rockchip/rk3399: Add pwm_regulator.c for pwm then ramp boot up cpu

Before, we calculate the pwm duties for cpu cores and centerlogic by
hand, adding pwm_regulator.c to handle this. The default pwm design
min/max voltage may be different between revs.

With the pwm regulator, this patch changes the little cpu frequency from
600M to 1512M, and raises CPU voltage to 1.2V correspondingly.

This also means we decide to drop the ES1 because it may fail to
bootup with 1.5G ~ 1.2v.

BRANCH=none
BUG=chrome-os-partner:54376,chrome-os-partner:54862
TEST=Bootup on kevin board

Change-Id: Id04c176bddfb9cdf3d25b65736e40249a85f6aa1
Signed-off-by: Martin Roth <martinroth@chromium.org>
Original-Commit-Id: ee4365c787ec523b7ee1028ea100dcfbb331b3a9
Original-Change-Id: Ide75bbd92d1cbb14f934baeec0e38862bc08402b
Original-Signed-off-by: Eric Gao <eric.gao@rock-chips.com>
Original-Signed-off-by: Shunqian Zheng <zhengsq@rock-chips.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/364410
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/16368
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 82 insertions, 0 deletions

diff --git a/src/mainboard/google/gru/pwm_regulator.c b/src/mainboard/google/gru/pwm_regulator.c
new file mode 100644
index 0000000000..f382b2b58c
--- /dev/null
+++ b/src/mainboard/google/gru/pwm_regulator.c
@@ -0,0 +1,82 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2016 Rockchip Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/io.h>
+#include <assert.h>
+#include <boardid.h>
+#include <console/console.h>
+#include <soc/grf.h>
+#include <soc/pwm.h>
+
+#include "pwm_regulator.h"
+
+/*
+ * Apparently a period of 3333 is determined by EEs to be ideal for our
+ * board design / resistors / capacitors / regulators but due to
+ * clock dividers we actually get 3337.
+ */
+#define PWM_PERIOD		3337
+#define PWM_DESIGN_VOLTAGE_MIN	8000
+#define PWM_DESIGN_VOLTAGE_MAX	15000
+
+/* The min & max design voltages are different after kevin-r6 */
+int kevin_voltage_min_max_r6[][2] = {
+	[PWM_REGULATOR_GPU] = {7910, 12139},
+	[PWM_REGULATOR_BIG] = {7986, 13057},
+	[PWM_REGULATOR_LIT] = {7997, 13002},
+	[PWM_REGULATOR_CENTERLOG] = {7996, 10507}
+};
+
+void pwm_regulator_configure(enum pwm_regulator pwm, int millivolt)
+{
+	int duty_ns, voltage_max, voltage_min;
+	int voltage = millivolt * 10; /* for higer calculation accuracy */
+
+	switch (pwm) {
+	case PWM_REGULATOR_GPU:
+		write32(&rk3399_grf->iomux_pwm_0, IOMUX_PWM_0);
+		break;
+	case PWM_REGULATOR_BIG:
+		write32(&rk3399_grf->iomux_pwm_1, IOMUX_PWM_1);
+		break;
+	case PWM_REGULATOR_LIT:
+		write32(&rk3399_pmugrf->iomux_pwm_2, IOMUX_PWM_2);
+		break;
+	case PWM_REGULATOR_CENTERLOG:
+		write32(&rk3399_pmugrf->iomux_pwm_3a, IOMUX_PWM_3_A);
+		break;
+	}
+
+	voltage_min = PWM_DESIGN_VOLTAGE_MIN;
+	voltage_max = PWM_DESIGN_VOLTAGE_MAX;
+	if (IS_ENABLED(CONFIG_BOARD_GOOGLE_KEVIN) && board_id() >= 6) {
+		voltage_min = kevin_voltage_min_max_r6[pwm][0];
+		voltage_max = kevin_voltage_min_max_r6[pwm][1];
+	}
+
+	assert(voltage <= voltage_max && voltage >= voltage_min);
+
+	/*
+	 * Intentionally round down (higher volt) to be safe.
+	 * eg, for the default min & max design voltage:
+	 *    period = 3337, volt = 1.1: 1906
+	 *    period = 3337, volt = 1.0: 2383
+	 *    period = 3337, volt = 0.9: 2860
+	 */
+	duty_ns = PWM_PERIOD * (voltage_max - voltage)
+			     / (voltage_max - voltage_min);
+
+	pwm_init(pwm, PWM_PERIOD, duty_ns);
+}