SFI: add sysfs interface for SFI tables.

Analogous to ACPI's /sys/firmware/acpi/tables/...

create /sys/firmware/sfi/tables/

The tables are primariy for the kernel,
but sometimes it is useful for user-space to be
able to read them.

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

4 files changed, 167 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-firmware-sfi b/Documentation/ABI/testing/sysfs-firmware-sfi
new file mode 100644
index 000000000000..4be7d44aeacf
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-firmware-sfi
@@ -0,0 +1,15 @@
+What:           /sys/firmware/sfi/tables/
+Date:           May 2010
+Contact:        Len Brown <lenb@kernel.org>
+Description:
+                SFI defines a number of small static memory tables
+                so the kernel can get platform information from firmware.
+
+                The tables are defined in the latest SFI specification:
+                http://simplefirmware.org/documentation
+
+                While the tables are used by the kernel, user-space
+                can observe them this way:
+
+                # cd /sys/firmware/sfi/tables
+                # cat $TABLENAME > $TABLENAME.bin
diff --git a/drivers/sfi/sfi_acpi.c b/drivers/sfi/sfi_acpi.c
index 34aba30eb84b..f5b4ca581541 100644
--- a/drivers/sfi/sfi_acpi.c
+++ b/drivers/sfi/sfi_acpi.c
@@ -173,3 +173,44 @@ int sfi_acpi_table_parse(char *signature, char *oem_id, char *oem_table_id,
         sfi_acpi_put_table(table);
         return ret;
 }
+
+static ssize_t sfi_acpi_table_show(struct file *filp, struct kobject *kobj,
+                               struct bin_attribute *bin_attr, char *buf,
+                               loff_t offset, size_t count)
+{
+        struct sfi_table_attr *tbl_attr =
+            container_of(bin_attr, struct sfi_table_attr, attr);
+        struct acpi_table_header *th = NULL;
+        struct sfi_table_key key;
+        ssize_t cnt;
+
+        key.sig = tbl_attr->name;
+        key.oem_id = NULL;
+        key.oem_table_id = NULL;
+
+        th = sfi_acpi_get_table(&key);
+        if (!th)
+                return 0;
+
+        cnt =  memory_read_from_buffer(buf, count, &offset,
+                                        th, th->length);
+        sfi_acpi_put_table(th);
+
+        return cnt;
+}
+
+
+void __init sfi_acpi_sysfs_init(void)
+{
+        u32 tbl_cnt, i;
+        struct sfi_table_attr *tbl_attr;
+
+        tbl_cnt = XSDT_GET_NUM_ENTRIES(xsdt_va, u64);
+        for (i = 0; i < tbl_cnt; i++) {
+                tbl_attr =
+                        sfi_sysfs_install_table(xsdt_va->table_offset_entry[i]);
+                tbl_attr->attr.read = sfi_acpi_table_show;
+        }
+
+        return;
+}
diff --git a/drivers/sfi/sfi_core.c b/drivers/sfi/sfi_core.c
index aba6a461365b..005195958647 100644
--- a/drivers/sfi/sfi_core.c
+++ b/drivers/sfi/sfi_core.c
@@ -67,6 +67,7 @@
 #include <linux/acpi.h>
 #include <linux/init.h>
 #include <linux/sfi.h>
+#include <linux/slab.h>
 
 #include "sfi_core.h"
 
@@ -382,6 +383,102 @@ static __init int sfi_find_syst(void)
         return -1;
 }
 
+static struct kobject *sfi_kobj;
+static struct kobject *tables_kobj;
+
+static ssize_t sfi_table_show(struct file *filp, struct kobject *kobj,
+                               struct bin_attribute *bin_attr, char *buf,
+                               loff_t offset, size_t count)
+{
+        struct sfi_table_attr *tbl_attr =
+            container_of(bin_attr, struct sfi_table_attr, attr);
+        struct sfi_table_header *th = NULL;
+        struct sfi_table_key key;
+        ssize_t cnt;
+
+        key.sig = tbl_attr->name;
+        key.oem_id = NULL;
+        key.oem_table_id = NULL;
+
+        if (strncmp(SFI_SIG_SYST, tbl_attr->name, SFI_SIGNATURE_SIZE)) {
+                th = sfi_get_table(&key);
+                if (!th)
+                        return 0;
+
+                cnt =  memory_read_from_buffer(buf, count, &offset,
+                                                th, th->len);
+                sfi_put_table(th);
+        } else
+                cnt =  memory_read_from_buffer(buf, count, &offset,
+                                        syst_va, syst_va->header.len);
+
+        return cnt;
+}
+
+struct sfi_table_attr __init *sfi_sysfs_install_table(u64 pa)
+{
+        struct sfi_table_attr *tbl_attr;
+        struct sfi_table_header *th;
+        int ret;
+
+        tbl_attr = kzalloc(sizeof(struct sfi_table_attr), GFP_KERNEL);
+        if (!tbl_attr)
+                return NULL;
+
+        th = sfi_map_table(pa);
+        if (!th || !th->sig[0]) {
+                kfree(tbl_attr);
+                return NULL;
+        }
+
+        sysfs_attr_init(&tbl_attr->attr.attr);
+        memcpy(tbl_attr->name, th->sig, SFI_SIGNATURE_SIZE);
+
+        tbl_attr->attr.size = 0;
+        tbl_attr->attr.read = sfi_table_show;
+        tbl_attr->attr.attr.name = tbl_attr->name;
+        tbl_attr->attr.attr.mode = 0400;
+
+        ret = sysfs_create_bin_file(tables_kobj,
+                                  &tbl_attr->attr);
+        if (ret)
+                kfree(tbl_attr);
+
+        sfi_unmap_table(th);
+        return tbl_attr;
+}
+
+static int __init sfi_sysfs_init(void)
+{
+        int tbl_cnt, i;
+
+        if (sfi_disabled)
+                return 0;
+
+        sfi_kobj = kobject_create_and_add("sfi", firmware_kobj);
+        if (!sfi_kobj)
+                return 0;
+
+        tables_kobj = kobject_create_and_add("tables", sfi_kobj);
+        if (!tables_kobj) {
+                kobject_put(sfi_kobj);
+                return 0;
+        }
+
+        sfi_sysfs_install_table(syst_pa);
+
+        tbl_cnt = SFI_GET_NUM_ENTRIES(syst_va, u64);
+
+        for (i = 0; i < tbl_cnt; i++)
+                sfi_sysfs_install_table(syst_va->pentry[i]);
+
+        sfi_acpi_sysfs_init();
+        kobject_uevent(sfi_kobj, KOBJ_ADD);
+        kobject_uevent(tables_kobj, KOBJ_ADD);
+        pr_info("SFI sysfs interfaces init success\n");
+        return 0;
+}
+
 void __init sfi_init(void)
 {
         if (!acpi_disabled)
@@ -414,3 +511,9 @@ void __init sfi_init_late(void)
 
         sfi_acpi_init();
 }
+
+/*
+ * The reason we put it here becasue we need wait till the /sys/firmware
+ * is setup, then our interface can be registered in /sys/firmware/sfi
+ */
+core_initcall(sfi_sysfs_init);
diff --git a/drivers/sfi/sfi_core.h b/drivers/sfi/sfi_core.h
index da82d39e104d..b7cf220d44ec 100644
--- a/drivers/sfi/sfi_core.h
+++ b/drivers/sfi/sfi_core.h
@@ -61,6 +61,12 @@ struct sfi_table_key{
         char    *oem_table_id;
 };
 
+/* sysfs interface */
+struct sfi_table_attr {
+        struct bin_attribute attr;
+        char name[8];
+};
+
 #define SFI_ANY_KEY { .sig = NULL, .oem_id = NULL, .oem_table_id = NULL }
 
 extern int __init sfi_acpi_init(void);
@@ -68,3 +74,5 @@ extern  struct sfi_table_header *sfi_check_table(u64 paddr,
                                         struct sfi_table_key *key);
 struct sfi_table_header *sfi_get_table(struct sfi_table_key *key);
 extern void sfi_put_table(struct sfi_table_header *table);
+extern struct sfi_table_attr __init *sfi_sysfs_install_table(u64 pa);
+extern void __init sfi_acpi_sysfs_init(void);