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openwrtv3/target/linux/brcm47xx/patches-4.9/820-wgt634u-nvram-fix.patch
Rafał Miłecki b1f5dd34ed brcm47xx: backport upstream patches for Netgear WNR1000 V3 
This includes fix for reading NVRAM content.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
2018-04-23 13:33:09 +02:00

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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
@@ -1,2 +1,2 @@
-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 <asm/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
@@ -37,6 +37,8 @@ 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)
{
@@ -56,7 +58,9 @@ 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) {
@@ -64,6 +68,26 @@ 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) {
@@ -174,6 +198,13 @@ 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)
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