drm/nouveau/bios: add parsing of BIT M(v2) +0x03 table

We only support one kind of matching here (ramcfg strap), but it appears
alternate methods are possible.  I wrote a tool to scan our vbios repo
for other types, but did not see any used.  Hopefully this means there
aren't any in the wild that will now break.
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/Makefile

@@ -62,6 +62,7 @@ nouveau-y += core/subdev/bios/therm.o
 nouveau-y += core/subdev/bios/vmap.o
 nouveau-y += core/subdev/bios/volt.o
 nouveau-y += core/subdev/bios/xpio.o
+nouveau-y += core/subdev/bios/M0203.o
 nouveau-y += core/subdev/bios/M0205.o
 nouveau-y += core/subdev/bios/M0209.o
 nouveau-y += core/subdev/bios/P0260.o

drivers/gpu/drm/nouveau/core/include/subdev/bios/M0203.h

+#ifndef __NVBIOS_M0203_H__
+#define __NVBIOS_M0203_H__
+
+struct nvbios_M0203T {
+#define M0203T_TYPE_RAMCFG 0x00
+	u8  type;
+	u16 pointer;
+};
+
+u32 nvbios_M0203Te(struct nouveau_bios *, u8 *ver, u8 *hdr, u8 *cnt, u8 *len);
+u32 nvbios_M0203Tp(struct nouveau_bios *, u8 *ver, u8 *hdr, u8 *cnt, u8 *len,
+		   struct nvbios_M0203T *);
+
+struct nvbios_M0203E {
+#define M0203E_TYPE_DDR2  0x0
+#define M0203E_TYPE_DDR3  0x1
+#define M0203E_TYPE_GDDR3 0x2
+#define M0203E_TYPE_GDDR5 0x3
+#define M0203E_TYPE_SKIP  0xf
+	u8 type;
+	u8 strap;
+	u8 group;
+};
+
+u32 nvbios_M0203Ee(struct nouveau_bios *, int idx, u8 *ver, u8 *hdr);
+u32 nvbios_M0203Ep(struct nouveau_bios *, int idx, u8 *ver, u8 *hdr,
+		   struct nvbios_M0203E *);
+u32 nvbios_M0203Em(struct nouveau_bios *, u8 ramcfg, u8 *ver, u8 *hdr,
+		   struct nvbios_M0203E *);
+
+#endif

drivers/gpu/drm/nouveau/core/subdev/bios/M0203.c

+/*
+ * Copyright 2014 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: Ben Skeggs
+ */
+
+#include <subdev/bios.h>
+#include <subdev/bios/bit.h>
+#include <subdev/bios/M0203.h>
+
+u32
+nvbios_M0203Te(struct nouveau_bios *bios, u8 *ver, u8 *hdr, u8 *cnt, u8 *len)
+{
+	struct bit_entry bit_M;
+	u32 data = 0x00000000;
+
+	if (!bit_entry(bios, 'M', &bit_M)) {
+		if (bit_M.version == 2 && bit_M.length > 0x04)
+			data = nv_ro16(bios, bit_M.offset + 0x03);
+		if (data) {
+			*ver = nv_ro08(bios, data + 0x00);
+			switch (*ver) {
+			case 0x10:
+				*hdr = nv_ro08(bios, data + 0x01);
+				*len = nv_ro08(bios, data + 0x02);
+				*cnt = nv_ro08(bios, data + 0x03);
+				return data;
+			default:
+				break;
+			}
+		}
+	}
+
+	return 0x00000000;
+}
+
+u32
+nvbios_M0203Tp(struct nouveau_bios *bios, u8 *ver, u8 *hdr, u8 *cnt, u8 *len,
+	       struct nvbios_M0203T *info)
+{
+	u32 data = nvbios_M0203Te(bios, ver, hdr, cnt, len);
+	memset(info, 0x00, sizeof(*info));
+	switch (!!data * *ver) {
+	case 0x10:
+		info->type    = nv_ro08(bios, data + 0x04);
+		info->pointer = nv_ro16(bios, data + 0x05);
+		break;
+	default:
+		break;
+	}
+	return data;
+}
+
+u32
+nvbios_M0203Ee(struct nouveau_bios *bios, int idx, u8 *ver, u8 *hdr)
+{
+	u8  cnt, len;
+	u32 data = nvbios_M0203Te(bios, ver, hdr, &cnt, &len);
+	if (data && idx < cnt) {
+		data = data + *hdr + idx * len;
+		*hdr = len;
+		return data;
+	}
+	return 0x00000000;
+}
+
+u32
+nvbios_M0203Ep(struct nouveau_bios *bios, int idx, u8 *ver, u8 *hdr,
+	       struct nvbios_M0203E *info)
+{
+	u32 data = nvbios_M0203Ee(bios, idx, ver, hdr);
+	memset(info, 0x00, sizeof(*info));
+	switch (!!data * *ver) {
+	case 0x10:
+		info->type  = (nv_ro08(bios, data + 0x00) & 0x0f) >> 0;
+		info->strap = (nv_ro08(bios, data + 0x00) & 0xf0) >> 4;
+		info->group = (nv_ro08(bios, data + 0x01) & 0x0f) >> 0;
+		return data;
+	default:
+		break;
+	}
+	return 0x00000000;
+}
+
+u32
+nvbios_M0203Em(struct nouveau_bios *bios, u8 ramcfg, u8 *ver, u8 *hdr,
+	       struct nvbios_M0203E *info)
+{
+	struct nvbios_M0203T M0203T;
+	u8  cnt, len, idx = 0xff;
+	u32 data;
+
+	if (!nvbios_M0203Tp(bios, ver, hdr, &cnt, &len, &M0203T)) {
+		nv_warn(bios, "M0203T not found\n");
+		return 0x00000000;
+	}
+
+	while ((data = nvbios_M0203Ep(bios, ++idx, ver, hdr, info))) {
+		switch (M0203T.type) {
+		case M0203T_TYPE_RAMCFG:
+			if (info->strap != ramcfg)
+				continue;
+			return data;
+		default:
+			nv_warn(bios, "M0203T type %02x\n", M0203T.type);
+			return 0x00000000;
+		}
+	}
+
+	return data;
+}