Enabling write-combining may also enable read reordering. The BIU is
only guaranteed to read from a 128-bit CSR or 64-bit SRAM word when
the host reads from its lowest address; otherwise the BIU may use the
latched value. Therefore we need to reinstate the read memory
barriers after the first read operation for each CSR or SRAM word.
Signed-off-by; Ben Hutchings <bhutchings@solarflare.com>
Based on work by Neil Turton <nturton@solarflare.com> and
Kieran Mansley <kmansley@solarflare.com>.
The BIU has now been verified to handle 3- and 4-dword writes within a
single 128-bit register correctly. This means we can enable write-
combining and only insert write barriers between writes to distinct
registers.
This has been observed to save about 0.5 us when pushing a TX
descriptor to an empty TX queue.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
It is not necessary to serialise writes to the paged 128-bit
registers. However, if we don't then we must always write the last
dword separately, not as part of a qword write.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Document exactly which registers and functions have special behaviour,
and why races on writes to descriptor pointers are safe.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
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: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While we're at it, use type suffixes of 'd', 'q' and 'o', consistent
with register type names.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
