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Date:      Mon, 22 Oct 2018 03:29:54 +0000 (UTC)
From:      Ben Widawsky <bwidawsk@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r339577 - head/sys/dev/acpica
Message-ID:  <201810220329.w9M3Tsx4070473@repo.freebsd.org>
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Author: bwidawsk
Date: Mon Oct 22 03:29:54 2018
New Revision: 339577
URL: https://svnweb.freebsd.org/changeset/base/339577

Log:
  acpi: Add an interface to obtain DSM information
  
  The Device Specific Method (_DSM) is on optional object that defines
  device specific controls. This will be useful for our power management
  controller in upcoming patches. More information can be found in ACPI
  spec 6.2 section 9.1.1
  
  https://www.uefi.org/sites/default/files/resources/ACPI_6_2.pdf
  
  This patch had a minor modification changing ENOMEM to AE_NO_MEMORY
  after it got review and approval but before committing.
  
  Test Plan: Tested in my s0ix branch
  
  Reviewed by:	kib
  Approved by:	emaste (mentor)
  Differential Revision: https://reviews.freebsd.org/D17121

Modified:
  head/sys/dev/acpica/acpi.c
  head/sys/dev/acpica/acpivar.h

Modified: head/sys/dev/acpica/acpi.c
==============================================================================
--- head/sys/dev/acpica/acpi.c	Mon Oct 22 02:42:14 2018	(r339576)
+++ head/sys/dev/acpica/acpi.c	Mon Oct 22 03:29:54 2018	(r339577)
@@ -2570,6 +2570,98 @@ acpi_AppendBufferResource(ACPI_BUFFER *buf, ACPI_RESOU
     return (AE_OK);
 }
 
+UINT8
+acpi_DSMQuery(ACPI_HANDLE h, uint8_t *uuid, int revision)
+{
+    /*
+     * ACPI spec 9.1.1 defines this.
+     *
+     * "Arg2: Function Index Represents a specific function whose meaning is
+     * specific to the UUID and Revision ID. Function indices should start
+     * with 1. Function number zero is a query function (see the special
+     * return code defined below)."
+     */
+    ACPI_BUFFER buf;
+    ACPI_OBJECT *obj;
+    UINT8 ret = 0;
+
+    if (!ACPI_SUCCESS(acpi_EvaluateDSM(h, uuid, revision, 0, NULL, &buf))) {
+	ACPI_INFO(("Failed to enumerate DSM functions\n"));
+	return (0);
+    }
+
+    obj = (ACPI_OBJECT *)buf.Pointer;
+    KASSERT(obj, ("Object not allowed to be NULL\n"));
+
+    /*
+     * From ACPI 6.2 spec 9.1.1:
+     * If Function Index = 0, a Buffer containing a function index bitfield.
+     * Otherwise, the return value and type depends on the UUID and revision
+     * ID (see below).
+     */
+    switch (obj->Type) {
+    case ACPI_TYPE_BUFFER:
+	ret = *(uint8_t *)obj->Buffer.Pointer;
+	break;
+    case ACPI_TYPE_INTEGER:
+	ACPI_BIOS_WARNING((AE_INFO,
+	    "Possibly buggy BIOS with ACPI_TYPE_INTEGER for function enumeration\n"));
+	ret = obj->Integer.Value & 0xFF;
+	break;
+    default:
+	ACPI_WARNING((AE_INFO, "Unexpected return type %u\n", obj->Type));
+    };
+
+    AcpiOsFree(obj);
+    return ret;
+}
+
+/*
+ * DSM may return multiple types depending on the function. It is therefore
+ * unsafe to use the typed evaluation. It is highly recommended that the caller
+ * check the type of the returned object.
+ */
+ACPI_STATUS
+acpi_EvaluateDSM(ACPI_HANDLE handle, uint8_t *uuid, int revision,
+    uint64_t function, union acpi_object *package, ACPI_BUFFER *out_buf)
+{
+    ACPI_OBJECT arg[4];
+    ACPI_OBJECT_LIST arglist;
+    ACPI_BUFFER buf;
+    ACPI_STATUS status;
+
+    if (out_buf == NULL)
+	return (AE_NO_MEMORY);
+
+    arg[0].Type = ACPI_TYPE_BUFFER;
+    arg[0].Buffer.Length = ACPI_UUID_LENGTH;
+    arg[0].Buffer.Pointer = uuid;
+    arg[1].Type = ACPI_TYPE_INTEGER;
+    arg[1].Integer.Value = revision;
+    arg[2].Type = ACPI_TYPE_INTEGER;
+    arg[2].Integer.Value = function;
+    if (package) {
+	arg[3] = *package;
+    } else {
+	arg[3].Type = ACPI_TYPE_PACKAGE;
+	arg[3].Package.Count = 0;
+	arg[3].Package.Elements = NULL;
+    }
+
+    arglist.Pointer = arg;
+    arglist.Count = 4;
+    buf.Pointer = NULL;
+    buf.Length = ACPI_ALLOCATE_BUFFER;
+    status = AcpiEvaluateObject(handle, "_DSM", &arglist, &buf);
+    if (ACPI_FAILURE(status))
+	return (status);
+
+    KASSERT(ACPI_SUCCESS(status), ("Unexpected status"));
+
+    *out_buf = buf;
+    return (status);
+}
+
 ACPI_STATUS
 acpi_EvaluateOSC(ACPI_HANDLE handle, uint8_t *uuid, int revision, int count,
     uint32_t *caps_in, uint32_t *caps_out, bool query)

Modified: head/sys/dev/acpica/acpivar.h
==============================================================================
--- head/sys/dev/acpica/acpivar.h	Mon Oct 22 02:42:14 2018	(r339576)
+++ head/sys/dev/acpica/acpivar.h	Mon Oct 22 03:29:54 2018	(r339577)
@@ -349,6 +349,10 @@ ACPI_STATUS	acpi_FindIndexedResource(ACPI_BUFFER *buf,
 		    ACPI_RESOURCE **resp);
 ACPI_STATUS	acpi_AppendBufferResource(ACPI_BUFFER *buf,
 		    ACPI_RESOURCE *res);
+UINT8		acpi_DSMQuery(ACPI_HANDLE h, uint8_t *uuid, int revision);
+ACPI_STATUS	acpi_EvaluateDSM(ACPI_HANDLE handle, uint8_t *uuid,
+		    int revision, uint64_t function, union acpi_object *package,
+		    ACPI_BUFFER *out_buf);
 ACPI_STATUS	acpi_EvaluateOSC(ACPI_HANDLE handle, uint8_t *uuid,
 		    int revision, int count, uint32_t *caps_in,
 		    uint32_t *caps_out, bool query);

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