Merge pull request #3833 from hathach/claude/ci-hs-set-address-order

dcd(ci_hs): stage the device address before priming the status stage

2 files changed, 19 insertions, 6 deletions

diff --git a/src/portable/chipidea/ci_hs/ci_hs_type.h b/src/portable/chipidea/ci_hs/ci_hs_type.h
index 5baa14821..b3ef3b6af 100644
--- a/src/portable/chipidea/ci_hs/ci_hs_type.h
+++ b/src/portable/chipidea/ci_hs/ci_hs_type.h
@@ -29,6 +29,14 @@ enum {
   USBCMD_INTR_THRESHOLD_MASK = 0x00FF0000u, // Interrupt Threshold bit 23:16
 };
 
+// DEVICEADDR
+#define DEVICEADDR_USBADR_POS 25
+
+enum {
+  DEVICEADDR_USBADRA     = TU_BIT(24),  ///< Device Address Advance: stage USBADR until the next EP0 IN is ACKed
+  DEVICEADDR_USBADR_MASK = 0xFE000000u, ///< Device Address bit 31:25
+};
+
 // PORTSC1
 #define PORTSC1_PORT_SPEED_POS    26
 
diff --git a/src/portable/chipidea/ci_hs/dcd_ci_hs.c b/src/portable/chipidea/ci_hs/dcd_ci_hs.c
index 6ab28e0be..f1c333280 100644
--- a/src/portable/chipidea/ci_hs/dcd_ci_hs.c
+++ b/src/portable/chipidea/ci_hs/dcd_ci_hs.c
@@ -361,12 +361,17 @@ void dcd_int_disable(uint8_t rhport) {
 }
 
 void dcd_set_address(uint8_t rhport, uint8_t dev_addr) {
-  // Response with status first before changing device address. A refused prime means a new
-  // setup superseded this transfer; staging an address whose ACK will never arrive would
-  // leave the device answering on it, so only arm the address when the status went out.
-  if (dcd_edpt_xfer(rhport, tu_edpt_addr(0, TUSB_DIR_IN), NULL, 0, false)) {
-    ci_hs_regs_t *dcd_reg = CI_HS_REG(rhport);
-    dcd_reg->DEVICEADDR   = (dev_addr << 25) | TU_BIT(24);
+  ci_hs_regs_t  *dcd_reg = CI_HS_REG(rhport);
+  const uint32_t prev    = dcd_reg->DEVICEADDR & DEVICEADDR_USBADR_MASK;
+
+  // IMXRT1060RM 42.7.23 / UM10503 Table 478: stage the address before priming the status stage so
+  // hardware loads USBADR at the status ACK. Priming first races that ACK against this write.
+  dcd_reg->DEVICEADDR = ((uint32_t)dev_addr << DEVICEADDR_USBADR_POS) | DEVICEADDR_USBADRA;
+
+  if (!dcd_edpt_xfer(rhport, tu_edpt_addr(0, TUSB_DIR_IN), NULL, 0, false)) {
+    // USB 2.0 9.4.6: the address changes only after the status stage completes successfully. The
+    // status never went out, so drop the stage - USBADRA=0 takes effect instantly.
+    dcd_reg->DEVICEADDR = prev;
   }
 }