USB can get past set address

bootloader.c

@@ -1,27 +1,114 @@
 #include <stdint.h>
 
-#pragma GCC diagnostic ignored "-Wprio-ctor-dtor"
+typedef struct USBD_descriptor {
-__attribute__((constructor(0))) static void setup_qingke() {
+    uint32_t addr_tx;
-    asm volatile(
+    uint32_t count_tx;
-        // Undocumented "Configure pipelining and instruction prediction"
+    uint32_t addr_rx;
-        "li t0, 0x1f\n"
+    uint32_t count_rx;
-        "csrw 0xbc0, t0\n"
+} USBD_descriptor;
-    );
-}
 
+// USBD memory allocation:
+// WARNING THIS IS A 16-bit MEMORY LMAO
+// +0x00
+//      descriptors (two sets of two endpoints)
+// +0x20
+//      EP 0 OUT (8 bytes)
+// +0x30
+//      EP 0 IN (8 bytes)
+// +0x40
+//      EP 1 OUT (64 bytes)
+// +0xc0
+//      EP 1 IN (64 bytes)
+// +0x140
+//      <unused>
+// +0x200
+//      <256-byte flash page buffer>
+
+#define USB_DESCS           ((USBD_descriptor*)0x40006000)
+#define USB_EP0_OUT(offs)   (*(volatile uint32_t *)(0x40006020 + 2 * (offs)))
+#define USB_EP0_IN(offs)    (*(volatile uint32_t *)(0x40006030 + 2 * (offs)))
+#define USB_EP1_OUT(offs)   (*(volatile uint32_t *)(0x40006040 + 2 * (offs)))
+#define USB_EP1_IN(offs)    (*(volatile uint32_t *)(0x400060C0 + 2 * (offs)))
+
+#define R32_RCC_CTLR        (*(volatile uint32_t*)0x40021000)
+#define R32_RCC_CFGR0       (*(volatile uint32_t*)0x40021004)
 #define R32_RCC_APB2PCENR   (*(volatile uint32_t*)0x40021018)
+#define R32_RCC_APB1PCENR   (*(volatile uint32_t*)0x4002101C)
 #define R32_GPIOA_CFGLR     (*(volatile uint32_t*)0x40010800)
+#define R32_GPIOA_CFGHR     (*(volatile uint32_t*)0x40010804)
 #define R32_GPIOA_BSHR      (*(volatile uint32_t*)0x40010810)
 
+#define R16_USBD_EPR(n)     (*(volatile uint16_t*)(0x40005C00 + 4 * (n)))
+#define R16_USBD_CNTR       (*(volatile uint16_t*)0x40005C40)
+#define R16_USBD_ISTR       (*(volatile uint16_t*)0x40005C44)
+#define R16_USBD_DADDR      (*(volatile uint16_t*)0x40005C4C)
+
+#define R32_EXTEN_CTR       (*(volatile uint32_t*)0x40023800)
+
 int main(void) {
-    R32_RCC_APB2PCENR |= 1 << 2;
+    // PLL setup: system clock 96 MHz
-    R32_GPIOA_CFGLR = (R32_GPIOA_CFGLR & ~0xf) | (0b0010 << 0);
+    R32_EXTEN_CTR |= (1 << 4);  // sneaky div2
+    R32_RCC_CFGR0 = (R32_RCC_CFGR0 & ~0xff0000) | (0b01101000 << 16);
+    R32_RCC_CTLR |= (1 << 24);
+    while (!(R32_RCC_CTLR & (1 << 25))) {}
+    R32_RCC_CFGR0 = (R32_RCC_CFGR0 & ~0b11) | 0b10;
+    while ((R32_RCC_CFGR0 & 0b1100) != 0b1000) {}
+
+    // As recommended in the manual, output low on these pins before enabling USB
+    R32_RCC_APB2PCENR |= (1 << 2);
+    R32_GPIOA_CFGHR = (R32_GPIOA_CFGHR & ~(0xff << 12)) | (0b00100010 << 12);
+    R32_GPIOA_BSHR = (1 << 27) | (1 << 28);
+
+    // Enable USB
+    R32_RCC_APB1PCENR |= (1 << 23);
+    R16_USBD_CNTR &= ~(1 << 1);
+    USB_DESCS[0].addr_tx = 0x30 / 2;
+    USB_DESCS[0].addr_rx = 0x20 / 2;
+    USB_DESCS[0].count_rx = (8 << 10);
+    USB_DESCS[1].addr_tx = 0xc0 / 2;
+    USB_DESCS[1].addr_rx = 0x40 / 2;
+    USB_DESCS[1].count_rx = (2 << 10) | (1 << 15);
+    // XXX because the table is at offset 0 don't bother writing this
+
+    // Attach USB
+    R16_USBD_CNTR &= ~(1 << 0);
+    R32_EXTEN_CTR |= (1 << 1);
+
+    uint32_t need_to_set_addr = 0;
+
+    // R32_GPIOA_CFGLR = (R32_GPIOA_CFGLR & ~0xf) | (0b0010 << 0);
     while (1) {
-        R32_GPIOA_BSHR = 1 << 0;
+        uint32_t usb_int_status = R16_USBD_ISTR;
-        for (int i = 0; i < 500000; i++)
+        if (usb_int_status & (1 << 10)) {
-            asm volatile("");
+            // RESET
-        R32_GPIOA_BSHR = 1 << 16;
+            R16_USBD_EPR(0) = (0b11 << 12) | (0b01 << 9) | (0b01 << 4);
-        for (int i = 0; i < 500000; i++)
+            R16_USBD_DADDR = 0x80;
-            asm volatile("");
+        } else if (usb_int_status & (1 << 15)) {
+            if ((usb_int_status & 0x1f) == 0x10) {
+                uint32_t ep0_status = R16_USBD_EPR(0);
+                if (ep0_status & (1 << 11)) {
+                    // setup, STAT_RX and STAT_TX both now NAK
+                    uint16_t bRequest_bmRequestType = USB_EP0_OUT(0);
+                    if (bRequest_bmRequestType == 0x0500) {
+                        // SET_ADDRESS
+                        need_to_set_addr = USB_EP0_OUT(2);
+                        USB_DESCS[0].count_tx = 0;
+                        R16_USBD_EPR(0) = (0b01 << 9) | (0b11 << 12) | (0b01 << 4);  // STALL for OUT, ACK for IN
+                    } else {
+                        // unknown
+                        R16_USBD_EPR(0) = (0b01 << 9) | (0b11 << 12) | (0b11 << 4);   // STALL for both
+                        while (1) {}
+                    }
+                }
+            }
+            if ((usb_int_status & 0x1f) == 0x00) {
+                if (need_to_set_addr) {
+                    R16_USBD_DADDR = 0x80 | need_to_set_addr;
+                    need_to_set_addr = 0;
+                    R16_USBD_EPR(0) = (0b01 << 9) | (0b11 << 4);  // STALL if another IN
+                }
+            }
+        }
+        R16_USBD_ISTR = 0;
     }
 }

linker.lds

@@ -4,18 +4,12 @@ MEMORY
 {
     /* Try to squeeze down to this target size */
     FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 2K
-    /* We have a total of 512 bytes here.
+    LOL_NO_RAM (rw) : ORIGIN = 0x400060c0, LENGTH = 0
-    - Need 256 bytes to buffer a flash page across USB packets
-    - Need space for USB buffers
-    - Tiny tiny amount of free space
-    */
-    USBRAM (rw) : ORIGIN = 0x400060c0, LENGTH = 64
 }
 
 SECTIONS
 {
     PROVIDE(_bootloader_limit = ORIGIN(FLASH) + LENGTH(FLASH));
-    PROVIDE(_bootloader_stack = ORIGIN(USBRAM) + LENGTH(USBRAM));
 
     .vector :
     {
@@ -54,7 +48,7 @@ SECTIONS
         *(.srodata .srodata.*)
         . = ALIGN(4);
         PROVIDE( _edata = .);
-    } >USBRAM AT>FLASH
+    } >LOL_NO_RAM AT>FLASH
 
     .bss :
     {
@@ -66,7 +60,7 @@ SECTIONS
         *(COMMON*)
         . = ALIGN(4);
         PROVIDE( _ebss = .);
-    } >USBRAM
+    } >LOL_NO_RAM
 
     PROVIDE( _end = _ebss);
 }

startup.S

@@ -92,7 +92,7 @@ _enter_bootloader:
 .option norelax
     la gp, __global_pointer$
 .option pop
-    la sp, _bootloader_stack
+    la sp, 0
 
     // Load data section from flash to RAM
     la a0, _data_lma
@@ -117,6 +117,9 @@ _enter_bootloader:
     bltu a0, a1, 1b
 2:
 
+    li t0, 0x1f
+    csrw 0xbc0, t0
+
     // Invoke main
     la t0, main
     csrw mepc, t0