Index: stable/12/sys/dev/uart/uart_cpu_acpi.c
===================================================================
--- stable/12/sys/dev/uart/uart_cpu_acpi.c	(revision 366941)
+++ stable/12/sys/dev/uart/uart_cpu_acpi.c	(revision 366942)
@@ -1,164 +1,199 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
  * Copyright (c) 2016 The FreeBSD Foundation
  * Copyright (c) 2019 Colin Percival
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
 
 #include <machine/bus.h>
 
 #include <dev/uart/uart.h>
 #include <dev/uart/uart_bus.h>
 #include <dev/uart/uart_cpu.h>
 #include <dev/uart/uart_cpu_acpi.h>
 
 #include <contrib/dev/acpica/include/acpi.h>
 #include <contrib/dev/acpica/include/accommon.h>
 #include <contrib/dev/acpica/include/actables.h>
 
 static struct acpi_uart_compat_data *
 uart_cpu_acpi_scan(uint8_t interface_type)
 {
 	struct acpi_uart_compat_data **cd, *curcd;
 	int i;
 
 	SET_FOREACH(cd, uart_acpi_class_and_device_set) {
 		curcd = *cd;
 		for (i = 0; curcd[i].cd_hid != NULL; i++) {
 			if (curcd[i].cd_port_subtype == interface_type)
 				return (&curcd[i]);
 		}
 	}
 
 	SET_FOREACH(cd, uart_acpi_class_set) {
 		curcd = *cd;
 		for (i = 0; curcd[i].cd_hid != NULL; i++) {
 			if (curcd[i].cd_port_subtype == interface_type)
 				return (&curcd[i]);
 		}
 	}
 
 	return (NULL);
 }
 
 int
 uart_cpu_acpi_spcr(int devtype, struct uart_devinfo *di)
 {
 	vm_paddr_t spcr_physaddr;
 	ACPI_TABLE_SPCR *spcr;
 	struct acpi_uart_compat_data *cd;
 	struct uart_class *class;
 	int error = ENXIO;
 
 	/* SPCR only tells us about consoles. */
 	if (devtype != UART_DEV_CONSOLE)
 		return (error);
 
 	/* Look for the SPCR table. */
 	spcr_physaddr = acpi_find_table(ACPI_SIG_SPCR);
 	if (spcr_physaddr == 0)
 		return (error);
 	spcr = acpi_map_table(spcr_physaddr, ACPI_SIG_SPCR);
 	if (spcr == NULL) {
 		printf("Unable to map the SPCR table!\n");
 		return (error);
 	}
 
 	/* Search for information about this SPCR interface type. */
 	cd = uart_cpu_acpi_scan(spcr->InterfaceType);
 	if (cd == NULL)
 		goto out;
 	class = cd->cd_class;
 
 	/* Fill in some fixed details. */
 	di->bas.chan = 0;
 	di->bas.rclk = 0;
 	di->databits = 8;
 	di->stopbits = 1;
 	di->parity = UART_PARITY_NONE;
 	di->ops = uart_getops(class);
 
 	/* Fill in details from SPCR table. */
 	switch (spcr->SerialPort.SpaceId) {
 	case 0:
 		di->bas.bst = uart_bus_space_mem;
 		break;
 	case 1:
 		di->bas.bst = uart_bus_space_io;
 		break;
 	default:
 		printf("UART in unrecognized address space: %d!\n",
 		    (int)spcr->SerialPort.SpaceId);
 		goto out;
 	}
-	if (spcr->SerialPort.AccessWidth == 0)
+	switch (spcr->SerialPort.AccessWidth) {
+	case 0: /* EFI_ACPI_6_0_UNDEFINED */
+		/* FALLTHROUGH */
+	case 1: /* EFI_ACPI_6_0_BYTE */
+		di->bas.regiowidth = 1;
+		break;
+	case 2: /* EFI_ACPI_6_0_WORD */
+		di->bas.regiowidth = 2;
+		break;
+	case 3: /* EFI_ACPI_6_0_DWORD */
+		di->bas.regiowidth = 4;
+		break;
+	case 4: /* EFI_ACPI_6_0_QWORD */
+		di->bas.regiowidth = 8;
+		break;
+	default:
+		printf("UART unsupported access width: %d!\n",
+		    (int)spcr->SerialPort.AccessWidth);
+		goto out;
+	}
+	switch (spcr->SerialPort.BitWidth) {
+	case 0:
+		/* FALLTHROUGH */
+	case 8:
 		di->bas.regshft = 0;
-	else
-		di->bas.regshft = spcr->SerialPort.AccessWidth - 1;
-	di->bas.regiowidth = spcr->SerialPort.BitWidth / 8;
+		break;
+	case 16:
+		di->bas.regshft = 1;
+		break;
+	case 32:
+		di->bas.regshft = 2;
+		break;
+	case 64:
+		di->bas.regshft = 3;
+		break;
+	default:
+		printf("UART unsupported bit width: %d!\n",
+		    (int)spcr->SerialPort.BitWidth);
+		goto out;
+	}
 	switch (spcr->BaudRate) {
 	case 0:
 		/* Special value; means "keep current value unchanged". */
 		di->baudrate = 0;
 		break;
 	case 3:
 		di->baudrate = 9600;
 		break;
 	case 4:
 		di->baudrate = 19200;
 		break;
 	case 6:
 		di->baudrate = 57600;
 		break;
 	case 7:
 		di->baudrate = 115200;
 		break;
 	default:
 		printf("SPCR has reserved BaudRate value: %d!\n",
 		    (int)spcr->BaudRate);
 		goto out;
 	}
 
 	/* Apply device tweaks. */
 	if ((cd->cd_quirks & UART_F_IGNORE_SPCR_REGSHFT) ==
 	    UART_F_IGNORE_SPCR_REGSHFT) {
 		di->bas.regshft = cd->cd_regshft;
 	}
 
 	/* Create a bus space handle. */
 	error = bus_space_map(di->bas.bst, spcr->SerialPort.Address,
 	    uart_getrange(class), 0, &di->bas.bsh);
 
 out:
 	acpi_unmap_table(spcr);
 	return (error);
 }