cma: Add vc_cma driver to enable use of CMA

Signed-off-by: popcornmix <popcornmix@gmail.com>

vc_cma: Make the vc_cma area the default contiguous DMA area

vc_cma: Provide empty functions when module is not built

Providing empty functions saves the users from guarding the
function call with an #if clause.
Move __init markings from prototypes to functions.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

drivers/char/Kconfig

@@ -4,6 +4,8 @@
 
 menu "Character devices"
 
+source "drivers/char/broadcom/Kconfig"
+
 source "drivers/tty/Kconfig"
 
 config DEVMEM

drivers/char/Makefile

@@ -60,3 +60,4 @@ js-rtc-y = rtc.o
 
 obj-$(CONFIG_TILE_SROM)		+= tile-srom.o
 obj-$(CONFIG_XILLYBUS)		+= xillybus/
+obj-$(CONFIG_BRCM_CHAR_DRIVERS) += broadcom/

drivers/char/broadcom/Kconfig

@@ -0,0 +1,15 @@
+#
+# Broadcom char driver config
+#
+
+menuconfig BRCM_CHAR_DRIVERS
+	bool "Broadcom Char Drivers"
+	help
+	  Broadcom's char drivers
+
+config BCM_VC_CMA
+	bool "Videocore CMA"
+	depends on CMA && BRCM_CHAR_DRIVERS && BCM2708_VCHIQ
+	default n
+        help
+          Helper for videocore CMA access.

drivers/char/broadcom/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_BCM_VC_CMA)	+= vc_cma/

drivers/char/broadcom/vc_cma/Makefile

@@ -0,0 +1,14 @@
+ccflags-y  += -Wall -Wstrict-prototypes -Wno-trigraphs
+ccflags-y  += -Werror
+ccflags-y  += -Iinclude/linux/broadcom
+ccflags-y  += -Idrivers/misc/vc04_services
+ccflags-y  += -Idrivers/misc/vc04_services/interface/vchi
+ccflags-y  += -Idrivers/misc/vc04_services/interface/vchiq_arm
+
+ccflags-y  += -D__KERNEL__
+ccflags-y  += -D__linux__
+ccflags-y  += -Werror
+
+obj-$(CONFIG_BCM_VC_CMA) += vc-cma.o
+
+vc-cma-objs := vc_cma.o

include/linux/broadcom/vc_cma.h

@@ -0,0 +1,36 @@
+/*****************************************************************************
+* Copyright 2012 Broadcom Corporation.  All rights reserved.
+*
+* Unless you and Broadcom execute a separate written software license
+* agreement governing use of this software, this software is licensed to you
+* under the terms of the GNU General Public License version 2, available at
+* http://www.broadcom.com/licenses/GPLv2.php (the "GPL").
+*
+* Notwithstanding the above, under no circumstances may you combine this
+* software in any way with any other Broadcom software provided under a
+* license other than the GPL, without Broadcom's express prior written
+* consent.
+*****************************************************************************/
+
+#if !defined( VC_CMA_H )
+#define VC_CMA_H
+
+#include <linux/ioctl.h>
+
+#define VC_CMA_IOC_MAGIC 0xc5
+
+#define VC_CMA_IOC_RESERVE _IO(VC_CMA_IOC_MAGIC, 0)
+
+#ifdef __KERNEL__
+
+#ifdef CONFIG_BCM_VC_CMA
+void vc_cma_early_init(void);
+void vc_cma_reserve(void);
+#else
+static inline void vc_cma_early_init(void) { }
+static inline void vc_cma_reserve(void) { }
+#endif
+
+#endif
+
+#endif /* VC_CMA_H */