rpmsg: glink: Allow unaligned data access

Glink protocol requires that each message is aligned on a 8 byte offset.
This is purely a restriction from glink, so in order to support clients
which do not adher to this, allow data packets of any size, but align
the head index accordingly, effectively removing the alignment
restriction.

Acked-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index ffdf88e436a7296c16cea632545d0976d7ff456f..a6394cdce1ace493921c7fe68d88913c0b3f505e 100644 (file)
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -227,9 +227,6 @@ static int qcom_glink_tx(struct qcom_glink *glink,
        if (tlen >= glink->tx_pipe->length)
                return -EINVAL;
 
-       if (WARN(tlen % 8, "Unaligned TX request"))
-               return -EINVAL;
-
        ret = mutex_lock_interruptible(&glink->tx_lock);
        if (ret)
                return ret;
@@ -695,9 +692,6 @@ static int __qcom_glink_send(struct glink_channel *channel,
                __le32 left_size;
        } __packed req;
 
-       if (WARN(len % 8, "RPM GLINK expects 8 byte aligned messages\n"))
-               return -EINVAL;
-
        req.msg.cmd = cpu_to_le16(RPM_CMD_TX_DATA);
        req.msg.param1 = cpu_to_le16(channel->lcid);
        req.msg.param2 = cpu_to_le32(channel->rcid);

diff --git a/drivers/rpmsg/qcom_glink_rpm.c b/drivers/rpmsg/qcom_glink_rpm.c
index 33daa3223ce07bdddbdb900a64218c86f51d7146..cc73af0aae8a0b0a1915e58867d20cfe92f867b8 100644 (file)
--- a/drivers/rpmsg/qcom_glink_rpm.c
+++ b/drivers/rpmsg/qcom_glink_rpm.c
@@ -156,11 +156,31 @@ static void glink_rpm_tx_write(struct qcom_glink_pipe *glink_pipe,
                               const void *data, size_t dlen)
 {
        struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
+       size_t tlen = hlen + dlen;
+       size_t aligned_dlen;
        unsigned int head;
+       char padding[8] = {0};
+       size_t pad;
+
+       /* Header length comes from glink native and is always 4 byte aligned */
+       if (WARN(hlen % 4, "Glink Header length must be 4 bytes aligned\n"))
+               return;
+
+       /*
+        * Move the unaligned tail of the message to the padding chunk, to
+        * ensure word aligned accesses
+        */
+       aligned_dlen = ALIGN_DOWN(dlen, 4);
+       if (aligned_dlen != dlen)
+               memcpy(padding, data + aligned_dlen, dlen - aligned_dlen);
 
        head = readl(pipe->head);
        head = glink_rpm_tx_write_one(pipe, head, hdr, hlen);
-       head = glink_rpm_tx_write_one(pipe, head, data, dlen);
+       head = glink_rpm_tx_write_one(pipe, head, data, aligned_dlen);
+
+       pad = ALIGN(tlen, 8) - ALIGN_DOWN(tlen, 4);
+       if (pad)
+               head = glink_rpm_tx_write_one(pipe, head, padding, pad);
        writel(head, pipe->head);
 }