CVS commit: src/sys/arch/arm/acpi

[Jared D. McNeill]

Module Name:    src
Committed By:   jmcneill
Date:           Sun Oct 24 11:58:23 UTC 2021

Modified Files:
        src/sys/arch/arm/acpi: acpi_platform.c

Log Message:
More SPCR cleanup:

 - For 16550 style UARTs, always honour GAS if BitWidth != 0
 - Use BitWidth instead of AccessWidth to determine register stride
 - For baud rate ID of 0, assume 115200 until we have a way of probing
   the baud rate configured by firmware.


To generate a diff of this commit:
cvs rdiff -u -r1.31 -r1.32 src/sys/arch/arm/acpi/acpi_platform.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/arch/arm/acpi/acpi_platform.c
diff -u src/sys/arch/arm/acpi/acpi_platform.c:1.31 src/sys/arch/arm/acpi/acpi_platform.c:1.32
--- src/sys/arch/arm/acpi/acpi_platform.c:1.31	Sat Oct 23 17:45:55 2021
+++ src/sys/arch/arm/acpi/acpi_platform.c	Sun Oct 24 11:58:23 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: acpi_platform.c,v 1.31 2021/10/23 17:45:55 jmcneill Exp $ */
+/* $NetBSD: acpi_platform.c,v 1.32 2021/10/24 11:58:23 jmcneill Exp $ */
 
 /*-
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
 #include "opt_multiprocessor.h"
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_platform.c,v 1.31 2021/10/23 17:45:55 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_platform.c,v 1.32 2021/10/24 11:58:23 jmcneill Exp $");
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -95,7 +95,20 @@ static const struct acpi_spcr_baud_rate 
 	uint8_t		id;
 	int		baud_rate;
 } acpi_spcr_baud_rates[] = {
-	{ SPCR_BAUD_DEFAULT,	-1 },
+	/*
+	 * SPCR_BAUD_DEFAULT means:
+	 *   "As is, operating system relies on the current configuration
+	 *    of serial port until the full featured driver will be
+	 *    initialized."
+	 *
+	 * We don't currently have a good way of telling the UART driver
+	 * to detect the currently configured baud rate, so just pick
+	 * something sensible here.
+	 *
+	 * In the past we have tried baud_rate values of 0 and -1, but
+	 * these cause problems with the com(4) driver.
+	 */
+	{ SPCR_BAUD_DEFAULT,	115200 },
 	{ SPCR_BAUD_9600,	9600 },
 	{ SPCR_BAUD_19200,	19200 },
 	{ SPCR_BAUD_57600,	57600 },
@@ -192,16 +205,27 @@ acpi_platform_attach_uart(ACPI_TABLE_SPC
 	case ACPI_DBG2_16550_SUBSET:
 	case ACPI_DBG2_16550_GAS:
 		memset(&dummy_bsh, 0, sizeof(dummy_bsh));
-		if (spcr->InterfaceType == ACPI_DBG2_16550_COMPATIBLE) {
+		switch (spcr->SerialPort.BitWidth) {
+		case 8:
 			reg_shift = 0;
-		} else if (spcr->InterfaceType == ACPI_DBG2_16550_SUBSET) {
+			break;
+		case 16:
+			reg_shift = 1;
+			break;
+		case 32:
 			reg_shift = 2;
-		} else {
-			if (ACPI_ACCESS_BIT_WIDTH(spcr->SerialPort.AccessWidth) == 8) {
+			break;
+		default:
+			/*
+			 * Bit width 0 is possible for types 0 and 1. Otherwise,
+			 * possibly buggy firmware.
+			 */
+			if (spcr->InterfaceType == ACPI_DBG2_16550_COMPATIBLE) {
 				reg_shift = 0;
 			} else {
 				reg_shift = 2;
 			}
+			break;
 		}
 		com_init_regs_stride(&regs, &arm_generic_bs_tag, dummy_bsh,
 		    le64toh(spcr->SerialPort.Address), reg_shift);