1 files changed, 329 insertions, 53 deletions

diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c
index 04da2f288ef8..4e6f2f6b1095 100644
--- a/drivers/mfd/cros_ec_spi.c
+++ b/drivers/mfd/cros_ec_spi.c
@@ -65,12 +65,6 @@
   */
 #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
  *
@@ -87,7 +81,7 @@ struct cros_ec_spi {
 };
 
 static void debug_packet(struct device *dev, const char *name, u8 *ptr,
-                          int len)
+                         int len)
 {
 #ifdef DEBUG
         int i;
@@ -100,6 +94,172 @@ static void debug_packet(struct device *dev, const char *name, u8 *ptr,
 #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.
  *
@@ -115,34 +275,27 @@ static void debug_packet(struct device *dev, const char *name, u8 *ptr,
 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;
@@ -187,21 +340,9 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
                 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;
@@ -214,6 +355,128 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
 }
 
 /**
+ * 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;
+        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;
+        }
+
+        /* 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_init(&msg);
+        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
  *
  * @ec_dev: ChromeOS EC device
@@ -227,6 +490,7 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
         struct spi_message msg;
         int i, len;
         u8 *ptr;
+        u8 *rx_buf;
         int sum;
         int ret = 0, final_ret;
 
@@ -242,10 +506,17 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
                         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);
@@ -254,29 +525,32 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
 
         /* 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;
 
@@ -315,6 +589,7 @@ static int cros_ec_cmd_xfer_spi(struct cros_ec_device *ec_dev,
 
         ret = len;
 exit:
+        kfree(rx_buf);
         if (ec_msg->command == EC_CMD_REBOOT_EC)
                 msleep(EC_REBOOT_DELAY_MS);
 
@@ -361,7 +636,7 @@ static int cros_ec_spi_probe(struct spi_device *spi)
         ec_dev->priv = ec_spi;
         ec_dev->irq = spi->irq;
         ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi;
-        ec_dev->pkt_xfer = NULL;
+        ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi;
         ec_dev->ec_name = ec_spi->spi->modalias;
         ec_dev->phys_name = dev_name(&ec_spi->spi->dev);
         ec_dev->din_size = EC_MSG_PREAMBLE_COUNT +
@@ -369,6 +644,7 @@ static int cros_ec_spi_probe(struct spi_device *spi)
                            sizeof(struct ec_response_get_protocol_info);
         ec_dev->dout_size = sizeof(struct ec_host_request);
 
+
         err = cros_ec_register(ec_dev);
         if (err) {
                 dev_err(dev, "cannot register EC\n");