svn commit: r330835 - in head: share/man/man4 sys/x86/isa

[Roger Pau Monné]

Author: royger
Date: Tue Mar 13 09:42:33 2018
New Revision: 330835
URL: https://svnweb.freebsd.org/changeset/base/330835

Log:
  at_rtc: check in ACPI FADT boot flags if the RTC is present
  
  Or else disable the device. Note that the detection can be bypassed by
  setting the hw.atrtc.enable option in the loader configuration file.
  More information can be found on atrtc(4).
  
  Sponsored by:		Citrix Systems R&D
  Reviewed by:		ian
  Differential revision:	https://reviews.freebsd.org/D14399

Modified:
  head/share/man/man4/atrtc.4
  head/sys/x86/isa/atrtc.c

Modified: head/share/man/man4/atrtc.4
==============================================================================
--- head/share/man/man4/atrtc.4	Tue Mar 13 09:38:53 2018	(r330834)
+++ head/share/man/man4/atrtc.4	Tue Mar 13 09:42:33 2018	(r330835)
@@ -33,13 +33,18 @@
 .Sh SYNOPSIS
 This driver is a mandatory part of i386/amd64 kernels.
 .Pp
-The following tunable is settable from the
+The following tunables are settable from the
 .Xr loader 8 :
 .Bl -ohang
 .It Va hint.atrtc. Ns Ar X Ns Va .clock
 controls event timers functionality support.
 Setting to 0, disables it.
 Default value is 1.
+.It Va hw.atrtc.enable
+Forces enabling or disabling of the device(s).
+Setting to 0 disables it, setting to 1 enables it, bypassing any platform
+configuration hints.
+Default value is -1 (autodetect).
 .El
 .Sh DESCRIPTION
 This driver uses RTC hardware to supply kernel with time-of-day clock

Modified: head/sys/x86/isa/atrtc.c
==============================================================================
--- head/sys/x86/isa/atrtc.c	Tue Mar 13 09:38:53 2018	(r330834)
+++ head/sys/x86/isa/atrtc.c	Tue Mar 13 09:42:33 2018	(r330835)
@@ -32,6 +32,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "opt_acpi.h"
 #include "opt_isa.h"
 
 #include <sys/param.h>
@@ -55,6 +56,10 @@ __FBSDID("$FreeBSD$");
 #include <machine/intr_machdep.h>
 #include "clock_if.h"
 
+#ifdef DEV_ACPI
+#include <contrib/dev/acpica/include/acpi.h>
+#endif
+
 /*
  * atrtc_lock protects low-level access to individual hardware registers.
  * atrtc_time_lock protects the entire sequence of accessing multiple registers
@@ -63,6 +68,10 @@ __FBSDID("$FreeBSD$");
 static struct mtx atrtc_lock;
 MTX_SYSINIT(atrtc_lock_init, &atrtc_lock, "atrtc", MTX_SPIN);
 
+/* Force RTC enabled/disabled. */
+static int atrtc_enabled = -1;
+TUNABLE_INT("hw.atrtc.enabled", &atrtc_enabled);
+
 struct mtx atrtc_time_lock;
 MTX_SYSINIT(atrtc_time_lock_init, &atrtc_time_lock, "atrtc_time", MTX_DEF);
 
@@ -249,11 +258,43 @@ static struct isa_pnp_id atrtc_ids[] = {
 	{ 0 }
 };
 
+static bool
+atrtc_acpi_disabled(void)
+{
+#ifdef DEV_ACPI
+	ACPI_TABLE_FADT *fadt;
+	vm_paddr_t physaddr;
+	uint16_t flags;
+
+	physaddr = acpi_find_table(ACPI_SIG_FADT);
+	if (physaddr == 0)
+		return (false);
+
+	fadt = acpi_map_table(physaddr, ACPI_SIG_FADT);
+	if (fadt == NULL) {
+		printf("at_rtc: unable to map FADT ACPI table\n");
+		return (false);
+	}
+
+	flags = fadt->BootFlags;
+	acpi_unmap_table(fadt);
+
+	if (flags & ACPI_FADT_NO_CMOS_RTC)
+		return (true);
+#endif
+
+	return (false);
+}
+
 static int
 atrtc_probe(device_t dev)
 {
 	int result;
-	
+
+	if ((atrtc_enabled == -1 && atrtc_acpi_disabled()) ||
+	    (atrtc_enabled == 0))
+		return (ENXIO);
+
 	result = ISA_PNP_PROBE(device_get_parent(dev), dev, atrtc_ids);
 	/* ENOENT means no PnP-ID, device is hinted. */
 	if (result == ENOENT) {