powerpc/powernv: Add support for direct mapped LPC on POWER9

Use the new non-PCI ISA bridge support to expose the POWER9
LPC bus as direct mapped via the ISA IO port range. This
enables direct access via drivers such as 8250

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

2 files changed, 15 insertions, 6 deletions

diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c
index bc525ea0dc09..0694d20f85b6 100644
--- a/arch/powerpc/kernel/legacy_serial.c
+++ b/arch/powerpc/kernel/legacy_serial.c
@@ -233,7 +233,8 @@ static int __init add_legacy_isa_port(struct device_node *np,
          *
          * Note: Don't even try on P8 lpc, we know it's not directly mapped
          */
-        if (!of_device_is_compatible(isa_brg, "ibm,power8-lpc")) {
+        if (!of_device_is_compatible(isa_brg, "ibm,power8-lpc") ||
+            of_get_property(isa_brg, "ranges", NULL)) {
                 taddr = of_translate_address(np, reg);
                 if (taddr == OF_BAD_ADDR)
                         taddr = 0;
diff --git a/arch/powerpc/platforms/powernv/opal-lpc.c b/arch/powerpc/platforms/powernv/opal-lpc.c
index 2048ce7912f4..1a8cd54c1e74 100644
--- a/arch/powerpc/platforms/powernv/opal-lpc.c
+++ b/arch/powerpc/platforms/powernv/opal-lpc.c
@@ -407,9 +407,17 @@ void opal_lpc_init(void)
         if (opal_lpc_chip_id < 0)
                 return;
 
-        /* Setup special IO ops */
-        ppc_pci_io = opal_lpc_io;
-        isa_io_special = true;
-
-        pr_info("OPAL: Power8 LPC bus found, chip ID %d\n", opal_lpc_chip_id);
+        /* Does it support direct mapping ? */
+        if (of_get_property(np, "ranges", NULL)) {
+                pr_info("OPAL: Found memory mapped LPC bus on chip %d\n",
+                        opal_lpc_chip_id);
+                isa_bridge_init_non_pci(np);
+        } else {
+                pr_info("OPAL: Found non-mapped LPC bus on chip %d\n",
+                        opal_lpc_chip_id);
+
+                /* Setup special IO ops */
+                ppc_pci_io = opal_lpc_io;
+                isa_io_special = true;
+        }
 }