drm/nouveau/bios: parse the pwm divisor from the perf table

v2: perf_table now is more in line with the other functions
Signed-off-by: Martin Peres <martin.peres@labri.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/Makefile

@@ -35,6 +35,7 @@ nouveau-y += core/subdev/bios/gpio.o
 nouveau-y += core/subdev/bios/i2c.o
 nouveau-y += core/subdev/bios/init.o
 nouveau-y += core/subdev/bios/mxm.o
+nouveau-y += core/subdev/bios/perf.o
 nouveau-y += core/subdev/bios/pll.o
 nouveau-y += core/subdev/bios/therm.o
 nouveau-y += core/subdev/clock/nv04.o

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

+#ifndef __NVBIOS_PERF_H__
+#define __NVBIOS_PERF_H__
+
+struct nouveau_bios;
+
+struct nvbios_perf_fan {
+	u32 pwm_divisor;
+};
+
+int
+nvbios_perf_fan_parse(struct nouveau_bios *, struct nvbios_perf_fan *);
+
+
+#endif

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

+/*
+ * Copyright 2012 Nouveau Community
+ *
+ * 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: Martin Peres
+ */
+
+#include <subdev/bios.h>
+#include <subdev/bios/bit.h>
+#include <subdev/bios/perf.h>
+
+static u16
+perf_table(struct nouveau_bios *bios, u8 *ver, u8 *hdr, u8 *cnt, u8 *len)
+{
+	struct bit_entry bit_P;
+	u16 perf = 0x0000;
+
+	if (!bit_entry(bios, 'P', &bit_P)) {
+		if (bit_P.version <= 2) {
+			perf = nv_ro16(bios, bit_P.offset + 0);
+			if (perf) {
+				*ver = nv_ro08(bios, perf + 0);
+				*hdr = nv_ro08(bios, perf + 1);
+			}
+		} else
+			nv_error(bios, "unknown offset for perf in BIT P %d\n",
+				bit_P.version);
+	}
+
+	if (bios->bmp_offset) {
+		if (nv_ro08(bios, bios->bmp_offset + 6) >= 0x25) {
+			perf = nv_ro16(bios, bios->bmp_offset + 0x94);
+			if (perf) {
+				*hdr = nv_ro08(bios, perf + 0);
+				*ver = nv_ro08(bios, perf + 1);
+			}
+		}
+	}
+
+	return perf;
+}
+
+int
+nvbios_perf_fan_parse(struct nouveau_bios *bios,
+		      struct nvbios_perf_fan *fan)
+{
+	u8 ver = 0, hdr = 0, cnt = 0, len = 0;
+	u16 perf = perf_table(bios, &ver, &hdr, &cnt, &len);
+	if (!perf)
+		return -ENODEV;
+
+	if (ver >= 0x20 && ver < 0x40 && hdr > 6)
+		fan->pwm_divisor = nv_ro16(bios, perf + 6);
+	else
+		fan->pwm_divisor = 0;
+
+	return 0;
+}