nvram: Introduce helper functions for CHRP "system" and "free space" partitions

The "system partition" and "free space" partition layouts are
defined by the CHRP and LoPAPR specification, and used by
OpenBIOS and SLOF. We can re-use this code for other machines
that use OpenBIOS and SLOF, too. So let's make this code independent
from the MAC NVRAM environment and put it into two proper helper
functions.
Signed-off-by: NThomas Huth <thuth@redhat.com>
Tested-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

hw/nvram/Makefile.objs

 common-obj-$(CONFIG_DS1225Y) += ds1225y.o
 common-obj-y += eeprom93xx.o
 common-obj-y += fw_cfg.o
+common-obj-y += chrp_nvram.o
 common-obj-$(CONFIG_MAC_NVRAM) += mac_nvram.o
 obj-$(CONFIG_PSERIES) += spapr_nvram.o

hw/nvram/chrp_nvram.c

+/*
+ * Common Hardware Reference Platform NVRAM helper functions.
+ *
+ * The CHRP NVRAM layout is used by OpenBIOS and SLOF. See CHRP
+ * specification, chapter 8, or the LoPAPR specification for details
+ * about the NVRAM layout.
+ *
+ * This code is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/cutils.h"
+#include "hw/hw.h"
+#include "hw/nvram/chrp_nvram.h"
+#include "hw/nvram/openbios_firmware_abi.h"
+#include "sysemu/sysemu.h"
+
+/**
+ * Create a "system partition", used for the Open Firmware
+ * environment variables.
+ */
+int chrp_nvram_create_system_partition(uint8_t *data, int min_len)
+{
+    struct OpenBIOS_nvpart_v1 *part_header;
+    unsigned int i;
+    int end;
+
+    part_header = (struct OpenBIOS_nvpart_v1 *)data;
+    part_header->signature = OPENBIOS_PART_SYSTEM;
+    pstrcpy(part_header->name, sizeof(part_header->name), "system");
+
+    end = sizeof(struct OpenBIOS_nvpart_v1);
+    for (i = 0; i < nb_prom_envs; i++) {
+        end = OpenBIOS_set_var(data, end, prom_envs[i]);
+    }
+
+    /* End marker */
+    data[end++] = '\0';
+
+    end = (end + 15) & ~15;
+    /* XXX: OpenBIOS is not able to grow up a partition. Leave some space for
+       new variables. */
+    if (end < min_len) {
+        end = min_len;
+    }
+    OpenBIOS_finish_partition(part_header, end);
+
+    return end;
+}
+
+/**
+ * Create a "free space" partition
+ */
+int chrp_nvram_create_free_partition(uint8_t *data, int len)
+{
+    struct OpenBIOS_nvpart_v1 *part_header;
+
+    part_header = (struct OpenBIOS_nvpart_v1 *)data;
+    part_header->signature = OPENBIOS_PART_FREE;
+    pstrcpy(part_header->name, sizeof(part_header->name), "free");
+
+    OpenBIOS_finish_partition(part_header, len);
+
+    return len;
+}

hw/nvram/mac_nvram.c

@@ -25,7 +25,7 @@
 #include "qemu/osdep.h"
 #include "hw/hw.h"
 #include "hw/nvram/openbios_firmware_abi.h"
-#include "sysemu/sysemu.h"
+#include "hw/nvram/chrp_nvram.h"
 #include "hw/ppc/mac.h"
 #include "qemu/cutils.h"
 #include <zlib.h>
@@ -146,38 +146,14 @@ static void macio_nvram_register_types(void)
 static void pmac_format_nvram_partition_of(MacIONVRAMState *nvr, int off,
                                            int len)
 {
-    unsigned int i;
-    uint32_t start = off, end;
-    struct OpenBIOS_nvpart_v1 *part_header;
+    int sysp_end;
+
+    /* OpenBIOS nvram variables partition */
+    sysp_end = chrp_nvram_create_system_partition(&nvr->data[off],
+                                                  DEF_SYSTEM_SIZE) + off;
 
-    // OpenBIOS nvram variables
-    // Variable partition
-    part_header = (struct OpenBIOS_nvpart_v1 *)&nvr->data[start];
-    part_header->signature = OPENBIOS_PART_SYSTEM;
-    pstrcpy(part_header->name, sizeof(part_header->name), "system");
-
-    end = start + sizeof(struct OpenBIOS_nvpart_v1);
-    for (i = 0; i < nb_prom_envs; i++)
-        end = OpenBIOS_set_var(nvr->data, end, prom_envs[i]);
-
-    // End marker
-    nvr->data[end++] = '\0';
-
-    end = start + ((end - start + 15) & ~15);
-    /* XXX: OpenBIOS is not able to grow up a partition. Leave some space for
-       new variables. */
-    if (end < DEF_SYSTEM_SIZE)
-        end = DEF_SYSTEM_SIZE;
-    OpenBIOS_finish_partition(part_header, end - start);
-
-    // free partition
-    start = end;
-    part_header = (struct OpenBIOS_nvpart_v1 *)&nvr->data[start];
-    part_header->signature = OPENBIOS_PART_FREE;
-    pstrcpy(part_header->name, sizeof(part_header->name), "free");
-
-    end = len;
-    OpenBIOS_finish_partition(part_header, end - start);
+    /* Free space partition */
+    chrp_nvram_create_free_partition(&nvr->data[sysp_end], len - sysp_end);
 }
 
 #define OSX_NVRAM_SIGNATURE     (0x5A)

include/hw/nvram/chrp_nvram.h

+/*
+ * Common Hardware Reference Platform NVRAM functions.
+ *
+ * This code is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef CHRP_NVRAM_H
+#define CHRP_NVRAM_H
+
+int chrp_nvram_create_system_partition(uint8_t *data, int min_len);
+int chrp_nvram_create_free_partition(uint8_t *data, int len);
+
+#endif