1. 23 1月, 2013 1 次提交
    • C
      arm64: Add simple earlyprintk support · 2475ff9d
      Catalin Marinas 提交于
      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>
      2475ff9d
  2. 17 9月, 2012 1 次提交