[Skiboot] [PATCH 2/5] lpc: Mark the power9 LPC bus as compatible with power8

[Benjamin Herrenschmidt]

We support all the OPAL calls, and it avoids bugs in existing
Linux kernels that would otherwise crash when attempting to
access devices using a direct mapping.

When Linux is fixed it will recognize that direct mapping is
supported and avoid the OPAL calls.

Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---
 hdata/fsp.c |  3 ++-
 hw/lpc.c    | 12 ++++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/hdata/fsp.c b/hdata/fsp.c
index 656aad7..998724b 100644
--- a/hdata/fsp.c
+++ b/hdata/fsp.c
@@ -364,7 +364,8 @@ static void bmc_create_node(const struct HDIF_common_hdr *sp)
 	lpc = dt_new_addr(lpcm, "lpc", 0x0);
 	dt_add_property_cells(lpc, "#address-cells", 2);
 	dt_add_property_cells(lpc, "#size-cells", 1);
-	dt_add_property_strings(lpc, "compatible", "ibm,power9-lpc");
+	dt_add_property_strings(lpc, "compatible",
+				"ibm,power9-lpc", "ibm,power8-lpc");
 
 	dt_add_property_cells(lpc, "ranges",
 		0, 0, mem_bar, 0x10000000, /* MEM space */
diff --git a/hw/lpc.c b/hw/lpc.c
index 9ba8217..babc788 100644
--- a/hw/lpc.c
+++ b/hw/lpc.c
@@ -1119,14 +1119,18 @@ void lpc_init(void)
 	struct dt_node *xn;
 	bool has_lpc = false;
 
-	dt_for_each_compatible(dt_root, xn, "ibm,power8-lpc") {
-		lpc_init_chip_p8(xn);
-		has_lpc = true;
-	}
+	/* Look for P9 first as the DT is compatile for both 8 and 9 */
 	dt_for_each_compatible(dt_root, xn, "ibm,power9-lpcm-opb") {
 		lpc_init_chip_p9(xn);
 		has_lpc = true;
 	}
+
+	if (!has_lpc) {
+		dt_for_each_compatible(dt_root, xn, "ibm,power8-lpc") {
+			lpc_init_chip_p8(xn);
+			has_lpc = true;
+		}
+	}
 	if (lpc_default_chip_id >= 0)
 		printf("LPC: Default bus on chip 0x%x\n", lpc_default_chip_id);
 
-- 
2.9.3