The coalesce settings behave badly when changing just one value:

... # ethtool -c eth0
rx-usecs: 249
... # ethtool -C eth0 tx-usecs 250
... # ethtool -c eth0
rx-usecs: 248

This occurs due to rounding errors when calculating the microseconds
value - the divisons round down.  This causes (eg) the rx-usecs to
decrease by one every time the tx-usecs value is set as per the above.

Fix this by making the divison round-to-nearest.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The MAC is capable of RGMII mode and that is probably a more typical
connection type than GMII today (eg it is used by Marvell Reference
designs for several SOCs). Let DT users specify the standard

   phy-connection-type = "rgmii-id";

On a phy node.
Signed-off-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is no need to clk_disable_unprepare(dev->clk)
before it was initialized.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We get 2 warnings when building kernel with W=1:
drivers/net/ethernet/marvell/mvneta.c:639:27: warning: no previous prototype for 'mvneta_get_stats64' [-Wmissing-prototypes]
drivers/net/ethernet/marvell/mvneta.c:3529:5: warning: no previous prototype for 'mvneta_ethtool_set_link_ksettings' [-Wmissing-prototypes]

In fact, these two functions are only used in the file in which they are
declared and don't need a declaration, but can be made static.
so this patch marks these functions with 'static'.
Signed-off-by: NBaoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The IS_ENABLED() macro checks if a Kconfig symbol has been enabled either
built-in or as a module, use that macro instead of open coding the same.

Using the macro makes the code more readable by helping abstract away some
of the Kconfig built-in and module enable details.
Signed-off-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: netdev@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160818125731.27256-9-bigeasy@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Update the sky2 driver to pass number of packets done to NAPI.
The driver was never updated when napi_complete_done was added.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ethtool api {get|set}_settings is deprecated.
We move the mvneta driver to new api {get|set}_link_ksettings.

We use the generic function phy_ethtool_get_link_ksettings,
and update old mvneta_ethtool_set_settings to the new api.
Signed-off-by: NPhilippe Reynes <tremyfr@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The private structure contain a pointer to phydev, but the structure
net_device already contain such pointer. So we can remove the pointer
phy_dev in the private structure, and update the driver to use the
one contained in struct net_device.
Signed-off-by: NPhilippe Reynes <tremyfr@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

of_node_put needs to be called when the device node which is got
from of_parse_phandle has finished using.
Signed-off-by: NPeter Chen <peter.chen@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

of_node_put needs to be called when the device node which is got
from of_parse_phandle has finished using.
Signed-off-by: NPeter Chen <peter.chen@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

of_node_put needs to be called when the device node which is got
from of_parse_phandle has finished using.
Signed-off-by: NPeter Chen <peter.chen@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are two generics functions phy_ethtool_{get|set}_link_ksettings,
so we can use them instead of defining the same code in the driver.
Signed-off-by: NPhilippe Reynes <tremyfr@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The private structure contain a pointer to phydev, but the structure
net_device already contain such pointer. So we can remove the pointer
phydev in the private structure, and update the driver to use the
one contained in struct net_device.
Signed-off-by: NPhilippe Reynes <tremyfr@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit aebea2ba ("net: mvneta: fix Tx interrupt delay") intended to
set coalescing threshold to a value guaranteeing interrupt generation
per each sent packet, so that buffers can be released with no delay.

In fact setting threshold to '1' was wrong, because it causes interrupt
every two packets. According to the documentation a reason behind it is
following - interrupt occurs once sent buffers counter reaches a value,
which is higher than one specified in MVNETA_TXQ_SIZE_REG(q). This
behavior was confirmed during tests. Also when testing the SoC working
as a NAS device, better performance was observed with int-per-packet,
as it strongly depends on the fact that all transmitted packets are
released immediately.

This commit enables NETA controller work in interrupt per sent packet mode
by setting coalescing threshold to 0.
Signed-off-by: NDmitri Epshtein <dima@marvell.com>
Signed-off-by: NMarcin Wojtas <mw@semihalf.com>
Cc: <stable@vger.kernel.org> # v3.10+
Fixes aebea2ba ("net: mvneta: fix Tx interrupt delay")
Acked-by: NWilly Tarreau <w@1wt.eu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If mvneta_mdio_probe() fails, a kernel warning is triggered due to
missing cleanup in the error path.  Add the necessary cleanup.

------------[ cut here ]------------
WARNING: CPU: 1 PID: 281 at kernel/irq/manage.c:1814 __free_percpu_irq+0xfc/0x130
percpu IRQ 38 still enabled on CPU0!
Modules linked in: bnep bluetooth xhci_plat_hcd xhci_hcd marvell_cesa armada_thermal des_generic ehci_orion mcp3021 spi_orion sfp mdio_i2c evbug fuse
CPU: 1 PID: 281 Comm: connmand Not tainted 4.7.0-rc2+ #53
Hardware name: Marvell Armada 380/385 (Device Tree)
Backtrace:
[<c0013488>] (dump_backtrace) from [<c00137d0>] (show_stack+0x18/0x1c)
 r6:60010093 r5:ffffffff r4:00000000 r3:dc8ba500
[<c00137b8>] (show_stack) from [<c02c6fe0>] (dump_stack+0xa4/0xdc)
[<c02c6f3c>] (dump_stack) from [<c002d4ec>] (__warn+0xd8/0x104)
 r6:c081e6a0 r5:00000000 r4:edfe5d50 r3:dc8ba500
[<c002d414>] (__warn) from [<c002d5d0>] (warn_slowpath_fmt+0x40/0x48)
 r10:a0010013 r8:c09356f8 r7:00000026 r6:ef11a260 r5:edd7b980 r4:ef11a200
[<c002d594>] (warn_slowpath_fmt) from [<c008c8e0>] (__free_percpu_irq+0xfc/0x130)
 r3:00000026 r2:c081e7ac
[<c008c7e4>] (__free_percpu_irq) from [<c008c95c>] (free_percpu_irq+0x48/0x74)
 r10:00008914 r8:00000000 r7:ffffffed r6:c09356f8 r5:00000026 r4:ef11a200
[<c008c914>] (free_percpu_irq) from [<c043dd70>] (mvneta_open+0x118/0x134)
 r6:ffffffed r5:ef01e640 r4:ef01e000 r3:ef01e000
[<c043dc58>] (mvneta_open) from [<c055f5b4>] (__dev_open+0xa4/0x108)
 r7:ef01e030 r6:c06ff3d8 r5:ffff9003 r4:ef01e000
[<c055f510>] (__dev_open) from [<c055f844>] (__dev_change_flags+0x94/0x150)
 r7:00001002 r6:00000001 r5:ffff9003 r4:ef01e000
[<c055f7b0>] (__dev_change_flags) from [<c055f938>] (dev_change_flags+0x20/0x50)
 r8:00000000 r7:c09334c8 r6:00001002 r5:00000148 r4:ef01e000 r3:00008914
[<c055f918>] (dev_change_flags) from [<c05de044>] (devinet_ioctl+0x6f4/0x7e0)
 r8:00000000 r7:c09334c8 r6:00000000 r5:ee87200c r4:00000000 r3:00008914
[<c05dd950>] (devinet_ioctl) from [<c05e0168>] (inet_ioctl+0x1b8/0x1c8)
 r10:beb4499c r9:edfe4000 r8:ecf13280 r7:c096cf00 r6:beb4499c r5:eef7c240
 r4:00008914
[<c05dffb0>] (inet_ioctl) from [<c053c898>] (sock_ioctl+0x78/0x300)
[<c053c820>] (sock_ioctl) from [<c0155ecc>] (do_vfs_ioctl+0x98/0xa60)
 r7:00000011 r6:00008914 r5:00000011 r4:c01568d0
[<c0155e34>] (do_vfs_ioctl) from [<c01568d0>] (SyS_ioctl+0x3c/0x60)
 r10:00000000 r9:edfe4000 r8:beb4499c r7:00000011 r6:00008914 r5:ecf13280
 r4:ecf13280
[<c0156894>] (SyS_ioctl) from [<c000fe60>] (ret_fast_syscall+0x0/0x1c)
 r8:c0010004 r7:00000036 r6:00000011 r5:000a2978 r4:00000000 r3:00009003
---[ end trace 711f625d5b04b3a7 ]---
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Tested-by: NJon Nettleton <jon@solid-run.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are two generics functions phy_ethtool_{get|set}_link_ksettings,
so we can use them instead of defining the same code in the driver.
Signed-off-by: NPhilippe Reynes <tremyfr@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The private structure contain a pointer to phydev, but the structure
net_device already contain such pointer. So we can remove the pointer
phydev in the private structure, and update the driver to use the
one contained in struct net_device.
Signed-off-by: NPhilippe Reynes <tremyfr@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The spinlock used by the hwbm functions must be initialized by the
network driver. This commit fixes this lack and the following erros when
lockdep is enabled:

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
[<c010ff80>] (unwind_backtrace) from [<c010bd08>] (show_stack+0x10/0x14)
[<c010bd08>] (show_stack) from [<c032913c>] (dump_stack+0xb4/0xe0)
[<c032913c>] (dump_stack) from [<c01670e4>] (__lock_acquire+0x1f58/0x2060)
[<c01670e4>] (__lock_acquire) from [<c0167dec>] (lock_acquire+0xa4/0xd0)
[<c0167dec>] (lock_acquire) from [<c06f6650>] (_raw_spin_lock_irqsave+0x54/0x68)
[<c06f6650>] (_raw_spin_lock_irqsave) from [<c058e830>] (hwbm_pool_add+0x1c/0xdc)
[<c058e830>] (hwbm_pool_add) from [<c043f4e8>] (mvneta_bm_pool_use+0x338/0x490)
[<c043f4e8>] (mvneta_bm_pool_use) from [<c0443198>] (mvneta_probe+0x654/0x1284)
[<c0443198>] (mvneta_probe) from [<c03b894c>] (platform_drv_probe+0x4c/0xb0)
[<c03b894c>] (platform_drv_probe) from [<c03b7158>] (driver_probe_device+0x214/0x2c0)
[<c03b7158>] (driver_probe_device) from [<c03b72c4>] (__driver_attach+0xc0/0xc4)
[<c03b72c4>] (__driver_attach) from [<c03b5440>] (bus_for_each_dev+0x68/0x9c)
[<c03b5440>] (bus_for_each_dev) from [<c03b65b8>] (bus_add_driver+0x1a0/0x218)
[<c03b65b8>] (bus_add_driver) from [<c03b79cc>] (driver_register+0x78/0xf8)
[<c03b79cc>] (driver_register) from [<c01018f4>] (do_one_initcall+0x90/0x1dc)
[<c01018f4>] (do_one_initcall) from [<c0900de4>] (kernel_init_freeable+0x15c/0x1fc)
[<c0900de4>] (kernel_init_freeable) from [<c06eed90>] (kernel_init+0x8/0x114)
[<c06eed90>] (kernel_init) from [<c0107910>] (ret_from_fork+0x14/0x24)

Fixes: baa11ebc ("net: mvneta: Use the new hwbm framework")
Reported-by: NRussell King <rmk+kernel@armlinux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Update the pxa168_eth driver to use the dma_rmb/wmb calls instead of the
full barriers in order to improve performance: reduced 97ns/39ns on
average in tx/rx path on Marvell BG4CT platform.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since appropriate memory barriers are already there, use the relaxed
version to improve performance a bit.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I tried to fix this before, but my previous fix was incomplete
and we can still get the same link error in randconfig builds
because of the way that Kconfig treats the

	default y if MVNETA=y && MVNETA_BM_ENABLE

line that does not actually trigger when MVNETA_BM_ENABLE=m,
unlike I intended.
Changing the line to use MVNETA_BM_ENABLE!=n however has
the desired effect and hopefully makes all configurations
work as expected.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: 019ded3a ("net: mvneta: bm: clarify dependencies")
Acked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that mdiobus_scan() doesn't return NULL on failure anymore, this driver
no  longer needs to check for it...
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace all trans_start updates with netif_trans_update helper.
change was done via spatch:

struct net_device *d;
@@
- d->trans_start = jiffies
+ netif_trans_update(d)

Compile tested only.

Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-xtensa@linux-xtensa.org
Cc: linux1394-devel@lists.sourceforge.net
Cc: linux-rdma@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: MPT-FusionLinux.pdl@broadcom.com
Cc: linux-scsi@vger.kernel.org
Cc: linux-can@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-omap@vger.kernel.org
Cc: linux-hams@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Cc: b.a.t.m.a.n@lists.open-mesh.org
Cc: linux-bluetooth@vger.kernel.org
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NFelipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: NMugunthan V N <mugunthanvnm@ti.com>
Acked-by: NAntonio Quartulli <a@unstable.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit 3b9d6da6 ("cpu/hotplug: Fix rollback during error-out
in __cpu_disable()") it is ensured that callbacks of CPU_ONLINE and
CPU_DOWN_PREPARE are processed on the hotplugged CPU. Due to this SMP
function calls are no longer required.

Replace smp_call_function_single() with a direct call to
mvneta_percpu_enable() or mvneta_percpu_disable(). The functions do
not require to be called with interrupts disabled, therefore the
smp_call_function_single() calling convention is not preserved.

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: netdev@vger.kernel.org
Signed-off-by: NAnna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since mdiobus_scan() returns either an error code or NULL on error, the
driver should check  for both,  not only for NULL, otherwise a crash is
imminent...
Reported-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After enabling per-cpu processing it appeared that under heavy load
changing MTU can result in blocking all port's interrupts and
transmitting data is not possible after the change.

This commit fixes above issue by disabling percpu interrupts for the
time, when TXQs and RXQs are reconfigured.
Signed-off-by: NMarcin Wojtas <mw@semihalf.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

L1_CACHE_BYTES may not be the real cacheline size, use cache_line_size
to determine the cacheline size in runtime.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Suggested-by: NMarcin Wojtas <mw@semihalf.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

L1_CACHE_BYTES may not be the real cacheline size, use cache_line_size
to determine the cacheline size in runtime.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Suggested-by: NMarcin Wojtas <mw@semihalf.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is to fix the following maybe-uninitialized warning:

drivers/net/ethernet/marvell/mvpp2.c:6007:18: warning: 'err' may be
used uninitialized in this function [-Wmaybe-uninitialized]
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The mvneta is also used in some Marvell berlin family SoCs which may
have 64bytes cacheline size. Replace the MVNETA_CPU_D_CACHE_LINE_SIZE
usage with L1_CACHE_BYTES.

And since dma_alloc_coherent() is always cacheline size aligned, so
remove the align checks.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The mvpp2 ip maybe used in SoCs which may have have 64bytes cacheline
size. Replace the MVPP2_CPU_D_CACHE_LINE_SIZE with L1_CACHE_BYTES.

And since dma_alloc_coherent() is always cacheline size aligned, so
remove the align checks.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

MVNETA_BM has a dependency on MVNETA, so we can only select the former
if the latter is enabled. However, the code dependency is the reverse:
The mvneta module can call into the mvneta_bm module, so mvneta cannot
be a built-in if mvneta_bm is a module, or we get a link error:

drivers/net/built-in.o: In function `mvneta_remove':
drivers/net/ethernet/marvell/mvneta.c:4211: undefined reference to `mvneta_bm_pool_destroy'
drivers/net/built-in.o: In function `mvneta_bm_update_mtu':
drivers/net/ethernet/marvell/mvneta.c:1034: undefined reference to `mvneta_bm_bufs_free'

This avoids the problem by further clarifying the dependency so that
MVNETA_BM is a silent Kconfig option that gets turned on by the
new MVNETA_BM_ENABLE option. This way both the core HWBM module and
the MVNETA_BM code are always built-in when needed.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Fixes: dc35a10f ("net: mvneta: bm: add support for hardware buffer management")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some literal values are actually already defined by macros, so let's use
them.

[gregory.clement@free-electrons.com: split intial commit in two
individual changes]
Signed-off-by: NDmitri Epshtein <dima@marvell.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This commit corrects error printing when shutting down the port.

[gregory.clement@free-electrons.com: split initial commit in two
individual changes]
Signed-off-by: NDmitri Epshtein <dima@marvell.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Function eth_prepare_mac_addr_change() is called as part of MAC
address change. This function check if interface is running.
To enable change MAC address when interface is running:
IFF_LIVE_ADDR_CHANGE flag must be set to dev->priv_flags field

Fixes: c5aff182 ("net: mvneta: driver for Marvell Armada 370/XP
network unit")
Cc: stable@vger.kernel.org
Signed-off-by: NDmitri Epshtein <dima@marvell.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the previous patch, the spinlock was not initialized. While it didn't
cause any trouble yet it could be a problem to use it uninitialized.

The most annoying part was the critical section protected by the spinlock
in mvneta_stop(). Some of the functions could sleep as pointed when
activated CONFIG_DEBUG_ATOMIC_SLEEP. Actually, in mvneta_stop() we only
need to protect the is_stopped flagged, indeed the code of the notifier
for CPU online is protected by the same spinlock, so when we get the
lock, the notifer work is done.
Reported-by: NPatrick Uiterwijk <patrick@puiterwijk.org>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The mvneta_percpu_notifier() hotplug callback lacks handling of the
CPU_DOWN_FAILED case. That means, if CPU_DOWN_PREPARE failes, the
driver is not well configured on the CPU.

Add handling for CPU_DOWN_FAILED[_FROZEN] hotplug notifier transition
to setup the driver.

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: netdev@vger.kernel.org
Signed-off-by: NAnna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that the hardware buffer management framework had been introduced,
let's use it.
Tested-by: NSebastian Careba <nitroshift@yahoo.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Buffer manager (BM) is a dedicated hardware unit that can be used by all
ethernet ports of Armada XP and 38x SoC's. It allows to offload CPU on RX
path by sparing DRAM access on refilling buffer pool, hardware-based
filling of descriptor ring data and better memory utilization due to HW
arbitration for using 'short' pools for small packets.

Tests performed with A388 SoC working as a network bridge between two
packet generators showed increase of maximum processed 64B packets by
~20k (~555k packets with BM enabled vs ~535 packets without BM). Also
when pushing 1500B-packets with a line rate achieved, CPU load decreased
from around 25% without BM to 20% with BM.

BM comprise up to 4 buffer pointers' (BP) rings kept in DRAM, which
are called external BP pools - BPPE. Allocating and releasing buffer
pointers (BP) to/from BPPE is performed indirectly by write/read access
to a dedicated internal SRAM, where internal BP pools (BPPI) are placed.
BM hardware controls status of BPPE automatically, as well as assigning
proper buffers to RX descriptors. For more details please refer to
Functional Specification of Armada XP or 38x SoC.

In order to enable support for a separate hardware block, common for all
ports, a new driver has to be implemented ('mvneta_bm'). It provides
initialization sequence of address space, clocks, registers, SRAM,
empty pools' structures and also obtaining optional configuration
from DT (please refer to device tree binding documentation). mvneta_bm
exposes also a necessary API to mvneta driver, as well as a dedicated
structure with BM information (bm_priv), whose presence is used as a
flag notifying of BM usage by port. It has to be ensured that mvneta_bm
probe is executed prior to the ones in ports' driver. In case BM is not
used or its probe fails, mvneta falls back to use software buffer
management.

A sequence executed in mvneta_probe function is modified in order to have
an access to needed resources before possible port's BM initialization is
done. According to port-pools mapping provided by DT appropriate registers
are configured and the buffer pools are filled. RX path is modified
accordingly. Becaues the hardware allows a wide variety of configuration
options, following assumptions are made:
* using BM mechanisms can be selectively disabled/enabled basing
  on DT configuration among the ports
* 'long' pool's single buffer size is tied to port's MTU
* using 'long' pool by port is obligatory and it cannot be shared
* using 'short' pool for smaller packets is optional
* one 'short' pool can be shared among all ports

This commit enables hardware buffer management operation cooperating with
existing mvneta driver. New device tree binding documentation is added and
the one of mvneta is updated accordingly.

[gregory.clement@free-electrons.com: removed the suspend/resume part]
Signed-off-by: NMarcin Wojtas <mw@semihalf.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>