can: c_can: Added support for Bosch C_CAN controller

Bosch C_CAN controller is a full-CAN implementation which is compliant
to CAN protocol version 2.0 part A and B. Bosch C_CAN user manual can be
obtained from:

http://www.semiconductors.bosch.de/media/en/pdf/ipmodules_1/c_can/users_manual_c_can.pdf

This patch adds the support for this controller.
The following are the design choices made while writing the controller
driver:
1. Interface Register set IF1 has be used only in the current design.
2. Out of the 32 Message objects available, 16 are kept aside for RX
   purposes and the rest for TX purposes.
3. NAPI implementation is such that both the TX and RX paths function
   in polling mode.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/can/Kconfig

@@ -115,6 +115,8 @@ source "drivers/net/can/mscan/Kconfig"
 
 source "drivers/net/can/sja1000/Kconfig"
 
+source "drivers/net/can/c_can/Kconfig"
+
 source "drivers/net/can/usb/Kconfig"
 
 source "drivers/net/can/softing/Kconfig"

drivers/net/can/Makefile

@@ -13,6 +13,7 @@ obj-y				+= softing/
 
 obj-$(CONFIG_CAN_SJA1000)	+= sja1000/
 obj-$(CONFIG_CAN_MSCAN)		+= mscan/
+obj-$(CONFIG_CAN_C_CAN)		+= c_can/
 obj-$(CONFIG_CAN_AT91)		+= at91_can.o
 obj-$(CONFIG_CAN_TI_HECC)	+= ti_hecc.o
 obj-$(CONFIG_CAN_MCP251X)	+= mcp251x.o

drivers/net/can/c_can/Kconfig

@@ -0,0 +1,15 @@
+menuconfig CAN_C_CAN
+	tristate "Bosch C_CAN devices"
+	depends on CAN_DEV && HAS_IOMEM
+
+if CAN_C_CAN
+
+config CAN_C_CAN_PLATFORM
+	tristate "Generic Platform Bus based C_CAN driver"
+	---help---
+	  This driver adds support for the C_CAN chips connected to
+	  the "platform bus" (Linux abstraction for directly to the
+	  processor attached devices) which can be found on various
+	  boards from ST Microelectronics (http://www.st.com)
+	  like the SPEAr1310 and SPEAr320 evaluation boards.
+endif

drivers/net/can/c_can/Makefile

@@ -0,0 +1,8 @@
+#
+#  Makefile for the Bosch C_CAN controller drivers.
+#
+
+obj-$(CONFIG_CAN_C_CAN) += c_can.o
+obj-$(CONFIG_CAN_C_CAN_PLATFORM) += c_can_platform.o
+
+ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG