watchdog: ziirave_wdt: Simplify ziirave_firm_write_pkt()

There no reason why ziirave_firm_write_pkt() has to take firmware
data via 'struct ihex_binrec' and it can just take address, data pointer
and data length as individual arguments. Make this change to allow us
to drastically simplify handling page crossing case by removing all of
the extra code required to split 'struct ihex_binrec' into two.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Rick Ramstetter <rick@anteaterllc.com>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20190812200906.31344-7-andrew.smirnov@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/ziirave_wdt.c

@@ -51,6 +51,7 @@ static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
 #define ZIIRAVE_FIRM_PKT_DATA_SIZE	16
 #define ZIIRAVE_FIRM_FLASH_MEMORY_START	0x1600
 #define ZIIRAVE_FIRM_FLASH_MEMORY_END	0x2bbf
+#define ZIIRAVE_FIRM_PAGE_SIZE		128
 
 /* Received and ready for next Download packet. */
 #define ZIIRAVE_FIRM_DOWNLOAD_ACK	1
@@ -244,27 +245,26 @@ static int ziirave_firm_write_byte(struct watchdog_device *wdd, u8 command,
  *     Data0 .. Data15: Array of 16 bytes of data.
  *     Checksum: Checksum byte to verify data integrity.
  */
-static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
-				  const struct ihex_binrec *rec)
+static int __ziirave_firm_write_pkt(struct watchdog_device *wdd,
+				    u32 addr, const u8 *data, u8 len)
 {
+	const u16 addr16 = (u16)addr / 2;
 	struct i2c_client *client = to_i2c_client(wdd->parent);
 	u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
 	int ret;
-	u16 addr;
 
 	memset(packet, 0, ARRAY_SIZE(packet));
 
 	/* Packet length */
-	packet[0] = (u8)be16_to_cpu(rec->len);
+	packet[0] = len;
 	/* Packet address */
-	addr = (be32_to_cpu(rec->addr) & 0xffff) >> 1;
-	packet[1] = addr & 0xff;
-	packet[2] = (addr & 0xff00) >> 8;
+	packet[1] = addr16 & 0xff;
+	packet[2] = (addr16 & 0xff00) >> 8;
 
 	/* Packet data */
-	if (be16_to_cpu(rec->len) > ZIIRAVE_FIRM_PKT_DATA_SIZE)
+	if (len > ZIIRAVE_FIRM_PKT_DATA_SIZE)
 		return -EMSGSIZE;
-	memcpy(packet + 3, rec->data, be16_to_cpu(rec->len));
+	memcpy(packet + 3, data, len);
 
 	/* Packet checksum */
 	for (i = 0; i < ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1; i++)
@@ -276,11 +276,35 @@ static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
 	if (ret)
 		dev_err(&client->dev,
 		      "Failed to write firmware packet at address 0x%04x: %d\n",
-		      addr, ret);
+		      addr16, ret);
 
 	return ret;
 }
 
+static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
+				  u32 addr, const u8 *data, u8 len)
+{
+	const u8 max_write_len = ZIIRAVE_FIRM_PAGE_SIZE -
+		(addr - ALIGN_DOWN(addr, ZIIRAVE_FIRM_PAGE_SIZE));
+	int ret;
+
+	if (len > max_write_len) {
+		/*
+		 * If data crossed page boundary we need to split this
+		 * write in two
+		 */
+		ret = __ziirave_firm_write_pkt(wdd, addr, data, max_write_len);
+		if (ret)
+			return ret;
+
+		addr += max_write_len;
+		data += max_write_len;
+		len  -= max_write_len;
+	}
+
+	return __ziirave_firm_write_pkt(wdd, addr, data, len);
+}
+
 static int ziirave_firm_verify(struct watchdog_device *wdd,
 			       const struct firmware *fw)
 {
@@ -333,9 +357,8 @@ static int ziirave_firm_upload(struct watchdog_device *wdd,
 			       const struct firmware *fw)
 {
 	struct i2c_client *client = to_i2c_client(wdd->parent);
-	int ret, words_till_page_break;
 	const struct ihex_binrec *rec;
-	struct ihex_binrec *rec_new;
+	int ret;
 
 	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_JUMP_TO_BOOTLOADER, 1,
 				      false);
@@ -366,68 +389,17 @@ static int ziirave_firm_upload(struct watchdog_device *wdd,
 			return -EMSGSIZE;
 		}
 
-		/* Calculate words till page break */
-		words_till_page_break = (64 - ((be32_to_cpu(rec->addr) >> 1) &
-					 0x3f));
-		if ((be16_to_cpu(rec->len) >> 1) > words_till_page_break) {
-			/*
-			 * Data in passes page boundary, so we need to split in
-			 * two blocks of data. Create a packet with the first
-			 * block of data.
-			 */
-			rec_new = kzalloc(sizeof(struct ihex_binrec) +
-					  (words_till_page_break << 1),
-					  GFP_KERNEL);
-			if (!rec_new)
-				return -ENOMEM;
-
-			rec_new->len = cpu_to_be16(words_till_page_break << 1);
-			rec_new->addr = rec->addr;
-			memcpy(rec_new->data, rec->data,
-			       be16_to_cpu(rec_new->len));
-
-			ret = ziirave_firm_write_pkt(wdd, rec_new);
-			kfree(rec_new);
-			if (ret)
-				return ret;
-
-			/* Create a packet with the second block of data */
-			rec_new = kzalloc(sizeof(struct ihex_binrec) +
-					  be16_to_cpu(rec->len) -
-					  (words_till_page_break << 1),
-					  GFP_KERNEL);
-			if (!rec_new)
-				return -ENOMEM;
-
-			/* Remaining bytes */
-			rec_new->len = rec->len -
-				       cpu_to_be16(words_till_page_break << 1);
-
-			rec_new->addr = cpu_to_be32(be32_to_cpu(rec->addr) +
-					(words_till_page_break << 1));
-
-			memcpy(rec_new->data,
-			       rec->data + (words_till_page_break << 1),
-			       be16_to_cpu(rec_new->len));
-
-			ret = ziirave_firm_write_pkt(wdd, rec_new);
-			kfree(rec_new);
-			if (ret)
-				return ret;
-		} else {
-			ret = ziirave_firm_write_pkt(wdd, rec);
-			if (ret)
-				return ret;
-		}
+		ret = ziirave_firm_write_pkt(wdd, be32_to_cpu(rec->addr),
+					     rec->data, be16_to_cpu(rec->len));
+		if (ret)
+			return ret;
 	}
 
-	/* For end of download, the length field will be set to 0 */
-	rec_new = kzalloc(sizeof(struct ihex_binrec) + 1, GFP_KERNEL);
-	if (!rec_new)
-		return -ENOMEM;
-
-	ret = ziirave_firm_write_pkt(wdd, rec_new);
-	kfree(rec_new);
+	/*
+	 * Finish firmware download process by sending a zero length
+	 * payload
+	 */
+	ret = ziirave_firm_write_pkt(wdd, 0, NULL, 0);
 	if (ret) {
 		dev_err(&client->dev, "Failed to send EMPTY packet: %d\n", ret);
 		return ret;