brcmfmac: enhance nvram processing

The driver serializes the nvram firmware file before sending it
to the device. This patch enhances this to assure serialized data
is properly formatted and provide warnings on syntax failures.
Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Reviewed-by: Franky Lin <frankyl@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/brcmfmac/nvram.c

@@ -18,72 +18,205 @@
 #include <linux/slab.h>
 #include <linux/firmware.h>
 
+#include "dhd_dbg.h"
 #include "nvram.h"
 
-/* brcmf_nvram_strip :Takes a buffer of "<var>=<value>\n" lines read from a file
+enum nvram_parser_state {
+	IDLE,
+	KEY,
+	VALUE,
+	COMMENT,
+	END
+};
+
+/**
+ * struct nvram_parser - internal info for parser.
+ *
+ * @state: current parser state.
+ * @fwnv: input buffer being parsed.
+ * @nvram: output buffer with parse result.
+ * @nvram_len: lenght of parse result.
+ * @line: current line.
+ * @column: current column in line.
+ * @pos: byte offset in input buffer.
+ * @entry: start position of key,value entry.
+ */
+struct nvram_parser {
+	enum nvram_parser_state state;
+	const struct firmware *fwnv;
+	u8 *nvram;
+	u32 nvram_len;
+	u32 line;
+	u32 column;
+	u32 pos;
+	u32 entry;
+};
+
+static bool is_nvram_char(char c)
+{
+	/* comment marker excluded */
+	if (c == '#')
+		return false;
+
+	/* key and value may have any other readable character */
+	return (c > 0x20 && c < 0x7f);
+}
+
+static bool is_whitespace(char c)
+{
+	return (c == ' ' || c == '\r' || c == '\n' || c == '\t');
+}
+
+static enum nvram_parser_state brcmf_nvram_handle_idle(struct nvram_parser *nvp)
+{
+	char c;
+
+	c = nvp->fwnv->data[nvp->pos];
+	if (c == '\n')
+		return COMMENT;
+	if (is_whitespace(c))
+		goto proceed;
+	if (c == '#')
+		return COMMENT;
+	if (is_nvram_char(c)) {
+		nvp->entry = nvp->pos;
+		return KEY;
+	}
+	brcmf_dbg(INFO, "warning: ln=%d:col=%d: ignoring invalid character\n",
+		  nvp->line, nvp->column);
+proceed:
+	nvp->column++;
+	nvp->pos++;
+	return IDLE;
+}
+
+static enum nvram_parser_state brcmf_nvram_handle_key(struct nvram_parser *nvp)
+{
+	enum nvram_parser_state st = nvp->state;
+	char c;
+
+	c = nvp->fwnv->data[nvp->pos];
+	if (c == '=') {
+		st = VALUE;
+	} else if (!is_nvram_char(c)) {
+		brcmf_dbg(INFO, "warning: ln=%d:col=%d: '=' expected, skip invalid key entry\n",
+			  nvp->line, nvp->column);
+		return COMMENT;
+	}
+
+	nvp->column++;
+	nvp->pos++;
+	return st;
+}
+
+static enum nvram_parser_state
+brcmf_nvram_handle_value(struct nvram_parser *nvp)
+{
+	char c;
+	char *skv;
+	char *ekv;
+	u32 cplen;
+
+	c = nvp->fwnv->data[nvp->pos];
+	if (!is_nvram_char(c)) {
+		/* key,value pair complete */
+		ekv = (u8 *)&nvp->fwnv->data[nvp->pos];
+		skv = (u8 *)&nvp->fwnv->data[nvp->entry];
+		cplen = ekv - skv;
+		/* copy to output buffer */
+		memcpy(&nvp->nvram[nvp->nvram_len], skv, cplen);
+		nvp->nvram_len += cplen;
+		nvp->nvram[nvp->nvram_len] = '\0';
+		nvp->nvram_len++;
+		return IDLE;
+	}
+	nvp->pos++;
+	nvp->column++;
+	return VALUE;
+}
+
+static enum nvram_parser_state
+brcmf_nvram_handle_comment(struct nvram_parser *nvp)
+{
+	char *eol, *sol;
+
+	sol = (char *)&nvp->fwnv->data[nvp->pos];
+	eol = strchr(sol, '\n');
+	if (eol == NULL)
+		return END;
+
+	/* eat all moving to next line */
+	nvp->line++;
+	nvp->column = 1;
+	nvp->pos += (eol - sol) + 1;
+	return IDLE;
+}
+
+static enum nvram_parser_state brcmf_nvram_handle_end(struct nvram_parser *nvp)
+{
+	/* final state */
+	return END;
+}
+
+static enum nvram_parser_state
+(*nv_parser_states[])(struct nvram_parser *nvp) = {
+	brcmf_nvram_handle_idle,
+	brcmf_nvram_handle_key,
+	brcmf_nvram_handle_value,
+	brcmf_nvram_handle_comment,
+	brcmf_nvram_handle_end
+};
+
+static int brcmf_init_nvram_parser(struct nvram_parser *nvp,
+				   const struct firmware *nv)
+{
+	memset(nvp, 0, sizeof(*nvp));
+	nvp->fwnv = nv;
+	/* Alloc for extra 0 byte + roundup by 4 + length field */
+	nvp->nvram = kzalloc(nv->size + 1 + 3 + sizeof(u32), GFP_KERNEL);
+	if (!nvp->nvram)
+		return -ENOMEM;
+
+	nvp->line = 1;
+	nvp->column = 1;
+	return 0;
+}
+
+/* brcmf_nvram_strip :Takes a buffer of "<var>=<value>\n" lines read from a fil
  * and ending in a NUL. Removes carriage returns, empty lines, comment lines,
  * and converts newlines to NULs. Shortens buffer as needed and pads with NULs.
  * End of buffer is completed with token identifying length of buffer.
  */
 void *brcmf_nvram_strip(const struct firmware *nv, u32 *new_length)
 {
-	u8 *nvram;
-	u32 i;
-	u32 len;
-	u32 column;
-	u8 val;
-	bool comment;
+	struct nvram_parser nvp;
+	u32 pad;
 	u32 token;
 	__le32 token_le;
 
-	/* Alloc for extra 0 byte + roundup by 4 + length field */
-	nvram = kmalloc(nv->size + 1 + 3 + sizeof(token_le), GFP_KERNEL);
-	if (!nvram)
+	if (brcmf_init_nvram_parser(&nvp, nv) < 0)
 		return NULL;
 
-	len = 0;
-	column = 0;
-	comment = false;
-	for (i = 0; i < nv->size; i++) {
-		val = nv->data[i];
-		if (val == 0)
+	while (nvp.pos < nv->size) {
+		nvp.state = nv_parser_states[nvp.state](&nvp);
+		if (nvp.state == END)
 			break;
-		if (val == '\r')
-			continue;
-		if (comment && (val != '\n'))
-			continue;
-		comment = false;
-		if (val == '#') {
-			comment = true;
-			continue;
 	}
-		if (val == '\n') {
-			if (column == 0)
-				continue;
-			nvram[len] = 0;
-			len++;
-			column = 0;
-			continue;
-		}
-		nvram[len] = val;
-		len++;
-		column++;
-	}
-	column = len;
-	*new_length = roundup(len + 1, 4);
-	while (column != *new_length) {
-		nvram[column] = 0;
-		column++;
+	pad = nvp.nvram_len;
+	*new_length = roundup(nvp.nvram_len + 1, 4);
+	while (pad != *new_length) {
+		nvp.nvram[pad] = 0;
+		pad++;
 	}
 
 	token = *new_length / 4;
 	token = (~token << 16) | (token & 0x0000FFFF);
 	token_le = cpu_to_le32(token);
 
-	memcpy(&nvram[*new_length], &token_le, sizeof(token_le));
+	memcpy(&nvp.nvram[*new_length], &token_le, sizeof(token_le));
 	*new_length += sizeof(token_le);
 
-	return nvram;
+	return nvp.nvram;
 }
 
 void brcmf_nvram_free(void *nvram)
@@ -91,4 +224,3 @@ void brcmf_nvram_free(void *nvram)
 	kfree(nvram);
 }
 
-