[RFC PATCH 03/11] firmware: arm_scmi: Add support for notifications message processing

Cristian Marussi
2020-01-20T12:24:56Z

From: Sudeep Holla <sudeep.holla@arm.com>

Add the mechanisms to distinguish notifications from delayed responses and
to properly fetch notification messages upon reception: notifications
processing does not continue further after the fetch phase.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
drivers/firmware/arm_scmi/driver.c | 92 +++++++++++++++++++++---------
1 file changed, 65 insertions(+), 27 deletions(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 9611e8037d77..28ed1f0cb417 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -212,6 +212,15 @@ static void scmi_fetch_response(struct scmi_xfer *xfer,
memcpy_fromio(xfer->rx.buf, mem->msg_payload + 4, xfer->rx.len);
}

+static void scmi_fetch_notification(struct scmi_xfer *xfer, size_t max_len,
+ struct scmi_shared_mem __iomem *mem)
+{
+ /* Skip only length of header in payload area i.e 4 bytes */
+ xfer->rx.len = min_t(size_t, max_len, ioread32(&mem->length) - 4);
+
+ memcpy_fromio(xfer->rx.buf, mem->msg_payload, xfer->rx.len);
+}
+
/**
* pack_scmi_header() - packs and returns 32-bit header
*
@@ -339,6 +348,58 @@ __scmi_xfer_put(struct scmi_xfers_info *minfo, struct scmi_xfer *xfer)
spin_unlock_irqrestore(&minfo->xfer_lock, flags);
}

+static void scmi_handle_notification(struct scmi_chan_info *cinfo, u32 msg_hdr)
+{
+ struct scmi_xfer *xfer;
+ struct device *dev = cinfo->dev;
+ struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+ struct scmi_xfers_info *minfo = &info->rx_minfo;
+ struct scmi_shared_mem __iomem *mem = cinfo->payload;
+
+ xfer = scmi_xfer_get(cinfo->handle, minfo);
+ if (IS_ERR(xfer)) {
+ dev_err(dev, "failed to get free message slot (%ld)\n",
+ PTR_ERR(xfer));
+ iowrite32(SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE,
+ &mem->channel_status);
+ return;
+ }
+
+ unpack_scmi_header(msg_hdr, &xfer->hdr);
+ scmi_dump_header_dbg(dev, &xfer->hdr);
+ scmi_fetch_notification(xfer, info->desc->max_msg_size, mem);
+ __scmi_xfer_put(minfo, xfer);
+
+ iowrite32(SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE, &mem->channel_status);
+}
+
+static void scmi_handle_xfer_delayed_resp(struct scmi_chan_info *cinfo,
+ u16 xfer_id, bool delayed_resp)
+{
+ struct scmi_xfer *xfer;
+ struct device *dev = cinfo->dev;
+ struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+ struct scmi_xfers_info *minfo = &info->tx_minfo;
+ struct scmi_shared_mem __iomem *mem = cinfo->payload;
+
+ /* Are we even expecting this? */
+ if (!test_bit(xfer_id, minfo->xfer_alloc_table)) {
+ dev_err(dev, "message for %d is not expected!\n", xfer_id);
+ return;
+ }
+
+ xfer = &minfo->xfer_block[xfer_id];
+
+ scmi_dump_header_dbg(dev, &xfer->hdr);
+
+ scmi_fetch_response(xfer, mem);
+
+ if (delayed_resp)
+ complete(xfer->async_done);
+ else
+ complete(&xfer->done);
+}
+
/**
* scmi_rx_callback() - mailbox client callback for receive messages
*
@@ -355,41 +416,18 @@ static void scmi_rx_callback(struct mbox_client *cl, void *m)
{
u8 msg_type;
u32 msg_hdr;
- u16 xfer_id;
- struct scmi_xfer *xfer;
struct scmi_chan_info *cinfo = client_to_scmi_chan_info(cl);
- struct device *dev = cinfo->dev;
- struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
- struct scmi_xfers_info *minfo = &info->tx_minfo;
struct scmi_shared_mem __iomem *mem = cinfo->payload;

msg_hdr = ioread32(&mem->msg_header);
msg_type = MSG_XTRACT_TYPE(msg_hdr);
- xfer_id = MSG_XTRACT_TOKEN(msg_hdr);

if (msg_type == MSG_TYPE_NOTIFICATION)
- return; /* Notifications not yet supported */
-
- /* Are we even expecting this? */
- if (!test_bit(xfer_id, minfo->xfer_alloc_table)) {
- dev_err(dev, "message for %d is not expected!\n", xfer_id);
- return;
- }
-
- xfer = &minfo->xfer_block[xfer_id];
-
- scmi_dump_header_dbg(dev, &xfer->hdr);
-
- scmi_fetch_response(xfer, mem);
-
- trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id,
- xfer->hdr.protocol_id, xfer->hdr.seq,
- msg_type);
-
- if (msg_type == MSG_TYPE_DELAYED_RESP)
- complete(xfer->async_done);
+ scmi_handle_notification(cinfo, msg_hdr);
else
- complete(&xfer->done);
+ scmi_handle_xfer_delayed_resp(cinfo, MSG_XTRACT_TOKEN(msg_hdr),
+ msg_type);
+
}

/**
--
2.17.1