meowth: zoombini: Add HPD support.

The HPD pins for meowth and zoombini go from the EC to the AP.  This
commit drives the HPD correctly.

BUG=b:72413020
BRANCH=None
TEST=Flash meowth; Use a couple charge-through hubs, unplug HDMI cable,
replug, verify AP sees new DP sink.

Change-Id: Ie1f86378c59fc4a717edc537ff8afe01b21d9b68
Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Reviewed-on: https://chromium-review.googlesource.com/888226
Commit-Ready: Aseda Aboagye <aaboagye@chromium.org>
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Edward Hill <ecgh@chromium.org>

2 files changed, 51 insertions, 1 deletions

diff --git a/board/zoombini/gpio.inc b/board/zoombini/gpio.inc
index 7b04a0651a..025841e1d9 100644
--- a/board/zoombini/gpio.inc
+++ b/board/zoombini/gpio.inc
@@ -87,6 +87,9 @@ GPIO(USB_C2_BC12_CHG_DET, PIN(E, 4), GPIO_INPUT)
 GPIO(USB_C0_OC_L,         PIN(6, 7), GPIO_ODR_HIGH)
 GPIO(USB_C1_OC_L,         PIN(7, 0), GPIO_ODR_HIGH)
 GPIO(USB_C2_OC_L,         PIN(6, 3), GPIO_ODR_HIGH)
+GPIO(USB_C0_DP_HPD,       PIN(C, 5), GPIO_OUT_LOW)
+GPIO(USB_C1_DP_HPD,       PIN(C, 6), GPIO_OUT_LOW)
+GPIO(USB_C2_DP_HPD,       PIN(C, 7), GPIO_OUT_LOW)
 
 GPIO(BOARD_VERSION1, PIN(9, 6), GPIO_INPUT)
 GPIO(BOARD_VERSION2, PIN(9, 3), GPIO_INPUT)
@@ -164,6 +167,8 @@ GPIO(PMIC_EN,             PIN(8, 6), GPIO_ODR_LOW)
 GPIO(USB_C0_OC_L,         PIN(6, 7), GPIO_ODR_HIGH)
 GPIO(USB_C1_OC_L,         PIN(7, 0), GPIO_ODR_HIGH)
 GPIO(ENABLE_BACKLIGHT,    PIN(D, 3), GPIO_ODR_LOW) /* EC_BL_EN_OD */
+GPIO(USB_C0_DP_HPD,       PIN(C, 5), GPIO_OUT_LOW)
+GPIO(USB_C1_DP_HPD,       PIN(C, 6), GPIO_OUT_LOW)
 
 GPIO(PCH_DSW_PWROK,    PIN(3, 7), GPIO_OUT_LOW)  /* EC_PCH_DSW_PWROK */
 GPIO(PCH_RSMRST_L,     PIN(C, 2), GPIO_OUT_LOW)  /* EC_PCH_RSMRST_L */
diff --git a/board/zoombini/usb_pd_policy.c b/board/zoombini/usb_pd_policy.c
index e5c7a975f7..2a0f580718 100644
--- a/board/zoombini/usb_pd_policy.c
+++ b/board/zoombini/usb_pd_policy.c
@@ -293,6 +293,18 @@ static int svdm_dp_config(int port, uint32_t *payload)
 	return 2;
 };
 
+/*
+ * timestamp of the next possible toggle to ensure the 2-ms spacing
+ * between IRQ_HPD.
+ */
+static uint64_t hpd_deadline[CONFIG_USB_PD_PORT_COUNT];
+
+#ifdef BOARD_MEOWTH
+#define PORT_TO_HPD(port) ((port) ? GPIO_USB_C1_DP_HPD : GPIO_USB_C0_DP_HPD)
+#else
+#define PORT_TO_HPD(port) ((port == 2) ? GPIO_USB_C2_DP_HPD :		\
+			   (port) ? GPIO_USB_C1_DP_HPD : GPIO_USB_C0_DP_HPD)
+#endif /* defined(BOARD_MEOWTH) */
 static void svdm_dp_post_config(int port)
 {
 	const struct usb_mux *mux = &usb_muxes[port];
@@ -300,23 +312,55 @@ static void svdm_dp_post_config(int port)
 	dp_flags[port] |= DP_FLAGS_DP_ON;
 	if (!(dp_flags[port] & DP_FLAGS_HPD_HI_PENDING))
 		return;
+
+	gpio_set_level(PORT_TO_HPD(port), 1);
+
+	/* set the minimum time delay (2ms) for the next HPD IRQ */
+	hpd_deadline[port] = get_time().val + HPD_USTREAM_DEBOUNCE_LVL;
+
 	mux->hpd_update(port, 1, 0);
 }
 
 static int svdm_dp_attention(int port, uint32_t *payload)
 {
+	int cur_lvl;
 	int lvl = PD_VDO_DPSTS_HPD_LVL(payload[1]);
 	int irq = PD_VDO_DPSTS_HPD_IRQ(payload[1]);
+	enum gpio_signal hpd = PORT_TO_HPD(port);
 	const struct usb_mux *mux = &usb_muxes[port];
 
+	cur_lvl = gpio_get_level(hpd);
 	dp_status[port] = payload[1];
+
+	/* Its initial DP status message prior to config */
 	if (!(dp_flags[port] & DP_FLAGS_DP_ON)) {
 		if (lvl)
 			dp_flags[port] |= DP_FLAGS_HPD_HI_PENDING;
 		return 1;
 	}
-	mux->hpd_update(port, lvl, irq);
 
+	if (irq & cur_lvl) {
+		uint64_t now = get_time().val;
+		/* wait for the minimum spacing between IRQ_HPD if needed */
+		if (now < hpd_deadline[port])
+			usleep(hpd_deadline[port] - now);
+
+		/* generate IRQ_HPD pulse */
+		gpio_set_level(hpd, 0);
+		usleep(HPD_DSTREAM_DEBOUNCE_IRQ);
+		gpio_set_level(hpd, 1);
+
+		/* set the minimum time delay (2ms) for the next HPD IRQ */
+		hpd_deadline[port] = get_time().val + HPD_USTREAM_DEBOUNCE_LVL;
+	} else if (irq & !cur_lvl) {
+		CPRINTF("ERR:HPD:IRQ&LOW\n");
+		return 0; /* nak */
+	} else {
+		gpio_set_level(hpd, lvl);
+		/* set the minimum time delay (2ms) for the next HPD IRQ */
+		hpd_deadline[port] = get_time().val + HPD_USTREAM_DEBOUNCE_LVL;
+	}
+	mux->hpd_update(port, lvl, irq);
 	/* ack */
 	return 1;
 }
@@ -326,6 +370,7 @@ static void svdm_exit_dp_mode(int port)
 	const struct usb_mux *mux = &usb_muxes[port];
 
 	svdm_safe_dp_mode(port);
+	gpio_set_level(PORT_TO_HPD(port), 0);
 	mux->hpd_update(port, 0, 0);
 }