[RESEND 1/1] soc: qcom: geni: Provide parameter error checking

[Lee Jones <lee.jones@linaro.org>]

When booting with ACPI, the Geni Serial Engine is not set as the I2C/SPI
parent and thus, the wrapper (parent device) is unassigned.  This causes
the kernel to crash with a null dereference error.

Fixes: 8bc529b25354 ("soc: qcom: geni: Add support for ACPI")
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 * Collecting Acks

NB: If someone could send this to Linus for -rc7, it would make v5.3 work
    when booting with ACPI, meaning the newly released distros, due out
    in October will be bootable.  I'd be happy to send it myself with a
    nod from someone prominant (QCom, Andy, Bjorn, etc).

drivers/soc/qcom/qcom-geni-se.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index d5cf953b4337..7d622ea1274e 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -630,6 +630,9 @@ int geni_se_tx_dma_prep(struct geni_se *se, void *buf, size_t len,
 	struct geni_wrapper *wrapper = se->wrapper;
 	u32 val;
 
+	if (!wrapper)
+		return -EINVAL;
+
 	*iova = dma_map_single(wrapper->dev, buf, len, DMA_TO_DEVICE);
 	if (dma_mapping_error(wrapper->dev, *iova))
 		return -EIO;
@@ -663,6 +666,9 @@ int geni_se_rx_dma_prep(struct geni_se *se, void *buf, size_t len,
 	struct geni_wrapper *wrapper = se->wrapper;
 	u32 val;
 
+	if (!wrapper)
+		return -EINVAL;
+
 	*iova = dma_map_single(wrapper->dev, buf, len, DMA_FROM_DEVICE);
 	if (dma_mapping_error(wrapper->dev, *iova))
 		return -EIO;
-- 
2.17.1