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path: root/drivers/net/ethernet/sfc/siena.c
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2015-08-28sfc: Allow driver to cope with a lower number of VIs than it needs for RSSShradha Shah
Previously, the driver would refuse to load if it couldn't secure enough VIs from the MC to fulfill its RSS requirements. This was causing probe to fail on later functions in configurations where we'd run out of VIs, such as having many VFs. This change allows the driver to load with fewer VIs, down to a minimum of 2. A warning will be printed saying that RSS requirements were not met, possibly affecting performance. efx->max_tx_channels needs to be set to avoid going down the failure path in efx_probe_nic() immediately in the loop after the probe() NIC-type function. Also, Set rc=ENOSPC when bombing out of efx_probe_nic due to lack of VIs. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-17siena: only report generic filters in get_ts_infoJacob Keller
CC: Solarflare linux maintainers <linux-net-drivers@solarflare.com> CC: Shradha Shah <sshah@solarflare.com> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2015-05-21sfc: set the MAC address using MC_CMD_VADAPTOR_SET_MACShradha Shah
Add a set_mac_address() NIC-type function for EF10 only, and use this to set the MAC address on the vadaptor. For Siena and earlier, the MAC address continues to be set by MC_CMD_SET_MAC; this is still called on EF10, and including a MAC address in this command has no effect. The sriov_mac_address_changed() NIC-type function is no longer needed on EF10, but it is needed for Siena where it is used to update the peer address of the PF for VFDI. Change this to use the new set_mac_address function pointer. efx_ef10_sriov_mac_address_changed() is no longer called, as VFs will try to change the MAC address on their vadaptor rather than trying to change to the context of the PF to alter the vport. When a VF is running in direct passthrough mode with MAC spoofing enabled, it will be able to change the MAC address on its vadaptor. In this case, there is a link to the PF, so find the correct VF in its ef10_vf array and update the MAC address. ndo_set_mac_address() can be called during driver unload while bonding, and in this case the device has already been stopped, so don't call efx_net_open() to restart it after reconfiguration. efx->port_enabled is set to false in efx_stop_port(), so it is indicator of whether the device needs to be restarted. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-09sfc: Bind the sfc driver to any available VF'sShradha Shah
Add the device ID of the VF to the PCI device ID table. Added a boolean flag is_vf in efx_nic_type to differentiate between a VF and PF at probe time. This flag is useful in later patches while setting MAC address specially in the PCI-passthrough case. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-09sfc: Add use of shared RSS contexts.Jon Cooper
Allow PFs to allocate shared RSS contexts if we exhaust our exclusive RSS contexts. Make VFs use shared RSS contexts in all cases. Spruce up error handling so that the shadow copy of the RSS table is updated after successful update, rather than in all cases, so that we report the actual contents of the RSS table after a failure to set it, rather than what we'd like it to be. Populate context_size parameter when vacuously allocating RSS context of size 1. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-09sfc: Prepare to bind the sfc driver to the VF.Shradha Shah
Added efx_nic_type structure for VF. Mapped a different BAR for VF as it uses BAR 0 for memory. Added functions sriov_init and sriov_fini. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-09sfc: create VEB vswitch and vport above default firmware setupDaniel Pieczko
Adds functions to allocate and free vswitches and vports; vadaptors are automatically allocated and freed when TX/RX queues are initialised and finalised. This vswitching structure is only created if the firmware supports it, so a check that full-featured firmware is running is performed first. If the MC resets, the vswitching infrastructure will need to be recreated, so mark the "must_probe_vswitching" flag when an MC reboot is detected. Don't try to create a vswitch if vf-count=0 This allocation of vswitches and vports does not currently support configuring VLAN tags, but that can be added in a future change. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-09sfc: Enable VF's via a write to the sysfs file sriov_numvfsShradha Shah
This patch adds support for the use of sriov_configure on EF10 to enable Virtual Functions while the driver is loaded. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-09sfc: Own header for nic-specific sriov functions, single instance of ↵Shradha Shah
netdev_ops and sriov removed from Falcon code By putting all the efx_{siena,ef10}_sriov_* declarations in {siena,ef10}_sriov.h, ensure they cannot be called from nic-generic code. Also fixes up an instance of this, where mcdi.c was calling efx_siena_sriov_flr. The single instance of netdev_ops should call general high level functions that can then call something adapter specific in efx_nic_type. We should only do adapter specialisation via efx_nic_type. Removal of sriov functionality from the Falcon code means that tests are needed for the presence of some callbacks. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-24net/ethernet/sfc: Don't use of_node_to_eeh_dev()Benjamin Herrenschmidt
This is deprecated, it forces the driver to hop via the OF node that may or may not exist, instead use pci_dev_to_eeh_dev() which is simpler. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Shradha Shah <sshah@solarflare.com>
2014-11-06sfc: Add NIC type operations to replace direct calls from efx.c into ↵Shradha Shah
siena_sriov.c Also add dummy functions where required to avoid NULL pointer dereference. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-11-06sfc: Rename implementations in siena_sriov.c to have a 'siena' prefixShradha Shah
Patch in preparation for the upcoming EF10 sriov support. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-11-06sfc: Move the current VF state from efx_nic into siena_nic_dataShradha Shah
This patch series provides a base and cleanup for the upcoming EF10 SRIOV support. This patch moves the VF state into siena_nic_data as a basis to save the VF state based on nic type. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-15sfc: add extra RX drop counters for nodesc_trunc and noskb_dropEdward Cree
Added a counter rx_noskb_drop for failure to allocate an skb. Summed the per-channel rx_nodesc_trunc counters earlier so that they can be included in rx_dropped. Signed-off-by: Edward Cree <ecree@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-16sfc:On MCDI timeout, issue an FLR (and mark MCDI to fail-fast)Edward Cree
When an MCDI command times out (whether or not we find it completed when we poll), call efx_mcdi_abandon(), which tells all subsequent MCDI calls to fail-fast, and queues up an FLR. Because an FLR doesn't lead to receiving any reboot even from the MC (unlike most other types of reset), we have to call efx_ef10_reset_mc_allocations. In efx_start_all(), if a reset (of any kind) is pending, we bail out. Without this, attempts to reconfigure (e.g. change mtu) can cause driver/mc state inconsistency if the first MCDI call triggers an FLR. For similar reasons, on EF10, in efx_reset_down(method=RESET_TYPE_MCDI_TIMEOUT), set the number of active queues to zero before calling efx_stop_all(). And, on farch, in efx_reset_up(method=RESET_TYPE_MCDI_TIMEOUT), set active_queues and flushes pending & outstanding to zero. efx_mcdi_mode_{poll,event}() should not take us out of fail-fast mode. Instead, this is done by efx_mcdi_reset() after the FLR completes. The new FLR reset_type RESET_TYPE_MCDI_TIMEOUT doesn't really fit into the hierarchy of reset 'scopes' whereby efx_reset() decides some resets subsume others. Thus, it uses separate logic. Also, fixed up some inconsistency around RESET_TYPE_MC_BIST, which was in the wrong place in that hierarchy. Signed-off-by: Shradha Shah <sshah@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-12sfc: Change efx_nic_type::rx_push_indir_table to push hash key as wellAndrew Rybchenko
The EF10 implementation already does this, and it makes more logical sense to group the RSS hash key and indirection table together. Rename the operation to rx_push_rss_config. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-12-12sfc: split setup of hardware timestamping into NIC-type operationDaniel Pieczko
I added efx_ptp_get_mode() to avoid moving the definition for efx_ptp_data, since the current PTP mode is needed for siena.c:siena_set_ptp_hwtstamp. [bwh: Also move the rx_filters mask, and add kernel-doc] Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-12-12sfc: Remove dependency of PTP on having a dedicated channelBen Hutchings
We need a dedicated channel on Siena to ensure we can match up the separate RX and timestamp events for each PTP packet. We won't do this for EF10 as timestamps are delivered inline. Pass a channel index of 0 to MC_CMD_PTP_OP_ENABLE when there is no dedicated channel. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-12-12sfc: Correct RX dropped count for drops while interface is downJon Cooper
We don't directly control RX ingress on Siena or any later controllers, and so we cannot prevent packets from entering the RX datapath while the RX queues are not set up. This results in the hardware incrementing RX_NODESC_DROP_CNT, but it's not an error and we should not include it in error stats. When bringing an interface up or down, pull (or wait for) stats and count the number of packets that were dropped while the interface was down. Subtract this from the reported RX dropped count. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-29sfc: Update copyright bannersBen Hutchings
Update the dates for files that have been added to in 2012-2013. Drop the 'Solarstorm' brand name that's still lingering here. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-29sfc: Make efx_mcdi_{init,fini}() call efx_mcdi_drv_attach()Ben Hutchings
This should be done during MCDI initialisation for any NIC. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-29sfc: Allow efx_nic_type::dimension_resources to failBen Hutchings
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-27sfc: Generalise packet hash lookup to support EF10 RX prefixJon Cooper
EF10 uses an entirely different RX prefix format from Falcon-arch. Extend struct efx_nic_type to describe this. [bwh: Also replace the magic numbers used for the Falcon-arch RX prefix] Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-27sfc: Add a function pointer to abstract write of host time into NIC shared ↵Laurence Evans
memory Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-27sfc: Delegate MAC/NIC statistic description to efx_nic_typeBen Hutchings
Various hardware statistics that are available for Siena are unavailable or meaningless for Falcon. Huntington adds further to the NIC-type-specific statistics, as it has different MAC blocks from Falcon/Siena. All NIC types still provide most statistics by DMA, and use little-endian byte order. Therefore: 1. Add some general utility functions for reporting hardware statistics, efx_nic_describe_stats() and efx_nic_update_stats(). 2. Add an efx_nic_type::describe_stats operation to get the number and names of statistics, implemented using efx_nic_describe_stats() 3. Change efx_nic_type::update_stats to store the core statistics (struct rtnl_link_stats64) or full statistics (array of u64) in a caller-provided buffer. Use efx_nic_update_stats() to aid in the implementation. 4. Rename struct efx_ethtool_stat to struct efx_sw_stat_desc and EFX_ETHTOOL_NUM_STATS to EFX_ETHTOOL_SW_STAT_COUNT. 5. Remove efx_nic::mac_stats and struct efx_mac_stats. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-27sfc: Move MTD operations into efx_nic_typeBen Hutchings
Merge the per-NIC-type MTD probe selection and struct efx_mtd_ops into struct efx_nic_type. Move the implementations into the appropriate source files. Several NVRAM functions are now only called from MTD operations which are now implemented in the same file (falcon.c or mcdi.c). There is no need for them to be extern, or to be defined at all if CONFIG_SFC_MTD is not enabled, so move them into the #ifdef CONFIG_SFC_MTD sections in those files. Most of the SPI-related definitions are also only used in falcon.c, so move them there. Put the remainder of spi.h into nic.h (which previously included it). Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-22sfc: Cleanup Falcon-arch simple MAC filter stateBen Hutchings
On Falcon we implement MAC filtering requested by the stack using the MAC wrapper's single unicast filter and multicast hash filter. Siena is very similar, though MAC configuration is mediated by the MC. Since MCDI operations may sleep, reconfiguration is deferred from ndo_set_rx_mode to a work item. However, it still updates the private variables describing the filter state synchronously. Contrary to comments, the later use of these variables is not protected using the address lock, resulting in race conditions. Move the state update to a new function efx_farch_filter_sync_rx_mode() and make the Falcon-arch MAC configuration functions call that, so that its use is consistently serialised by the mac_lock. Invert and rename the promiscuous flag to the more accurate unicast_filter, and comment that both this and multicast_hash are not used on EF10. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-22sfc: Make most filter operations NIC-type-specificBen Hutchings
Aside from accelerated RFS, there is almost nothing that can be shared between the filter table implementations for the Falcon architecture and EF10. Move the few shared functions into efx.c and rx.c and the rest into farch.c. Introduce efx_nic_type operations for the implementation and inline wrapper functions that call these. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Get rid of per-NIC-type phys_addr_channels and mem_map_sizeBen Hutchings
EF10 functions don't have a fixed BAR size, and the minimum is not large enough for all the queues we might want to allocate. We have to find out the BAR size at run-time, and therefore phys_addr_channels and mem_map_size cannot be defined per-NIC-type. Change efx_nic_type::mem_map_size to a function pointer which is called to find the wanted memory map size (before probe). Replace efx_nic_type::phys_addr_channels with efx_nic::max_channels, to be initialised by the probe function. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Add support for MCDI v2Ben Hutchings
MCDI v2 adds a second header dword with wider command and length fields. It also defines extra error codes. Change the fallback error number for unknown MCDI error codes from EIO to EPROTO. EIO is treated as indicating the MCDI transport has failed and we need to reset the function, which is rather drastic. v2 error codes and lengths don't fit into completion events, so for a v2-capable transport, always read the response header rather then using the event fields. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Move and rename Falcon/Siena common NIC operationsBen Hutchings
Add efx_nic_type operations for the many efx_nic functions that need to be implemented different on EF10. For now, change most of the existing efx_nic_*() functions into inline wrappers. As a later step, we may be able to improve branch prediction for operations used on the fast path by copying the pointers into each queue/channel structure. Move the Falcon/Siena implementations to new file farch.c and rename the functions and static data to use a prefix of 'efx_farch_'. Move efx_may_push_tx_desc() to nic.h, as the EF10 TX code will also use it. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Refactor queue teardown sequence to allow for EF10 flush behaviourBen Hutchings
Currently efx_stop_datapath() will try to flush our DMA queues (if DMA is enabled), then finalise software and hardware state for each queue. However, for EF10 we must ask the MC to finalise each queue, which implicitly starts flushing it, and then wait for the flush events. We therefore need to delegate more of this to the NIC type. Combine all the hardware operations into a new NIC-type operation efx_nic_type::fini_dmaq, and call this before tearing down the software state and buffers for all the DMA queues. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Rename Falcon-architecture register definitionsBen Hutchings
The EF10 architecture has a very different register layout from previous controllers, so we'll use separate files for the two sets of register definitions. Use 'farch' as an abbreviation for Falcon-architecture. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Add GFP flags to efx_nic_alloc_buffer() and make most callers allow ↵Ben Hutchings
blocking Most call sites for efx_nic_alloc_buffer() are part of the probe or reconfiguration paths and can allocate with GFP_KERNEL. A few others should use GFP_NOIO (I think). Only one is in atomic context and must use the current GFP_ATOMIC. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Make MCDI independent of SienaBen Hutchings
Move the lowest layer (transport) of the current MCDI code to per-NIC-type operations. Introduce a new structure and efx_nic member for MCDI-specific data. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Make efx_mcdi_init() call efx_mcdi_handle_assertion()Ben Hutchings
This should probably be done during MCDI initialisation for any NIC. Change efx_mcdi_init() to return an error code. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Collect all MCDI port functions into mcdi_port.cBen Hutchings
Collect together MCDI port functions from mcdi.c, mcdi_mac.c, mcdi_phy.c and siena.c. Rename the 'siena' functions accordingly. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Move efx_mcdi_mac_reconfigure() to siena.c and renameBen Hutchings
EF10 does not include a multicast hash filter, so this function is specific to Siena. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-08-21sfc: Move siena_reset_hw() and siena_map_reset_reason() into MCDI moduleBen Hutchings
These implementations should work for EF10 too. Rename them accordingly. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-06-12sfc: Store port number in private data, not net_device::dev_idBen Hutchings
We should not use net_device::dev_id to indicate the port number, as this affects the way the local part of IPv6 addresses is normally generated. This field was intended for use where multiple devices may share a single assigned MAC address and need to have different IPv6 addresses. Siena's two ports each have their own MAC addresses. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-07sfc: Enable RX DMA scattering where possibleBen Hutchings
Enable RX DMA scattering iff an RX buffer large enough for the current MTU will not fit into a single page and the NIC supports DMA scattering for kernel-mode RX queues. On Falcon and Siena, the RX_USR_BUF_SIZE field is used as the DMA limit for both all RX queues with scatter enabled. Set it to 1824, matching what Onload uses now. Maintain a statistic for frames truncated due to lack of descriptors (rx_nodesc_trunc). This is distinct from rx_frm_trunc which may be incremented when scattering is disabled and implies an over-length frame. Whenever an MTU change causes scattering to be turned on or off, update filters that point to the PF queues, but leave others unchanged, as VF drivers assume scattering is off. Add n_frags parameters to various functions, and make them iterate: - efx_rx_packet() - efx_recycle_rx_buffers() - efx_rx_mk_skb() - efx_rx_deliver() Make efx_handle_rx_event() responsible for updating efx_rx_queue::removed_count. Change the RX pipeline state to a starting ring index and number of fragments, and make __efx_rx_packet() responsible for clearing it. Based on earlier versions by David Riddoch and Jon Cooper. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2013-03-07sfc: Add AER and EEH support for SienaAlexandre Rames
The Linux side of EEH is triggered by MMIO reads, but this driver's data path does not issue any MMIO reads (except in legacy interrupt mode). Therefore add a monitor function to poll EEH periodically. When preparing to reset the device based on our own error detection, also poll EEH and defer to its recovery mechanism if appropriate. [bwh: Use a separate condition for the initial link poll; fix some style errors] Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2012-12-01sfc: Correctly initialise reset_method in siena_test_chip()Ben Hutchings
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2012-12-01sfc: Really disable flow control while flushingBen Hutchings
Receiving pause frames can block TX queue flushes. Earlier changes work around this by reconfiguring the MAC during flushes for VFs, but during flushes for the PF we would only change the fc_disable counter. Unless the MAC is reconfigured for some other reason during the flush (which I would not expect to happen) this had no effect at all. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2012-09-19sfc: Add support for IEEE-1588 PTPStuart Hodgson
Add PTP IEEE-1588 support and make accesible via the PHC subsystem. This work is based on prior code by Andrew Jackson Signed-off-by: Stuart Hodgson <smhodgson@solarflare.com> [bwh: - Add byte order conversion in efx_ptp_send_times() - Simplify conversion of PPS event times - Add the built-in vs module check to CONFIG_SFC_PTP dependencies] Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2012-07-17sfc: Fix interface statistics running backwardBen Hutchings
Some interface statistics are computed in such a way that they can sometimes decrease (and even underflow). Since the computed value will never be greater than the true value, we fix this by only storing the computed value when it increases. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2012-07-17sfc: Disable VF queues during register self-testBen Hutchings
Currently VF queues and drivers may remain active during this test. This could cause memory corruption or spurious test failures. Therefore we reset the port/function before running these tests on Siena. On Falcon this doesn't work: we have to do some additional initialisation before some blocks will work again. So refactor the reset/register-test sequence into an efx_nic_type method so efx_selftest() doesn't have to consider such quirks. In the process, fix another minor bug: Siena does not have an 'invisible' reset and the self-test currently fails to push the PHY configuration after resetting. Passing RESET_TYPE_ALL to efx_reset_{down,up}() fixes this. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2012-03-06sfc: Remove redundant function efx_nic_has_mc()Ben Hutchings
This function is now used in only one place, where it always returns true. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2012-02-16sfc: Add SR-IOV back-end support for SFC9000 familyBen Hutchings
On the SFC9000 family, each port has 1024 Virtual Interfaces (VIs), each with an RX queue, a TX queue, an event queue and a mailbox register. These may be assigned to up to 127 SR-IOV virtual functions per port, with up to 64 VIs per VF. We allocate an extra channel (IRQ and event queue only) to receive requests from VF drivers. There is a per-port limit of 4 concurrent RX queue flushes, and queue flushes may be initiated by the MC in response to a Function Level Reset (FLR) of a VF. Therefore, when SR-IOV is in use, we submit all flush requests via the MC. The RSS indirection table is shared with VFs, so the number of RX queues used in the PF is limited to the number of VIs per VF. This is almost entirely the work of Steve Hodgson, formerly shodgson@solarflare.com. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2012-02-16sfc: Allocate SRAM between buffer table and descriptor caches at init timeBen Hutchings
Each port has a block of 64-bit SRAM that is divided between buffer table and descriptor cache regions at initialisation time. Currently we use a fixed allocation, but it needs to be changed to support larger numbers of queues. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>