio_dev *indio_dev, struct device *dev = regmap_get_device(data->regmap); int ret, i; u8 count; - u16 buffer[BMC150_ACCEL_FIFO_LENGTH * 3]; int64_t tstamp; uint64_t sample_period; unsigned int val; @@ -993,7 +990,7 @@ static int __bmc150_accel_fifo_flush(struct iio_dev *indio_dev, count = min_t(u8, count, BMC150_ACCEL_FIFO_LENGTH); - ret = bmc150_accel_fifo_transfer(data, (u8 *)buffer, count); + ret = bmc150_accel_fifo_transfer(data, data->fifo_buff, count); if (ret) return ret; @@ -1008,7 +1005,8 @@ static int __bmc150_accel_fifo_flush(struct iio_dev *indio_dev, j = 0; iio_for_each_active_channel(indio_dev, bit) - memcpy(&data->scan.channels[j++], &buffer[i * 3 + bit], + memcpy(&data->scan.channels[j++], + &data->fifo_buff[i * 3 + bit], sizeof(data->scan.channels[0])); iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, diff --git a/drivers/iio/accel/bmc150-accel.h b/drivers/iio/accel/bmc150-accel.h index 9deff256aed5..8f64b24339e4 100644 --- a/drivers/iio/accel/bmc150-accel.h +++ b/drivers/iio/accel/bmc150-accel.h @@ -56,6 +56,8 @@ enum bmc150_accel_trigger_id { BMC150_ACCEL_TRIGGERS, }; +#define BMC150_ACCEL_FIFO_LENGTH 32 + struct bmc150_accel_data { struct regmap *regmap; int irq; @@ -81,6 +83,9 @@ struct bmc150_accel_data { __le16 channels[3]; aligned_s64 ts; } scan __aligned(IIO_DMA_MINALIGN); + /* DMA-safe buffers for bulk/raw reads */ + __le16 fifo_buff[BMC150_ACCEL_FIFO_LENGTH * 3] __aligned(IIO_DMA_MINALIGN); + __le16 regval __aligned(IIO_DMA_MINALIGN); }; int bmc150_accel_core_probe(struct device *dev, struct regmap *regmap, int irq, -- 2.43.0