*/
#define EC_SPI_RECOVERY_TIME_NS (200 * 1000)
-/*
- * The EC is unresponsive for a time after a reboot command. Add a
- * simple delay to make sure that the bus stays locked.
- */
-#define EC_REBOOT_DELAY_MS 50
-
/**
* struct cros_ec_spi - information about a SPI-connected EC
*
* @spi: SPI device we are connected to
* @last_transfer_ns: time that we last finished a transfer, or 0 if there
* if no record
+ * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that
+ * is sent when we want to turn on CS at the start of a transaction.
* @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that
* is sent when we want to turn off CS at the end of a transaction.
*/
struct cros_ec_spi {
struct spi_device *spi;
s64 last_transfer_ns;
+ unsigned int start_of_msg_delay;
unsigned int end_of_msg_delay;
};
static void debug_packet(struct device *dev, const char *name, u8 *ptr,
- int len)
+ int len)
{
#ifdef DEBUG
int i;
#endif
}
+static int terminate_request(struct cros_ec_device *ec_dev)
+{
+ struct cros_ec_spi *ec_spi = ec_dev->priv;
+ struct spi_message msg;
+ struct spi_transfer trans;
+ int ret;
+
+ /*
+ * Turn off CS, possibly adding a delay to ensure the rising edge
+ * doesn't come too soon after the end of the data.
+ */
+ spi_message_init(&msg);
+ memset(&trans, 0, sizeof(trans));
+ trans.delay_usecs = ec_spi->end_of_msg_delay;
+ spi_message_add_tail(&trans, &msg);
+
+ ret = spi_sync(ec_spi->spi, &msg);
+
+ /* Reset end-of-response timer */
+ ec_spi->last_transfer_ns = ktime_get_ns();
+ if (ret < 0) {
+ dev_err(ec_dev->dev,
+ "cs-deassert spi transfer failed: %d\n",
+ ret);
+ }
+
+ return ret;
+}
+
+/**
+ * receive_n_bytes - receive n bytes from the EC.
+ *
+ * Assumes buf is a pointer into the ec_dev->din buffer
+ */
+static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
+{
+ struct cros_ec_spi *ec_spi = ec_dev->priv;
+ struct spi_transfer trans;
+ struct spi_message msg;
+ int ret;
+
+ BUG_ON(buf - ec_dev->din + n > ec_dev->din_size);
+
+ memset(&trans, 0, sizeof(trans));
+ trans.cs_change = 1;
+ trans.rx_buf = buf;
+ trans.len = n;
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&trans, &msg);
+ ret = spi_sync(ec_spi->spi, &msg);
+ if (ret < 0)
+ dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
+
+ return ret;
+}
+
+/**
+ * cros_ec_spi_receive_packet - Receive a packet from the EC.
+ *
+ * This function has two phases: reading the preamble bytes (since if we read
+ * data from the EC before it is ready to send, we just get preamble) and
+ * reading the actual message.
+ *
+ * The received data is placed into ec_dev->din.
+ *
+ * @ec_dev: ChromeOS EC device
+ * @need_len: Number of message bytes we need to read
+ */
+static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
+ int need_len)
+{
+ struct ec_host_response *response;
+ u8 *ptr, *end;
+ int ret;
+ unsigned long deadline;
+ int todo;
+
+ BUG_ON(EC_MSG_PREAMBLE_COUNT > ec_dev->din_size);
+
+ /* Receive data until we see the header byte */
+ deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
+ while (true) {
+ unsigned long start_jiffies = jiffies;
+
+ ret = receive_n_bytes(ec_dev,
+ ec_dev->din,
+ EC_MSG_PREAMBLE_COUNT);
+ if (ret < 0)
+ return ret;
+
+ ptr = ec_dev->din;
+ for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
+ if (*ptr == EC_SPI_FRAME_START) {
+ dev_dbg(ec_dev->dev, "msg found at %zd\n",
+ ptr - ec_dev->din);
+ break;
+ }
+ }
+ if (ptr != end)
+ break;
+
+ /*
+ * Use the time at the start of the loop as a timeout. This
+ * gives us one last shot at getting the transfer and is useful
+ * in case we got context switched out for a while.
+ */
+ if (time_after(start_jiffies, deadline)) {
+ dev_warn(ec_dev->dev, "EC failed to respond in time\n");
+ return -ETIMEDOUT;
+ }
+ }
+
+ /*
+ * ptr now points to the header byte. Copy any valid data to the
+ * start of our buffer
+ */
+ todo = end - ++ptr;
+ BUG_ON(todo < 0 || todo > ec_dev->din_size);
+ todo = min(todo, need_len);
+ memmove(ec_dev->din, ptr, todo);
+ ptr = ec_dev->din + todo;
+ dev_dbg(ec_dev->dev, "need %d, got %d bytes from preamble\n",
+ need_len, todo);
+ need_len -= todo;
+
+ /* If the entire response struct wasn't read, get the rest of it. */
+ if (todo < sizeof(*response)) {
+ ret = receive_n_bytes(ec_dev, ptr, sizeof(*response) - todo);
+ if (ret < 0)
+ return -EBADMSG;
+ ptr += (sizeof(*response) - todo);
+ todo = sizeof(*response);
+ }
+
+ response = (struct ec_host_response *)ec_dev->din;
+
+ /* Abort if data_len is too large. */
+ if (response->data_len > ec_dev->din_size)
+ return -EMSGSIZE;
+
+ /* Receive data until we have it all */
+ while (need_len > 0) {
+ /*
+ * We can't support transfers larger than the SPI FIFO size
+ * unless we have DMA. We don't have DMA on the ISP SPI ports
+ * for Exynos. We need a way of asking SPI driver for
+ * maximum-supported transfer size.
+ */
+ todo = min(need_len, 256);
+ dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
+ todo, need_len, ptr - ec_dev->din);
+
+ ret = receive_n_bytes(ec_dev, ptr, todo);
+ if (ret < 0)
+ return ret;
+
+ ptr += todo;
+ need_len -= todo;
+ }
+
+ dev_dbg(ec_dev->dev, "loop done, ptr=%zd\n", ptr - ec_dev->din);
+
+ return 0;
+}
+
/**
* cros_ec_spi_receive_response - Receive a response from the EC.
*
static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
int need_len)
{
- struct cros_ec_spi *ec_spi = ec_dev->priv;
- struct spi_transfer trans;
- struct spi_message msg;
u8 *ptr, *end;
int ret;
unsigned long deadline;
int todo;
+ BUG_ON(EC_MSG_PREAMBLE_COUNT > ec_dev->din_size);
+
/* Receive data until we see the header byte */
deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
while (true) {
unsigned long start_jiffies = jiffies;
- memset(&trans, 0, sizeof(trans));
- trans.cs_change = 1;
- trans.rx_buf = ptr = ec_dev->din;
- trans.len = EC_MSG_PREAMBLE_COUNT;
-
- spi_message_init(&msg);
- spi_message_add_tail(&trans, &msg);
- ret = spi_sync(ec_spi->spi, &msg);
- if (ret < 0) {
- dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
+ ret = receive_n_bytes(ec_dev,
+ ec_dev->din,
+ EC_MSG_PREAMBLE_COUNT);
+ if (ret < 0)
return ret;
- }
+ ptr = ec_dev->din;
for (end = ptr + EC_MSG_PREAMBLE_COUNT; ptr != end; ptr++) {
- if (*ptr == EC_MSG_HEADER) {
+ if (*ptr == EC_SPI_FRAME_START) {
dev_dbg(ec_dev->dev, "msg found at %zd\n",
ptr - ec_dev->din);
break;
dev_dbg(ec_dev->dev, "loop, todo=%d, need_len=%d, ptr=%zd\n",
todo, need_len, ptr - ec_dev->din);
- memset(&trans, 0, sizeof(trans));
- trans.cs_change = 1;
- trans.rx_buf = ptr;
- trans.len = todo;
- spi_message_init(&msg);
- spi_message_add_tail(&trans, &msg);
-
- /* send command to EC and read answer */
- BUG_ON((u8 *)trans.rx_buf - ec_dev->din + todo >
- ec_dev->din_size);
- ret = spi_sync(ec_spi->spi, &msg);
- if (ret < 0) {
- dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
+ ret = receive_n_bytes(ec_dev, ptr, todo);
+ if (ret < 0)
return ret;
- }
debug_packet(ec_dev->dev, "interim", ptr, todo);
ptr += todo;
return 0;
}
+/**
+ * cros_ec_pkt_xfer_spi - Transfer a packet over SPI and receive the reply
+ *
+ * @ec_dev: ChromeOS EC device
+ * @ec_msg: Message to transfer
+ */
+static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev,
+ struct cros_ec_command *ec_msg)
+{
+ struct ec_host_request *request;
+ struct ec_host_response *response;
+ struct cros_ec_spi *ec_spi = ec_dev->priv;
+ struct spi_transfer trans, trans_delay;
+ struct spi_message msg;
+ int i, len;
+ u8 *ptr;
+ u8 *rx_buf;
+ u8 sum;
+ int ret = 0, final_ret;
+
+ len = cros_ec_prepare_tx(ec_dev, ec_msg);
+ request = (struct ec_host_request *)ec_dev->dout;
+ dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
+
+ /* If it's too soon to do another transaction, wait */
+ if (ec_spi->last_transfer_ns) {
+ unsigned long delay; /* The delay completed so far */
+
+ delay = ktime_get_ns() - ec_spi->last_transfer_ns;
+ if (delay < EC_SPI_RECOVERY_TIME_NS)
+ ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
+ }
+
+ rx_buf = kzalloc(len, GFP_KERNEL);
+ if (!rx_buf) {
+ ret = -ENOMEM;
+ goto exit;
+ }
+
+ /*
+ * Leave a gap between CS assertion and clocking of data to allow the
+ * EC time to wakeup.
+ */
+ spi_message_init(&msg);
+ if (ec_spi->start_of_msg_delay) {
+ memset(&trans_delay, 0, sizeof(trans_delay));
+ trans_delay.delay_usecs = ec_spi->start_of_msg_delay;
+ spi_message_add_tail(&trans_delay, &msg);
+ }
+
+ /* Transmit phase - send our message */
+ memset(&trans, 0, sizeof(trans));
+ trans.tx_buf = ec_dev->dout;
+ trans.rx_buf = rx_buf;
+ trans.len = len;
+ trans.cs_change = 1;
+ spi_message_add_tail(&trans, &msg);
+ ret = spi_sync(ec_spi->spi, &msg);
+
+ /* Get the response */
+ if (!ret) {
+ /* Verify that EC can process command */
+ for (i = 0; i < len; i++) {
+ switch (rx_buf[i]) {
+ case EC_SPI_PAST_END:
+ case EC_SPI_RX_BAD_DATA:
+ case EC_SPI_NOT_READY:
+ ret = -EAGAIN;
+ ec_msg->result = EC_RES_IN_PROGRESS;
+ default:
+ break;
+ }
+ if (ret)
+ break;
+ }
+ if (!ret)
+ ret = cros_ec_spi_receive_packet(ec_dev,
+ ec_msg->insize + sizeof(*response));
+ } else {
+ dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
+ }
+
+ final_ret = terminate_request(ec_dev);
+ if (!ret)
+ ret = final_ret;
+ if (ret < 0)
+ goto exit;
+
+ ptr = ec_dev->din;
+
+ /* check response error code */
+ response = (struct ec_host_response *)ptr;
+ ec_msg->result = response->result;
+
+ ret = cros_ec_check_result(ec_dev, ec_msg);
+ if (ret)
+ goto exit;
+
+ len = response->data_len;
+ sum = 0;
+ if (len > ec_msg->insize) {
+ dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
+ len, ec_msg->insize);
+ ret = -EMSGSIZE;
+ goto exit;
+ }
+
+ for (i = 0; i < sizeof(*response); i++)
+ sum += ptr[i];
+
+ /* copy response packet payload and compute checksum */
+ memcpy(ec_msg->data, ptr + sizeof(*response), len);
+ for (i = 0; i < len; i++)
+ sum += ec_msg->data[i];
+
+ if (sum) {
+ dev_err(ec_dev->dev,
+ "bad packet checksum, calculated %x\n",
+ sum);
+ ret = -EBADMSG;
+ goto exit;
+ }
+
+ ret = len;
+exit:
+ kfree(rx_buf);
+ if (ec_msg->command == EC_CMD_REBOOT_EC)
+ msleep(EC_REBOOT_DELAY_MS);
+
+ return ret;
+}
+
/**
* cros_ec_cmd_xfer_spi - Transfer a message over SPI and receive the reply
*
struct spi_message msg;
int i, len;
u8 *ptr;
+ u8 *rx_buf;
int sum;
int ret = 0, final_ret;
ndelay(EC_SPI_RECOVERY_TIME_NS - delay);
}
+ rx_buf = kzalloc(len, GFP_KERNEL);
+ if (!rx_buf) {
+ ret = -ENOMEM;
+ goto exit;
+ }
+
/* Transmit phase - send our message */
debug_packet(ec_dev->dev, "out", ec_dev->dout, len);
memset(&trans, 0, sizeof(trans));
trans.tx_buf = ec_dev->dout;
+ trans.rx_buf = rx_buf;
trans.len = len;
trans.cs_change = 1;
spi_message_init(&msg);
/* Get the response */
if (!ret) {
- ret = cros_ec_spi_receive_response(ec_dev,
- ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
+ /* Verify that EC can process command */
+ for (i = 0; i < len; i++) {
+ switch (rx_buf[i]) {
+ case EC_SPI_PAST_END:
+ case EC_SPI_RX_BAD_DATA:
+ case EC_SPI_NOT_READY:
+ ret = -EAGAIN;
+ ec_msg->result = EC_RES_IN_PROGRESS;
+ default:
+ break;
+ }
+ if (ret)
+ break;
+ }
+ if (!ret)
+ ret = cros_ec_spi_receive_response(ec_dev,
+ ec_msg->insize + EC_MSG_TX_PROTO_BYTES);
} else {
dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
}
- /*
- * Turn off CS, possibly adding a delay to ensure the rising edge
- * doesn't come too soon after the end of the data.
- */
- spi_message_init(&msg);
- memset(&trans, 0, sizeof(trans));
- trans.delay_usecs = ec_spi->end_of_msg_delay;
- spi_message_add_tail(&trans, &msg);
-
- final_ret = spi_sync(ec_spi->spi, &msg);
- ec_spi->last_transfer_ns = ktime_get_ns();
+ final_ret = terminate_request(ec_dev);
if (!ret)
ret = final_ret;
- if (ret < 0) {
- dev_err(ec_dev->dev, "spi transfer failed: %d\n", ret);
+ if (ret < 0)
goto exit;
- }
ptr = ec_dev->din;
for (i = 0; i < len; i++) {
sum += ptr[i + 2];
if (ec_msg->insize)
- ec_msg->indata[i] = ptr[i + 2];
+ ec_msg->data[i] = ptr[i + 2];
}
sum &= 0xff;
ret = len;
exit:
+ kfree(rx_buf);
if (ec_msg->command == EC_CMD_REBOOT_EC)
msleep(EC_REBOOT_DELAY_MS);
u32 val;
int ret;
+ ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val);
+ if (!ret)
+ ec_spi->start_of_msg_delay = val;
+
ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
if (!ret)
ec_spi->end_of_msg_delay = val;
ec_dev->priv = ec_spi;
ec_dev->irq = spi->irq;
ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
- ec_dev->ec_name = ec_spi->spi->modalias;
+ ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
- ec_dev->parent = &ec_spi->spi->dev;
- ec_dev->din_size = EC_MSG_BYTES + EC_MSG_PREAMBLE_COUNT;
- ec_dev->dout_size = EC_MSG_BYTES;
+ ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
+ sizeof(struct ec_host_response) +
+ sizeof(struct ec_response_get_protocol_info);
+ ec_dev->dout_size = sizeof(struct ec_host_request);
+
err = cros_ec_register(ec_dev);
if (err) {
static SIMPLE_DEV_PM_OPS(cros_ec_spi_pm_ops, cros_ec_spi_suspend,
cros_ec_spi_resume);
+static const struct of_device_id cros_ec_spi_of_match[] = {
+ { .compatible = "google,cros-ec-spi", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, cros_ec_spi_of_match);
+
static const struct spi_device_id cros_ec_spi_id[] = {
{ "cros-ec-spi", 0 },
{ }
static struct spi_driver cros_ec_driver_spi = {
.driver = {
.name = "cros-ec-spi",
- .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(cros_ec_spi_of_match),
.pm = &cros_ec_spi_pm_ops,
},
.probe = cros_ec_spi_probe,
Code Review / kvmfornfv.git / blobdiff