First upload. Untested software

2026-04-08 17:02:29 +02:00
commit 9b83763318
11 changed files with 698 additions and 0 deletions
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+/* Baremetal Risc-V USB <=> Amiga Joystick/Mouse HID converter. 
+ * March 2026 - Anders Holck
+ * This software has no license. If you choose to use, please include my name :)
+*/
+
+#include "usb_dwc2.h"
+#include "usb_descriptors.h"
+
+// Endpoint 0 State
+#define EP0_IDLE        0
+#define EP0_SETUP       1
+#define EP0_DATA_IN     2
+#define EP0_DATA_OUT    3
+#define EP0_STATUS_IN   4
+#define EP0_STATUS_OUT  5
+
+static uint8_t ep0_state = EP0_IDLE;
+static uint8_t usb_address = 0;
+
+// Setup Packet Structure
+typedef struct {
+    uint8_t  bmRequestType;
+    uint8_t  bRequest;
+    uint16_t wValue;
+    uint16_t wIndex;
+    uint16_t wLength;
+} usb_setup_t;
+
+void dwc2_setup_fifo() {
+    // Total FIFO size is often 512 or 1024 words.
+    // Configure RX FIFO (Shared)
+    write32(GRXFSIZ, 128); // 128 words
+    
+    // Configure TX FIFO 0 (EP0 IN)
+    // Offset = GRXFSIZ
+    write32(GNPTXFSIZ, (128 << 16) | 128); // Size 128, Start 128
+    
+    // Configure TX FIFO 1 (EP1 IN - HID)
+    // Offset = GRXFSIZ + GNPTXFSIZ
+    write32(USB_DWC2_BASE + 0x104, (128 << 16) | 256); // Size 128, Start 256
+}
+
+void dwc2_send_packet(uint8_t ep_num, const uint8_t *data, uint32_t len) {
+    uint32_t fifo_addr = USB_DWC2_BASE + 0x1000 + (ep_num * 0x1000);
+    
+    // 1. Set Transfer Size and Packet Count
+    uint32_t dieptsiz = (1 << 19) | len; // 1 packet, 'len' bytes
+    write32(USB_DWC2_BASE + 0x908 + (ep_num * 0x20), dieptsiz);
+    
+    // 2. Enable Endpoint and Clear NAK
+    uint32_t diepctl = read32(USB_DWC2_BASE + 0x900 + (ep_num * 0x20));
+    diepctl |= (1 << 31) | (1 << 26); // EPEna, Cnak
+    write32(USB_DWC2_BASE + 0x900 + (ep_num * 0x20), diepctl);
+    
+    // 3. Write data to FIFO (Word-aligned writes)
+    uint32_t words = (len + 3) / 4;
+    uint32_t *data32 = (uint32_t *)data;
+    for (uint32_t i = 0; i < words; i++) {
+        write32(fifo_addr, data32[i]);
+    }
+}
+
+void dwc2_handle_setup(usb_setup_t *setup) {
+    if ((setup->bmRequestType & 0x60) == 0) { // Standard Request
+        switch (setup->bRequest) {
+            case USB_REQ_GET_DESCRIPTOR: {
+                uint8_t type = setup->wValue >> 8;
+                const uint8_t *ptr = 0;
+                uint32_t len = 0;
+                
+                if (type == USB_DESC_DEVICE) {
+                    ptr = device_desc;
+                    len = sizeof(device_desc);
+                } else if (type == USB_DESC_CONFIGURATION) {
+                    ptr = config_desc;
+                    len = sizeof(config_desc);
+                } else if (type == USB_DESC_REPORT) {
+                    ptr = hid_report_desc;
+                    len = sizeof(hid_report_desc);
+                }
+                
+                if (ptr) {
+                    if (len > setup->wLength) len = setup->wLength;
+                    dwc2_send_packet(0, ptr, len);
+                    ep0_state = EP0_DATA_IN;
+                }
+                break;
+            }
+            case USB_REQ_SET_ADDRESS:
+                usb_address = setup->wValue & 0x7F;
+                // Address is applied after the status phase
+                dwc2_send_packet(0, 0, 0); // ZLP Status
+                ep0_state = EP0_STATUS_IN;
+                break;
+            case USB_REQ_SET_CONFIGURATION:
+                dwc2_send_packet(0, 0, 0); // ZLP Status
+                ep0_state = EP0_STATUS_IN;
+                break;
+        }
+    }
+}
+
+void dwc2_poll() {
+    uint32_t gintsts = read32(GINTSTS);
+    
+    // 1. USB Reset
+    if (gintsts & (1 << 12)) {
+        write32(GINTSTS, (1 << 12));
+        usb_address = 0;
+        ep0_state = EP0_IDLE;
+        dwc2_setup_fifo();
+        // Enable EP0 OUT
+        write32(DOEPCTL0, (1 << 31) | (1 << 26)); // EPEna, Cnak
+    }
+    
+    // 2. Enumeration Done
+    if (gintsts & (1 << 13)) {
+        write32(GINTSTS, (1 << 13));
+        // High speed or Full speed detected...
+    }
+    
+    // 3. Receive FIFO Level (Data available)
+    if (gintsts & (1 << 4)) {
+        uint32_t grxstsp = read32(GRXSTSP);
+        uint8_t ep_num = grxstsp & 0xF;
+        uint32_t bcnt = (grxstsp >> 4) & 0x7FF;
+        uint8_t pktsts = (grxstsp >> 17) & 0xF;
+        
+        if (pktsts == 6) { // SETUP Packet Received
+            usb_setup_t setup;
+            uint32_t *setup_ptr = (uint32_t *)&setup;
+            uint32_t fifo_addr = USB_DWC2_BASE + 0x1000;
+            setup_ptr[0] = read32(fifo_addr);
+            setup_ptr[1] = read32(fifo_addr);
+            dwc2_handle_setup(&setup);
+        }
+    }
+    
+    // 4. Update Address after Status Phase
+    if (ep0_state == EP0_STATUS_IN) {
+        uint32_t daint = read32(DAINT);
+        if (daint & (1 << 0)) { // EP0 IN Complete
+            uint32_t dcfg = read32(DCFG);
+            dcfg &= ~(0x7F << 4);
+            dcfg |= (usb_address << 4);
+            write32(DCFG, dcfg);
+            ep0_state = EP0_IDLE;
+        }
+    }
+}