Merge branch 'mvneta-hwbm'

Gregory CLEMENT says:

====================
API set for HW Buffer management

This is the sixth version of the API set for HW Buffer management (that was
initially submitted here:
http://thread.gmane.org/gmane.linux.kernel/2125152).

This version is just a rebasing onto the last net-next. I also added
the Tested-by flag from Sebastian Careba : "The patch set applies
successfully and it works well, no more Samba issues any longer".

For the record in the previous versions I made the following changes:
v4 -> v5:
- Add a field with the size of the buffer of the pool was added. It
  then allow to fix some misused size in the mvneta_bm code when using
  the new framework.

- Add a new patch from Marcin for sram allowing to require
  non-bufferable access to the memory. It was needed for the hardware
  buffer management of the mvneta.

- Fix the build issue notified by the 0-day builder when building the
  drivers as module.

v3 -> v4
- Fix build issue when HWBM is not selected

v2 -> v3
- Make a HWBM and a SWBM version of the mvneta_rx() function in order
  to reduce the the conditional code. Kept a condition inside the
  mvneta_poll because specializing this function would have means
  duplicating 95% of the code.

- Put back the register_netdev() call at the end of the mvneta_probe()
  function. In order to have a unique ID for each port, just used a
  global variable in the driver.

- Added a fix from Marcin in the "net: mvneta: bm: add support for
  hardware buffer management" patch: "when dropping packets, only
  buffer pointers passed from BM to descriptors have to be returned to
  the pool. In submitted version after closing the port and
  mvneta_rxq_deinit(), it was very likely that a lot of fake buffers
  are added to the pool, because all descriptors took part in
  iteration."

- Removed the select MVNETA_BM from the Kconfig, it will let the user
  the choice to use not use it if they want.

v1 -> v2
- The hardware buffer management helpers are no more built by default
  and now depend on a hidden config symbol which has to be selected
  by the driver if needed
- The hwbm_pool_refill() and hwbm_pool_add() now receive a gfp_t as
  argument allowing the caller to specify the flag it needs.
- buf_num is now tested to ensure there is no wrapping
- A spinlock has been added to protect the hwbm_pool_add() function in
  SMP or irq context.
- used pr_warn instead of pr_debug in case of errors.
- fixed the mvneta implementation by returning the buffer to the pool
  at various place instead of ignoring it.
- Squashed "bus: mvenus-mbus: Fix size test for
   mvebu_mbus_get_dram_win_info" into bus: mvebu-mbus: provide api for
   obtaining IO and DRAM window information.
- Added my signed-otf-by on all the patches as submitter of the series.
- Renamed the dts patches with the pattern "ARM: dts: platform:"
- Removed the patch "ARM: mvebu: enable SRAM support in
  mvebu_v7_defconfig" of this series and already applied it
- Modified the order of the patches.

In order to ease the test the branch mvneta-BM-framework-v6 is
available at git@github.com:MISL-EBU-System-SW/mainline-public.git.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 91 insertions, 0 deletions

diff --git a/net/Kconfig b/net/Kconfig
index 10640d5f8bee..e13449870d06 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -253,6 +253,9 @@ config XPS
 	depends on SMP
 	default y
 
+config HWBM
+       bool
+
 config SOCK_CGROUP_DATA
 	bool
 	default n
diff --git a/net/core/Makefile b/net/core/Makefile
index 014422e2561f..d6508c2ddca5 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -25,4 +25,5 @@ obj-$(CONFIG_CGROUP_NET_PRIO) += netprio_cgroup.o
 obj-$(CONFIG_CGROUP_NET_CLASSID) += netclassid_cgroup.o
 obj-$(CONFIG_LWTUNNEL) += lwtunnel.o
 obj-$(CONFIG_DST_CACHE) += dst_cache.o
+obj-$(CONFIG_HWBM) += hwbm.o
 obj-$(CONFIG_NET_DEVLINK) += devlink.o
diff --git a/net/core/hwbm.c b/net/core/hwbm.c
new file mode 100644
index 000000000000..941c28486896
--- /dev/null
+++ b/net/core/hwbm.c
@@ -0,0 +1,87 @@
+/* Support for hardware buffer manager.
+ *
+ * Copyright (C) 2016 Marvell
+ *
+ * Gregory CLEMENT <gregory.clement@free-electrons.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/skbuff.h>
+#include <net/hwbm.h>
+
+void hwbm_buf_free(struct hwbm_pool *bm_pool, void *buf)
+{
+	if (likely(bm_pool->frag_size <= PAGE_SIZE))
+		skb_free_frag(buf);
+	else
+		kfree(buf);
+}
+EXPORT_SYMBOL_GPL(hwbm_buf_free);
+
+/* Refill processing for HW buffer management */
+int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp)
+{
+	int frag_size = bm_pool->frag_size;
+	void *buf;
+
+	if (likely(frag_size <= PAGE_SIZE))
+		buf = netdev_alloc_frag(frag_size);
+	else
+		buf = kmalloc(frag_size, gfp);
+
+	if (!buf)
+		return -ENOMEM;
+
+	if (bm_pool->construct)
+		if (bm_pool->construct(bm_pool, buf)) {
+			hwbm_buf_free(bm_pool, buf);
+			return -ENOMEM;
+		}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hwbm_pool_refill);
+
+int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num, gfp_t gfp)
+{
+	int err, i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bm_pool->lock, flags);
+	if (bm_pool->buf_num == bm_pool->size) {
+		pr_warn("pool already filled\n");
+		return bm_pool->buf_num;
+	}
+
+	if (buf_num + bm_pool->buf_num > bm_pool->size) {
+		pr_warn("cannot allocate %d buffers for pool\n",
+			buf_num);
+		return 0;
+	}
+
+	if ((buf_num + bm_pool->buf_num) < bm_pool->buf_num) {
+		pr_warn("Adding %d buffers to the %d current buffers will overflow\n",
+			buf_num,  bm_pool->buf_num);
+		return 0;
+	}
+
+	for (i = 0; i < buf_num; i++) {
+		err = hwbm_pool_refill(bm_pool, gfp);
+		if (err < 0)
+			break;
+	}
+
+	/* Update BM driver with number of buffers added to pool */
+	bm_pool->buf_num += i;
+
+	pr_debug("hwpm pool: %d of %d buffers added\n", i, buf_num);
+	spin_unlock_irqrestore(&bm_pool->lock, flags);
+
+	return i;
+}
+EXPORT_SYMBOL_GPL(hwbm_pool_add);