* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#include <config.h>
+/*
+ * Communicate to the Devantech ETH008 relay card via TCP and Ethernet.
+ *
+ * See http://www.robot-electronics.co.uk/files/eth008b.pdf for device
+ * capabilities and a protocol discussion.
+ * See https://github.com/devantech/devantech_eth_python for Python
+ * source code which is maintained by the vendor.
+ *
+ * The device provides several means of communication: HTTP requests
+ * (as well as an interactive web form). Raw TCP communication with
+ * binary requests and responses. Text requests and responses over
+ * TCP sockets. Some of these depend on the firmware version. Version
+ * checks before command transmission is essentially non-existent in
+ * this sigrok driver implementation. Binary transmission is preferred
+ * because it is assumed that this existed in all firmware versions.
+ * The firmware interestingly accepts concurrent network connections
+ * (up to five of them, all share the same password). Which means that
+ * the peripheral's state can change even while we control it.
+ *
+ * It's assumed that WLAN models differ from Ethernet devices in terms
+ * of their hardware, but TCP communication should not bother about the
+ * underlying physics, and WLAN cards can re-use model IDs and firmware
+ * implementations. Given sigrok's abstraction of the serial transport
+ * those cards could also be attached by means of COM ports.
+ *
+ * TCP communication seems to rely on network fragmentation and assumes
+ * that software stacks provide all of a request in a single receive
+ * call on the firmware side. Which works for local communication, but
+ * could become an issue when long distances and tunnels are involved.
+ * This sigrok driver also assumes complete reception within a single
+ * receive call. The short length of binary transmission helps here
+ * (the largest payloads has a length of three bytes).
+ *
+ * The lack of length specs as well as termination in the protocol
+ * (both binary as well as text variants over TCP sockets) results in
+ * the inability to synchronize to the firmware when connecting and
+ * after hiccups in an established connection. The fixed length of
+ * requests and responses for binary payloads helps a little bit,
+ * assuming that TCP connect is used to recover. The overhead of
+ * HTTP requests and responses is considered undesirable for this
+ * sigrok driver implementation. [This also means that a transport
+ * which lacks the concept of network frames cannot send passwords.]
+ * The binary transport appears to lack HELLO or NOP requests that
+ * could be used to synchronize. Firmware just would not respond to
+ * unsupported commands. Maybe a repeated sequence of identity reads
+ * combined with a read timeout could help synchronize, but only if
+ * the response is known because the model was identified before.
+ *
+ * The sigrok driver source code was phrased with the addition of more
+ * models in mind. Only few code paths require adjustment when similar
+ * variants of requests or responses are involved in the communication
+ * to relay cards that support between two and twenty channels. Chances
+ * are good, existing firmware is compatible across firmware versions,
+ * and even across hardware revisions (model upgrades). Firmware just
+ * happens to not respond to unknown requests.
+ *
+ * TODO
+ * - Add support for other models. Currently exclusively supports the
+ * ETH008-B model which was used during implementation of the driver.
+ * - Add support for password protection?
+ * - See command 0x79 to "login" (beware of the differing return value
+ * compared to other commands), command 0x7a to check if passwords
+ * are involved and whether the login needs refreshing, command 0x7b
+ * for immediate "logout" in contrast to expiration.
+ * - Alternatively consider switching to the "text protocol" in that
+ * use case, which can send an optional password in every request
+ * that controls relays (command 0x3a).
+ * - How to specify the password in applications and how to pass them
+ * to this driver is yet another issue that needs consideration.
+ */
+
+#include "config.h"
+
+#include <string.h>
+
#include "protocol.h"
-SR_PRIV int devantech_eth008_receive_data(int fd, int revents, void *cb_data)
+#define READ_TIMEOUT_MS 20
+
+enum cmd_code {
+ CMD_GET_MODULE_INFO = 0x10,
+ CMD_DIGITAL_ACTIVE = 0x20,
+ CMD_DIGITAL_INACTIVE = 0x21,
+ CMD_DIGITAL_SET_OUTPUTS = 0x23,
+ CMD_DIGITAL_GET_OUTPUTS = 0x24,
+ CMD_ASCII_TEXT_COMMAND = 0x3a,
+ CMD_GET_SERIAL_NUMBER = 0x77,
+ CMD_GET_SUPPLY_VOLTS = 0x78,
+ CMD_PASSWORD_ENTRY = 0x79,
+ CMD_GET_UNLOCK_TIME = 0x7a,
+ CMD_IMMEDIATE_LOGOUT = 0x7b,
+};
+
+/*
+ * Transmit a request to the relay card. Checks that all bytes get sent,
+ * short writes are considered fatal.
+ */
+static int send_request(struct sr_serial_dev_inst *ser,
+ const uint8_t *data, size_t dlen)
+{
+ int ret;
+ size_t written;
+
+ if (sr_log_loglevel_get() >= SR_LOG_SPEW) {
+ GString *txt = sr_hexdump_new(data, dlen);
+ sr_spew("TX --> %s.", txt->str);
+ sr_hexdump_free(txt);
+ }
+ ret = serial_write_blocking(ser, data, dlen, 0);
+ if (ret < 0)
+ return ret;
+ written = (size_t)ret;
+ if (written != dlen)
+ return SR_ERR_DATA;
+ return SR_OK;
+}
+
+/*
+ * Receive a response from the relay card. Assumes fixed size payload,
+ * considers short reads fatal.
+ */
+static int recv_response(struct sr_serial_dev_inst *ser,
+ uint8_t *data, size_t dlen)
+{
+ int ret;
+ size_t got;
+
+ ret = serial_read_blocking(ser, data, dlen, READ_TIMEOUT_MS);
+ if (ret < 0)
+ return ret;
+ got = (size_t)ret;
+ if (sr_log_loglevel_get() >= SR_LOG_SPEW) {
+ GString *txt = sr_hexdump_new(data, got);
+ sr_spew("<-- RX %s.", txt->str);
+ sr_hexdump_free(txt);
+ }
+ if (got != dlen)
+ return SR_ERR_DATA;
+ return SR_OK;
+}
+
+/* Send a request then receive a response. Convenience routine. */
+static int send_then_recv(struct sr_serial_dev_inst *serial,
+ const uint8_t *tx_data, size_t tx_length,
+ uint8_t *rx_data, size_t rx_length)
+{
+ int ret;
+
+ if (tx_data && tx_length) {
+ ret = send_request(serial, tx_data, tx_length);
+ if (ret != SR_OK)
+ return ret;
+ }
+
+ if (rx_data && rx_length) {
+ ret = recv_response(serial, rx_data, rx_length);
+ if (ret != SR_OK)
+ return ret;
+ }
+
+ return SR_OK;
+}
+
+/* Identify the relay card, gather version information details. */
+SR_PRIV int devantech_eth008_get_model(struct sr_serial_dev_inst *serial,
+ uint8_t *model_code, uint8_t *hw_version, uint8_t *fw_version)
{
- const struct sr_dev_inst *sdi;
+ uint8_t req[1], *wrptr;
+ uint8_t rsp[3], v8;
+ const uint8_t *rdptr;
+ int ret;
+
+ if (model_code)
+ *model_code = 0;
+ if (hw_version)
+ *hw_version = 0;
+ if (fw_version)
+ *fw_version = 0;
+
+ wrptr = req;
+ write_u8_inc(&wrptr, CMD_GET_MODULE_INFO);
+ ret = send_then_recv(serial, req, wrptr - req, rsp, sizeof(rsp));
+ if (ret != SR_OK)
+ return ret;
+ rdptr = rsp;
+
+ v8 = read_u8_inc(&rdptr);
+ if (model_code)
+ *model_code = v8;
+ v8 = read_u8_inc(&rdptr);
+ if (hw_version)
+ *hw_version = v8;
+ v8 = read_u8_inc(&rdptr);
+ if (fw_version)
+ *fw_version = v8;
+
+ return SR_OK;
+}
+
+/* Get the relay card's serial number (its MAC address). */
+SR_PRIV int devantech_eth008_get_serno(struct sr_serial_dev_inst *serial,
+ char *text_buffer, size_t text_length)
+{
+ uint8_t req[1], *wrptr;
+ uint8_t rsp[6], b;
+ const uint8_t *rdptr, *endptr;
+ size_t written;
+ int ret;
+
+ if (text_buffer && !text_length)
+ return SR_ERR_ARG;
+ if (text_buffer)
+ memset(text_buffer, 0, text_length);
+
+ wrptr = req;
+ write_u8_inc(&wrptr, CMD_GET_SERIAL_NUMBER);
+ ret = send_then_recv(serial, req, wrptr - req, rsp, sizeof(rsp));
+ if (ret != SR_OK)
+ return ret;
+ rdptr = rsp;
+
+ endptr = rsp + sizeof(rsp);
+ while (rdptr < endptr && text_buffer && text_length >= 3) {
+ b = read_u8_inc(&rdptr);
+ written = snprintf(text_buffer, text_length, "%02x", b);
+ text_buffer += written;
+ text_length -= written;
+ }
+
+ return SR_OK;
+}
+
+/* Update an internal cache from the relay card's current state. */
+SR_PRIV int devantech_eth008_cache_state(const struct sr_dev_inst *sdi)
+{
+ struct sr_serial_dev_inst *serial;
struct dev_context *devc;
+ size_t rx_size;
+ uint8_t req[1], *wrptr;
+ uint8_t rsp[1];
+ const uint8_t *rdptr;
+ uint32_t have;
+ int ret;
- (void)fd;
+ serial = sdi->conn;
+ if (!serial)
+ return SR_ERR_ARG;
+ devc = sdi->priv;
+ if (!devc)
+ return SR_ERR_ARG;
- if (!(sdi = cb_data))
- return TRUE;
+ rx_size = devc->model->width_do;
+ if (rx_size > sizeof(rsp))
+ return SR_ERR_NA;
- if (!(devc = sdi->priv))
- return TRUE;
+ wrptr = req;
+ write_u8_inc(&wrptr, CMD_DIGITAL_GET_OUTPUTS);
+ ret = send_then_recv(serial, req, wrptr - req, rsp, rx_size);
+ if (ret != SR_OK)
+ return ret;
+ rdptr = rsp;
- if (revents == G_IO_IN) {
- /* TODO */
+ switch (rx_size) {
+ case 1:
+ have = read_u8_inc(&rdptr);
+ break;
+ default:
+ return SR_ERR_NA;
}
+ have &= devc->mask_do;
+ devc->curr_do = have;
+
+ return SR_OK;
+}
+
+/* Query the state of an individual relay channel. */
+SR_PRIV int devantech_eth008_query_do(const struct sr_dev_inst *sdi,
+ const struct sr_channel_group *cg, gboolean *on)
+{
+ struct dev_context *devc;
+ struct channel_group_context *cgc;
+ uint32_t have;
+ int ret;
+
+ devc = sdi->priv;
+ if (!devc)
+ return SR_ERR_ARG;
+
+ /* Unconditionally update the internal cache. */
+ ret = devantech_eth008_cache_state(sdi);
+ if (ret != SR_OK)
+ return ret;
+
+ /*
+ * Only reject unexpected requeusts after the update. Get the
+ * individual channel's state from the cache of all channels.
+ */
+ if (!cg)
+ return SR_ERR_ARG;
+ cgc = cg->priv;
+ if (!cgc)
+ return SR_ERR_BUG;
+ if (cgc->index >= devc->model->ch_count_do)
+ return SR_ERR_ARG;
+ have = devc->curr_do;
+ have >>= cgc->index;
+ have &= 1 << 0;
+ if (on)
+ *on = have ? TRUE : FALSE;
+
+ return SR_OK;
+}
+
+/*
+ * Manipulate the state of an individual relay channel (when cg is given).
+ * Or set/clear all channels at the same time (when cg is NULL).
+ */
+SR_PRIV int devantech_eth008_setup_do(const struct sr_dev_inst *sdi,
+ const struct sr_channel_group *cg, gboolean on)
+{
+ struct sr_serial_dev_inst *serial;
+ struct dev_context *devc;
+ size_t width_do;
+ struct channel_group_context *cgc;
+ size_t number;
+ uint32_t reg;
+ uint8_t req[3], *wrptr, cmd;
+ uint8_t rsp[1], v8;
+ const uint8_t *rdptr;
+ int ret;
+
+ serial = sdi->conn;
+ if (!serial)
+ return SR_ERR_ARG;
+ devc = sdi->priv;
+ if (!devc)
+ return SR_ERR_ARG;
+ cgc = cg ? cg->priv : NULL;
+ if (cgc && cgc->index >= devc->model->ch_count_do)
+ return SR_ERR_ARG;
+
+ width_do = devc->model->width_do;
+ if (1 + width_do > sizeof(req))
+ return SR_ERR_NA;
+
+ wrptr = req;
+ if (cgc) {
+ /* Manipulate an individual channel. */
+ cmd = on ? CMD_DIGITAL_ACTIVE : CMD_DIGITAL_INACTIVE;
+ number = cgc->number;
+ write_u8_inc(&wrptr, cmd);
+ write_u8_inc(&wrptr, number & 0xff);
+ write_u8_inc(&wrptr, 0); /* Just set/clear, no pulse. */
+ } else {
+ /* Manipulate all channels at the same time. */
+ reg = on ? devc->mask_do : 0;
+ write_u8_inc(&wrptr, CMD_DIGITAL_SET_OUTPUTS);
+ switch (width_do) {
+ case 1:
+ write_u8_inc(&wrptr, reg & 0xff);
+ break;
+ default:
+ return SR_ERR_NA;
+ }
+ }
+ ret = send_then_recv(serial, req, wrptr - req, rsp, sizeof(rsp));
+ if (ret != SR_OK)
+ return ret;
+ rdptr = rsp;
+
+ v8 = read_u8_inc(&rdptr);
+ if (v8 != 0)
+ return SR_ERR_DATA;
+
+ return SR_OK;
+}
+
+SR_PRIV int devantech_eth008_query_supply(const struct sr_dev_inst *sdi,
+ const struct sr_channel_group *cg, uint16_t *millivolts)
+{
+ struct sr_serial_dev_inst *serial;
+ uint8_t req[1], *wrptr;
+ uint8_t rsp[1];
+ const uint8_t *rdptr;
+ uint16_t have;
+ int ret;
+
+ (void)cg;
+
+ serial = sdi->conn;
+ if (!serial)
+ return SR_ERR_ARG;
+
+ wrptr = req;
+ write_u8_inc(&wrptr, CMD_GET_SUPPLY_VOLTS);
+ ret = send_then_recv(serial, req, wrptr - req, rsp, sizeof(rsp));
+ if (ret != SR_OK)
+ return ret;
+ rdptr = rsp;
+
+ /* Gets a byte for voltage in units of 0.1V. Scale up to mV. */
+ have = read_u8_inc(&rdptr);
+ have *= 100;
+ if (millivolts)
+ *millivolts = have;
- return TRUE;
+ return SR_OK;
}
projects / libsigrok.git / blobdiff