bgmac: driver for GBit MAC core on BCMA bus

BCMA is a Broadcom specific bus with devices AKA cores. All recent BCMA
based SoCs have gigabit ethernet provided by the GBit MAC core. This
patch adds driver for such a cores registering itself as a netdev. It
has been tested on a BCM4706 and BCM4718 chipsets.

In the kernel tree there is already b44 driver which has some common
things with bgmac, however there are many differences that has led to
the decision or writing a new driver:
1) GBit MAC cores appear on BCMA bus (not SSB as in case of b44)
2) There is 64bit DMA engine which differs from 32bit one
3) There is no CAM (Content Addressable Memory) in GBit MAC
4) We have 4 TX queues on GBit MAC devices (instead of 1)
5) Many registers have different addresses/values
6) RX header flags are also different

The driver in it's state is functional how, however there is of course
place for improvements:
1) Supporting more net_device_ops
2) SUpporting more ethtool_ops
3) Unaligned addressing in DMA
4) Writing separated PHY driver

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/bcma/driver_chipcommon_pmu.c

@@ -264,7 +264,7 @@ static u32 bcma_pmu_pll_clock_bcm4706(struct bcma_drv_cc *cc, u32 pll0, u32 m)
 }
 
 /* query bus clock frequency for PMU-enabled chipcommon */
-static u32 bcma_pmu_get_bus_clock(struct bcma_drv_cc *cc)
+u32 bcma_pmu_get_bus_clock(struct bcma_drv_cc *cc)
 {
 	struct bcma_bus *bus = cc->core->bus;
 
@@ -293,6 +293,7 @@ static u32 bcma_pmu_get_bus_clock(struct bcma_drv_cc *cc)
 	}
 	return BCMA_CC_PMU_HT_CLOCK;
 }
+EXPORT_SYMBOL_GPL(bcma_pmu_get_bus_clock);
 
 /* query cpu clock frequency for PMU-enabled chipcommon */
 u32 bcma_pmu_get_cpu_clock(struct bcma_drv_cc *cc)

drivers/net/ethernet/broadcom/Kconfig

@@ -130,4 +130,13 @@ config BNX2X_SRIOV
 	  Virtualization support in the 578xx and 57712 products. This
 	  allows for virtual function acceleration in virtual environments.
 
+config BGMAC
+	tristate "BCMA bus GBit core support"
+	depends on BCMA_HOST_SOC && HAS_DMA
+	---help---
+	  This driver supports GBit MAC and BCM4706 GBit MAC cores on BCMA bus.
+	  They can be found on BCM47xx SoCs and provide gigabit ethernet.
+	  In case of using this driver on BCM4706 it's also requires to enable
+	  BCMA_DRIVER_GMAC_CMN to make it work.
+
 endif # NET_VENDOR_BROADCOM

drivers/net/ethernet/broadcom/Makefile

@@ -9,3 +9,4 @@ obj-$(CONFIG_CNIC) += cnic.o
 obj-$(CONFIG_BNX2X) += bnx2x/
 obj-$(CONFIG_SB1250_MAC) += sb1250-mac.o
 obj-$(CONFIG_TIGON3) += tg3.o
+obj-$(CONFIG_BGMAC) += bgmac.o