[RFC 13/16] drm/nouveau/ibus: add GK20A support

[Alexandre Courbot <acourbot@nvidia.com>]

Add support for initializing the priv ring of GK20A. This is done by the
BIOS on desktop GPUs, but needs to be done by hand on Tegra.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpu/drm/nouveau/Makefile                   |   1 +
 drivers/gpu/drm/nouveau/core/include/subdev/ibus.h |   1 +
 drivers/gpu/drm/nouveau/core/subdev/ibus/nvea.c    | 108 +++++++++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 drivers/gpu/drm/nouveau/core/subdev/ibus/nvea.c

diff --git a/drivers/gpu/drm/nouveau/Makefile b/drivers/gpu/drm/nouveau/Makefile
index 6c4b76d..3548fcd 100644
--- a/drivers/gpu/drm/nouveau/Makefile
+++ b/drivers/gpu/drm/nouveau/Makefile
@@ -132,6 +132,7 @@ nouveau-y += core/subdev/i2c/nv94.o
 nouveau-y += core/subdev/i2c/nvd0.o
 nouveau-y += core/subdev/ibus/nvc0.o
 nouveau-y += core/subdev/ibus/nve0.o
+nouveau-y += core/subdev/ibus/nvea.o
 nouveau-y += core/subdev/instmem/base.o
 nouveau-y += core/subdev/instmem/nv04.o
 nouveau-y += core/subdev/instmem/nv40.o
diff --git a/drivers/gpu/drm/nouveau/core/include/subdev/ibus.h b/drivers/gpu/drm/nouveau/core/include/subdev/ibus.h
index 88814f1..056a42f 100644
--- a/drivers/gpu/drm/nouveau/core/include/subdev/ibus.h
+++ b/drivers/gpu/drm/nouveau/core/include/subdev/ibus.h
@@ -30,5 +30,6 @@ nouveau_ibus(void *obj)
 
 extern struct nouveau_oclass nvc0_ibus_oclass;
 extern struct nouveau_oclass nve0_ibus_oclass;
+extern struct nouveau_oclass nvea_ibus_oclass;
 
 #endif
diff --git a/drivers/gpu/drm/nouveau/core/subdev/ibus/nvea.c b/drivers/gpu/drm/nouveau/core/subdev/ibus/nvea.c
new file mode 100644
index 0000000..0bcd281
--- /dev/null
+++ b/drivers/gpu/drm/nouveau/core/subdev/ibus/nvea.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2014, NVIDIA Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <subdev/ibus.h>
+
+struct nvea_ibus_priv {
+	struct nouveau_ibus base;
+};
+
+static void
+nvea_ibus_init_priv_ring(struct nvea_ibus_priv *priv)
+{
+	u32 data;
+
+	data = nv_rd32(priv, 0x137250);
+	data &= (~0x3f);
+	nv_wr32(priv, 0x137250, data);
+
+	nv_mask(priv, 0x000200, 0x20, 0);
+	udelay(20);
+	nv_mask(priv, 0x000200, 0x20, 0x20);
+
+	nv_wr32(priv, 0x12004c, 0x4);
+	nv_wr32(priv, 0x122204, 0x2);
+	nv_rd32(priv, 0x122204);
+}
+
+static void
+nvea_ibus_intr(struct nouveau_subdev *subdev)
+{
+	struct nvea_ibus_priv *priv = (void *)subdev;
+	u32 status0 = nv_rd32(priv, 0x120058);
+	s32 retry = 100;
+	u32 command;
+
+	if (status0 & 0x7) {
+		nv_debug(priv, "resetting priv ring\n");
+		nvea_ibus_init_priv_ring(priv);
+	}
+
+	/* Acknowledge interrupt */
+	command = nv_rd32(priv, 0x0012004c);
+	command |= 0x2;
+	nv_wr32(priv, 0x0012004c, command);
+
+	while (--retry >= 0) {
+		command = nv_rd32(priv, 0x12004c) & 0x3f;
+		if (command == 0)
+			break;
+	}
+
+	if (retry < 0)
+		nv_debug(priv, "timeout waiting for ringmaster ack\n");
+}
+
+static int
+nvea_ibus_init(struct nouveau_object *object)
+{
+	struct nvea_ibus_priv *priv = (void *)object;
+	int ret;
+
+	ret = _nouveau_ibus_init(object);
+	if (ret)
+		return ret;
+
+	nvea_ibus_init_priv_ring(priv);
+
+	return 0;
+}
+
+static int
+nvea_ibus_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
+	       struct nouveau_oclass *oclass, void *data, u32 size,
+	       struct nouveau_object **pobject)
+{
+	struct nvea_ibus_priv *priv;
+	int ret;
+
+	ret = nouveau_ibus_create(parent, engine, oclass, &priv);
+	*pobject = nv_object(priv);
+	if (ret)
+		return ret;
+
+	nv_subdev(priv)->intr = nvea_ibus_intr;
+	return 0;
+}
+
+struct nouveau_oclass
+nvea_ibus_oclass = {
+	.handle = NV_SUBDEV(IBUS, 0xea),
+	.ofuncs = &(struct nouveau_ofuncs) {
+		.ctor = nvea_ibus_ctor,
+		.dtor = _nouveau_ibus_dtor,
+		.init = nvea_ibus_init,
+		.fini = _nouveau_ibus_fini,
+	},
+};
-- 
1.8.5.3