From f4d3b68a5c1ffd99581efa8e3378f3449a7cd20d Mon Sep 17 00:00:00 2001
From: Polprzewodnikowy <sc@mateuszfaderewski.pl>
Date: Wed, 5 Oct 2022 17:43:11 +0200
Subject: [PATCH] USB unplugged cable handling

---
 fw/rtl/mcu/mcu_top.sv    |  4 +++-
 fw/rtl/usb/usb_ft1248.sv | 15 ++++++++++++---
 sw/controller/src/fpga.h |  2 ++
 sw/controller/src/usb.c  | 20 +++++++++++++++-----
 4 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/fw/rtl/mcu/mcu_top.sv b/fw/rtl/mcu/mcu_top.sv
index a0dcc09..9e025df 100644
--- a/fw/rtl/mcu/mcu_top.sv
+++ b/fw/rtl/mcu/mcu_top.sv
@@ -387,7 +387,9 @@ module mcu_top (
 
                 REG_USB_SCR: begin
                     reg_rdata <= {
-                        4'd0,
+                        2'd0,
+                        usb_scb.pwrsav,
+                        usb_scb.reset_state,
                         usb_scb.tx_count,
                         usb_scb.rx_count,
                         2'b00,
diff --git a/fw/rtl/usb/usb_ft1248.sv b/fw/rtl/usb/usb_ft1248.sv
index 5251c10..9b2153b 100644
--- a/fw/rtl/usb/usb_ft1248.sv
+++ b/fw/rtl/usb/usb_ft1248.sv
@@ -6,6 +6,8 @@ interface usb_scb ();
     logic write_buffer_flush;
     logic [10:0] rx_count;
     logic [10:0] tx_count;
+    logic pwrsav;
+    logic reset_state;
 
     modport controller (
         output fifo_flush,
@@ -13,7 +15,9 @@ interface usb_scb ();
         output reset_ack,
         output write_buffer_flush,
         input rx_count,
-        input tx_count
+        input tx_count,
+        input pwrsav,
+        input reset_state
     );
 
     modport usb (
@@ -22,7 +26,9 @@ interface usb_scb ();
         input reset_ack,
         input write_buffer_flush,
         output rx_count,
-        output tx_count
+        output tx_count,
+        output pwrsav,
+        output reset_state
     );
 
 endinterface
@@ -144,7 +150,10 @@ module usb_ft1248 (
     always_ff @(posedge clk) begin
         state <= next_state;
         cmd <= next_cmd;
-        
+
+        usb_scb.pwrsav <= !ft_pwrsav;
+        usb_scb.reset_state <= last_reset_status;
+
         phase <= {phase[2:0], phase[3]};
         if (state == STATE_IDLE) begin
             phase <= 4'b0100;
diff --git a/sw/controller/src/fpga.h b/sw/controller/src/fpga.h
index e9082cd..a6cec0d 100644
--- a/sw/controller/src/fpga.h
+++ b/sw/controller/src/fpga.h
@@ -83,6 +83,8 @@ typedef enum {
 #define USB_SCR_RX_COUNT_MASK           (0x7FF << USB_SCR_RX_COUNT_BIT)
 #define USB_SCR_TX_COUNT_BIT            (17)
 #define USB_SCR_TX_COUNT_MASK           (0x7FF << USB_SCR_TX_COUNT_BIT)
+#define USB_SCR_RESET_STATE             (1 << 28)
+#define USB_SCR_PWRSAV                  (1 << 29)
 
 #define DMA_SCR_START                   (1 << 0)
 #define DMA_SCR_STOP                    (1 << 1)
diff --git a/sw/controller/src/usb.c b/sw/controller/src/usb.c
index e986979..ea8fa27 100644
--- a/sw/controller/src/usb.c
+++ b/sw/controller/src/usb.c
@@ -408,6 +408,7 @@ bool usb_prepare_read (uint32_t *args) {
 }
 
 void usb_get_read_info (uint32_t *args) {
+    uint32_t scr = fpga_reg_get(REG_USB_SCR);
     args[0] = 0;
     args[1] = 0;
     if (p.rx_state == RX_STATE_DATA && p.rx_cmd == 'U') {
@@ -415,6 +416,8 @@ void usb_get_read_info (uint32_t *args) {
         args[1] = p.rx_args[1];
     }
     args[0] |= (p.read_length > 0) ? (1 << 31) : 0;
+    args[0] |= (scr & USB_SCR_RESET_STATE) ? (1 << 30) : 0;
+    args[0] |= (scr & USB_SCR_PWRSAV) ? (1 << 29) : 0;
 }
 
 void usb_init (void) {
@@ -438,12 +441,19 @@ void usb_init (void) {
 }
 
 void usb_process (void) {
-    if (fpga_reg_get(REG_USB_SCR) & USB_SCR_RESET_PENDING) {
-        if (p.tx_state != TX_STATE_IDLE && p.tx_info.done_callback) {
-            p.tx_info.done_callback();
+    uint32_t scr = fpga_reg_get(REG_USB_SCR);
+    if (scr & (USB_SCR_PWRSAV | USB_SCR_RESET_STATE | USB_SCR_RESET_PENDING)) {
+        if (p.packet_pending && p.packet_info.done_callback) {
+            p.packet_pending = false;
+            p.packet_info.done_callback();
+        }
+        if (scr & USB_SCR_RESET_PENDING) {
+            if (p.tx_state != TX_STATE_IDLE && p.tx_info.done_callback) {
+                p.tx_info.done_callback();
+            }
+            usb_init();
+            fpga_reg_set(REG_USB_SCR, USB_SCR_RESET_ACK);
         }
-        usb_init();
-        fpga_reg_set(REG_USB_SCR, USB_SCR_RESET_ACK);
     } else {
         usb_rx_process();
         usb_tx_process();