Patch by Jian Zhang, 20 May 2004:
add support for environment in NAND flash
diff --git a/common/env_nand.c b/common/env_nand.c
new file mode 100644
index 0000000..2412b10
--- /dev/null
+++ b/common/env_nand.c
@@ -0,0 +1,171 @@
+/*
+ * (C) Copyright 2004
+ * Jian Zhang, Texas Instruments, jzhang@ti.com.
+
+ * (C) Copyright 2000-2004
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Andreas Heppel <aheppel@sysgo.de>
+
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/* #define DEBUG */
+
+#include <common.h>
+
+#if defined(CFG_ENV_IS_IN_NAND) /* Environment is in Nand Flash */
+
+#include <command.h>
+#include <environment.h>
+#include <linux/stddef.h>
+#include <malloc.h>
+#include <linux/mtd/nand.h>
+
+#if ((CONFIG_COMMANDS&(CFG_CMD_ENV|CFG_CMD_NAND)) == (CFG_CMD_ENV|CFG_CMD_NAND))
+#define CMD_SAVEENV
+#endif
+
+#if defined(CFG_ENV_SIZE_REDUND)
+#error CFG_ENV_SIZE_REDUND not supported yet
+#endif
+
+#if defined(CFG_ENV_ADDR_REDUND)
+#error CFG_ENV_ADDR_REDUND and CFG_ENV_IS_IN_NAND not supported yet
+#endif
+
+
+#ifdef CONFIG_INFERNO
+#error CONFIG_INFERNO not supported yet
+#endif
+
+/* references to names in cmd_nand.c */
+#define NANDRW_READ 0x01
+#define NANDRW_WRITE 0x00
+#define NANDRW_JFFS2 0x02
+extern struct nand_chip nand_dev_desc[];
+int nand_rw (struct nand_chip* nand, int cmd,
+ size_t start, size_t len,
+ size_t * retlen, u_char * buf);
+int nand_erase(struct nand_chip* nand, size_t ofs,
+ size_t len, int clean);
+
+/* references to names in env_common.c */
+extern uchar default_environment[];
+extern int default_environment_size;
+
+char * env_name_spec = "NAND";
+
+
+#ifdef ENV_IS_EMBEDDED
+extern uchar environment[];
+env_t *env_ptr = (env_t *)(&environment[0]);
+#else /* ! ENV_IS_EMBEDDED */
+env_t *env_ptr = 0; //(env_t *)CFG_ENV_ADDR;
+#endif /* ENV_IS_EMBEDDED */
+
+
+/* local functions */
+static void use_default(void);
+
+
+uchar env_get_char_spec (int index)
+{
+ DECLARE_GLOBAL_DATA_PTR;
+
+ return ( *((uchar *)(gd->env_addr + index)) );
+}
+
+
+/* this is called before nand_init()
+ * so we can't read Nand to validate env data.
+ * Mark it OK for now. env_relocate() in env_common.c
+ * will call our relocate function which will does
+ * the real validation.
+ */
+int env_init(void)
+{
+ DECLARE_GLOBAL_DATA_PTR;
+
+ gd->env_addr = (ulong)&default_environment[0];
+ gd->env_valid = 1;
+
+ return (0);
+}
+
+#ifdef CMD_SAVEENV
+int saveenv(void)
+{
+ int total, ret = 0;
+ puts ("Erasing Nand...");
+ if (nand_erase(nand_dev_desc + 0, CFG_ENV_OFFSET, CFG_ENV_SIZE, 0))
+ return 1;
+
+ puts ("Writing to Nand... ");
+ ret = nand_rw(nand_dev_desc + 0,
+ NANDRW_WRITE | NANDRW_JFFS2, CFG_ENV_OFFSET, CFG_ENV_SIZE,
+ &total, (u_char*)env_ptr);
+ if (ret || total != CFG_ENV_SIZE)
+ return 1;
+
+ puts ("done\n");
+ return ret;
+}
+#endif /* CMD_SAVEENV */
+
+
+void env_relocate_spec (void)
+{
+#if !defined(ENV_IS_EMBEDDED)
+ int ret, total;
+
+ ret = nand_rw(nand_dev_desc + 0,
+ NANDRW_READ | NANDRW_JFFS2, CFG_ENV_OFFSET, CFG_ENV_SIZE,
+ &total, (u_char*)env_ptr);
+ if (ret || total != CFG_ENV_SIZE)
+ return use_default();
+
+ if (crc32(0, env_ptr->data, ENV_SIZE) != env_ptr->crc)
+ return use_default();
+#endif /* ! ENV_IS_EMBEDDED */
+
+}
+
+static void use_default()
+{
+ DECLARE_GLOBAL_DATA_PTR;
+
+ puts ("*** Warning - bad CRC or NAND, using default environment\n\n");
+
+ if (default_environment_size > CFG_ENV_SIZE){
+ puts ("*** Error - default environment is too large\n\n");
+ return;
+ }
+
+ memset (env_ptr, 0, sizeof(env_t));
+ memcpy (env_ptr->data,
+ default_environment,
+ default_environment_size);
+ env_ptr->crc = crc32(0, env_ptr->data, ENV_SIZE);
+ gd->env_valid = 1;
+
+}
+
+#endif /* CFG_ENV_IS_IN_NAND */