SFI: add capability to parse ACPI tables

Extend SFI to access standard ACPI tables.
(eg. the PCI MCFG) using sfi_acpi_table_parse().

Note that this is _not_ a hybrid ACPI + SFI mode.
The platform boots in either ACPI mode or SFI mode.

SFI runs only with acpi_disabled=1, which can be set
at build-time via CONFIG_ACPI=n, or at boot time by
the failure to find ACPI platform support.

So this extension simply allows SFI-platforms to
re-use existing standard table formats that happen to
be defined to live in ACPI envelopes.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

2 files changed, 268 insertions, 0 deletions

diff --git a/drivers/sfi/sfi_acpi.c b/drivers/sfi/sfi_acpi.c
new file mode 100644
index 000000000000..34aba30eb84b
--- /dev/null
+++ b/drivers/sfi/sfi_acpi.c
@@ -0,0 +1,175 @@
+/* sfi_acpi.c Simple Firmware Interface - ACPI extensions */
+
+/*
+
+  This file is provided under a dual BSD/GPLv2 license.  When using or
+  redistributing this file, you may do so under either license.
+
+  GPL LICENSE SUMMARY
+
+  Copyright(c) 2009 Intel Corporation. All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of version 2 of the GNU General Public License as
+  published by the Free Software Foundation.
+
+  This program is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+  The full GNU General Public License is included in this distribution
+  in the file called LICENSE.GPL.
+
+  BSD LICENSE
+
+  Copyright(c) 2009 Intel Corporation. All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * 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.
+    * Neither the name of Intel Corporation nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+  "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 COPYRIGHT
+  OWNER OR CONTRIBUTORS 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.
+
+*/
+
+#define KMSG_COMPONENT "SFI"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kernel.h>
+#include <acpi/acpi.h>
+
+#include <linux/sfi.h>
+#include "sfi_core.h"
+
+/*
+ * SFI can access ACPI-defined tables via an optional ACPI XSDT.
+ *
+ * This allows re-use, and avoids re-definition, of standard tables.
+ * For example, the "MCFG" table is defined by PCI, reserved by ACPI,
+ * and is expected to be present many SFI-only systems.
+ */
+
+static struct acpi_table_xsdt *xsdt_va __read_mostly;
+
+#define XSDT_GET_NUM_ENTRIES(ptable, entry_type) \
+        ((ptable->header.length - sizeof(struct acpi_table_header)) / \
+        (sizeof(entry_type)))
+
+static inline struct sfi_table_header *acpi_to_sfi_th(
+                                struct acpi_table_header *th)
+{
+        return (struct sfi_table_header *)th;
+}
+
+static inline struct acpi_table_header *sfi_to_acpi_th(
+                                struct sfi_table_header *th)
+{
+        return (struct acpi_table_header *)th;
+}
+
+/*
+ * sfi_acpi_parse_xsdt()
+ *
+ * Parse the ACPI XSDT for later access by sfi_acpi_table_parse().
+ */
+static int __init sfi_acpi_parse_xsdt(struct sfi_table_header *th)
+{
+        struct sfi_table_key key = SFI_ANY_KEY;
+        int tbl_cnt, i;
+        void *ret;
+
+        xsdt_va = (struct acpi_table_xsdt *)th;
+        tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
+        for (i = 0; i < tbl_cnt; i++) {
+                ret = sfi_check_table(xsdt_va->table_offset_entry[i], &key);
+                if (IS_ERR(ret)) {
+                        disable_sfi();
+                        return -1;
+                }
+        }
+
+        return 0;
+}
+
+int __init sfi_acpi_init(void)
+{
+        struct sfi_table_key xsdt_key = { .sig = SFI_SIG_XSDT };
+
+        sfi_table_parse(SFI_SIG_XSDT, NULL, NULL, sfi_acpi_parse_xsdt);
+
+        /* Only call the get_table to keep the table mapped */
+        xsdt_va = (struct acpi_table_xsdt *)sfi_get_table(&xsdt_key);
+        return 0;
+}
+
+static struct acpi_table_header *sfi_acpi_get_table(struct sfi_table_key *key)
+{
+        u32 tbl_cnt, i;
+        void *ret;
+
+        tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
+        for (i = 0; i < tbl_cnt; i++) {
+                ret = sfi_check_table(xsdt_va->table_offset_entry[i], key);
+                if (!IS_ERR(ret) && ret)
+                        return sfi_to_acpi_th(ret);
+        }
+
+        return NULL;
+}
+
+static void sfi_acpi_put_table(struct acpi_table_header *table)
+{
+        sfi_put_table(acpi_to_sfi_th(table));
+}
+
+/*
+ * sfi_acpi_table_parse()
+ *
+ * Find specified table in XSDT, run handler on it and return its return value
+ */
+int sfi_acpi_table_parse(char *signature, char *oem_id, char *oem_table_id,
+                        int(*handler)(struct acpi_table_header *))
+{
+        struct acpi_table_header *table = NULL;
+        struct sfi_table_key key;
+        int ret = 0;
+
+        if (sfi_disabled)
+                return -1;
+
+        key.sig = signature;
+        key.oem_id = oem_id;
+        key.oem_table_id = oem_table_id;
+
+        table = sfi_acpi_get_table(&key);
+        if (!table)
+                return -EINVAL;
+
+        ret = handler(table);
+        sfi_acpi_put_table(table);
+        return ret;
+}
diff --git a/include/linux/sfi_acpi.h b/include/linux/sfi_acpi.h
new file mode 100644
index 000000000000..c4a5a8cd4469
--- /dev/null
+++ b/include/linux/sfi_acpi.h
@@ -0,0 +1,93 @@
+/* sfi.h Simple Firmware Interface */
+
+/*
+
+  This file is provided under a dual BSD/GPLv2 license.  When using or
+  redistributing this file, you may do so under either license.
+
+  GPL LICENSE SUMMARY
+
+  Copyright(c) 2009 Intel Corporation. All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of version 2 of the GNU General Public License as
+  published by the Free Software Foundation.
+
+  This program is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Softw