HOWTO: Enable UART1 for DM365EVM (Linux 2.6.32)

Here is my HOWTO for UART1 (DM365EVM & DVSDK4.02 & LINUX 2.6.32).

Note (DM365EVM rev.E): Three wires are soldered:

* TP49 (near Altera) = UART1_TX (instead of PWM1)

* RN3(5,6) = UART1_RX (instead of SPI4_SDO)

* C86(gnd) = GND

1. Patch some files in Linux:

1.1.  arch/arm/mach-davinci/include/mach/serial.h

Set two UARTS for DM365 and set correct UART1 addr.

#include <mach/hardware.h>

#define DAVINCI_UART0_BASE    (IO_PHYS + 0x20000)
 
#ifdef CONFIG_ARCH_DAVINCI_DM365
  #define DAVINCI_MAX_NR_UARTS    2
  #define DAVINCI_UART1_BASE    (IO_PHYS + 0x106000)
#else
  #define DAVINCI_MAX_NR_UARTS    3
  #define DAVINCI_UART1_BASE    (IO_PHYS + 0x20400)
  #define DAVINCI_UART2_BASE    (IO_PHYS + 0x20800)
#endif

...

1.2. arch/arm/mach-davinci/include/mach/dm365.h

Add new function prototype 'dm365_init_uart1_instead_spi'

... 
  void __init dm365_init_rtc(void);
  void __init dm365_init_uart1_instead_spi(void);
  void __init dm365_init_ks(struct davinci_ks_platform_data *pdata)
...


1.3. arch/arm/mach-davinci/dm365.c

Add 'dm365_init_uart1_instead_spi' realisation.

void __init dm365_init_uart1_instead_spi(void) {
    static void __iomem *SystemRegisters; //access to system registers via memory remap
    u32 regval; //Register value
    SystemRegisters=ioremap(DAVINCI_SYSTEM_MODULE_BASE,SECTION_SIZE);
    if(!SystemRegisters) {
        release_mem_region(DAVINCI_SYSTEM_MODULE_BASE,SECTION_SIZE);
        pr_err("ERROR: can't map DAVINCI_SYSTEM_MODULE_BASE\n");
        return;
    }
    regval= __raw_readl(SystemRegisters+0x0C); //Read PINMUX3
    regval=regval | 0x60000000;
    __raw_writel(regval,SystemRegisters+0x0C); //GIO25=UART1_TXD
    regval= __raw_readl(SystemRegisters+0x10); //Read PINMUX4
    regval=regval | 0x0000C000;
    __raw_writel(regval,SystemRegisters+0x10); //GIO34=UART1_RXD
    printk("UART1 enabled instead of SPI!\n");
}

1.4. arch/arm/mach-davinci/board-dm365-evm.c

Make some changes in 'dm365_evm_init'.

Move 'davinci_serial_init(&uart_config)' to the end of 'dm365_evm_init' function. And add some code before 'davinci_serial_init'.

Here is old:
static __init void dm365_evm_init(void)
{
    evm_init_i2c();
    davinci_serial_init(&uart_config); //Move this line to the end of func
...

Here is new (end of 'dm365_evm_init'):
...
#ifdef CONFIG_DAVINCI_DM365_UART1RXGIO34_UART1TXGIO25
    dm365_init_uart1_instead_spi();
#endif
    davinci_serial_init(&uart_config); //NEW POSITION!
}
//END OF 'dm365_evm_init'

1.5. arch/arm/mach-davinci/Kconfig

Add menuconfig for UART1 support.

Before THIS SECTION
  config DAVINCI_MUX
      bool "DAVINCI multiplexing support"
      depends on ARCH_DAVINCI

Add THIS SECTION
config DAVINCI_DM365_UART1RXGIO34_UART1TXGIO25
    bool "Enable UART1_RXD on GIO34 and UART1_TXD on GIO25"
    depends on ARCH_DAVINCI_DM365
    help
      GIO34/SPI4_SIMO/SPI4_SOMI/UART1_RXD
      GIO25/'SPI0_SCS[0]/PWM1/UART1_TXD
      Say Y here to select UART1_RXD and UART1_TXD on theese pins.
      See 'arch/arm/mach-davinci/dm365.c' for details.


2. Linux config
When configure Linux set
    CONFIG_DAVINCI_DM365_UART1RXGIO34_UART1TXGIO25=y
in config file.
If using menuconfig.. goto "System Type", "TI DaVinci Implementations", select "Enable UART1_RXD on GIO34 and UART_TXD on GIO25".

3. Rebuild Linux

4. Reboot board and test some message.

# dmesg | grep UART
UART1 enabled instead of SPI!

5.  Configure via ssty
# stty -F /dev/ttyS1 115200

Test current ssty.
# stty -F /dev/ttyS1
speed 115200 baud;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W;
lnext = ^V; flush = ^O; min = 1; time = 0;
-brkint -imaxbel


NOTE: It's not saved. 'stty' setup must be in your starting script!

6. TEST.
Open HOST TERMINAL (minicom or picocom) which is connected to board ttyS1 port.
Try this from board:
# cat > hello.txt << "EOF"
> Hello
> World!
> EOF
# cat hello.txt > /dev/ttyS1
HOST TERMINAL (minicom or picocom) must print:
Hello
World!

----
GOOD LUCK!!!