hcd rp2 add double buffered for control endpoint transfers.

3 files changed, 39 insertions, 44 deletions

diff --git a/src/portable/raspberrypi/rp2040/hcd_rp2040.c b/src/portable/raspberrypi/rp2040/hcd_rp2040.c
index 31bbfc0be..3a99e7275 100644
--- a/src/portable/raspberrypi/rp2040/hcd_rp2040.c
+++ b/src/portable/raspberrypi/rp2040/hcd_rp2040.c
@@ -55,12 +55,6 @@
 static hw_endpoint_t  ep_pool[USB_MAX_ENDPOINTS];
 static hw_endpoint_t *epx = &ep_pool[0]; // current active endpoint
 
-// Flags we set by default in sie_ctrl (we add other bits on top)
-enum {
-  SIE_CTRL_BASE      = USB_SIE_CTRL_PULLDOWN_EN_BITS | USB_SIE_CTRL_EP0_INT_1BUF_BITS,
-  SIE_CTRL_BASE_MASK = USB_SIE_CTRL_PULLDOWN_EN_BITS | USB_SIE_CTRL_EP0_INT_1BUF_BITS | USB_SIE_CTRL_SOF_EN_BITS |
-                       USB_SIE_CTRL_KEEP_ALIVE_EN_BITS
-};
 
 enum {
   SIE_CTRL_SPEED_DISCONNECT = 0,
@@ -187,7 +181,7 @@ static void __tusb_irq_path_func(epx_switch_ep)(hw_endpoint_t *ep) {
     io_rw_32     *buf_reg = &usbh_dpram->epx_buf_ctrl;
 
     epx_ctrl_prepare(ep);
-    rp2usb_buffer_start(ep, ep_reg, buf_reg, is_rx, is_rx || ep->transfer_type == TUSB_XFER_INTERRUPT);
+    rp2usb_buffer_start(ep, ep_reg, buf_reg, is_rx, ep->transfer_type == TUSB_XFER_INTERRUPT);
 
     usb_hw->dev_addr_ctrl = (uint32_t)(ep->dev_addr | (ep_num << USB_ADDR_ENDP_ENDPOINT_LSB));
     sie_start_xfer(false, is_rx, ep->need_pre); // start transfer
@@ -340,26 +334,20 @@ static void __tusb_irq_path_func(hcd_rp2040_irq)(void) {
   // RP2040: on SOF, stop and switch if there's a pending ep
   if (status & USB_INTS_HOST_SOF_BITS) {
     (void)usb_hw->sof_rd; // clear SOF by reading SOF_RD
-    if (epx->active && tu_edpt_number(epx->ep_addr) != 0) {
-      hw_endpoint_t *next_ep = epx_next_pending(epx);
-      if (next_ep) {
+    hw_endpoint_t *next_ep = epx_next_pending(epx);
+    if (next_ep == NULL) {
+      // no more pending --> disable SOF
+      usb_hw_clear->inte = USB_INTE_HOST_SOF_BITS;
+      usb_hw->nak_poll   = USB_NAK_POLL_RESET;
+    } else {
+      // stop transfer if is active
+      if (epx->active) {
         usb_hw_set->sie_ctrl = USB_SIE_CTRL_STOP_TRANS_BITS;
         while (usb_hw->sie_ctrl & USB_SIE_CTRL_STOP_TRANS_BITS) {}
-        busy_wait_at_least_cycles(12);
-        if (usb_hw->buf_status & 1u) {
-          usb_hw->nak_poll = USB_NAK_POLL_RESET;
-          handle_buf_status_isr();
-        } else {
-          epx_switch_ep(next_ep);
-        }
-      } else {
-        usb_hw_clear->inte = USB_INTE_HOST_SOF_BITS;
-        usb_hw->nak_poll   = USB_NAK_POLL_RESET;
       }
-    } else if (!epx_next_pending(epx)) {
-      // EPX is on control endpoint or inactive — disable SOF if nothing pending
-      usb_hw_clear->inte = USB_INTE_HOST_SOF_BITS;
-      usb_hw->nak_poll   = USB_NAK_POLL_RESET;
+
+      epx_save_context();
+      epx_switch_ep(next_ep);
     }
   }
   #endif
@@ -602,10 +590,8 @@ bool hcd_edpt_xfer(uint8_t rhport, uint8_t dev_addr, uint8_t ep_addr, uint8_t *b
       usb_hw_set->nak_poll = USB_NAK_POLL_STOP_EPX_ON_NAK_BITS;
   #else
       // Only enable SOF round-robin for non-control endpoints
-      if (tu_edpt_number(epx->ep_addr) != 0) {
-        usb_hw->nak_poll = (300 << USB_NAK_POLL_DELAY_FS_LSB) | (300 << USB_NAK_POLL_DELAY_LS_LSB);
-        usb_hw_set->inte = USB_INTE_HOST_SOF_BITS;
-      }
+      usb_hw->nak_poll = (300 << USB_NAK_POLL_DELAY_FS_LSB) | (300 << USB_NAK_POLL_DELAY_LS_LSB);
+      usb_hw_set->inte = USB_INTE_HOST_SOF_BITS;
   #endif
     } else {
       const uint8_t    ep_num  = tu_edpt_number(ep->ep_addr);
diff --git a/src/portable/raspberrypi/rp2040/rp2040_usb.c b/src/portable/raspberrypi/rp2040/rp2040_usb.c
index 49c948af6..ffb5fcbc6 100644
--- a/src/portable/raspberrypi/rp2040/rp2040_usb.c
+++ b/src/portable/raspberrypi/rp2040/rp2040_usb.c
@@ -283,7 +283,7 @@ void rp2usb_xfer_start(hw_endpoint_t *ep, io_rw_32 *ep_reg, io_rw_32 *buf_reg, u
 
   const bool is_rx = (is_host == (tu_edpt_dir(ep->ep_addr) == TUSB_DIR_IN));
   #if CFG_TUH_ENABLED
-  const bool force_single = (is_host && (is_rx || ep->transfer_type == TUSB_XFER_INTERRUPT));
+  const bool force_single = (is_host && ep->transfer_type == TUSB_XFER_INTERRUPT);
   #else
   const bool force_single = false;
   #endif
@@ -339,23 +339,17 @@ bool __tusb_irq_path_func(rp2usb_xfer_continue)(hw_endpoint_t *ep, io_rw_32 *ep_
     return false;
   }
 
-  const bool is_double = (ep_reg != NULL && ((*ep_reg) & EP_CTRL_DOUBLE_BUFFERED_BITS));
   const bool is_host   = rp2usb_is_host_mode();
-
-  #if CFG_TUSB_RP2_ERRATA_E4
-  const bool need_e4_fix = (is_host && !is_double);
-  #endif
+  const bool is_double = (ep_reg != NULL && ((*ep_reg) & EP_CTRL_DOUBLE_BUFFERED_BITS));
 
   // Double-buffered: buf_id from BUFF_CPU_SHOULD_HANDLE indicates which buffer completed.
-
   // RP2040-E4 (host only): in single-buffered multi-packet transfers, the controller may write completion status to
-  //   BUF1 half instead of BUF0. The side effect that controller can execute an extra packet after writing to BUF1
-  //   since it leave BUF0 intact, which can be poll before buf_status interrupt is trigger.
-  // Workaround for the side effect, we will enable double-buffered for rx but only prepare 1 buf at a time.
+  // BUF1 half instead of BUF0. The side effect is that controller can execute an extra packet after writing to BUF1
+  // since it leaves BUF0 intact, which can be polled before buf_status interrupt is triggered.
   uint8_t *dpram_buf = ep->dpram_buf;
   if (buf_id) {
   #if CFG_TUSB_RP2_ERRATA_E4
-    if (!need_e4_fix)  // incorrect buf_id, buffer pointer is still buf0
+    if (!(is_host && !is_double)) // incorrect buf_id, buffer data is still buf0
   #endif
     {
       dpram_buf += 64; // buf1 offset
@@ -368,16 +362,24 @@ bool __tusb_irq_path_func(rp2usb_xfer_continue)(hw_endpoint_t *ep, io_rw_32 *ep_
   const uint16_t xact_bytes = bufctrl_sync16(ep, is_rx, buf_ctrl16, dpram_buf);
   const bool     is_last    = buf_ctrl16 & USB_BUF_CTRL_LAST;
   const bool     is_short   = xact_bytes < ep->max_packet_size;
-  const bool     is_done    = is_short || (buf_ctrl16 & USB_BUF_CTRL_LAST);
+  const bool     is_done    = is_short || is_last;
 
-  // Short packet on rx with double buffer: abort the other half (if not last) and reset double-buffer state.
+  // Short packet on rx with double buffer: abort the other half (if not last) and reset the buffer control.
   // The other buffer may be: (a) still AVAIL, (b) in-progress (controller receiving), or (c) already completed.
   // We must abort to safely reclaim it. If it has valid data (FULL), save as future for the next transfer.
-  // After abort, zero buf_ctrl.
-  // Note: Host mode we cannot save next transfer data due to shared epx --> force single
+  // Note: Host mode current does not save next transfer data due to shared epx --> potential issue. However, RP2040-E4
+  // causes more or less of the same issue since it write to buf1 and next time it continues to transfer on buf0 (stale)
   if (is_short && is_double && is_rx && !is_last) {
   #if CFG_TUH_ENABLED
-    if (is_host) {}
+    if (is_host) {
+      // stop current transfer
+      uint32_t sie_ctrl = usb_hw->sie_ctrl & SIE_CTRL_BASE_MASK;
+      sie_ctrl |= USB_SIE_CTRL_STOP_TRANS_BITS;
+      usb_hw->sie_ctrl = sie_ctrl;
+      // maybe wait until STOP_TRANS bit is clear
+
+      *buf_reg = 0; // reset buffer control
+    }
   #endif
 
   #if CFG_TUD_ENABLED
diff --git a/src/portable/raspberrypi/rp2040/rp2040_usb.h b/src/portable/raspberrypi/rp2040/rp2040_usb.h
index c4c7e625e..2ba9d018e 100644
--- a/src/portable/raspberrypi/rp2040/rp2040_usb.h
+++ b/src/portable/raspberrypi/rp2040/rp2040_usb.h
@@ -70,6 +70,13 @@
   #define __tusb_irq_path_func(x) x
 #endif
 
+// Flags we set by default in sie_ctrl (we add other bits on top)
+enum {
+  SIE_CTRL_BASE      = USB_SIE_CTRL_PULLDOWN_EN_BITS | USB_SIE_CTRL_EP0_INT_1BUF_BITS,
+  SIE_CTRL_BASE_MASK = USB_SIE_CTRL_PULLDOWN_EN_BITS | USB_SIE_CTRL_EP0_INT_1BUF_BITS | USB_SIE_CTRL_SOF_EN_BITS |
+                       USB_SIE_CTRL_KEEP_ALIVE_EN_BITS
+};
+
 //--------------------------------------------------------------------+
 //
 //--------------------------------------------------------------------+