drm/nouveau/bios: Add parsing of VPSTATE table

This table contains three important clocks:

base  clock: This is the non boosted max clock.
tdp   clock: The clock at wich the vbios guarentees the TDP won't ever be
             exceeded at max load (seems to be always the same as the base
             clock, but behaves differently).
boost clock: The avg clock the gpu will stay boosted to. It doesn't seem to
             affect the behaviour of the nvidia driver at all though.

v2: Make clear that base/boost/tdp fields are ids.
v5: Rename Base clock to vpstate.
    Make vbios pointers 32bit.
Signed-off-by: Karol Herbst <karolherbst@gmail.com>
Reviewed-by: Martin Peres <martin.peres@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvkm/subdev/bios/vpstate.h

+#ifndef __NVBIOS_VPSTATE_H__
+#define __NVBIOS_VPSTATE_H__
+struct nvbios_vpstate_header {
+	u32 offset;
+
+	u8 version;
+	u8 hlen;
+	u8 ecount;
+	u8 elen;
+	u8 scount;
+	u8 slen;
+
+	u8 base_id;
+	u8 boost_id;
+	u8 tdp_id;
+};
+struct nvbios_vpstate_entry {
+	u8  pstate;
+	u16 clock_mhz;
+};
+int nvbios_vpstate_parse(struct nvkm_bios *, struct nvbios_vpstate_header *);
+int nvbios_vpstate_entry(struct nvkm_bios *, struct nvbios_vpstate_header *,
+			 u8 idx, struct nvbios_vpstate_entry *);
+#endif

drivers/gpu/drm/nouveau/nvkm/subdev/bios/Kbuild

@@ -31,6 +31,7 @@ nvkm-y += nvkm/subdev/bios/timing.o
 nvkm-y += nvkm/subdev/bios/therm.o
 nvkm-y += nvkm/subdev/bios/vmap.o
 nvkm-y += nvkm/subdev/bios/volt.o
+nvkm-y += nvkm/subdev/bios/vpstate.o
 nvkm-y += nvkm/subdev/bios/xpio.o
 nvkm-y += nvkm/subdev/bios/M0203.o
 nvkm-y += nvkm/subdev/bios/M0205.o

drivers/gpu/drm/nouveau/nvkm/subdev/bios/vpstate.c

+/*
+ * Copyright 2016 Karol Herbst
+ *
+ * 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: Karol Herbst
+ */
+#include <subdev/bios.h>
+#include <subdev/bios/bit.h>
+#include <subdev/bios/vpstate.h>
+
+static u32
+nvbios_vpstate_offset(struct nvkm_bios *b)
+{
+	struct bit_entry bit_P;
+
+	if (!bit_entry(b, 'P', &bit_P)) {
+		if (bit_P.version == 2)
+			return nvbios_rd32(b, bit_P.offset + 0x38);
+	}
+
+	return 0x0000;
+}
+
+int
+nvbios_vpstate_parse(struct nvkm_bios *b, struct nvbios_vpstate_header *h)
+{
+	if (!h)
+		return -EINVAL;
+
+	h->offset = nvbios_vpstate_offset(b);
+	if (!h->offset)
+		return -ENODEV;
+
+	h->version = nvbios_rd08(b, h->offset);
+	switch (h->version) {
+	case 0x10:
+		h->hlen     = nvbios_rd08(b, h->offset + 0x1);
+		h->elen     = nvbios_rd08(b, h->offset + 0x2);
+		h->slen     = nvbios_rd08(b, h->offset + 0x3);
+		h->scount   = nvbios_rd08(b, h->offset + 0x4);
+		h->ecount   = nvbios_rd08(b, h->offset + 0x5);
+
+		h->base_id  = nvbios_rd08(b, h->offset + 0x0f);
+		h->boost_id = nvbios_rd08(b, h->offset + 0x10);
+		h->tdp_id   = nvbios_rd08(b, h->offset + 0x11);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+int
+nvbios_vpstate_entry(struct nvkm_bios *b, struct nvbios_vpstate_header *h,
+		     u8 idx, struct nvbios_vpstate_entry *e)
+{
+	u32 offset;
+
+	if (!e || !h || idx > h->ecount)
+		return -EINVAL;
+
+	offset = h->offset + h->hlen + idx * (h->elen + (h->slen * h->scount));
+	e->pstate    = nvbios_rd08(b, offset);
+	e->clock_mhz = nvbios_rd16(b, offset + 0x5);
+	return 0;
+}