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usb: xhci: use cached HCSPARAMS1 value

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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>
This commit is contained in:
Niklas Neronin 2025-11-19 16:24:08 +02:00 committed by Greg Kroah-Hartman
parent 2085fa6c0f
commit 70651cc3f5
1 changed files with 1 additions and 2 deletions
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3
drivers/usb/host/xhci.c
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@ -4235,8 +4235,7 @@ 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;
}