[POWERPC] Add a helper for calculating RTAS "config_addr" parameters

Several RTAS calls take a "config_addr" parameter, which is a particular
way of specifying a PCI busno, devfn and register number into a 32-bit word.
Currently these are open-coded, and I'll be adding another soon, replace
them with a helper that encapsulates the logic. Be more strict about masking
the busno too, just in case.

Booted on P5 LPAR.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/rtas_pci.c b/arch/powerpc/kernel/rtas_pci.c
index 5a798ac6aecf..b4a0de79c060 100644
--- a/arch/powerpc/kernel/rtas_pci.c
+++ b/arch/powerpc/kernel/rtas_pci.c
@@ -81,8 +81,7 @@ int rtas_read_config(struct pci_dn *pdn, int where, int size, u32 *val)
         if (!config_access_valid(pdn, where))
                 return PCIBIOS_BAD_REGISTER_NUMBER;
 
-        addr = ((where & 0xf00) << 20) | (pdn->busno << 16) |
-                (pdn->devfn << 8) | (where & 0xff);
+        addr = rtas_config_addr(pdn->busno, pdn->devfn, where);
         buid = pdn->phb->buid;
         if (buid) {
                 ret = rtas_call(ibm_read_pci_config, 4, 2, &returnval,
@@ -134,8 +133,7 @@ int rtas_write_config(struct pci_dn *pdn, int where, int size, u32 val)
         if (!config_access_valid(pdn, where))
                 return PCIBIOS_BAD_REGISTER_NUMBER;
 
-        addr = ((where & 0xf00) << 20) | (pdn->busno << 16) |
-                (pdn->devfn << 8) | (where & 0xff);
+        addr = rtas_config_addr(pdn->busno, pdn->devfn, where);
         buid = pdn->phb->buid;
         if (buid) {
                 ret = rtas_call(ibm_write_pci_config, 5, 1, NULL, addr,