summaryrefslogtreecommitdiff
path: root/drivers/net/ethernet/sfc/io.h
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2012-12-12 18:07:07 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-12 18:07:07 -0800
commit6be35c700f742e911ecedd07fcc43d4439922334 (patch)
treeca9f37214d204465fcc2d79c82efd291e357c53c /drivers/net/ethernet/sfc/io.h
parente37aa63e87bd581f9be5555ed0ba83f5295c92fc (diff)
parent520dfe3a3645257bf83660f672c47f8558f3d4c4 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking changes from David Miller: 1) Allow to dump, monitor, and change the bridge multicast database using netlink. From Cong Wang. 2) RFC 5961 TCP blind data injection attack mitigation, from Eric Dumazet. 3) Networking user namespace support from Eric W. Biederman. 4) tuntap/virtio-net multiqueue support by Jason Wang. 5) Support for checksum offload of encapsulated packets (basically, tunneled traffic can still be checksummed by HW). From Joseph Gasparakis. 6) Allow BPF filter access to VLAN tags, from Eric Dumazet and Daniel Borkmann. 7) Bridge port parameters over netlink and BPDU blocking support from Stephen Hemminger. 8) Improve data access patterns during inet socket demux by rearranging socket layout, from Eric Dumazet. 9) TIPC protocol updates and cleanups from Ying Xue, Paul Gortmaker, and Jon Maloy. 10) Update TCP socket hash sizing to be more in line with current day realities. The existing heurstics were choosen a decade ago. From Eric Dumazet. 11) Fix races, queue bloat, and excessive wakeups in ATM and associated drivers, from Krzysztof Mazur and David Woodhouse. 12) Support DOVE (Distributed Overlay Virtual Ethernet) extensions in VXLAN driver, from David Stevens. 13) Add "oops_only" mode to netconsole, from Amerigo Wang. 14) Support set and query of VEB/VEPA bridge mode via PF_BRIDGE, also allow DCB netlink to work on namespaces other than the initial namespace. From John Fastabend. 15) Support PTP in the Tigon3 driver, from Matt Carlson. 16) tun/vhost zero copy fixes and improvements, plus turn it on by default, from Michael S. Tsirkin. 17) Support per-association statistics in SCTP, from Michele Baldessari. And many, many, driver updates, cleanups, and improvements. Too numerous to mention individually. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1722 commits) net/mlx4_en: Add support for destination MAC in steering rules net/mlx4_en: Use generic etherdevice.h functions. net: ethtool: Add destination MAC address to flow steering API bridge: add support of adding and deleting mdb entries bridge: notify mdb changes via netlink ndisc: Unexport ndisc_{build,send}_skb(). uapi: add missing netconf.h to export list pkt_sched: avoid requeues if possible solos-pci: fix double-free of TX skb in DMA mode bnx2: Fix accidental reversions. bna: Driver Version Updated to 3.1.2.1 bna: Firmware update bna: Add RX State bna: Rx Page Based Allocation bna: TX Intr Coalescing Fix bna: Tx and Rx Optimizations bna: Code Cleanup and Enhancements ath9k: check pdata variable before dereferencing it ath5k: RX timestamp is reported at end of frame ath9k_htc: RX timestamp is reported at end of frame ...
Diffstat (limited to 'drivers/net/ethernet/sfc/io.h')
-rw-r--r--drivers/net/ethernet/sfc/io.h43
1 files changed, 14 insertions, 29 deletions
diff --git a/drivers/net/ethernet/sfc/io.h b/drivers/net/ethernet/sfc/io.h
index 751d1ec112cc..96759aee1c6c 100644
--- a/drivers/net/ethernet/sfc/io.h
+++ b/drivers/net/ethernet/sfc/io.h
@@ -22,22 +22,21 @@
*
* Notes on locking strategy:
*
- * Most CSRs are 128-bit (oword) and therefore cannot be read or
- * written atomically. Access from the host is buffered by the Bus
- * Interface Unit (BIU). Whenever the host reads from the lowest
- * address of such a register, or from the address of a different such
- * register, the BIU latches the register's value. Subsequent reads
- * from higher addresses of the same register will read the latched
- * value. Whenever the host writes part of such a register, the BIU
- * collects the written value and does not write to the underlying
- * register until all 4 dwords have been written. A similar buffering
- * scheme applies to host access to the NIC's 64-bit SRAM.
+ * Many CSRs are very wide and cannot be read or written atomically.
+ * Writes from the host are buffered by the Bus Interface Unit (BIU)
+ * up to 128 bits. Whenever the host writes part of such a register,
+ * the BIU collects the written value and does not write to the
+ * underlying register until all 4 dwords have been written. A
+ * similar buffering scheme applies to host access to the NIC's 64-bit
+ * SRAM.
*
- * Access to different CSRs and 64-bit SRAM words must be serialised,
- * since interleaved access can result in lost writes or lost
- * information from read-to-clear fields. We use efx_nic::biu_lock
- * for this. (We could use separate locks for read and write, but
- * this is not normally a performance bottleneck.)
+ * Writes to different CSRs and 64-bit SRAM words must be serialised,
+ * since interleaved access can result in lost writes. We use
+ * efx_nic::biu_lock for this.
+ *
+ * We also serialise reads from 128-bit CSRs and SRAM with the same
+ * spinlock. This may not be necessary, but it doesn't really matter
+ * as there are no such reads on the fast path.
*
* The DMA descriptor pointers (RX_DESC_UPD and TX_DESC_UPD) are
* 128-bit but are special-cased in the BIU to avoid the need for
@@ -204,20 +203,6 @@ static inline void efx_reado_table(struct efx_nic *efx, efx_oword_t *value,
efx_reado(efx, value, reg + index * sizeof(efx_oword_t));
}
-/* Write a 32-bit CSR forming part of a table, or 32-bit SRAM */
-static inline void efx_writed_table(struct efx_nic *efx, efx_dword_t *value,
- unsigned int reg, unsigned int index)
-{
- efx_writed(efx, value, reg + index * sizeof(efx_oword_t));
-}
-
-/* Read a 32-bit CSR forming part of a table, or 32-bit SRAM */
-static inline void efx_readd_table(struct efx_nic *efx, efx_dword_t *value,
- unsigned int reg, unsigned int index)
-{
- efx_readd(efx, value, reg + index * sizeof(efx_dword_t));
-}
-
/* Page-mapped register block size */
#define EFX_PAGE_BLOCK_SIZE 0x2000