openwrt/target/linux/bcm47xx/patches-5.4/820-wgt634u-nvram-fix.patch

The Netgear wgt634u uses a different format for storing the 
configuration. This patch is needed to read out the correct 
configuration. The cfe_env.c file uses a different method way to read 
out the configuration than the in kernel cfe config reader.

--- a/drivers/firmware/broadcom/Makefile
+++ b/drivers/firmware/broadcom/Makefile
@@ -1,3 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_BCM47XX_NVRAM)		+= bcm47xx_nvram.o
+obj-$(CONFIG_BCM47XX_NVRAM)		+= bcm47xx_nvram.o cfe_env.o
 obj-$(CONFIG_BCM47XX_SPROM)		+= bcm47xx_sprom.o
--- /dev/null
+++ b/drivers/firmware/broadcom/cfe_env.c
@@ -0,0 +1,228 @@
+/*
+ * CFE environment variable access
+ *
+ * Copyright 2001-2003, Broadcom Corporation
+ * Copyright 2006, Felix Fietkau <nbd@nbd.name>
+ * 
+ * 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.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <asm/io.h>
+#include <linux/uaccess.h>
+
+#define NVRAM_SIZE       (0x1ff0)
+static char _nvdata[NVRAM_SIZE];
+static char _valuestr[256];
+
+/*
+ * TLV types.  These codes are used in the "type-length-value"
+ * encoding of the items stored in the NVRAM device (flash or EEPROM)
+ *
+ * The layout of the flash/nvram is as follows:
+ *
+ * <type> <length> <data ...> <type> <length> <data ...> <type_end>
+ *
+ * The type code of "ENV_TLV_TYPE_END" marks the end of the list.
+ * The "length" field marks the length of the data section, not
+ * including the type and length fields.
+ *
+ * Environment variables are stored as follows:
+ *
+ * <type_env> <length> <flags> <name> = <value>
+ *
+ * If bit 0 (low bit) is set, the length is an 8-bit value.
+ * If bit 0 (low bit) is clear, the length is a 16-bit value
+ * 
+ * Bit 7 set indicates "user" TLVs.  In this case, bit 0 still
+ * indicates the size of the length field.  
+ *
+ * Flags are from the constants below:
+ *
+ */
+#define ENV_LENGTH_16BITS	0x00	/* for low bit */
+#define ENV_LENGTH_8BITS	0x01
+
+#define ENV_TYPE_USER		0x80
+
+#define ENV_CODE_SYS(n,l) (((n)<<1)|(l))
+#define ENV_CODE_USER(n,l) ((((n)<<1)|(l)) | ENV_TYPE_USER)
+
+/*
+ * The actual TLV types we support
+ */
+
+#define ENV_TLV_TYPE_END	0x00	
+#define ENV_TLV_TYPE_ENV	ENV_CODE_SYS(0,ENV_LENGTH_8BITS)
+
+/*
+ * Environment variable flags 
+ */
+
+#define ENV_FLG_NORMAL		0x00	/* normal read/write */
+#define ENV_FLG_BUILTIN		0x01	/* builtin - not stored in flash */
+#define ENV_FLG_READONLY	0x02	/* read-only - cannot be changed */
+
+#define ENV_FLG_MASK		0xFF	/* mask of attributes we keep */
+#define ENV_FLG_ADMIN		0x100	/* lets us internally override permissions */
+
+
+/*  *********************************************************************
+    *  _nvram_read(buffer,offset,length)
+    *  
+    *  Read data from the NVRAM device
+    *  
+    *  Input parameters: 
+    *  	   buffer - destination buffer
+    *  	   offset - offset of data to read
+    *  	   length - number of bytes to read
+    *  	   
+    *  Return value:
+    *  	   number of bytes read, or <0 if error occured
+    ********************************************************************* */
+static int
+_nvram_read(unsigned char *nv_buf, unsigned char *buffer, int offset, int length)
+{
+    int i;
+    if (offset > NVRAM_SIZE)
+	return -1; 
+
+    for ( i = 0; i < length; i++) {
+	buffer[i] = ((volatile unsigned char*)nv_buf)[offset + i];
+    }
+    return length;
+}
+
+
+static char*
+_strnchr(const char *dest,int c,size_t cnt)
+{
+	while (*dest && (cnt > 0)) {
+	if (*dest == c) return (char *) dest;
+	dest++;
+	cnt--;
+	}
+	return NULL;
+}
+
+
+
+/*
+ * Core support API: Externally visible.
+ */
+
+/*
+ * Get the value of an NVRAM variable
+ * @param	name	name of variable to get
+ * @return	value of variable or NULL if undefined
+ */
+
+char *cfe_env_get(unsigned char *nv_buf, const char *name)
+{
+    int size;
+    unsigned char *buffer;
+    unsigned char *ptr;
+    unsigned char *envval;
+    unsigned int reclen;
+    unsigned int rectype;
+    int offset;
+    int flg;
+    
+	if (!strcmp(name, "nvram_type"))
+		return "cfe";
+	
+    size = NVRAM_SIZE;
+    buffer = &_nvdata[0];
+
+    ptr = buffer;
+    offset = 0;
+
+    /* Read the record type and length */
+    if (_nvram_read(nv_buf, ptr,offset,1) != 1) {
+	goto error;
+    }
+    
+    while ((*ptr != ENV_TLV_TYPE_END)  && (size > 1)) {
+
+	/* Adjust pointer for TLV type */
+	rectype = *(ptr);
+	offset++;
+	size--;
+
+	/* 
+	 * Read the length.  It can be either 1 or 2 bytes
+	 * depending on the code 
+	 */
+	if (rectype & ENV_LENGTH_8BITS) {
+	    /* Read the record type and length - 8 bits */
+	    if (_nvram_read(nv_buf, ptr,offset,1) != 1) {
+		goto error;
+	    }
+	    reclen = *(ptr);
+	    size--;
+	    offset++;
+	}
+	else {
+	    /* Read the record type and length - 16 bits, MSB first */
+	    if (_nvram_read(nv_buf, ptr,offset,2) != 2) {
+		goto error;
+	    }
+	    reclen = (((unsigned int) *(ptr)) << 8) + (unsigned int) *(ptr+1);
+	    size -= 2;
+	    offset += 2;
+	}
+
+	if (reclen > size)
+	    break;	/* should not happen, bad NVRAM */
+
+	switch (rectype) {
+	    case ENV_TLV_TYPE_ENV:
+		/* Read the TLV data */
+		if (_nvram_read(nv_buf, ptr,offset,reclen) != reclen)
+		    goto error;
+		flg = *ptr++;
+		envval = (unsigned char *) _strnchr(ptr,'=',(reclen-1));
+		if (envval) {
+		    *envval++ = '\0';
+		    memcpy(_valuestr,envval,(reclen-1)-(envval-ptr));
+		    _valuestr[(reclen-1)-(envval-ptr)] = '\0';
+#if 0			
+		    printk(KERN_INFO "NVRAM:%s=%s\n", ptr, _valuestr);
+#endif
+		    if(!strcmp(ptr, name)){
+			return _valuestr;
+		    }
+		    if((strlen(ptr) > 1) && !strcmp(&ptr[1], name))
+			return _valuestr;
+		}
+		break;
+		
+	    default: 
+		/* Unknown TLV type, skip it. */
+		break;
+	    }
+
+	/*
+	 * Advance to next TLV 
+	 */
+		
+	size -= (int)reclen;
+	offset += reclen;
+
+	/* Read the next record type */
+	ptr = buffer;
+	if (_nvram_read(nv_buf, ptr,offset,1) != 1)
+	    goto error;
+	}
+
+error:
+    return NULL;
+
+}
+
--- a/drivers/firmware/broadcom/bcm47xx_nvram.c
+++ b/drivers/firmware/broadcom/bcm47xx_nvram.c
@@ -33,6 +33,8 @@ struct nvram_header {
 static char nvram_buf[NVRAM_SPACE];
 static size_t nvram_len;
 static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000};
+static int cfe_env;
+extern char *cfe_env_get(char *nv_buf, const char *name);
 
 static u32 find_nvram_size(void __iomem *end)
 {
@@ -52,7 +54,9 @@ static u32 find_nvram_size(void __iomem
 static int nvram_find_and_copy(void __iomem *iobase, u32 lim)
 {
 	struct nvram_header __iomem *header;
+	int i;
 	u32 off;
+	u32 *src, *dst;
 	u32 size;
 
 	if (nvram_len) {
@@ -60,6 +64,26 @@ static int nvram_find_and_copy(void __io
 		return -EEXIST;
 	}
 
+	cfe_env = 0;
+
+	/* XXX: hack for supporting the CFE environment stuff on WGT634U */
+	if (lim >= 8 * 1024 * 1024) {
+		src = (u32 *)(iobase + 8 * 1024 * 1024 - 0x2000);
+		dst = (u32 *)nvram_buf;
+
+		if ((*src & 0xff00ff) == 0x000001) {
+			printk("early_nvram_init: WGT634U NVRAM found.\n");
+
+			for (i = 0; i < 0x1ff0; i++) {
+				if (*src == 0xFFFFFFFF)
+					break;
+				*dst++ = *src++;
+			}
+			cfe_env = 1;
+			return 0;
+		}
+	}
+
 	/* TODO: when nvram is on nand flash check for bad blocks first. */
 	off = FLASH_MIN;
 	while (off <= lim) {
@@ -170,6 +194,13 @@ int bcm47xx_nvram_getenv(const char *nam
 	if (!name)
 		return -EINVAL;
 
+	if (cfe_env) {
+		value = cfe_env_get(nvram_buf, name);
+		if (!value)
+			return -ENOENT;
+		return snprintf(val, val_len, "%s", value);
+	}
+
 	if (!nvram_len) {
 		err = nvram_init();
 		if (err)