mfd: cros_ec: add proto v3 skeleton
authorStephen Barber <smbarber@chromium.org>
Tue, 9 Jun 2015 11:04:45 +0000 (13:04 +0200)
committerLee Jones <lee.jones@linaro.org>
Mon, 15 Jun 2015 12:18:21 +0000 (13:18 +0100)
Add support in cros_ec.c to handle EC host command protocol v3.
For v3+, probe for maximum shared protocol version and max
request, response, and passthrough sizes. For now, this will
always fall back to v2, since there is no bus-specific code
for handling proto v3 packets.

Signed-off-by: Stephen Barber <smbarber@chromium.org>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
drivers/mfd/cros_ec.c
drivers/mfd/cros_ec_i2c.c
drivers/mfd/cros_ec_spi.c
drivers/platform/chrome/cros_ec_lpc.c
drivers/platform/chrome/cros_ec_proto.c
include/linux/mfd/cros_ec.h

index d857f6a..08d82bf 100644 (file)
@@ -36,19 +36,22 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
        struct device *dev = ec_dev->dev;
        int err = 0;
 
-       if (ec_dev->din_size) {
-               ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
-               if (!ec_dev->din)
-                       return -ENOMEM;
-       }
-       if (ec_dev->dout_size) {
-               ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
-               if (!ec_dev->dout)
-                       return -ENOMEM;
-       }
+       ec_dev->max_request = sizeof(struct ec_params_hello);
+       ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
+       ec_dev->max_passthru = 0;
+
+       ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
+       if (!ec_dev->din)
+               return -ENOMEM;
+
+       ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
+       if (!ec_dev->dout)
+               return -ENOMEM;
 
        mutex_init(&ec_dev->lock);
 
+       cros_ec_query_all(ec_dev);
+
        err = mfd_add_devices(dev, 0, cros_devs,
                              ARRAY_SIZE(cros_devs),
                              NULL, ec_dev->irq, NULL);
index fbf7819..b400bfa 100644 (file)
@@ -143,8 +143,12 @@ static int cros_ec_i2c_probe(struct i2c_client *client,
        ec_dev->priv = client;
        ec_dev->irq = client->irq;
        ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c;
+       ec_dev->pkt_xfer = NULL;
        ec_dev->ec_name = client->name;
        ec_dev->phys_name = client->adapter->name;
+       ec_dev->din_size = 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) {
index 573730f..04da2f2 100644 (file)
@@ -361,10 +361,13 @@ 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->ec_name = ec_spi->spi->modalias;
        ec_dev->phys_name = dev_name(&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) {
index 4c7f0df..05aeb55 100644 (file)
@@ -215,7 +215,11 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
        ec_dev->ec_name = pdev->name;
        ec_dev->phys_name = dev_name(dev);
        ec_dev->cmd_xfer = cros_ec_cmd_xfer_lpc;
+       ec_dev->pkt_xfer = NULL;
        ec_dev->cmd_readmem = cros_ec_lpc_readmem;
+       ec_dev->din_size = sizeof(struct ec_host_response) +
+                          sizeof(struct ec_response_get_protocol_info);
+       ec_dev->dout_size = sizeof(struct ec_host_request);
 
        ret = cros_ec_register(ec_dev);
        if (ret) {
index 58e98a2..990308c 100644 (file)
 
 #define EC_COMMAND_RETRIES     50
 
+static int prepare_packet(struct cros_ec_device *ec_dev,
+                         struct cros_ec_command *msg)
+{
+       struct ec_host_request *request;
+       u8 *out;
+       int i;
+       u8 csum = 0;
+
+       BUG_ON(ec_dev->proto_version != EC_HOST_REQUEST_VERSION);
+       BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
+
+       out = ec_dev->dout;
+       request = (struct ec_host_request *)out;
+       request->struct_version = EC_HOST_REQUEST_VERSION;
+       request->checksum = 0;
+       request->command = msg->command;
+       request->command_version = msg->version;
+       request->reserved = 0;
+       request->data_len = msg->outsize;
+
+       for (i = 0; i < sizeof(*request); i++)
+               csum += out[i];
+
+       /* Copy data and update checksum */
+       memcpy(out + sizeof(*request), msg->data, msg->outsize);
+       for (i = 0; i < msg->outsize; i++)
+               csum += msg->data[i];
+
+       request->checksum = -csum;
+
+       return sizeof(*request) + msg->outsize;
+}
+
+static int send_command(struct cros_ec_device *ec_dev,
+                       struct cros_ec_command *msg)
+{
+       int ret;
+
+       if (ec_dev->proto_version > 2)
+               ret = ec_dev->pkt_xfer(ec_dev, msg);
+       else
+               ret = ec_dev->cmd_xfer(ec_dev, msg);
+
+       if (msg->result == EC_RES_IN_PROGRESS) {
+               int i;
+               struct cros_ec_command *status_msg;
+               struct ec_response_get_comms_status *status;
+
+               status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
+                                    GFP_KERNEL);
+               if (!status_msg)
+                       return -ENOMEM;
+
+               status_msg->version = 0;
+               status_msg->command = EC_CMD_GET_COMMS_STATUS;
+               status_msg->insize = sizeof(*status);
+               status_msg->outsize = 0;
+
+               /*
+                * Query the EC's status until it's no longer busy or
+                * we encounter an error.
+                */
+               for (i = 0; i < EC_COMMAND_RETRIES; i++) {
+                       usleep_range(10000, 11000);
+
+                       ret = ec_dev->cmd_xfer(ec_dev, status_msg);
+                       if (ret < 0)
+                               break;
+
+                       msg->result = status_msg->result;
+                       if (status_msg->result != EC_RES_SUCCESS)
+                               break;
+
+                       status = (struct ec_response_get_comms_status *)
+                                status_msg->data;
+                       if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
+                               break;
+               }
+
+               kfree(status_msg);
+       }
+
+       return ret;
+}
+
 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
                       struct cros_ec_command *msg)
 {
-       uint8_t *out;
-       int csum, i;
+       u8 *out;
+       u8 csum;
+       int i;
+
+       if (ec_dev->proto_version > 2)
+               return prepare_packet(ec_dev, msg);
 
        BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
        out = ec_dev->dout;
@@ -36,7 +125,7 @@ int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
        csum = out[0] + out[1] + out[2];
        for (i = 0; i < msg->outsize; i++)
                csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
-       out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = (uint8_t)(csum & 0xff);
+       out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;
 
        return EC_MSG_TX_PROTO_BYTES + msg->outsize;
 }
@@ -60,54 +149,232 @@ int cros_ec_check_result(struct cros_ec_device *ec_dev,
 }
 EXPORT_SYMBOL(cros_ec_check_result);
 
-int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
-                    struct cros_ec_command *msg)
+static int cros_ec_host_command_proto_query(struct cros_ec_device *ec_dev,
+                                           int devidx,
+                                           struct cros_ec_command *msg)
 {
+       /*
+        * Try using v3+ to query for supported protocols. If this
+        * command fails, fall back to v2. Returns the highest protocol
+        * supported by the EC.
+        * Also sets the max request/response/passthru size.
+        */
        int ret;
 
-       mutex_lock(&ec_dev->lock);
-       ret = ec_dev->cmd_xfer(ec_dev, msg);
-       if (msg->result == EC_RES_IN_PROGRESS) {
-               int i;
-               struct cros_ec_command *status_msg;
-               struct ec_response_get_comms_status *status;
+       if (!ec_dev->pkt_xfer)
+               return -EPROTONOSUPPORT;
 
-               status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
-                                    GFP_KERNEL);
-               if (!status_msg) {
-                       ret = -ENOMEM;
-                       goto exit;
-               }
+       memset(msg, 0, sizeof(*msg));
+       msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
+       msg->insize = sizeof(struct ec_response_get_protocol_info);
 
-               status_msg->version = 0;
-               status_msg->command = EC_CMD_GET_COMMS_STATUS;
-               status_msg->insize = sizeof(*status);
-               status_msg->outsize = 0;
+       ret = send_command(ec_dev, msg);
+
+       if (ret < 0) {
+               dev_dbg(ec_dev->dev,
+                       "failed to check for EC[%d] protocol version: %d\n",
+                       devidx, ret);
+               return ret;
+       }
+
+       if (devidx > 0 && msg->result == EC_RES_INVALID_COMMAND)
+               return -ENODEV;
+       else if (msg->result != EC_RES_SUCCESS)
+               return msg->result;
+
+       return 0;
+}
+
+static int cros_ec_host_command_proto_query_v2(struct cros_ec_device *ec_dev)
+{
+       struct cros_ec_command *msg;
+       struct ec_params_hello *hello_params;
+       struct ec_response_hello *hello_response;
+       int ret;
+       int len = max(sizeof(*hello_params), sizeof(*hello_response));
+
+       msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL);
+       if (!msg)
+               return -ENOMEM;
+
+       msg->version = 0;
+       msg->command = EC_CMD_HELLO;
+       hello_params = (struct ec_params_hello *)msg->data;
+       msg->outsize = sizeof(*hello_params);
+       hello_response = (struct ec_response_hello *)msg->data;
+       msg->insize = sizeof(*hello_response);
+
+       hello_params->in_data = 0xa0b0c0d0;
+
+       ret = send_command(ec_dev, msg);
+
+       if (ret < 0) {
+               dev_dbg(ec_dev->dev,
+                       "EC failed to respond to v2 hello: %d\n",
+                       ret);
+               goto exit;
+       } else if (msg->result != EC_RES_SUCCESS) {
+               dev_err(ec_dev->dev,
+                       "EC responded to v2 hello with error: %d\n",
+                       msg->result);
+               ret = msg->result;
+               goto exit;
+       } else if (hello_response->out_data != 0xa1b2c3d4) {
+               dev_err(ec_dev->dev,
+                       "EC responded to v2 hello with bad result: %u\n",
+                       hello_response->out_data);
+               ret = -EBADMSG;
+               goto exit;
+       }
+
+       ret = 0;
+
+ exit:
+       kfree(msg);
+       return ret;
+}
+
+int cros_ec_query_all(struct cros_ec_device *ec_dev)
+{
+       struct device *dev = ec_dev->dev;
+       struct cros_ec_command *proto_msg;
+       struct ec_response_get_protocol_info *proto_info;
+       int ret;
+
+       proto_msg = kzalloc(sizeof(*proto_msg) + sizeof(*proto_info),
+                           GFP_KERNEL);
+       if (!proto_msg)
+               return -ENOMEM;
+
+       /* First try sending with proto v3. */
+       ec_dev->proto_version = 3;
+       ret = cros_ec_host_command_proto_query(ec_dev, 0, proto_msg);
+
+       if (ret == 0) {
+               proto_info = (struct ec_response_get_protocol_info *)
+                       proto_msg->data;
+               ec_dev->max_request = proto_info->max_request_packet_size -
+                       sizeof(struct ec_host_request);
+               ec_dev->max_response = proto_info->max_response_packet_size -
+                       sizeof(struct ec_host_response);
+               ec_dev->proto_version =
+                       min(EC_HOST_REQUEST_VERSION,
+                                       fls(proto_info->protocol_versions) - 1);
+               dev_dbg(ec_dev->dev,
+                       "using proto v%u\n",
+                       ec_dev->proto_version);
+
+               ec_dev->din_size = ec_dev->max_response +
+                       sizeof(struct ec_host_response) +
+                       EC_MAX_RESPONSE_OVERHEAD;
+               ec_dev->dout_size = ec_dev->max_request +
+                       sizeof(struct ec_host_request) +
+                       EC_MAX_REQUEST_OVERHEAD;
 
                /*
-                * Query the EC's status until it's no longer busy or
-                * we encounter an error.
+                * Check for PD
                 */
-               for (i = 0; i < EC_COMMAND_RETRIES; i++) {
-                       usleep_range(10000, 11000);
+               ret = cros_ec_host_command_proto_query(ec_dev, 1, proto_msg);
 
-                       ret = ec_dev->cmd_xfer(ec_dev, status_msg);
-                       if (ret < 0)
-                               break;
+               if (ret) {
+                       dev_dbg(ec_dev->dev, "no PD chip found: %d\n", ret);
+                       ec_dev->max_passthru = 0;
+               } else {
+                       dev_dbg(ec_dev->dev, "found PD chip\n");
+                       ec_dev->max_passthru =
+                               proto_info->max_request_packet_size -
+                               sizeof(struct ec_host_request);
+               }
+       } else {
+               /* Try querying with a v2 hello message. */
+               ec_dev->proto_version = 2;
+               ret = cros_ec_host_command_proto_query_v2(ec_dev);
 
-                       msg->result = status_msg->result;
-                       if (status_msg->result != EC_RES_SUCCESS)
-                               break;
+               if (ret == 0) {
+                       /* V2 hello succeeded. */
+                       dev_dbg(ec_dev->dev, "falling back to proto v2\n");
 
-                       status = (struct ec_response_get_comms_status *)
-                                status_msg->data;
-                       if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
-                               break;
+                       ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
+                       ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
+                       ec_dev->max_passthru = 0;
+                       ec_dev->pkt_xfer = NULL;
+                       ec_dev->din_size = EC_MSG_BYTES;
+                       ec_dev->dout_size = EC_MSG_BYTES;
+               } else {
+                       /*
+                        * It's possible for a test to occur too early when
+                        * the EC isn't listening. If this happens, we'll
+                        * test later when the first command is run.
+                        */
+                       ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
+                       dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
+                       goto exit;
                }
+       }
 
-               kfree(status_msg);
+       devm_kfree(dev, ec_dev->din);
+       devm_kfree(dev, ec_dev->dout);
+
+       ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
+       if (!ec_dev->din) {
+               ret = -ENOMEM;
+               goto exit;
        }
+
+       ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
+       if (!ec_dev->dout) {
+               devm_kfree(dev, ec_dev->din);
+               ret = -ENOMEM;
+               goto exit;
+       }
+
 exit:
+       kfree(proto_msg);
+       return ret;
+}
+EXPORT_SYMBOL(cros_ec_query_all);
+
+int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
+                    struct cros_ec_command *msg)
+{
+       int ret;
+
+       mutex_lock(&ec_dev->lock);
+       if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
+               ret = cros_ec_query_all(ec_dev);
+               if (ret) {
+                       dev_err(ec_dev->dev,
+                               "EC version unknown and query failed; aborting command\n");
+                       mutex_unlock(&ec_dev->lock);
+                       return ret;
+               }
+       }
+
+       if (msg->insize > ec_dev->max_response) {
+               dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
+               msg->insize = ec_dev->max_response;
+       }
+
+       if (msg->command < EC_CMD_PASSTHRU_OFFSET(1)) {
+               if (msg->outsize > ec_dev->max_request) {
+                       dev_err(ec_dev->dev,
+                               "request of size %u is too big (max: %u)\n",
+                               msg->outsize,
+                               ec_dev->max_request);
+                       mutex_unlock(&ec_dev->lock);
+                       return -EMSGSIZE;
+               }
+       } else {
+               if (msg->outsize > ec_dev->max_passthru) {
+                       dev_err(ec_dev->dev,
+                               "passthru rq of size %u is too big (max: %u)\n",
+                               msg->outsize,
+                               ec_dev->max_passthru);
+                       mutex_unlock(&ec_dev->lock);
+                       return -EMSGSIZE;
+               }
+       }
+       ret = send_command(ec_dev, msg);
        mutex_unlock(&ec_dev->lock);
 
        return ret;
index 7eee38a..59d9094 100644 (file)
 #include <linux/mutex.h>
 
 /*
+ * Max bus-specific overhead incurred by request/responses.
+ * I2C requires 1 additional byte for requests.
+ * I2C requires 2 additional bytes for responses.
+ * */
+#define EC_PROTO_VERSION_UNKNOWN       0
+#define EC_MAX_REQUEST_OVERHEAD                1
+#define EC_MAX_RESPONSE_OVERHEAD       2
+
+/*
  * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
  */
 enum {
@@ -88,6 +97,7 @@ struct cros_ec_command {
  *     Returns the number of bytes received if the communication succeeded, but
  *     that doesn't mean the EC was happy with the command. The caller
  *     should check msg.result for the EC's result code.
+ * @pkt_xfer: send packet to EC and get response
  * @lock: one transaction at a time
  */
 struct cros_ec_device {
@@ -104,15 +114,21 @@ struct cros_ec_device {
                           unsigned int bytes, void *dest);
 
        /* These are used to implement the platform-specific interface */
+       u16 max_request;
+       u16 max_response;
+       u16 max_passthru;
+       u16 proto_version;
        void *priv;
        int irq;
-       uint8_t *din;
-       uint8_t *dout;
+       u8 *din;
+       u8 *dout;
        int din_size;
        int dout_size;
        bool wake_enabled;
        int (*cmd_xfer)(struct cros_ec_device *ec,
                        struct cros_ec_command *msg);
+       int (*pkt_xfer)(struct cros_ec_device *ec,
+                       struct cros_ec_command *msg);
        struct mutex lock;
 };
 
@@ -194,4 +210,12 @@ int cros_ec_remove(struct cros_ec_device *ec_dev);
  */
 int cros_ec_register(struct cros_ec_device *ec_dev);
 
+/**
+ * cros_ec_register -  Query the protocol version supported by the ChromeOS EC
+ *
+ * @ec_dev: Device to register
+ * @return 0 if ok, -ve on error
+ */
+int cros_ec_query_all(struct cros_ec_device *ec_dev);
+
 #endif /* __LINUX_MFD_CROS_EC_H */