Long before this driver went into mainline, it had support for
multiple TX queues per port, with lockless TX enabled.  Since Linux
did not know anything of this, filling up any hardware TX queue would
stop the core TX queue and multiple hardware TX queues could fill up
before the scheduler reacted.  Thus it was necessary to keep a count
of how many TX queues were stopped and to wake the core TX queue only
when all had free space again.

The driver also previously (ab)used the per-hardware-queue stopped
flag as a counter to deal with various things that can inhibit TX, but
it no longer does that.

Remove the per-channel tx_stop_count, tx_stop_lock and
per-hardware-queue stopped count and just use the networking core
queue state directly.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>

If we are using a legacy interrupt, our IRQ may be shared and our
interrupt handler may be called even though interrupts are disabled on
the NIC. When we change ring sizes, we reallocate the event queue and
the interrupt handler may use an invalid pointer when called for
another device's interrupt.

Maintain a legacy_irq_enabled flag and test that at the top of the
interrupt handler.  Note that this problem results from the need to
work around broken INT_ISR0 reads, and does not affect the legacy
interrupt handler for Falcon A1.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>

Whenever we add DMA descriptors to a TX ring and update the ring
pointer, the TX DMA engine must first read the new DMA descriptors and
then start reading packet data.  However, all released Solarflare 10G
controllers have a 'TX push' feature that allows us to reduce latency
by writing the first new DMA descriptor along with the pointer update.
This is only useful when the queue is empty.  The hardware should
ignore the pushed descriptor if the queue is not empty, but this check
is buggy, so we must do it in software.

In order to tell whether a TX queue is empty, we need to compare the
previous transmission count (write_count) and completion count
(read_count).  However, if we do that every time we update the ring
pointer then read_count may ping-pong between the caches of two CPUs
running the transmission and completion paths for the queue.
Therefore, we split the check for an empty queue between the
completion path and the transmission path:

- Add an empty_read_count field representing a point at which the
  completion path saw the TX queue as empty.
- Add an old_write_count field for use on the completion path.
- On the completion path, whenever read_count reaches or passes
  old_write_count the TX queue may be empty.  We then read
  write_count, set empty_read_count if read_count == write_count,
  and update old_write_count.
- On the transmission path, we read empty_read_count.  If it's set, we
  compare it with the value of write_count before the current set of
  descriptors was added.  If they match, the queue really is empty and
  we can use TX push.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>

Place the regularly updated fields (locks, MAC stats, etc.) on a
separate cache-line from fields which are mostly constant.  This
should reduce cache misses for access to the latter on the data path.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>

For some reason we failed to make this change when perm_addr was
introduced.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We only have direct access to MDIO on Falcon, so move this out of
struct efx_nic.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We only have direct access to SPI on Falcon, so move all this state
out of struct efx_nic.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make local functions and variable static. Do some rearrangement
of the string table stuff to put it where it gets used.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Acked-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Change "return (EXPR);" to "return EXPR;"

return is not a function, parentheses are not required.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SFN4111T never reached production and is not being used for internal
or customer testing.

Since we have no production Falcon boards using the SFT9001 or the
GMAC, remove support for them as well.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/sfc/filter.c: In function ‘efx_probe_filters’:
drivers/net/sfc/filter.c:422: error: implicit declaration of function ‘vmalloc’
drivers/net/sfc/filter.c:422: warning: assignment makes pointer from integer without a cast
drivers/net/sfc/filter.c: In function ‘efx_remove_filters’:
drivers/net/sfc/filter.c:442: error: implicit declaration of function ‘vfree’
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This requires some reorganisation of channel setup and teardown to
ensure that we can always roll-back a failed change.

Based on work by Steve Hodgson <shodgson@solarflare.com>
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Allow the ring size to be specified in non
   power-of-two sizes (for instance to limit
   the amount of receive buffers).
 - Automatically size the event queue.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This will allow for reallocation of channel structures and rings.

Change module parameter separate_tx_channels to be read-only, since we
now require its value to be constant.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation for changes to the way channels and queue structures
are allocated, revise the macros and functions used to look up and
iterator over them.

- Replace efx_for_each_tx_queue() with iteration over channels then TX
  queues
- Replace efx_for_each_rx_queue() with iteration over channels then RX
  queues (with one exception, shortly to be removed)
- Introduce efx_get_{channel,rx_queue,tx_queue}() functions to look up
  channels and queues by index
- Introduce efx_channel_get_{rx,tx}_queue() functions to look up a
  channel's queues
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit eedc765c merged changes from
net-2.6 that added and then removed efx_nic::port_num, which was also
added in net-next-2.6.  The end result should be that it is removed,
since it is now unused.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allow ethtool to query the number of RX rings, the fields used in RX
flow hashing and the hash indirection table.

Allow ethtool to update the RX flow hash indirection table.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We will use this hash key for Toeplitz IPv4 hashing too.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace EFX_ERR() with netif_err(), EFX_INFO() with netif_info(),
EFX_LOG() with netif_dbg() and EFX_TRACE() and EFX_REGDUMP() with
netif_vdbg().

Replace EFX_ERR_RL(), EFX_INFO_RL() and EFX_LOG_RL() using explicit
calls to net_ratelimit().

Implement the ethtool operations to get and set message level flags,
and add a 'debug' module parameter for the initial value.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This exposes the port number to userland through sysfs.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A single shared memory region used to communicate with firmware is
mapped into both PCI PFs of the SFC9020 and SFL9021.  Drivers must be
able to identify which port they are addressing in order to use the
correct sub-region.  Currently we use the PCI function number, but the
PCI address may be virtualised.  Use the CS_PORT_NUM register field
defined for just this purpose.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A single shared memory region used to communicate with firmware is
mapped into both PCI PFs of the SFC9020 and SFL9021.  Drivers must be
able to identify which port they are addressing in order to use the
correct sub-region.  Currently we use the PCI function number, but the
PCI address may be virtualised.  Use the CS_PORT_NUM register field
defined for just this purpose.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Insert a structure at the start of the shared page that
tracks the dma mapping refcnt. DMA into the next cache
line of the (shared) page (plus EFX_PAGE_IP_ALIGN).

When recycling a page, check the page refcnt. If the
page is otherwise unused, then resurrect the other
receive buffer that previously referenced the page.
Be careful not to overflow the receive ring, since we
can now resurrect n receive buffers in a row.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- Pull the loop handling into efx_init_rx_buffers_(skb|page)
- Remove rx_queue->buf_page, and associated clean up code
- Remove unmap_addr, since unmap_addr is trivially calculable

This will allow us to recycle discarded buffers directly
from efx_rx_packet(), since will never be in the middle of
splitting a page.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Ensure that efx_fast_push_rx_descriptors() must only run
from efx_process_channel() [NAPI], or when napi_disable()
has been executed.

Reimplement the slow fill by sending an event to the
channel, so that NAPI runs, and hanging the subsequent
fast fill off the event handler. Replace the sfc_refill
workqueue and delayed work items with a timer. We do
not need to stop this timer in efx_flush_all() because
it's safe to send the event always; receiving it will
be delayed until NAPI is restarted.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Formerly, efx_test_eventq_irq() assumed it was the only user of
driver generated events. Allow it to interoperate with other users.

We can create more than 16 channels, so align event codes with
a multiple of 256 not 16.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Create a core TX queue and 2 hardware TX queues for each channel.
If separate_tx_channels is set, create equal numbers of RX and TX
channels instead.

Rewrite the channel and queue iteration macros accordingly.
Eliminate efx_channel::used_flags as redundant.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is no need for this to be unsigned long; make it unsigned int.
It does need a line in kernel-doc, so add that.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

'Fatal' errors set an interrupt flag associated with a specific event
queue; only read the syndrome vector if we see that queue's flag set
(legacy interrupts) or in the interrupt handler for that queue (MSI).

Do not ignore an interrupt if the fatal error flag is set but specific
error flags are all zero.  Even if we don't schedule a reset, we must
respect the queue mask and rearm the appropriate event queues.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Earlier refactoring has made these inclusions unnecessary.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>