From ec64baba95195e4e124e4c9112fd286677f6fce5 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Sat, 11 Oct 2025 19:54:48 -0400
Subject: kern: usb: Extract HCSPARAMS1 register fields

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/sys/include/io/usb/xhciregs.h |  9 +++++++++
 src/sys/include/io/usb/xhcivar.h  |  6 ++++++
 src/sys/io/usb/hcd/xhci.c         | 14 +++++++++++++-
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/sys/include/io/usb/xhciregs.h b/src/sys/include/io/usb/xhciregs.h
index 85a8630..726d883 100644
--- a/src/sys/include/io/usb/xhciregs.h
+++ b/src/sys/include/io/usb/xhciregs.h
@@ -84,6 +84,15 @@ struct __packed xhci_opregs {
  */
 #define USBSTS_CNR  BIT(11)     /* Controller not ready */
 
+/*
+ * USB structural parameters 1 register bits
+ *
+ * See section 5.3.3 of the xHCI spec
+ */
+#define HCSPARAMS1_MAXSLOTS(HCSPARAMS1) ((HCSPARAMS1) & 0xFF)
+#define HCSPARAMS1_MAXINTRS(HCSPARAMS1) (((HCSPARAMS1) >> 8) & 0x7FF)
+#define HCSPARAMS1_MAXPORTS(HCSPARAMS1) (((HCSPARAMS1) >> 24) & 0xFF)
+
 /*
  * Macros to get various register spaces
  */
diff --git a/src/sys/include/io/usb/xhcivar.h b/src/sys/include/io/usb/xhcivar.h
index c0b3a39..bc5f59b 100644
--- a/src/sys/include/io/usb/xhcivar.h
+++ b/src/sys/include/io/usb/xhcivar.h
@@ -37,9 +37,15 @@
  * Represents the host controller
  *
  * @io: I/O space
+ * @max_slots: Max device slots
+ * @max_intrs: Max interrupters
+ * @max_ports: Max ports
  */
 struct xhci_hcd {
     struct xhci_capregs *capspace;
+    uint8_t max_slots;
+    uint32_t max_intrs;
+    uint32_t max_ports;
 };
 
 #define XHCI_TIMEOUT_MSEC 500
diff --git a/src/sys/io/usb/hcd/xhci.c b/src/sys/io/usb/hcd/xhci.c
index f363bcf..0125e96 100644
--- a/src/sys/io/usb/hcd/xhci.c
+++ b/src/sys/io/usb/hcd/xhci.c
@@ -137,7 +137,8 @@ static int
 xhci_init_hc(struct xhci_hcd *hcd)
 {
     struct xhci_opregs *opregs;
-    uint32_t usbcmd;
+    struct xhci_capregs *capspace;
+    uint32_t usbcmd, hcsparams1;
     int error;
 
     if (hcd == NULL) {
@@ -147,6 +148,17 @@ xhci_init_hc(struct xhci_hcd *hcd)
     if ((error = xhci_reset_hc(hcd)) < 0) {
         return error;
     }
+
+    if ((capspace = hcd->capspace) == NULL) {
+        return -EIO;
+    }
+
+    /* Get the structural params 1 */
+    opregs = XHCI_OPBASE(capspace);
+    hcsparams1 = mmio_read32(&capspace->hcsparams1);
+    hcd->max_slots = HCSPARAMS1_MAXSLOTS(hcsparams1);
+    hcd->max_intrs = HCSPARAMS1_MAXINTRS(hcsparams1);
+    hcd->max_ports = HCSPARAMS1_MAXPORTS(hcsparams1);
     return 0;
 }
 
-- 
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