Commit dcd83aaf authored by Timur Tabi's avatar Timur Tabi Committed by Greg Kroah-Hartman
Browse files

tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver 



The ePAPR embedded hypervisor specification provides an API for "byte
channels", which are serial-like virtual devices for sending and receiving
streams of bytes.  This driver provides Linux kernel support for byte
channels via three distinct interfaces:

1) An early-console (udbg) driver.  This provides early console output
through a byte channel.  The byte channel handle must be specified in a
Kconfig option.

2) A normal console driver.  Output is sent to the byte channel designated
for stdout in the device tree.  The console driver is for handling kernel
printk calls.

3) A tty driver, which is used to handle user-space input and output.  The
byte channel used for the console is designated as the default tty.

Signed-off-by: default avatarTimur Tabi <timur@freescale.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent fcb8ce5c

arch/powerpc/include/asm/udbg.h

+1 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ extern void __init udbg_init_40x_realmode(void); 
extern void __init udbg_init_cpm(void);

extern void __init udbg_init_usbgecko(void);

extern void __init udbg_init_wsp(void);

extern void __init udbg_init_ehv_bc(void);



#endif /* __KERNEL__ */

#endif /* _ASM_POWERPC_UDBG_H */

arch/powerpc/kernel/udbg.c

+2 −0
Original line number Diff line number Diff line
@@ -67,6 +67,8 @@ void __init udbg_early_init(void) 
	udbg_init_usbgecko();

#elif defined(CONFIG_PPC_EARLY_DEBUG_WSP)

	udbg_init_wsp();

#elif defined(CONFIG_PPC_EARLY_DEBUG_EHV_BC)

	udbg_init_ehv_bc();

#endif



#ifdef CONFIG_PPC_EARLY_DEBUG

drivers/tty/Kconfig

+34 −0
Original line number Diff line number Diff line
@@ -350,3 +350,37 @@ config TRACE_SINK 


	  If you select this option, you need to select

	  "Trace data router for MIPI P1149.7 cJTAG standard".



config PPC_EPAPR_HV_BYTECHAN

	tristate "ePAPR hypervisor byte channel driver"

	depends on PPC

	help

	  This driver creates /dev entries for each ePAPR hypervisor byte

	  channel, thereby allowing applications to communicate with byte

	  channels as if they were serial ports.



config PPC_EARLY_DEBUG_EHV_BC

	bool "Early console (udbg) support for ePAPR hypervisors"

	depends on PPC_EPAPR_HV_BYTECHAN

	help

	  Select this option to enable early console (a.k.a. "udbg") support

	  via an ePAPR byte channel.  You also need to choose the byte channel

	  handle below.



config PPC_EARLY_DEBUG_EHV_BC_HANDLE

	int "Byte channel handle for early console (udbg)"

	depends on PPC_EARLY_DEBUG_EHV_BC

	default 0

	help

	  If you want early console (udbg) output through a byte channel,

	  specify the handle of the byte channel to use.



	  For this to work, the byte channel driver must be compiled

	  in-kernel, not as a module.



	  Note that only one early console driver can be enabled, so don't

	  enable any others if you enable this one.



	  If the number you specify is not a valid byte channel handle, then

	  there simply will be no early console output.  This is true also

	  if you don't boot under a hypervisor at all.

drivers/tty/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -26,5 +26,6 @@ obj-$(CONFIG_ROCKETPORT) += rocket.o 
obj-$(CONFIG_SYNCLINK_GT)	+= synclink_gt.o

obj-$(CONFIG_SYNCLINKMP)	+= synclinkmp.o

obj-$(CONFIG_SYNCLINK)		+= synclink.o

obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o



obj-y += ipwireless/

drivers/tty/ehv_bytechan.c

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