When compiling with allmodconfig. early_console is already defined as an
extern global pointer. Need let it point to the object which we intend
to (like arm32 done).
Signed-off-by: NChen Gang <gang.chen@asianux.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch adds support for using earlyprintk with 8250/16550 UART
ports. The 8250/16550 UART can either have 8-bit or 32-bit aligned
registers which is HW vendor dependent.

Kernel args for 8-bit aligned regs: earlyprintk=uart8250-8bit,<phys_address>

Kernel args for 32-bit aligned regs: earlyprintk=uart8250-32bit,<phys_address>
Signed-off-by: NAnup Patel <anup.patel@linaro.org>
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Enable early_printk to use the FastModel semihosting to output
the early kernel messages. Works both for host and guest kernels.

To use this feature, pass "early_printk=smh" to the kernel.
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

This patch adds support for "earlyprintk=" parameter on the kernel
command line. The format is:

  earlyprintk=<name>[,<addr>][,<options>]

where <name> is the name of the (UART) device, e.g. "pl011", <addr> is
the I/O address. The <options> aren't currently used.

The mapping of the earlyprintk device is done very early during kernel
boot and there are restrictions on which functions it can call. A
special early_io_map() function is added which creates the mapping from
the pre-defined EARLY_IOBASE to the device I/O address passed via the
kernel parameter. The pgd entry corresponding to EARLY_IOBASE is
pre-populated in head.S during kernel boot.

Only PL011 is currently supported and it is assumed that the interface
is already initialised by the boot loader before the kernel is started.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>