spi: bcm-qspi: return error if neither hif_mspi nor mspi is available

[ Upstream commit 7c1f23ad34fcdace50275a6aa1e1969b41c6233f ]

If neither a "hif_mspi" nor "mspi" resource is present, the driver will
just early exit in probe but still return success. Apart from not doing
anything meaningful, this would then also lead to a null pointer access
on removal, as platform_get_drvdata() would return NULL, which it would
then try to dereference when trying to unregister the spi master.

Fix this by unconditionally calling devm_ioremap_resource(), as it can
handle a NULL res and will then return a viable ERR_PTR() if we get one.

The "return 0;" was previously a "goto qspi_resource_err;" where then
ret was returned, but since ret was still initialized to 0 at this place
this was a valid conversion in 63c5395bb7a9 ("spi: bcm-qspi: Fix
use-after-free on unbind"). The issue was not introduced by this commit,
only made more obvious.

Fixes: fa236a7ef240 ("spi: bcm-qspi: Add Broadcom MSPI driver")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Reviewed-by: Kamal Dasu <kamal.dasu@broadcom.com>
Link: https://lore.kernel.org/r/20230629134306.95823-1-jonas.gorski@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
index cad2d55dcd3d..137e7315a3cf 100644
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -1543,13 +1543,9 @@ int bcm_qspi_probe(struct platform_device *pdev,
 		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 						   "mspi");
 
-	if (res) {
-		qspi->base[MSPI]  = devm_ioremap_resource(dev, res);
-		if (IS_ERR(qspi->base[MSPI]))
-			return PTR_ERR(qspi->base[MSPI]);
-	} else {
-		return 0;
-	}
+	qspi->base[MSPI]  = devm_ioremap_resource(dev, res);
+	if (IS_ERR(qspi->base[MSPI]))
+		return PTR_ERR(qspi->base[MSPI]);
 
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "bspi");
 	if (res) {