greybus: es2: sync up with recent es1 changes

Fix transfer-buffer alignment of es2 as well.

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/es2.c b/drivers/staging/greybus/es2.c
index 10b21df..45b6815 100644 (file)
--- a/drivers/staging/greybus/es2.c
+++ b/drivers/staging/greybus/es2.c
@@ -16,6 +16,7 @@
 #include <linux/kfifo.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
+#include <asm/unaligned.h>
 
 #include "greybus.h"
 #include "svc_msg.h"
@@ -127,13 +128,8 @@ static void usb_log_disable(struct es1_ap_dev *es1);
  */
 static void hd_buffer_constraints(struct greybus_host_device *hd)
 {
-       /*
-        * Only one byte is required, but this produces a result
-        * that's better aligned for the user.
-        */
-       hd->buffer_headroom = sizeof(u32);      /* For cport id */
-       hd->buffer_size_max = ES1_GBUF_MSG_SIZE_MAX - hd->buffer_headroom;
-       BUILD_BUG_ON(hd->buffer_headroom > GB_BUFFER_HEADROOM_MAX);
+       hd->buffer_headroom = 0;
+       hd->buffer_size_max = ES1_GBUF_MSG_SIZE_MAX;
 }
 
 #define ES1_TIMEOUT    500     /* 500 ms for the SVC to do something */
@@ -219,16 +215,13 @@ static void *message_send(struct greybus_host_device *hd, u16 cport_id,
 {
        struct es1_ap_dev *es1 = hd_to_es1(hd);
        struct usb_device *udev = es1->usb_dev;
-       u8 *transfer_buffer;
+       void *buffer;
        size_t buffer_size;
-       int transfer_buffer_size;
        int retval;
        struct urb *urb;
 
-       buffer_size = hd->buffer_headroom + sizeof(*message->header) +
-                                                       message->payload_size;
-       transfer_buffer = message->buffer + hd->buffer_headroom - 1;
-       transfer_buffer_size = buffer_size - (hd->buffer_headroom - 1);
+       buffer = message->buffer;
+       buffer_size = sizeof(*message->header) + message->payload_size;
 
        /*
         * The data actually transferred will include an indication
@@ -239,26 +232,27 @@ static void *message_send(struct greybus_host_device *hd, u16 cport_id,
                pr_err("request to send inbound data buffer\n");
                return ERR_PTR(-EINVAL);
        }
-       if (cport_id > U8_MAX) {
-               pr_err("cport_id (%hd) is out of range for ES1\n", cport_id);
-               return ERR_PTR(-EINVAL);
-       }
-       /* OK, the destination is fine; record it in the transfer buffer */
-       *transfer_buffer = cport_id;
 
        /* Find a free urb */
        urb = next_free_urb(es1, gfp_mask);
        if (!urb)
                return ERR_PTR(-ENOMEM);
 
+       /*
+        * We (ab)use the operation-message header pad bytes to transfer the
+        * cport id in order to minimise overhead.
+        */
+       put_unaligned_le16(cport_id, message->header->pad);
+
        usb_fill_bulk_urb(urb, udev,
                          usb_sndbulkpipe(udev, es1->cport_out_endpoint),
-                         transfer_buffer, transfer_buffer_size,
+                         buffer, buffer_size,
                          cport_out_callback, message);
        retval = usb_submit_urb(urb, gfp_mask);
        if (retval) {
                pr_err("error %d submitting URB\n", retval);
                free_urb(es1, urb);
+               put_unaligned_le16(0, message->header->pad);
                return ERR_PTR(retval);
        }
 
@@ -395,10 +389,10 @@ static void cport_in_callback(struct urb *urb)
 {
        struct greybus_host_device *hd = urb->context;
        struct device *dev = &urb->dev->dev;
+       struct gb_operation_msg_hdr *header;
        int status = check_urb_status(urb);
        int retval;
        u16 cport_id;
-       u8 *data;
 
        if (status) {
                if ((status == -EAGAIN) || (status == -EPROTO))
@@ -407,23 +401,17 @@ static void cport_in_callback(struct urb *urb)
                return;
        }
 
-       /* The size has to be at least one, for the cport id */
-       if (!urb->actual_length) {
-               dev_err(dev, "%s: no cport id in input buffer?\n", __func__);
+       if (urb->actual_length < sizeof(*header)) {
+               dev_err(dev, "%s: short message received\n", __func__);
                goto exit;
        }
 
-       /*
-        * Our CPort number is the first byte of the data stream,
-        * the rest of the stream is "real" data
-        */
-       data = urb->transfer_buffer;
-       cport_id = data[0];
-       data = &data[1];
-
-       /* Pass this data to the greybus core */
-       greybus_data_rcvd(hd, cport_id, data, urb->actual_length - 1);
+       header = urb->transfer_buffer;
+       cport_id = get_unaligned_le16(header->pad);
+       put_unaligned_le16(0, header->pad);
 
+       greybus_data_rcvd(hd, cport_id, urb->transfer_buffer,
+                                                       urb->actual_length);
 exit:
        /* put our urb back in the request pool */
        retval = usb_submit_urb(urb, GFP_ATOMIC);
@@ -439,6 +427,9 @@ static void cport_out_callback(struct urb *urb)
        struct es1_ap_dev *es1 = hd_to_es1(hd);
        int status = check_urb_status(urb);
 
+       /* Clear the pad bytes used for the cport id */
+       put_unaligned_le16(0, message->header->pad);
+
        /*
         * Tell the submitter that the message send (attempt) is
         * complete, and report the status.