static int vprbrd_i2c_read()

in busses/i2c-viperboard.c [113:216]

• 97 lines of code
• 11 McCabe index (conditional complexity)

static int vprbrd_i2c_read(struct vprbrd *vb, struct i2c_msg *msg)
{
	int ret;
	u16 remain_len, len1, len2, start = 0x0000;
	struct vprbrd_i2c_read_msg *rmsg =
		(struct vprbrd_i2c_read_msg *)vb->buf;

	remain_len = msg->len;
	rmsg->header.cmd = VPRBRD_I2C_CMD_READ;
	while (remain_len > 0) {
		rmsg->header.addr = cpu_to_le16(start + 0x4000);
		if (remain_len <= 255) {
			len1 = remain_len;
			len2 = 0x00;
			rmsg->header.len0 = remain_len;
			rmsg->header.len1 = 0x00;
			rmsg->header.len2 = 0x00;
			rmsg->header.len3 = 0x00;
			rmsg->header.len4 = 0x00;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 510) {
			len1 = remain_len;
			len2 = 0x00;
			rmsg->header.len0 = remain_len - 255;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0x00;
			rmsg->header.len3 = 0x00;
			rmsg->header.len4 = 0x00;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 512) {
			len1 = remain_len;
			len2 = 0x00;
			rmsg->header.len0 = remain_len - 510;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = 0x00;
			rmsg->header.len4 = 0x00;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 767) {
			len1 = 512;
			len2 = remain_len - 512;
			rmsg->header.len0 = 0x02;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = remain_len - 512;
			rmsg->header.len4 = 0x00;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 1022) {
			len1 = 512;
			len2 = remain_len - 512;
			rmsg->header.len0 = 0x02;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = remain_len - 767;
			rmsg->header.len4 = 0xff;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 1024) {
			len1 = 512;
			len2 = remain_len - 512;
			rmsg->header.len0 = 0x02;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = remain_len - 1022;
			rmsg->header.len4 = 0xff;
			rmsg->header.len5 = 0xff;
			remain_len = 0;
		} else {
			len1 = 512;
			len2 = 512;
			rmsg->header.len0 = 0x02;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = 0x02;
			rmsg->header.len4 = 0xff;
			rmsg->header.len5 = 0xff;
			remain_len -= 1024;
			start += 1024;
		}
		rmsg->header.tf1 = cpu_to_le16(len1);
		rmsg->header.tf2 = cpu_to_le16(len2);

		/* first read transfer */
		ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len1);
		if (ret < 0)
			return ret;
		/* copy the received data */
		memcpy(msg->buf + start, rmsg, len1);

		/* second read transfer if neccessary */
		if (len2 > 0) {
			ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len2);
			if (ret < 0)
				return ret;
			/* copy the received data */
			memcpy(msg->buf + start + 512, rmsg, len2);
		}
	}
	return 0;
}