usb: xhci: move command ring pointer write

Move command ring pointer write from xhci_mem_init() to xhci_init(),
and utilize the xhci_set_cmd_ring_deq() function.

The xhci_set_cmd_ring_deq() function is nearly identical to the Command
Ring Control register code in xhci_mem_init(). The only notable change is
the use of:
  xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg, xhci->cmd_ring->dequeue)
instead of:
  xhci->cmd_ring->first_seg->dma
but they are effectively the same in this context. The former represents
the exact position of the dequeue pointer, while the latter is the first
DMA in the first segment. Before use, the dequeue pointer is at the first
DMA in the first segment.

The xhci_set_cmd_ring_deq() function is moved without modification, except
for (long unsigned long) -> (unsigned long long) due to checkpatch.pl.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250515135621.335595-6-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 20 insertions, 17 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index ec0a2fa7d003..66a9106d8b31 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -495,6 +495,23 @@ static void xhci_enable_max_dev_slots(struct xhci_hcd *xhci)
 	writel(config_reg, &xhci->op_regs->config_reg);
 }
 
+static void xhci_set_cmd_ring_deq(struct xhci_hcd *xhci)
+{
+	u64	val_64;
+
+	/* step 2: initialize command ring buffer */
+	val_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
+	val_64 = (val_64 & (u64) CMD_RING_RSVD_BITS) |
+		(xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
+					xhci->cmd_ring->dequeue) &
+			(u64) ~CMD_RING_RSVD_BITS) |
+		xhci->cmd_ring->cycle_state;
+	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
+			"// Setting command ring address to 0x%llx",
+			(unsigned long long) val_64);
+	xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
+}
+
 /*
  * Initialize memory for HCD and xHC (one-time init).
  *
@@ -523,6 +540,9 @@ static int xhci_init(struct usb_hcd *hcd)
 	/* Set the Number of Device Slots Enabled to the maximum supported value */
 	xhci_enable_max_dev_slots(xhci);
 
+	/* Set the address in the Command Ring Control register */
+	xhci_set_cmd_ring_deq(xhci);
+
 	/* Initializing Compliance Mode Recovery Data If Needed */
 	if (xhci_compliance_mode_recovery_timer_quirk_check()) {
 		xhci->quirks |= XHCI_COMP_MODE_QUIRK;
@@ -793,23 +813,6 @@ static void xhci_restore_registers(struct xhci_hcd *xhci)
 	}
 }
 
-static void xhci_set_cmd_ring_deq(struct xhci_hcd *xhci)
-{
-	u64	val_64;
-
-	/* step 2: initialize command ring buffer */
-	val_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
-	val_64 = (val_64 & (u64) CMD_RING_RSVD_BITS) |
-		(xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
-				      xhci->cmd_ring->dequeue) &
-		 (u64) ~CMD_RING_RSVD_BITS) |
-		xhci->cmd_ring->cycle_state;
-	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
-			"// Setting command ring address to 0x%llx",
-			(long unsigned long) val_64);
-	xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
-}
-
 /*
  * The whole command ring must be cleared to zero when we suspend the host.
  *