Re: [PATCH v2 net-next 09/10] net: eth: altera: add msgdma prefetcher

On Tue, 2018-12-18 at 10:33 -0600, Thor Thayer wrote:

Hi Dalon,

On 12/13/18 11:52 AM, dwesterg@gmail.com wrote:

quoted

From: Dalon Westergreen <redacted>

Add support for the mSGDMA prefetcher.  The prefetcher adds support
for a linked list of descriptors in system memory.  The prefetcher
feeds these to the mSGDMA dispatcher.

The prefetcher is configured to poll for the next descriptor in the
list to be owned by hardware, then pass the descriptor to the
dispatcher.  It will then poll the next descriptor until it is
owned by hardware.

The dispatcher responses are written back to the appropriate
descriptor, and the owned by hardware bit is cleared.

The driver sets up a linked list twice the tx and rx ring sizes,
with the last descriptor pointing back to the first.  This ensures
that the ring of descriptors will always have inactive descriptors
preventing the prefetcher from looping over and reusing descriptors
inappropriately.  The prefetcher will continuously loop over these
descriptors.  The driver modifies descriptors as required to update
the skb address and length as well as the owned by hardware bit.

In addition to the above, the mSGDMA prefetcher can be used to
handle rx and tx timestamps coming from the ethernet ip.  These
can be included in the prefetcher response in the descriptor.

Signed-off-by: Dalon Westergreen <redacted>

---
Changes from v1:
  -> Alphabatize includes
  -> update xmit function to return type net_tx_t
  -> Cleanup msgdms descriptor ring by making is more apparent
     that the msgdma descriptor ring is 2 * ring_size
---
  drivers/net/ethernet/altera/Makefile          |   2 +-
  .../altera/altera_msgdma_prefetcher.c         | 432 ++++++++++++++++++
  .../altera/altera_msgdma_prefetcher.h         |  30 ++
  .../altera/altera_msgdmahw_prefetcher.h       |  87 ++++
  drivers/net/ethernet/altera/altera_tse.h      |  14 +
  drivers/net/ethernet/altera/altera_tse_main.c |  51 +++
  6 files changed, 615 insertions(+), 1 deletion(-)
  create mode 100644 drivers/net/ethernet/altera/altera_msgdma_prefetcher.c
  create mode 100644 drivers/net/ethernet/altera/altera_msgdma_prefetcher.h
  create mode 100644
drivers/net/ethernet/altera/altera_msgdmahw_prefetcher.h

diff --git a/drivers/net/ethernet/altera/Makefile

b/drivers/net/ethernet/altera/Makefile
index 3e622b4c105a..f6627615c6c1 100644

--- a/drivers/net/ethernet/altera/Makefile
+++ b/drivers/net/ethernet/altera/Makefile

@@ -5,4 +5,4 @@
  obj-$(CONFIG_ALTERA_TSE) += altera_tse.o
  altera_tse-objs := altera_tse_main.o altera_tse_ethtool.o \
  		   altera_msgdma.o altera_sgdma.o altera_utils.o \
-		   intel_fpga_tod.o
+		   intel_fpga_tod.o altera_msgdma_prefetcher.o

diff --git a/drivers/net/ethernet/altera/altera_msgdma_prefetcher.c

b/drivers/net/ethernet/altera/altera_msgdma_prefetcher.c
new file mode 100644
index 000000000000..f50ea62f687d

--- /dev/null
+++ b/drivers/net/ethernet/altera/altera_msgdma_prefetcher.c

@@ -0,0 +1,432 @@
+// SPDX-License-Identifier: GPL-2.0
+/* MSGDMA Prefetcher driver for Altera ethernet devices
+ *
+ * Copyright (C) 2018 Intel Corporation. All rights reserved.
+ * Author(s):
+ *   Dalon Westergreen <dalon.westergreen@intel.com>
+ */
+
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/net_tstamp.h>
+#include "altera_tse.h"
+#include "altera_msgdma.h"
+#include "altera_msgdmahw.h"
+#include "altera_msgdma_prefetcher.h"
+#include "altera_msgdmahw_prefetcher.h"
+#include "altera_utils.h"
+

Alphabetize includes. altera_tse.h can be just before altera_utils.h

snip...

quoted

  static const struct of_device_id altera_tse_ids[] = {
+	{ .compatible = "altr,tse-msgdma-2.0",
+		.data = &altera_dtype_prefetcher, },
  	{ .compatible = "altr,tse-msgdma-1.0", .data = &altera_dtype_msgdma, },
  	{ .compatible = "altr,tse-1.0", .data = &altera_dtype_sgdma, },
  	{ .compatible = "ALTR,tse-1.0", .data = &altera_dtype_sgdma, },

Hmm. I'm not sure you sent the right version - this looks very similar 
to v1.

Yes, something went wrong here.  I must have messed something up when playing
with git.

--dalon