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authorMarcin Wojtas <mw@semihalf.com>2016-03-14 09:39:03 +0100
committerDavid S. Miller <davem@davemloft.net>2016-03-14 12:19:46 -0400
commitdc35a10f68d3781c2345d60b22103785985ca849 (patch)
tree608e0bfccf0237e5dae05bab9b3bec9f7a6b6492 /drivers/net/ethernet/marvell/Kconfig
parentf2900acea8018c4525ddaa86c7f7cd8afd3f0cc4 (diff)
downloadlinux-dc35a10f68d3781c2345d60b22103785985ca849.tar.bz2
net: mvneta: bm: add support for hardware buffer management
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: Marcin Wojtas <mw@semihalf.com> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/marvell/Kconfig')
-rw-r--r--drivers/net/ethernet/marvell/Kconfig13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/net/ethernet/marvell/Kconfig b/drivers/net/ethernet/marvell/Kconfig
index a1c862b4664d..ac6605c62f46 100644
--- a/drivers/net/ethernet/marvell/Kconfig
+++ b/drivers/net/ethernet/marvell/Kconfig
@@ -40,6 +40,19 @@ config MVMDIO
This driver is used by the MV643XX_ETH and MVNETA drivers.
+config MVNETA_BM
+ tristate "Marvell Armada 38x/XP network interface BM support"
+ depends on MVNETA
+ ---help---
+ This driver supports auxiliary block of the network
+ interface units in the Marvell ARMADA XP and ARMADA 38x SoC
+ family, which is called buffer manager.
+
+ This driver, when enabled, strictly cooperates with mvneta
+ driver and is common for all network ports of the devices,
+ even for Armada 370 SoC, which doesn't support hardware
+ buffer management.
+
config MVNETA
tristate "Marvell Armada 370/38x/XP network interface support"
depends on PLAT_ORION