[PATCH 6.18.y 5/7] usb: xhci: use cached HCSPARAMS1 value

[Sasha Levin <sashal@kernel.org>]

From: Niklas Neronin <niklas.neronin@linux.intel.com>

[ Upstream commit 70651cc3f5a4c7cec529f121e36ea3b45ea84778 ]

The Structural Parameters 1 (HCSPARAMS1) register is read and cached in
'xhci->hcs_params1' during host controller initialization. Since this
register is read-only and its value remains constant for the lifetime of
the controller, re-reading it later is unnecessary.

Replace subsequent register reads with the cached 'xhci->hcs_params1'
value to avoid redundant MMIO access.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20251119142417.2820519-15-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 78203d5b54a4 ("usb: xhci: bail out of setup if the controller is inaccessible")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/host/xhci.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index aab2792be76da..4947a16c054e4 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4253,8 +4253,7 @@ int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
 		xhci_err(xhci, "Error while assigning device slot ID: %s\n",
 			 xhci_trb_comp_code_string(command->status));
 		xhci_err(xhci, "Max number of devices this xHCI host supports is %u.\n",
-				HCS_MAX_SLOTS(
-					readl(&xhci->cap_regs->hcs_params1)));
+			 HCS_MAX_SLOTS(xhci->hcs_params1));
 		xhci_free_command(xhci, command);
 		return 0;
 	}
-- 
2.53.0