[PATCH 2/2] watchdog: ziirave_wdt: Add support to upload the firmware.

[Enric Balletbo i Serra]

This patch adds and entry to the sysfs to start firmware upload process
on the specified device with the requested firmware.

The uploading of the firmware needs only to happen once per firmware
upgrade, as the firmware is stored in persistent storage. If the
firmware upload or the firmware verification fails then we print and
error message and exit.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
---
 drivers/watchdog/ziirave_wdt.c | 426 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 426 insertions(+)

diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
index fa1efef..63e81bc 100644
--- a/drivers/watchdog/ziirave_wdt.c
+++ b/drivers/watchdog/ziirave_wdt.c
@@ -18,7 +18,10 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/ctype.h>
+#include <linux/delay.h>
 #include <linux/i2c.h>
+#include <linux/firmware.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -36,6 +39,8 @@
 #define ZIIRAVE_STATE_OFF	0x1
 #define ZIIRAVE_STATE_ON	0x2
 
+#define ZIIRAVE_FW_NAME		"ziirave_fw.hex"
+
 static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
 				  "host request", NULL, "illegal configuration",
 				  "illegal instruction", "illegal trap",
@@ -50,6 +55,30 @@ static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
 #define ZIIRAVE_WDT_PING		0x9
 #define ZIIRAVE_WDT_RESET_DURATION	0xa
 
+#define ZIIRAVE_FIRM_PKT_TOTAL_SIZE	20
+#define ZIIRAVE_FIRM_PKT_DATA_SIZE	16
+#define ZIIRAVE_FIRM_FLASH_MEMORY_START	0x1600
+#define ZIIRAVE_FIRM_FLASH_MEMORY_END	0x2bbf
+/* Download message error. Ex: Message did not CRC properly */
+#define ZIIRAVE_FIRM_DOWNLOAD_NAK	0
+/* Received and ready for next Download packet. */
+#define ZIIRAVE_FIRM_DOWNLOAD_ACK	1
+/* Currently writing to flash. Retry Download status in a moment! */
+#define ZIIRAVE_FIRM_DOWNLOAD_BUSY	2
+/* Hardware error writing flash has occurred! */
+#define ZIIRAVE_FIRM_DOWNLOAD_FAIL	3
+
+/*
+ * Firmware commands
+ */
+#define ZIIRAVE_CMD_DOWNLOAD_START		0x10
+#define ZIIRAVE_CMD_DOWNLOAD_END		0x11
+#define ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR	0x12
+#define ZIIRAVE_CMD_DOWNLOAD_READ_BYTE		0x13
+#define ZIIRAVE_CMD_RESET_PROCESSOR		0x0b
+#define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER		0x0c
+#define ZIIRAVE_CMD_DOWNLOAD_PACKET		0x0e
+
 struct ziirave_wdt_rev {
 	unsigned char major;
 	unsigned char minor;
@@ -62,6 +91,23 @@ struct ziirave_wdt_data {
 	int reset_reason;
 };
 
+/*
+ * A packet to send to the firmware is composed by following bytes:
+ *     Count | Addr0 | Addr1 | Data0 .. Data15 | Checksum |
+ * Where,
+ *     Length: A data byte containing the length of the data.
+ *     Addr0: Low byte of the address.
+ *     Addr1: High byte of the address.
+ *     Data0 .. Data15: Array of 16 bytes of data.
+ *     Checksum: Checksum byte to verify data integrity.
+ */
+struct ziirave_fw_pkt_t {
+	u8 length;
+	u16 addr;
+	u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE];
+	u8 checksum;
+} __packed;
+
 static int wdt_timeout;
 module_param(wdt_timeout, int, 0);
 MODULE_PARM_DESC(wdt_timeout, "Watchdog timeout in seconds");
@@ -146,6 +192,339 @@ static unsigned int ziirave_wdt_get_timeleft(struct watchdog_device *wdd)
 	return ret;
 }
 
+static int ziirave_firm_wait_for_ack(struct watchdog_device *wdd)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int ret;
+
+	do {
+		usleep_range(5000, 5100);
+		ret = i2c_smbus_read_byte(client);
+		if (ret < 0) {
+			dev_err(&client->dev, "Failed to read byte\n");
+			return ret;
+		}
+	} while (ret == ZIIRAVE_FIRM_DOWNLOAD_BUSY);
+
+	return ret == ZIIRAVE_FIRM_DOWNLOAD_ACK ? 0 : -EIO;
+}
+
+/*
+ * Parse Microchip format Hex file (an extended Intel Hex file) to extract
+ * address and data.
+ */
+static int ziirave_firm_parse_hex_line(unsigned char *fw_data,
+				       struct ziirave_fw_pkt_t *fw_pkt,
+				       bool *addr_has_changed)
+{
+	int count = 0;
+	unsigned char *src, dst;
+
+	if (*fw_data++ != ':')
+		return -EFAULT;
+
+	/* locate end of line */
+	for (src = fw_data; *src != '\n'; src += 2) {
+		/*
+		 * Convert the ascii hexadecimal string to its binary
+		 * representation
+		 */
+		if (hex2bin(&dst, src, 1))
+			return -EINVAL;
+
+		/* Parse line to split addr / data */
+		switch (count) {
+		case 0:
+			fw_pkt->length = dst;
+			break;
+		case 1:
+			fw_pkt->addr = dst << 8;
+			break;
+		case 2:
+			fw_pkt->addr |= dst;
+			fw_pkt->addr >>= 1;
+			break;
+		case 3:
+			/* check if data is an address */
+			if (dst == 0x04)
+				*addr_has_changed = true;
+			else
+				*addr_has_changed = false;
+			break;
+		case  4:
+		case  5:
+			if (!*addr_has_changed)
+				fw_pkt->data[(count - 4)] = dst;
+			break;
+		default:
+			fw_pkt->data[(count - 4)] = dst;
+			break;
+		}
+		count++;
+	}
+
+	/* return read value + ':' + '\n' */
+	return (count * 2) + 2;
+}
+
+static int ziirave_firm_set_read_addr(struct watchdog_device *wdd, u16 addr)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	u8 address[2];
+
+	memset(address, 0, sizeof(address));
+	address[0] = addr & 0xff;
+	address[1] = (addr >> 8) & 0xff;
+
+	return i2c_smbus_write_block_data(client,
+					  ZIIRAVE_CMD_DOWNLOAD_SET_READ_ADDR,
+					  ARRAY_SIZE(address), address);
+}
+
+static int ziirave_firm_write_block_data(struct watchdog_device *wdd,
+					 u8 command, u8 length, const u8 *data,
+					 bool wait_for_ack)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int ret;
+
+	ret = i2c_smbus_write_block_data(client, command, length, data);
+
+	if (ret) {
+		dev_err(&client->dev,
+			"Failed to send command 0x%02x: %d\n", command, ret);
+		return ret;
+	}
+
+	if (wait_for_ack) {
+		ret = ziirave_firm_wait_for_ack(wdd);
+		if (ret)
+			dev_err(&client->dev,
+				"Failed waiting ACK from command 0x%02x: %d\n",
+				command, ret);
+	}
+
+	return ret;
+}
+
+static int ziirave_firm_write_byte(struct watchdog_device *wdd, u8 command,
+				   u8 byte, bool wait_for_ack)
+{
+	return ziirave_firm_write_block_data(wdd, command, 1, &byte,
+					     wait_for_ack);
+}
+
+static int ziirave_firm_write_pkt(struct watchdog_device *wdd,
+				  struct ziirave_fw_pkt_t *fw_pkt)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
+	int ret;
+
+	memset(&packet, 0, sizeof(packet));
+
+	packet[0] = fw_pkt->length;
+	packet[1] = (u8)(fw_pkt->addr & 0xff);
+	packet[2] = (u8)((fw_pkt->addr & 0xff00) >> 8);
+
+	/* Copy packet data */
+	memcpy(packet + 3, fw_pkt->data, fw_pkt->length);
+
+	/* Compute checksum */
+	for (i = 0; i < (ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1); i++)
+		checksum += packet[i];
+	packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE - 1] = checksum;
+
+	ret = ziirave_firm_write_block_data(wdd, ZIIRAVE_CMD_DOWNLOAD_PACKET,
+					    ARRAY_SIZE(packet), packet, true);
+	if (ret)
+		dev_err(&client->dev,
+		      "Failed to write firmware packet at address 0x%04x: %d\n",
+		      fw_pkt->addr, ret);
+
+	return ret;
+}
+
+static int ziirave_firm_verify(struct watchdog_device *wdd,
+			       const struct firmware *fw)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	int i, ret, read_bytes = 0, total_read_bytes = 0;
+	bool addr_has_changed;
+	struct ziirave_fw_pkt_t fw_pkt;
+	u8 data[ZIIRAVE_FIRM_PKT_DATA_SIZE];
+
+	while (total_read_bytes < fw->size) {
+		read_bytes = ziirave_firm_parse_hex_line(
+					(u8 *)(fw->data + total_read_bytes),
+					&fw_pkt, &addr_has_changed);
+
+		/* Detect the end of file */
+		total_read_bytes += read_bytes;
+		if (total_read_bytes == fw->size)
+			break;
+
+		if (addr_has_changed)
+			continue;
+
+		if (fw_pkt.addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
+		    fw_pkt.addr > ZIIRAVE_FIRM_FLASH_MEMORY_END)
+			continue;
+
+		ret = ziirave_firm_set_read_addr(wdd, fw_pkt.addr);
+		if (ret) {
+			dev_err(&client->dev,
+				"Failed to send SET_READ_ADDR command: %d\n",
+				ret);
+			return ret;
+		}
+
+		for (i = 0; i < ARRAY_SIZE(data); i++) {
+			ret = i2c_smbus_read_byte_data(client,
+						ZIIRAVE_CMD_DOWNLOAD_READ_BYTE);
+			if (ret < 0) {
+				dev_err(&client->dev,
+					"Failed to READ DATA: %d\n", ret);
+				return ret;
+			}
+			data[i] = (u8)ret;
+		}
+
+		if (memcmp(data, fw_pkt.data, fw_pkt.length)) {
+			dev_err(&client->dev,
+				"Firmware mismatch at address 0x%04x\n",
+				fw_pkt.addr);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int ziirave_firm_upload(struct watchdog_device *wdd,
+			       const struct firmware *fw)
+{
+	struct i2c_client *client = to_i2c_client(wdd->parent);
+	struct ziirave_fw_pkt_t fw_pkt;
+	struct ziirave_fw_pkt_t fw_pkt_new;
+	int ret, total_read_bytes = 0, words_till_page_break;
+	bool addr_has_changed;
+
+	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_JUMP_TO_BOOTLOADER, 1,
+				      false);
+	if (ret)
+		return ret;
+
+	msleep(500);
+
+	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_DOWNLOAD_START, 1, true);
+	if (ret)
+		return ret;
+
+	msleep(500);
+
+	while (total_read_bytes < fw->size) {
+		int read_bytes = 0;
+
+		read_bytes = ziirave_firm_parse_hex_line(
+					(u8 *)(fw->data + total_read_bytes),
+					&fw_pkt, &addr_has_changed);
+
+		if (read_bytes <= 0) {
+			dev_err(&client->dev,
+				"Failed to parse HEX file\n");
+			return -EINVAL;
+		}
+
+		/* Detect the end of file */
+		total_read_bytes += read_bytes;
+		if (total_read_bytes == fw->size) {
+			/*
+			 * For end of download, the length field will be set
+			 * to 0
+			 */
+			memset(&fw_pkt, 0, sizeof(fw_pkt));
+			ret = ziirave_firm_write_pkt(wdd, &fw_pkt);
+			if (ret) {
+				dev_err(&client->dev,
+					"Failed to send EMPTY packet: %d\n",
+					ret);
+				return ret;
+			}
+
+			/* This sleep seems to be required */
+			msleep(20);
+
+			/* Start firmware verification */
+			ret = ziirave_firm_verify(wdd, fw);
+			if (ret) {
+				dev_err(&client->dev,
+					"Failed to verify firmware: %d\n", ret);
+				return ret;
+			}
+
+			/* End download operation */
+			ret = ziirave_firm_write_byte(wdd,
+						      ZIIRAVE_CMD_DOWNLOAD_END,
+						      1, false);
+			if (ret)
+				return ret;
+			break;
+		}
+
+		if (addr_has_changed)
+			continue;
+
+		/* Calculate words till page break */
+		words_till_page_break = (64 - (fw_pkt.addr & 0x3f));
+		if ((fw_pkt.length >> 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.
+			 */
+			memset(&fw_pkt_new, 0, sizeof(fw_pkt_new));
+
+			fw_pkt_new.length = words_till_page_break << 1;
+			fw_pkt_new.addr = fw_pkt.addr;
+			memcpy(fw_pkt_new.data, fw_pkt.data, fw_pkt_new.length);
+
+			ret = ziirave_firm_write_pkt(wdd, &fw_pkt_new);
+			if (ret)
+				return ret;
+
+			/* Create a packet with the second block of data */
+			memset(&fw_pkt_new, 0, sizeof(fw_pkt_new));
+
+			/* Remaining bytes */
+			fw_pkt_new.length =
+				fw_pkt.length - (words_till_page_break << 1);
+			fw_pkt_new.addr = fw_pkt.addr + words_till_page_break;
+			memcpy(fw_pkt_new.data,
+			       fw_pkt.data + (words_till_page_break << 1),
+			       fw_pkt_new.length);
+
+			ret = ziirave_firm_write_pkt(wdd, &fw_pkt_new);
+			if (ret)
+				return ret;
+		} else {
+			ret = ziirave_firm_write_pkt(wdd, &fw_pkt);
+			if (ret)
+				return ret;
+		}
+	}
+
+	/* Reset the processor */
+	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_RESET_PROCESSOR, 1,
+				      false);
+	if (ret)
+		return ret;
+
+	msleep(500);
+
+	return 0;
+}
+
 static const struct watchdog_info ziirave_wdt_info = {
 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 	.identity = "Zodiac RAVE Watchdog",
@@ -201,10 +580,57 @@ static ssize_t ziirave_wdt_sysfs_show_reason(struct device *dev,
 static DEVICE_ATTR(reset_reason, S_IRUGO, ziirave_wdt_sysfs_show_reason,
 		   NULL);
 
+static ssize_t ziirave_wdt_sysfs_store_firm(struct device *dev,
+					    struct device_attribute *attr,
+					    const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct ziirave_wdt_data *w_priv = i2c_get_clientdata(client);
+	const struct firmware *fw;
+	int err;
+
+	err = request_firmware(&fw, ZIIRAVE_FW_NAME, dev);
+	if (err) {
+		dev_err(&client->dev, "Unable to open firmware %s: %d\n",
+			ZIIRAVE_FW_NAME, err);
+		return err;
+	}
+
+	err = ziirave_firm_upload(&w_priv->wdd, fw);
+	if (err) {
+		dev_err(&client->dev, "The firmware update failed: %d\n", err);
+		goto release_firmware;
+	}
+
+	/* Update firmware version */
+	err = ziirave_wdt_revision(client, &w_priv->firmware_rev,
+				   ZIIRAVE_WDT_FIRM_VER_MAJOR);
+	if (err) {
+		dev_err(&client->dev, "Failed to read firmware version: %d\n",
+			err);
+		goto release_firmware;
+	}
+
+	dev_info(&client->dev, "Firmware updated to version 02.%02u.%02u\n",
+		 w_priv->firmware_rev.major, w_priv->firmware_rev.minor);
+
+	/* Restore the watchdog timeout */
+	err = ziirave_wdt_set_timeout(&w_priv->wdd, w_priv->wdd.timeout);
+	if (err)
+		dev_err(&client->dev, "Failed to set timeout: %d\n", err);
+
+release_firmware:
+	release_firmware(fw);
+	return err ? err : count;
+}
+
+static DEVICE_ATTR(update_fw, S_IWUSR, NULL, ziirave_wdt_sysfs_store_firm);
+
 static struct attribute *ziirave_wdt_attrs[] = {
 	&dev_attr_firmware_version.attr,
 	&dev_attr_bootloader_version.attr,
 	&dev_attr_reset_reason.attr,
+	&dev_attr_update_fw.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(ziirave_wdt);
-- 
2.1.0