From 134b4b6a8bd61378d510175311b85bdc9e2f13d5 Mon Sep 17 00:00:00 2001
From: Ondrej Jirman <megous@megous.com>
Date: Mon, 2 Aug 2021 10:03:48 +0200
Subject: [PATCH] firmware: Move more of the USB shutdown control to
 usb_enable/usb_disable

- make sure USB resources are re-enabled before jumping to bootloader
- make sure all USB resources are disabled prior to jumping to user fw
---
 firmware/main.c | 91 +++++++++++++++++++++++++++++++------------------
 1 file changed, 58 insertions(+), 33 deletions(-)

diff --git a/firmware/main.c b/firmware/main.c
index 6b4b962..02abf86 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -150,7 +150,7 @@ static __bit jump_to_usb_bootloader = 0;
 
 uint8_t __idata __at(0xff) stock_flag = 1;
 
-//XXX: check if we want to jump to user FW
+static void usb_disable(void);
 
 // cleanup after stock firmware and jump to user firmware
 static void jmp_to_user_fw(void) __naked
@@ -184,17 +184,10 @@ static void jmp_to_user_fw(void) __naked
 	P0_PRST = 0;
 
 	// disable USB and clear irq flags
-	PAGESW = 1;
-	P1_PHYTEST0 &= ~BIT(6); // phy disable
-	P1_UDCCTRL &= ~BIT(6); // udc disable
-	P1_UDCINT0STA = 0;
-	P1_UDCINT1STA = 0;
-	P1_UDCINT2STA = 0;
-	P1_UDCINT0EN = 0;
-	P1_UDCINT1EN = 0;
-	P1_UDCINT2EN = 0;
+	usb_disable();
 
 	// disable pullups, set all pins to input
+	PAGESW = 1;
 	P1_PHCON2 = 0;
 	P1_P9M0 = 0xffu;
 	PAGESW = 0;
@@ -254,6 +247,24 @@ static void usb_bootloader_jump(void) __naked
 	P1_UDCINT1EN = 0;
 	P1_UDCINT2EN = 0;
 
+	// Bootloader would not enable these resources, so we need to make
+	// sure we enable them before jumping to it:
+
+	// USB on USB pins
+	P1_USBCTRL |= BIT(7);
+
+	// turn on PLL48
+	P1_UDCCTRL &= ~BIT(0);
+
+	// turn on USB resources (phy power up, PLL48 powerup)
+	P1_USBCTRL &= ~(BIT(0) | BIT(1));
+
+	// enable auto-tuning internal RC oscillator based on USB SOF packets
+	P1_IRCCTRL &= ~BIT(1); // disable manual trim
+
+	// wait for pll to stabilize
+	delay_us(5000);
+
 	// disable pullups, set all pins to input
 	P1_PHCON2 = 0;
 	P1_P9M0 = 0xffu;
@@ -1611,6 +1622,21 @@ static void usb_init(void)
 {
 	PAGESW = 1;
 
+	// USB on USB pins
+	P1_USBCTRL |= BIT(7);
+
+	// turn on PLL48
+	P1_UDCCTRL &= ~BIT(0);
+
+	// turn on USB resources (phy power up, PLL48 powerup)
+	P1_USBCTRL &= ~(BIT(0) | BIT(1));
+
+	// enable auto-tuning internal RC oscillator based on USB SOF packets
+	P1_IRCCTRL &= ~BIT(1); // disable manual trim
+
+	// wait for pll to stabilize
+	delay_us(5000);
+
 	P1_UDCCTRL |= BIT(6); // udc enable
 	// wait for UDC to complete initialization
 	while (!(P1_UDCCTRL & BIT(1)));
@@ -1646,9 +1672,6 @@ static void usb_init(void)
 	P1_UDCINT0EN = BIT(5) | BIT(1) | BIT(6) | BIT(3);
 	P1_UDCINT1EN = BIT(0) | BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(6);
 	P1_UDCINT2EN = BIT(2);
-	//P1_UDCINT0EN = 0;
-	//P1_UDCINT1EN = 0;
-	//P1_UDCINT2EN = 0;
 
 	// enable phy, wakeup enable
 	P1_PHYTEST0 |= BIT(5) | BIT(6);
@@ -1665,11 +1688,32 @@ static void usb_init(void)
 
 static void usb_disable(void)
 {
-	// reset phy/usb
+	// disable USB interrupts
+	PAGESW = 0;
+	P0_EIE2 &= ~BIT(2);
+
 	PAGESW = 1;
 
+	// disable interrupts
+	P1_UDCINT0EN = 0;
+	P1_UDCINT1EN = 0;
+	P1_UDCINT2EN = 0;
+
+	// reset phy/usb
 	P1_PHYTEST0 &= ~(BIT(6) | BIT(5)); // phy disable
 	P1_UDCCTRL &= ~BIT(6); // udc disable
+
+	// turn off PLL48
+	P1_UDCCTRL |= BIT(0);
+
+	// turn off unused USB resources (phy power down, PLL48 powerdown
+	P1_USBCTRL |= BIT(0) | BIT(1);
+
+	// disable auto-tuning internal RC oscillator based on USB SOF packets
+	P1_IRCCTRL |= BIT(1); // enable manual trim
+
+	// GPIO on USB pins
+	P1_USBCTRL &= ~BIT(7);
 }
 
 // }}}
@@ -1729,9 +1773,6 @@ void main(void)
 	PAGESW = 1;
 	P1_PHCON2 = 0x00;
 
-	// enable auto-tuning internal RC oscillator based on USB SOF packets
-	P1_IRCCTRL &= ~BIT(1); // disable manual trim
-
 #if CONFIG_STOCK_FW
 	puts("ppkb firmware " FW_REVISION_STR " (stock)\n");
 #else
@@ -1744,22 +1785,6 @@ void main(void)
 
 	usb_disable();
 
-#if !CONFIG_USB_STACK
-	PAGESW = 1;
-
-	// GPIO on USB pins
-	P1_USBCTRL &= ~BIT(7);
-
-	// turn off PLL48
-	P1_UDCCTRL |= BIT(0);
-
-	// turn off unused USB resources (phy power down, PLL48 powerdown
-	P1_USBCTRL |= BIT(0) | BIT(1);
-
-	// enable auto-tuning internal RC oscillator based on USB SOF packets
-	P1_IRCCTRL |= BIT(1); // enable manual trim
-#endif
-
 #if CONFIG_FLASH_ENABLE
 	for (uint8_t i = 0; i < 128; i++)
 		flash_content[i] = 0;