PCI: endpoint: Make *_get_first_free_bar() take into account 64 bit BAR

pci_epc_get_first_free_bar() uses only "reserved_bar" member in
epc_features to get the first unreserved BAR. However if the reserved BAR
is also a 64-bit BAR, then the next BAR shouldn't be returned (since 64-bit
BAR uses two BARs).

Make pci_epc_get_first_free_bar() take into account 64 bit BAR while
returning the first free unreserved BAR.

Link: https://lore.kernel.org/r/20210201195809.7342-3-kishon@ti.com
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index cadd3db..25e5767 100644 (file)
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -93,12 +93,20 @@ EXPORT_SYMBOL_GPL(pci_epc_get);
 unsigned int pci_epc_get_first_free_bar(const struct pci_epc_features
                                        *epc_features)
 {
-       int free_bar;
+       unsigned long free_bar;
 
        if (!epc_features)
                return 0;
 
-       free_bar = ffz(epc_features->reserved_bar);
+       /* Find if the reserved BAR is also a 64-bit BAR */
+       free_bar = epc_features->reserved_bar & epc_features->bar_fixed_64bit;
+
+       /* Set the adjacent bit if the reserved BAR is also a 64-bit BAR */
+       free_bar <<= 1;
+       free_bar |= epc_features->reserved_bar;
+
+       /* Now find the free BAR */
+       free_bar = ffz(free_bar);
        if (free_bar > 5)
                return 0;