rp2040: add support for EnterBootloader()

3 files changed, 72 insertions, 13 deletions

diff --git a/src/machine/machine_rp2040_enter_bootloader.go b/src/machine/machine_rp2040_enter_bootloader.go
new file mode 100644
index 000000000..7259b060b
--- /dev/null
+++ b/src/machine/machine_rp2040_enter_bootloader.go
@@ -0,0 +1,53 @@
+//go:build rp2040
+// +build rp2040
+
+package machine
+
+/*
+// https://github.com/raspberrypi/pico-sdk
+// src/rp2_common/pico_bootrom/include/pico/bootrom.h
+
+#define ROM_FUNC_POPCOUNT32             ROM_TABLE_CODE('P', '3')
+#define ROM_FUNC_REVERSE32              ROM_TABLE_CODE('R', '3')
+#define ROM_FUNC_CLZ32                  ROM_TABLE_CODE('L', '3')
+#define ROM_FUNC_CTZ32                  ROM_TABLE_CODE('T', '3')
+#define ROM_FUNC_MEMSET                 ROM_TABLE_CODE('M', 'S')
+#define ROM_FUNC_MEMSET4                ROM_TABLE_CODE('S', '4')
+#define ROM_FUNC_MEMCPY                 ROM_TABLE_CODE('M', 'C')
+#define ROM_FUNC_MEMCPY44               ROM_TABLE_CODE('C', '4')
+#define ROM_FUNC_RESET_USB_BOOT         ROM_TABLE_CODE('U', 'B')
+#define ROM_FUNC_CONNECT_INTERNAL_FLASH ROM_TABLE_CODE('I', 'F')
+#define ROM_FUNC_FLASH_EXIT_XIP         ROM_TABLE_CODE('E', 'X')
+#define ROM_FUNC_FLASH_RANGE_ERASE      ROM_TABLE_CODE('R', 'E')
+#define ROM_FUNC_FLASH_RANGE_PROGRAM    ROM_TABLE_CODE('R', 'P')
+#define ROM_FUNC_FLASH_FLUSH_CACHE      ROM_TABLE_CODE('F', 'C')
+#define ROM_FUNC_FLASH_ENTER_CMD_XIP    ROM_TABLE_CODE('C', 'X')
+
+#define ROM_TABLE_CODE(c1, c2) ((c1) | ((c2) << 8))
+
+typedef unsigned short uint16_t;
+typedef unsigned long uint32_t;
+typedef unsigned long uintptr_t;
+
+typedef void *(*rom_table_lookup_fn)(uint16_t *table, uint32_t code);
+typedef void __attribute__((noreturn)) (*rom_reset_usb_boot_fn)(uint32_t, uint32_t);
+#define rom_hword_as_ptr(rom_address) (void *)(uintptr_t)(*(uint16_t *)(uintptr_t)(rom_address))
+
+void *rom_func_lookup(uint32_t code) {
+  rom_table_lookup_fn rom_table_lookup = (rom_table_lookup_fn) rom_hword_as_ptr(0x18);
+  uint16_t *func_table = (uint16_t *) rom_hword_as_ptr(0x14);
+  return rom_table_lookup(func_table, code);
+}
+
+void reset_usb_boot(uint32_t usb_activity_gpio_pin_mask, uint32_t disable_interface_mask) {
+    rom_reset_usb_boot_fn func = (rom_reset_usb_boot_fn) rom_func_lookup(ROM_FUNC_RESET_USB_BOOT);
+    func(usb_activity_gpio_pin_mask, disable_interface_mask);
+}
+*/
+import "C"
+
+// EnterBootloader should perform a system reset in preparation
+// to switch to the bootloader to flash new firmware.
+func EnterBootloader() {
+	C.reset_usb_boot(0, 0)
+}
diff --git a/src/machine/machine_rp2040_usb.go b/src/machine/machine_rp2040_usb.go
index faa311b5f..c5ac0ada2 100644
--- a/src/machine/machine_rp2040_usb.go
+++ b/src/machine/machine_rp2040_usb.go
@@ -4,7 +4,6 @@
 package machine
 
 import (
-	"device/arm"
 	"device/rp"
 	"machine/usb"
 	"runtime/interrupt"
@@ -153,7 +152,8 @@ func initEndpoint(ep, config uint32) {
 
 	case usb.ENDPOINT_TYPE_CONTROL:
 		val |= usbEpControlEndpointTypeControl
-		usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBuf0CtrlAvail)
+		usbDPSRAM.EPxBufferControl[ep].Out.Set(usbBuf0CtrlData1Pid)
+		usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
 
 	}
 }
@@ -207,6 +207,21 @@ func sendUSBPacket(ep uint32, data []byte, maxsize uint16) {
 
 func ReceiveUSBControlPacket() ([cdcLineInfoSize]byte, error) {
 	var b [cdcLineInfoSize]byte
+	ep := 0
+
+	for !usbDPSRAM.EPxBufferControl[ep].Out.HasBits(usbBuf0CtrlFull) {
+		// TODO: timeout
+	}
+
+	ctrl := usbDPSRAM.EPxBufferControl[ep].Out.Get()
+	usbDPSRAM.EPxBufferControl[ep].Out.Set(USBBufferLen & usbBuf0CtrlLenMask)
+	sz := ctrl & usbBuf0CtrlLenMask
+
+	copy(b[:], usbDPSRAM.EPxBuffer[ep].Buffer0[:sz])
+
+	usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlData1Pid)
+	usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlAvail)
+
 	return b, nil
 }
 
@@ -218,7 +233,7 @@ func handleEndpointRx(ep uint32) []byte {
 	copy(buf, usbDPSRAM.EPxBuffer[ep].Buffer0[:sz])
 
 	epXdata0[ep] = !epXdata0[ep]
-	if epXdata0[ep] {
+	if epXdata0[ep] || ep == 0 {
 		usbDPSRAM.EPxBufferControl[ep].Out.SetBits(usbBuf0CtrlData1Pid)
 	}
 
@@ -259,16 +274,6 @@ func sendStallViaEPIn(ep uint32) {
 	usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
 }
 
-// EnterBootloader should perform a system reset in preparation
-// to switch to the bootloader to flash new firmware.
-func EnterBootloader() {
-	arm.DisableInterrupts()
-
-	// TODO: Perform magic reset into bootloader
-
-	arm.SystemReset()
-}
-
 type USBDPSRAM struct {
 	// Note that EPxControl[0] is not EP0Control but 8-byte setup data.
 	EPxControl [16]USBEndpointControlRegister
diff --git a/targets/rp2040.json b/targets/rp2040.json
index b06e2c09d..23edc5f68 100644
--- a/targets/rp2040.json
+++ b/targets/rp2040.json
@@ -1,6 +1,7 @@
 {
     "inherits": ["cortex-m0plus"],
     "build-tags": ["rp2040", "rp"],
+    "flash-1200-bps-reset": "true",
     "flash-method": "msd",
     "serial": "usb",
     "msd-volume-name": "RPI-RP2",