spi: core: Validate length of the transfers in message

SPI transfer length should be multiple of SPI word size,
where SPI word size should be power-of-two multiple

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index bb660145d19e..1b53eee2cbca 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1617,6 +1617,7 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 {
         struct spi_master *master = spi->master;
         struct spi_transfer *xfer;
+        int w_size, n_words;
 
         if (list_empty(&message->transfers))
                 return -EINVAL;
@@ -1668,6 +1669,22 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
                                 return -EINVAL;
                 }
 
+                /*
+                 * SPI transfer length should be multiple of SPI word size
+                 * where SPI word size should be power-of-two multiple
+                 */
+                if (xfer->bits_per_word <= 8)
+                        w_size = 1;
+                else if (xfer->bits_per_word <= 16)
+                        w_size = 2;
+                else
+                        w_size = 4;
+
+                n_words = xfer->len / w_size;
+                /* No partial transfers accepted */
+                if (!n_words || xfer->len % w_size)
+                        return -EINVAL;
+
                 if (xfer->speed_hz && master->min_speed_hz &&
                     xfer->speed_hz < master->min_speed_hz)
                         return -EINVAL;