Change in coreboot[master]: mb/google/hatch/vr/puff: Add psys_pmax calculation

[Tim Chen (Code Review)]

Hello Tim Chen,

I'd like you to do a code review. Please visit

https://review.coreboot.org/c/coreboot/+/40828

to review the following change.

Change subject: mb/google/hatch/vr/puff: Add psys_pmax calculation
......................................................................

mb/google/hatch/vr/puff: Add psys_pmax calculation

This patch adds psys_pmax calculation. There are two types of power
sources. One is barrel jack and the other is USB TYPE-C. The voltage
level is fixed for a barrel jack while TYPE-C may vary depending
on power ratings. We need to get voltage information from
EC and calculate correct psys_pmax value. The psys_pmax needs to be
set before FSP-S since FSP-S will handle the setting passing to pcode,
so move the routine ahead to variant_ramstage_init.

BUG=b:151972149
TEST=emerge-puff coreboot chromeos-bootimage
     check firmware log and ensure psys_pmax is passed to FSP
     check the data from dump_intel_rapl_consumption in the OS and
     ensure the power data is close to an external power meter.

Change-Id: Iff767d4b44a01e766258345545438a54a16d1af5
Signed-off-by: Tim Chen 
---
M src/mainboard/google/hatch/variants/duffy/mainboard.c
M src/mainboard/google/hatch/variants/kaisa/mainboard.c
2 files changed, 74 insertions(+), 36 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/28/40828/1

diff --git a/src/mainboard/google/hatch/variants/duffy/mainboard.c b/src/mainboard/google/hatch/variants/duffy/mainboard.c
index 3f74c96..ceeb0c5 100644
--- a/src/mainboard/google/hatch/variants/duffy/mainboard.c
+++ b/src/mainboard/google/hatch/variants/duffy/mainboard.c
@@ -31,23 +31,6 @@
           stopwatch_duration_msecs(&sw));
 }

-void variant_ramstage_init(void)
-{
-	static const long display_timeout_ms = 3000;
-
-	/* This is reconfigured back to whatever FSP-S expects by
-	   gpio_configure_pads. */
-	gpio_input(GPIO_HDMI_HPD);
-	gpio_input(GPIO_DP_HPD);
-	if (display_init_required()
-		&& !gpio_get(GPIO_HDMI_HPD)
-		&& !gpio_get(GPIO_DP_HPD)) {
-		/* This has to be done before FSP-S runs. */
-		if (google_chromeec_wait_for_displayport(display_timeout_ms))
-			wait_for_hpd(GPIO_DP_HPD, display_timeout_ms);
-	}
-}
-
 /*
  * For type-C chargers, set PL2 to 90% of max power to account for
  * cable loss and FET Rdson loss in the path from the source.
@@ -86,6 +69,24 @@
  * | n  (U22)    |  29 |   .9n   |   .9n   | x(43) |
  * +-------------+-----+---------+---------+-------+
  */
+
+/*
+ * Psys_pmax considerations
+ *
+ * Given the hardware design in puff, the serial shunt resistor is 0.01ohm.
+ * The full scale of hardware PSYS signal 0.8v maps to system current 9.6A
+ * instead of real system power. The equation is shown below:
+ * PSYS = 0.8v = (0.01ohm x Iinput) x 50 (INA213, gain 50V/V) x 15k/(15k + 75k)
+ * Hence, Iinput (Amps) = 9.6A
+ * Since there is no voltage information from PSYS, different voltage input
+ * would map to different Psys_pmax settings:
+ * For Type-C 15V, the Psys_pmax sholud be 15v x 9.6A = 144W
+ * For Type-C 20V, the Psys_pmax should be 20v x 9.6A = 192W
+ * For a barral jack, the Psys_pmax should be 19v x 9.6A = 182.4W
+ */
+#define PSYS_IMAX	9600
+#define BJ_VOLTS_MV	19000
+
 static void mainboard_set_power_limits(config_t *conf)
 {
    enum usb_chg_type type;
@@ -108,15 +109,33 @@
    	/* set minimum duty cycle */
    	conf->tdp_psyspl3_dutycycle = PUFF_MIN_DUTYCYCLE;
    	conf->tdp_pl4 = SET_PSYSPL2(psyspl2);
+	} else {
+		/* Input type is barrel jack */
+		volts_mv = BJ_VOLTS_MV;
    }
+	/* voltage unit is milliVolts and current is in milliAmps */
+	conf->psys_pmax = (u16)(((u32)PSYS_IMAX * volts_mv) / 1000000);

conf->tdp_pl2_override = PUFF_PL2;
    /* set psyspl2 to 90% of max adapter power */
    conf->tdp_psyspl2 = SET_PSYSPL2(psyspl2);
 }

-void variant_mainboard_enable(struct device *dev)
+void variant_ramstage_init(void)
 {
+	static const long display_timeout_ms = 3000;
    config_t *conf = config_of_soc();
+
+	/* This is reconfigured back to whatever FSP-S expects by gpio_configure_pads. */
+	gpio_input(GPIO_HDMI_HPD);
+	gpio_input(GPIO_DP_HPD);
+	if (display_init_required()
+		&& !gpio_get(GPIO_HDMI_HPD)
+		&& !gpio_get(GPIO_DP_HPD)) {
+		/* This has to be done before FSP-S runs. */
+		if (google_chromeec_wait_for_displayport(display_timeout_ms))
+			wait_for_hpd(GPIO_DP_HPD, display_timeout_ms);
+	}
+	/* Psys_pmax needs to be setup before FSP-S */
    mainboard_set_power_limits(conf);
 }
diff --git a/src/mainboard/google/hatch/variants/kaisa/mainboard.c b/src/mainboard/google/hatch/variants/kaisa/mainboard.c
index 3f74c96..ceeb0c5 100644
--- a/src/mainboard/google/hatch/variants/kaisa/mainboard.c
+++ b/src/mainboard/google/hatch/variants/kaisa/mainboard.c
@@ -31,23 +31,6 @@
           stopwatch_duration_msecs(&sw));
 }

-void variant_ramstage_init(void)
-{
-	static const long display_timeout_ms = 3000;
-
-	/* This is reconfigured back to whatever FSP-S expects by
-	   gpio_configure_pads. */
-	gpio_input(GPIO_HDMI_HPD);
-	gpio_input(GPIO_DP_HPD);
-	if (display_init_required()
-		&& !gpio_get(GPIO_HDMI_HPD)
-		&& !gpio_get(GPIO_DP_HPD)) {
-		/* This has to be done before FSP-S runs. */
-		if (google_chromeec_wait_for_displayport(display_timeout_ms))
-			wait_for_hpd(GPIO_DP_HPD, display_timeout_ms);
-	}
-}
-
 /*
  * For type-C chargers, set PL2 to 90% of max power to account for
  * cable loss and FET Rdson loss in the path from the source.
@@ -86,6 +69,24 @@
  * | n  (U22)    |  29 |   .9n   |   .9n   | x(43) |
  * +-------------+-----+---------+---------+-------+
  */
+
+/*
+ * Psys_pmax considerations
+ *
+ * Given the hardware design in puff, the serial shunt resistor is 0.01ohm.
+ * The full scale of hardware PSYS signal 0.8v maps to system current 9.6A
+ * instead of real system power. The equation is shown below:
+ * PSYS = 0.8v = (0.01ohm x Iinput) x 50 (INA213, gain 50V/V) x 15k/(15k + 75k)
+ * Hence, Iinput (Amps) = 9.6A
+ * Since there is no voltage information from PSYS, different voltage input
+ * would map to different Psys_pmax settings:
+ * For Type-C 15V, the Psys_pmax sholud be 15v x 9.6A = 144W
+ * For Type-C 20V, the Psys_pmax should be 20v x 9.6A = 192W
+ * For a barral jack, the Psys_pmax should be 19v x 9.6A = 182.4W
+ */
+#define PSYS_IMAX	9600
+#define BJ_VOLTS_MV	19000
+
 static void mainboard_set_power_limits(config_t *conf)
 {
    enum usb_chg_type type;
@@ -108,15 +109,33 @@
    	/* set minimum duty cycle */
    	conf->tdp_psyspl3_dutycycle = PUFF_MIN_DUTYCYCLE;
    	conf->tdp_pl4 = SET_PSYSPL2(psyspl2);
+	} else {
+		/* Input type is barrel jack */
+		volts_mv = BJ_VOLTS_MV;
    }
+	/* voltage unit is milliVolts and current is in milliAmps */
+	conf->psys_pmax = (u16)(((u32)PSYS_IMAX * volts_mv) / 1000000);

conf->tdp_pl2_override = PUFF_PL2;
    /* set psyspl2 to 90% of max adapter power */
    conf->tdp_psyspl2 = SET_PSYSPL2(psyspl2);
 }

-void variant_mainboard_enable(struct device *dev)
+void variant_ramstage_init(void)
 {
+	static const long display_timeout_ms = 3000;
    config_t *conf = config_of_soc();
+
+	/* This is reconfigured back to whatever FSP-S expects by gpio_configure_pads. */
+	gpio_input(GPIO_HDMI_HPD);
+	gpio_input(GPIO_DP_HPD);
+	if (display_init_required()
+		&& !gpio_get(GPIO_HDMI_HPD)
+		&& !gpio_get(GPIO_DP_HPD)) {
+		/* This has to be done before FSP-S runs. */
+		if (google_chromeec_wait_for_displayport(display_timeout_ms))
+			wait_for_hpd(GPIO_DP_HPD, display_timeout_ms);
+	}
+	/* Psys_pmax needs to be setup before FSP-S */
    mainboard_set_power_limits(conf);
 }