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

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>

diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
index 6b46a3b67c41695f621c522ede3f25d7cbee82aa..d91dfbe47aa50fac663b3fec9f958a7fd7f1dff8 100644 (file)
--- 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) {