usb: xhci: rework Event Ring Segment Table Address mask

JIRA: https://issues.redhat.com/browse/RHEL-116016

commit 74d7a75
Author: Niklas Neronin <niklas.neronin@linux.intel.com>
Date: Thu, 15 May 2025 16:56:16 +0300

  Event Ring Segment Table Base Address Register contain two fields:
   - Bits 5:0:	RsvdP (Reserved and Preserved)
   - Bits 63:6:	Event Ring Segment Table Base Address

  Currently, an inverted RsvdP mask (ERST_BASE_RSVDP) is used to extract
  bits 63:6. Replaces the inverted mask with a non-inverted mask,
  'ERST_BASE_ADDRESS_MASK', which makes the code easier to read.

  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/20250515135621.335595-20-mathias.nyman@linux.intel.com
  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Desnes Nunes <desnesn@redhat.com>

Author: Desnes Nunes

drivers/usb/host/xhci-mem.c

@@ -2338,8 +2338,8 @@ void xhci_add_interrupter(struct xhci_hcd *xhci, unsigned int intr_num)
 	writel(erst_size, &ir->ir_set->erst_size);
 
 	erst_base = xhci_read_64(xhci, &ir->ir_set->erst_base);
-	erst_base &= ERST_BASE_RSVDP;
-	erst_base |= ir->erst.erst_dma_addr & ~ERST_BASE_RSVDP;
+	erst_base &= ~ERST_BASE_ADDRESS_MASK;
+	erst_base |= ir->erst.erst_dma_addr & ERST_BASE_ADDRESS_MASK;
 	if (xhci->quirks & XHCI_WRITE_64_HI_LO)
 		hi_lo_writeq(erst_base, &ir->ir_set->erst_base);
 	else

drivers/usb/host/xhci.h

@@ -255,7 +255,8 @@ struct xhci_intr_reg {
 #define	ERST_SIZE_MASK		(0xffff)
 
 /* erst_base bitmasks */
-#define ERST_BASE_RSVDP		(GENMASK_ULL(5, 0))
+/* bits 63:6 - Event Ring Segment Table Base Address Register */
+#define ERST_BASE_ADDRESS_MASK	GENMASK_ULL(63, 6)
 
 /* erst_dequeue bitmasks */
 /* Dequeue ERST Segment Index (DESI) - Segment number (or alias)