On LS2K/LS7A, some non-existant devices don't return 0xffffffff when
scanning. This is a hardware flaw but we can only avoid it by software
now.
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
drivers/pci/controller/pci-loongson.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index a1222fc15454..e22142f75d97 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -134,10 +134,20 @@ static void __iomem *cfg0_map(struct loongson_pci *priv, int bus,
return priv->cfg0_base + addroff;
}
+static bool pdev_is_existant(unsigned char bus, unsigned int device, unsigned int function)
+{
+ if ((bus == 0) && (device >= 9 && device <= 20) && (function > 0))
+ return false;
+
+ return true;
+}
+
static void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devfn,
int where)
{
unsigned char busnum = bus->number;
+ unsigned int device = PCI_SLOT(devfn);
+ unsigned int function = PCI_FUNC(devfn);
struct loongson_pci *priv = pci_bus_to_loongson_pci(bus);
if (pci_is_root_bus(bus))
@@ -147,8 +157,13 @@ static void __iomem *pci_loongson_map_bus(struct pci_bus *bus, unsigned int devf
* Do not read more than one device on the bus other than
* the host bus.
*/
- if (priv->data->flags & FLAG_DEV_FIX &&
- !pci_is_root_bus(bus) && PCI_SLOT(devfn) > 0)
+ if ((priv->data->flags & FLAG_DEV_FIX) && bus->self) {
+ if (!pci_is_root_bus(bus) && (device > 0))
+ return NULL;
+ }
+
+ /* Don't access non-existant devices */
+ if (!pdev_is_existant(busnum, device, function))
return NULL;
/* CFG0 can only access standard space */
--
2.27.0
