ACPI / table: Add new function to get table entries

The acpi_table_parse() function has a callback that
passes a pointer to a table_header. Add a new function
which takes this pointer and parses its entries. This
eliminates the need to re-traverse all the tables for
each call. e.g. as in acpi_table_parse_madt() which is
normally called after acpi_table_parse().

Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 44 insertions, 19 deletions

diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index 6d5a6cda0734..f1debe97dcfc 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -190,30 +190,24 @@ void acpi_table_print_madt_entry(struct acpi_subtable_header *header)
         }
 }
 
-
 int __init
-acpi_table_parse_entries(char *id,
-                             unsigned long table_size,
-                             int entry_id,
-                             acpi_tbl_entry_handler handler,
-                             unsigned int max_entries)
+acpi_parse_entries(char *id, unsigned long table_size,
+                acpi_tbl_entry_handler handler,
+                struct acpi_table_header *table_header,
+                int entry_id, unsigned int max_entries)
 {
-        struct acpi_table_header *table_header = NULL;
         struct acpi_subtable_header *entry;
-        unsigned int count = 0;
+        int count = 0;
         unsigned long table_end;
-        acpi_size tbl_size;
 
         if (acpi_disabled)
                 return -ENODEV;
 
-        if (!handler)
+        if (!id || !handler)
                 return -EINVAL;
 
-        if (strncmp(id, ACPI_SIG_MADT, 4) == 0)
-                acpi_get_table_with_size(id, acpi_apic_instance, &table_header, &tbl_size);
-        else
-                acpi_get_table_with_size(id, 0, &table_header, &tbl_size);
+        if (!table_size)
+                return -EINVAL;
 
         if (!table_header) {
                 pr_warn("%4.4s not present\n", id);
@@ -232,7 +226,7 @@ acpi_table_parse_entries(char *id,
                 if (entry->type == entry_id
                     && (!max_entries || count++ < max_entries))
                         if (handler(entry, table_end))
-                                goto err;
+                                return -EINVAL;
 
                 /*
                  * If entry->length is 0, break from this loop to avoid
@@ -240,22 +234,53 @@ acpi_table_parse_entries(char *id,
                  */
                 if (entry->length == 0) {
                         pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, entry_id);
-                        goto err;
+                        return -EINVAL;
                 }
 
                 entry = (struct acpi_subtable_header *)
                     ((unsigned long)entry + entry->length);
         }
+
         if (max_entries && count > max_entries) {
                 pr_warn("[%4.4s:0x%02x] ignored %i entries of %i found\n",
                         id, entry_id, count - max_entries, count);
         }
 
-        early_acpi_os_unmap_memory((char *)table_header, tbl_size);
         return count;
-err:
+}
+
+int __init
+acpi_table_parse_entries(char *id,
+                         unsigned long table_size,
+                         int entry_id,
+                         acpi_tbl_entry_handler handler,
+                         unsigned int max_entries)
+{
+        struct acpi_table_header *table_header = NULL;
+        acpi_size tbl_size;
+        int count;
+        u32 instance = 0;
+
+        if (acpi_disabled)
+                return -ENODEV;
+
+        if (!id || !handler)
+                return -EINVAL;
+
+        if (!strncmp(id, ACPI_SIG_MADT, 4))
+                instance = acpi_apic_instance;
+
+        acpi_get_table_with_size(id, instance, &table_header, &tbl_size);
+        if (!table_header) {
+                pr_warn("%4.4s not present\n", id);
+                return -ENODEV;
+        }
+
+        count = acpi_parse_entries(id, table_size, handler, table_header,
+                        entry_id, max_entries);
+
         early_acpi_os_unmap_memory((char *)table_header, tbl_size);
-        return -EINVAL;
+        return count;
 }
 
 int __init