drm/nouveau/bios/power_budget: Add basic power budget parsing

v2: Set entry to 0xff if not found
    Add cap entry for ver 0x30 tables
    Rework to fix memory leak
v3: More error checks
    Simplify check for invalid entries
v4: disable for ver 0x10 for now
    move assignments after the second last return
Signed-off-by: Karol Herbst <karolherbst@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

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

+#ifndef __NVBIOS_POWER_BUDGET_H__
+#define __NVBIOS_POWER_BUDGET_H__
+
+#include <nvkm/subdev/bios.h>
+
+struct nvbios_power_budget_entry {
+	u32 min_w;
+	u32 avg_w;
+	u32 max_w;
+};
+
+struct nvbios_power_budget {
+	u32 offset;
+	u8  ver;
+	u8  hlen;
+	u8  elen;
+	u8  ecount;
+	u8  cap_entry;
+};
+
+int nvbios_power_budget_header(struct nvkm_bios *,
+                               struct nvbios_power_budget *);
+int nvbios_power_budget_entry(struct nvkm_bios *, struct nvbios_power_budget *,
+                              u8 idx, struct nvbios_power_budget_entry *);
+
+#endif

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

@@ -19,6 +19,7 @@ nvkm-y += nvkm/subdev/bios/pcir.o
 nvkm-y += nvkm/subdev/bios/perf.o
 nvkm-y += nvkm/subdev/bios/pll.o
 nvkm-y += nvkm/subdev/bios/pmu.o
+nvkm-y += nvkm/subdev/bios/power_budget.o
 nvkm-y += nvkm/subdev/bios/ramcfg.o
 nvkm-y += nvkm/subdev/bios/rammap.o
 nvkm-y += nvkm/subdev/bios/shadow.o

drivers/gpu/drm/nouveau/nvkm/subdev/bios/power_budget.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/power_budget.h>
+
+static u32
+nvbios_power_budget_table(struct nvkm_bios *bios, u8 *ver, u8 *hdr, u8 *cnt,
+			  u8 *len)
+{
+	struct bit_entry bit_P;
+	u32 power_budget;
+
+	if (bit_entry(bios, 'P', &bit_P) || bit_P.version != 2 ||
+	    bit_P.length < 0x2c)
+		return 0;
+
+	power_budget = nvbios_rd32(bios, bit_P.offset + 0x2c);
+	if (!power_budget)
+		return 0;
+
+	*ver = nvbios_rd08(bios, power_budget);
+	switch (*ver) {
+	case 0x20:
+	case 0x30:
+		*hdr = nvbios_rd08(bios, power_budget + 0x1);
+		*len = nvbios_rd08(bios, power_budget + 0x2);
+		*cnt = nvbios_rd08(bios, power_budget + 0x3);
+		return power_budget;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+int
+nvbios_power_budget_header(struct nvkm_bios *bios,
+                           struct nvbios_power_budget *budget)
+{
+	struct nvkm_subdev *subdev = &bios->subdev;
+	u8 ver, hdr, cnt, len, cap_entry;
+	u32 header;
+
+	if (!bios || !budget)
+		return -EINVAL;
+
+	header = nvbios_power_budget_table(bios, &ver, &hdr, &cnt, &len);
+	if (!header || !cnt)
+		return -ENODEV;
+
+	switch (ver) {
+	case 0x20:
+		cap_entry = nvbios_rd08(bios, header + 0x9);
+		break;
+	case 0x30:
+		cap_entry = nvbios_rd08(bios, header + 0xa);
+		break;
+	default:
+		cap_entry = 0xff;
+	}
+
+	if (cap_entry >= cnt && cap_entry != 0xff) {
+		nvkm_warn(subdev,
+		          "invalid cap_entry in power budget table found\n");
+		budget->cap_entry = 0xff;
+		return -EINVAL;
+	}
+
+	budget->offset = header;
+	budget->ver = ver;
+	budget->hlen = hdr;
+	budget->elen = len;
+	budget->ecount = cnt;
+
+	budget->cap_entry = cap_entry;
+
+	return 0;
+}
+
+int
+nvbios_power_budget_entry(struct nvkm_bios *bios,
+                          struct nvbios_power_budget *budget,
+                          u8 idx, struct nvbios_power_budget_entry *entry)
+{
+	u32 entry_offset;
+
+	if (!bios || !budget || !budget->offset || idx >= budget->ecount
+		|| !entry)
+		return -EINVAL;
+
+	entry_offset = budget->offset + budget->hlen + idx * budget->elen;
+
+	if (budget->ver >= 0x20) {
+		entry->min_w = nvbios_rd32(bios, entry_offset + 0x2);
+		entry->avg_w = nvbios_rd32(bios, entry_offset + 0x6);
+		entry->max_w = nvbios_rd32(bios, entry_offset + 0xa);
+	} else {
+		entry->min_w = 0;
+		entry->max_w = nvbios_rd32(bios, entry_offset + 0x2);
+		entry->avg_w = entry->max_w;
+	}
+
+	return 0;
+}