drm/nouveau/nvbios/iccsense: add parsing of the SENSE table

Karol Herbst:
v4: don't kmalloc(0)
v5: stricter validation
Signed-off-by: Karol Herbst <nouveau@karolherbst.de>
Reviewed-by: Martin Peres <martin.peres@free.fr>

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

+#ifndef __NVBIOS_ICCSENSE_H__
+#define __NVBIOS_ICCSENSE_H__
+struct pwr_rail_t {
+	u8 mode;
+	u8 extdev_id;
+	u8 resistor_mohm;
+	u8 rail;
+};
+
+struct nvbios_iccsense {
+	int nr_entry;
+	struct pwr_rail_t *rail;
+};
+
+int nvbios_iccsense_parse(struct nvkm_bios *, struct nvbios_iccsense *);
+#endif

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

@@ -10,6 +10,7 @@ nvkm-y += nvkm/subdev/bios/extdev.o
 nvkm-y += nvkm/subdev/bios/fan.o
 nvkm-y += nvkm/subdev/bios/gpio.o
 nvkm-y += nvkm/subdev/bios/i2c.o
+nvkm-y += nvkm/subdev/bios/iccsense.o
 nvkm-y += nvkm/subdev/bios/image.o
 nvkm-y += nvkm/subdev/bios/init.o
 nvkm-y += nvkm/subdev/bios/mxm.o

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

+/*
+ * Copyright 2015 Martin Peres
+ *
+ * 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/iccsense.h>
+
+static u16
+nvbios_iccsense_table(struct nvkm_bios *bios, u8 *ver, u8 *hdr, u8 *cnt,
+		      u8 *len)
+{
+	struct bit_entry bit_P;
+	u16 iccsense;
+
+	if (bit_entry(bios, 'P', &bit_P) || bit_P.version != 2 ||
+	    bit_P.length < 0x2c)
+		return 0;
+
+	iccsense = nvbios_rd16(bios, bit_P.offset + 0x28);
+	if (!iccsense)
+		return 0;
+
+	*ver = nvbios_rd08(bios, iccsense + 0);
+	switch (*ver) {
+	case 0x10:
+	case 0x20:
+		*hdr = nvbios_rd08(bios, iccsense + 1);
+		*len = nvbios_rd08(bios, iccsense + 2);
+		*cnt = nvbios_rd08(bios, iccsense + 3);
+		return iccsense;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+int
+nvbios_iccsense_parse(struct nvkm_bios *bios, struct nvbios_iccsense *iccsense)
+{
+	struct nvkm_subdev *subdev = &bios->subdev;
+	u8 ver, hdr, cnt, len, i;
+	u16 table, entry;
+
+	table = nvbios_iccsense_table(bios, &ver, &hdr, &cnt, &len);
+	if (!table || !cnt)
+		return -EINVAL;
+
+	if (ver != 0x10 && ver != 0x20) {
+		nvkm_error(subdev, "ICCSENSE version 0x%02x unknown\n", ver);
+		return -EINVAL;
+	}
+
+	iccsense->nr_entry = cnt;
+	iccsense->rail = kmalloc(sizeof(struct pwr_rail_t) * cnt, GFP_KERNEL);
+	if (!iccsense->rail)
+		return -ENOMEM;
+
+	for (i = 0; i < cnt; ++i) {
+		struct pwr_rail_t *rail = &iccsense->rail[i];
+		entry = table + hdr + i * len;
+
+		switch(ver) {
+		case 0x10:
+			rail->mode = nvbios_rd08(bios, entry + 0x1);
+			rail->extdev_id = nvbios_rd08(bios, entry + 0x2);
+			rail->resistor_mohm = nvbios_rd08(bios, entry + 0x3);
+			rail->rail = nvbios_rd08(bios, entry + 0x4);
+			break;
+		case 0x20:
+			rail->mode = nvbios_rd08(bios, entry);
+			rail->extdev_id = nvbios_rd08(bios, entry + 0x1);
+			rail->resistor_mohm = nvbios_rd08(bios, entry + 0x5);
+			rail->rail = nvbios_rd08(bios, entry + 0x6);
+			break;
+		};
+	}
+
+	return 0;
+}