target/linux/brcm47xx/patches-3.10/080-MIPS-Add-8250-16550-serial-early-printk-driver.patch

   1 commit 0a76092a63809a0e72e3e9552acadf42869c0293
   2 Author: Yoichi Yuasa <yuasa@linux-mips.org>
   3 Date:   Mon Feb 8 20:59:39 2010 +0900
   4
   5     MIPS: Add 8250/16550 serial early printk driver
   6
   7     Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
   8     Cc: linux-mips <linux-mips@linux-mips.org>
   9     Patchwork: https://patchwork.linux-mips.org/patch/947/
  10     Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  11
  12 --- a/arch/mips/Kconfig.debug
  13 +++ b/arch/mips/Kconfig.debug
  14 @@ -20,6 +20,14 @@ config EARLY_PRINTK
  15           doesn't cooperate with an X server. You should normally say N here,
  16           unless you want to debug such a crash.
  17
  18 +config EARLY_PRINTK_8250
  19 +       bool "8250/16550 and compatible serial early printk driver"
  20 +       depends on EARLY_PRINTK
  21 +       default n
  22 +       help
  23 +         If you say Y here, it will be possible to use a 8250/16550 serial
  24 +         port as the boot console.
  25 +
  26  config CMDLINE_BOOL
  27         bool "Built-in kernel command line"
  28         default n
  29 --- a/arch/mips/include/asm/setup.h
  30 +++ b/arch/mips/include/asm/setup.h
  31 @@ -5,6 +5,14 @@
  32
  33  extern void setup_early_printk(void);
  34
  35 +#ifdef CONFIG_EARLY_PRINTK_8250
  36 +extern void setup_8250_early_printk_port(unsigned long base,
  37 +       unsigned int reg_shift, unsigned int timeout);
  38 +#else
  39 +static inline void setup_8250_early_printk_port(unsigned long base,
  40 +       unsigned int reg_shift, unsigned int timeout) {}
  41 +#endif
  42 +
  43  extern void set_handler(unsigned long offset, void *addr, unsigned long len);
  44  extern void set_uncached_handler(unsigned long offset, void *addr, unsigned long len);
  45
  46 --- a/arch/mips/kernel/Makefile
  47 +++ b/arch/mips/kernel/Makefile
  48 @@ -84,6 +84,7 @@ obj-$(CONFIG_GPIO_TXX9)               += gpio_txx9.o
  49  obj-$(CONFIG_KEXEC)            += machine_kexec.o relocate_kernel.o crash.o
  50  obj-$(CONFIG_CRASH_DUMP)       += crash_dump.o
  51  obj-$(CONFIG_EARLY_PRINTK)     += early_printk.o
  52 +obj-$(CONFIG_EARLY_PRINTK_8250)        += early_printk_8250.o
  53  obj-$(CONFIG_SPINLOCK_TEST)    += spinlock_test.o
  54  obj-$(CONFIG_MIPS_MACHINE)     += mips_machine.o
  55
  56 --- /dev/null
  57 +++ b/arch/mips/kernel/early_printk_8250.c
  58 @@ -0,0 +1,66 @@
  59 +/*
  60 + *  8250/16550-type serial ports prom_putchar()
  61 + *
  62 + *  Copyright (C) 2010  Yoichi Yuasa <yuasa@linux-mips.org>
  63 + *
  64 + *  This program is free software; you can redistribute it and/or modify
  65 + *  it under the terms of the GNU General Public License as published by
  66 + *  the Free Software Foundation; either version 2 of the License, or
  67 + *  (at your option) any later version.
  68 + *
  69 + *  This program is distributed in the hope that it will be useful,
  70 + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  71 + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  72 + *  GNU General Public License for more details.
  73 + *
  74 + *  You should have received a copy of the GNU General Public License
  75 + *  along with this program; if not, write to the Free Software
  76 + *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  77 + */
  78 +#include <linux/io.h>
  79 +#include <linux/serial_core.h>
  80 +#include <linux/serial_reg.h>
  81 +
  82 +static void __iomem *serial8250_base;
  83 +static unsigned int serial8250_reg_shift;
  84 +static unsigned int serial8250_tx_timeout;
  85 +
  86 +void setup_8250_early_printk_port(unsigned long base, unsigned int reg_shift,
  87 +                                 unsigned int timeout)
  88 +{
  89 +       serial8250_base = (void __iomem *)base;
  90 +       serial8250_reg_shift = reg_shift;
  91 +       serial8250_tx_timeout = timeout;
  92 +}
  93 +
  94 +static inline u8 serial_in(int offset)
  95 +{
  96 +       return readb(serial8250_base + (offset << serial8250_reg_shift));
  97 +}
  98 +
  99 +static inline void serial_out(int offset, char value)
 100 +{
 101 +       writeb(value, serial8250_base + (offset << serial8250_reg_shift));
 102 +}
 103 +
 104 +void prom_putchar(char c)
 105 +{
 106 +       unsigned int timeout;
 107 +       int status, bits;
 108 +
 109 +       if (!serial8250_base)
 110 +               return;
 111 +
 112 +       timeout = serial8250_tx_timeout;
 113 +       bits = UART_LSR_TEMT | UART_LSR_THRE;
 114 +
 115 +       do {
 116 +               status = serial_in(UART_LSR);
 117 +
 118 +               if (--timeout == 0)
 119 +                       break;
 120 +       } while ((status & bits) != bits);
 121 +
 122 +       if (timeout)
 123 +               serial_out(UART_TX, c);
 124 +}