mfd: cros_ec: Use fixed size arrays to transfer data with the EC

The struct cros_ec_command will be used as an ioctl() argument for the
API to control the ChromeOS EC from user-space. So the data structure
has to be 64-bit safe to make it compatible between 32 and 64 avoiding
the need for a compat ioctl interface. Since pointers are self-aligned
to different byte boundaries, use fixed size arrays instead of pointers
for transferring ingoing and outgoing data with the Embedded Controller.

Also, re-arrange struct members by decreasing alignment requirements to
reduce the needing padding size.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Lee Jones <lee.jones@linaro.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
index 875c22ae54004d4aba33c4a72c4bc398d47ac0a8..fa8dedd8c3a2f88ca0fdf05ce784b79f3852c51c 100644 (file)
--- a/drivers/i2c/busses/i2c-cros-ec-tunnel.c
+++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
@@ -182,72 +182,41 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
        const u16 bus_num = bus->remote_bus;
        int request_len;
        int response_len;
-       u8 *request = NULL;
-       u8 *response = NULL;
        int result;
-       struct cros_ec_command msg;
+       struct cros_ec_command msg = { };
 
        request_len = ec_i2c_count_message(i2c_msgs, num);
        if (request_len < 0) {
                dev_warn(dev, "Error constructing message %d\n", request_len);
-               result = request_len;
-               goto exit;
+               return request_len;
        }
+
        response_len = ec_i2c_count_response(i2c_msgs, num);
        if (response_len < 0) {
                /* Unexpected; no errors should come when NULL response */
                dev_warn(dev, "Error preparing response %d\n", response_len);
-               result = response_len;
-               goto exit;
-       }
-
-       if (request_len <= ARRAY_SIZE(bus->request_buf)) {
-               request = bus->request_buf;
-       } else {
-               request = kzalloc(request_len, GFP_KERNEL);
-               if (request == NULL) {
-                       result = -ENOMEM;
-                       goto exit;
-               }
-       }
-       if (response_len <= ARRAY_SIZE(bus->response_buf)) {
-               response = bus->response_buf;
-       } else {
-               response = kzalloc(response_len, GFP_KERNEL);
-               if (response == NULL) {
-                       result = -ENOMEM;
-                       goto exit;
-               }
+               return response_len;
        }
 
-       result = ec_i2c_construct_message(request, i2c_msgs, num, bus_num);
+       result = ec_i2c_construct_message(msg.outdata, i2c_msgs, num, bus_num);
        if (result)
-               goto exit;
+               return result;
 
        msg.version = 0;
        msg.command = EC_CMD_I2C_PASSTHRU;
-       msg.outdata = request;
        msg.outsize = request_len;
-       msg.indata = response;
        msg.insize = response_len;
 
        result = cros_ec_cmd_xfer(bus->ec, &msg);
        if (result < 0)
-               goto exit;
+               return result;
 
-       result = ec_i2c_parse_response(response, i2c_msgs, &num);
+       result = ec_i2c_parse_response(msg.indata, i2c_msgs, &num);
        if (result < 0)
-               goto exit;
+               return result;
 
        /* Indicate success by saying how many messages were sent */
-       result = num;
-exit:
-       if (request != bus->request_buf)
-               kfree(request);
-       if (response != bus->response_buf)
-               kfree(response);
-
-       return result;
+       return num;
 }
 
 static u32 ec_i2c_functionality(struct i2c_adapter *adap)

diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
index ffa989f2c785100a0006f145816ca73e4f90c462..769f8f7f62b7338aa13d927476af758878cb782d 100644 (file)
--- a/drivers/input/keyboard/cros_ec_keyb.c
+++ b/drivers/input/keyboard/cros_ec_keyb.c
@@ -148,16 +148,19 @@ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
 
 static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state)
 {
+       int ret;
        struct cros_ec_command msg = {
-               .version = 0,
                .command = EC_CMD_MKBP_STATE,
-               .outdata = NULL,
-               .outsize = 0,
-               .indata = kb_state,
                .insize = ckdev->cols,
        };
 
-       return cros_ec_cmd_xfer(ckdev->ec, &msg);
+       ret = cros_ec_cmd_xfer(ckdev->ec, &msg);
+       if (ret < 0)
+               return ret;
+
+       memcpy(kb_state, msg.indata, ckdev->cols);
+
+       return 0;
 }
 
 static irqreturn_t cros_ec_keyb_irq(int irq, void *data)

diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
index fc0c81ef04ff08df4de9feae9e19add3b56c6379..c872e1b0eaf82109c57167d4f03793b8f428063e 100644 (file)
--- a/drivers/mfd/cros_ec.c
+++ b/drivers/mfd/cros_ec.c
@@ -74,15 +74,11 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
        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;
+               struct cros_ec_command status_msg = { };
+               struct ec_response_get_comms_status *status;
 
-               status_msg.version = 0;
                status_msg.command = EC_CMD_GET_COMMS_STATUS;
-               status_msg.outdata = NULL;
-               status_msg.outsize = 0;
-               status_msg.indata = (uint8_t *)&status;
-               status_msg.insize = sizeof(status);
+               status_msg.insize = sizeof(*status);
 
                /*
                 * Query the EC's status until it's no longer busy or
@@ -98,7 +94,10 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
                        msg->result = status_msg.result;
                        if (status_msg.result != EC_RES_SUCCESS)
                                break;
-                       if (!(status.flags & EC_COMMS_STATUS_PROCESSING))
+
+                       status = (struct ec_response_get_comms_status *)
+                                status_msg.indata;
+                       if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
                                break;
                }
        }

diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
index 0e166b92f5b4f8b5499d37f35f5d9d7b050b5cc5..71675b14b5ca42d765211ec489314eb5d4e16d3b 100644 (file)
--- a/include/linux/mfd/cros_ec.h
+++ b/include/linux/mfd/cros_ec.h
@@ -38,20 +38,20 @@ enum {
 /*
  * @version: Command version number (often 0)
  * @command: Command to send (EC_CMD_...)
- * @outdata: Outgoing data to EC
  * @outsize: Outgoing length in bytes
- * @indata: Where to put the incoming data from EC
  * @insize: Max number of bytes to accept from EC
  * @result: EC's response to the command (separate from communication failure)
+ * @outdata: Outgoing data to EC
+ * @indata: Where to put the incoming data from EC
  */
 struct cros_ec_command {
        uint32_t version;
        uint32_t command;
-       uint8_t *outdata;
        uint32_t outsize;
-       uint8_t *indata;
        uint32_t insize;
        uint32_t result;
+       uint8_t outdata[EC_PROTO2_MAX_PARAM_SIZE];
+       uint8_t indata[EC_PROTO2_MAX_PARAM_SIZE];
 };
 
 /**