icE1usb fw: Use green per-port LED to indicate alignment status

Whenever Rx is aligned, the green LED is permanently on.
Whenever Rx is not aligned, the green LED is blinking.

What's missing is to check for E1 clock ticks and turn the LED off
completely if there are no clock ticks.

Change-Id: I42d53544858dbbbae5206d9a62b08672966c9ebf

doc/manuals/chapters/firmware.adoc

@@ -128,9 +128,17 @@ Found Runtime: [1d50:6145] ver=0003, devnum=44, cfg=1, intf=1, path="1-2", alt=0
 
 === Use of the E1 Interface LEDs
 
-Each E1 interface has two LEDs integrated into the RJ45 connector.
+Each E1 interface has two LEDs integrated into the RJ45 connector. They
+are (starting to get) used by the firmware to indicate status
+information to the user.
+
+[options="header"]
+|===
+|Color  | Pattern         | Meaning
+|Green  | Blinking (slow) | E1 Receiver attempting to align
+|Green  | On              | E1 Receiver fully aligned
+|===
 
-FIXME: describe how they are used.
 
 === Use of the Multi-Color RGB LED
 

firmware/ice40-riscv/icE1usb/e1.c

@@ -412,10 +412,14 @@ e1_poll(void)
 		return;
 
 	/* HACK: LED link status */
-	if (e1_regs->rx.csr & E1_RX_SR_ALIGNED)
+	if (e1_regs->rx.csr & E1_RX_SR_ALIGNED) {
+		e1_platform_led_set(0, E1P_LED_GREEN, E1P_LED_ST_ON);
 		led_color(0, 48, 0);
-	else
+	} else {
+		e1_platform_led_set(0, E1P_LED_GREEN, E1P_LED_ST_BLINK);
+		/* TODO: completely off if rx tick counter not incrementing */
 		led_color(48, 0, 0);
+	}
 
 	/* Recover any done TX BD */
 	while ( (bd = e1_regs->tx.bd) & E1_BD_VALID ) {

firmware/ice40-riscv/icE1usb/e1.h

@@ -13,3 +13,19 @@ void e1_debug_print(bool data);
 
 volatile uint8_t *e1_data_ptr(int mf, int frame, int ts);
 unsigned int e1_data_ofs(int mf, int frame, int ts);
+
+enum e1_platform_led {
+	E1P_LED_GREEN		= 0,
+	E1P_LED_YELLOW		= 1,
+};
+
+enum e1_platform_led_state {
+	E1P_LED_ST_OFF		= 0,
+	E1P_LED_ST_ON		= 1,
+	E1P_LED_ST_BLINK	= 2,
+	E1P_LED_ST_BLINK_FAST	= 3
+};
+
+/* external function provided by the platform; used by E1 driver to control LEDs */
+extern void e1_platform_led_set(uint8_t port, enum e1_platform_led led,
+				enum e1_platform_led_state state);

firmware/ice40-riscv/icE1usb/misc.c

@@ -10,6 +10,7 @@
 
 #include "config.h"
 #include "misc.h"
+#include "e1.h"
 
 
 struct misc {
@@ -51,6 +52,24 @@ e1_led_set(bool enable, uint8_t cfg)
 	misc_regs->e1_led = (enable ? 0x100 : 0x000) | cfg;
 }
 
+void
+e1_platform_led_set(uint8_t port, enum e1_platform_led led,
+		    enum e1_platform_led_state state)
+{
+	uint32_t tmp;
+	unsigned int shift;
+
+	if (port >= 2)
+		return;
+
+	shift = 4*port + 2*led;
+
+	tmp = misc_regs->e1_led;
+	tmp &= ~(3 << shift);
+	tmp |= 0x100 | ((state & 3) << shift);
+	misc_regs->e1_led = tmp;
+}
+
 uint16_t
 e1_tick_read(void)
 {