USB: musb: add musb support for AM35x

AM35x has musb interface and uses CPPI4.1 DMA engine.
Current patch supports only PIO mode. DMA support can be
added later once basic CPPI4.1 DMA patch is accepted.

Also added USB_MUSB_AM35X which is required to differentiate musb ips
between OMAP3x and AM35x. This config would be used to for below
purposes,
        - Select am35x.c instead of omap2430.c for compilation
          at drivers/usb/musb directory. Please note there are
          significant differneces in these two files as musb ip
          in quite different on AM35x.

	  Please note that in multi omap configuration only omap2430.c
	  file will get compiled and we would require to select only
	  AM35x based board config to compile am35x.c

        - Select workaround codes applicable for AM35x musb issues.
          one such workaround is for bytewise read issue on AM35x.

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/Kconfig

@@ -60,6 +60,17 @@ comment "OMAP 44xx high speed USB support"
 comment "Blackfin high speed USB Support"
 	depends on USB_MUSB_HDRC && ((BF54x && !BF544) || (BF52x && !BF522 && !BF523))
 
+config USB_MUSB_AM35X
+	bool
+	depends on USB_MUSB_HDRC && !ARCH_OMAP2430 && !ARCH_OMAP4
+	select NOP_USB_XCEIV
+	default MACH_OMAP3517EVM
+	help
+	  Select this option if your platform is based on AM35x. As
+	  AM35x has an updated MUSB with CPPI4.1 DMA so this config
+	  is introduced to differentiate musb ip between OMAP3x and
+	  AM35x platforms.
+
 config USB_TUSB6010
 	boolean "TUSB 6010 support"
 	depends on USB_MUSB_HDRC && !USB_MUSB_SOC
@@ -147,7 +158,7 @@ config USB_MUSB_HDRC_HCD
 config MUSB_PIO_ONLY
 	bool 'Disable DMA (always use PIO)'
 	depends on USB_MUSB_HDRC
-	default USB_TUSB6010 || ARCH_DAVINCI_DA8XX
+	default USB_TUSB6010 || ARCH_DAVINCI_DA8XX || USB_MUSB_AM35X
 	help
 	  All data is copied between memory and FIFO by the CPU.
 	  DMA controllers are ignored.

drivers/usb/musb/Makefile

@@ -12,7 +12,11 @@ musb_hdrc-$(CONFIG_ARCH_DAVINCI_DMx)		+= davinci.o
 musb_hdrc-$(CONFIG_ARCH_DAVINCI_DA8XX)		+= da8xx.o
 musb_hdrc-$(CONFIG_USB_TUSB6010)		+= tusb6010.o
 musb_hdrc-$(CONFIG_ARCH_OMAP2430)		+= omap2430.o
-musb_hdrc-$(CONFIG_ARCH_OMAP3430)		+= omap2430.o
+ifeq ($(CONFIG_USB_MUSB_AM35X),y)
+	musb_hdrc-$(CONFIG_ARCH_OMAP3430)	+= am35x.o
+else
+	musb_hdrc-$(CONFIG_ARCH_OMAP3430)	+= omap2430.o
+endif
 musb_hdrc-$(CONFIG_ARCH_OMAP4)			+= omap2430.o
 musb_hdrc-$(CONFIG_BF54x)			+= blackfin.o
 musb_hdrc-$(CONFIG_BF52x)			+= blackfin.o