[U-Boot] [PATCH 2/2] nios2: convert altera_jtag_uart to driver model

[Marek Vasut]

On Sunday, September 13, 2015 at 10:32:10 AM, Thomas Chou wrote:
> Convert altera_jtag_uart to driver model.
> 
> Signed-off-by: Thomas Chou <thomas at wytron.com.tw>

[...]

> -static int altera_jtag_serial_init(void)
> +static int altera_jtaguart_putc(struct udevice *dev, const char c)
>  {
> -	return 0;
> -}
> +	struct altera_jtaguart_platdata *plat = dev->platdata;
> +	struct altera_jtaguart_regs *const regs = plat->reg;
> 
> -static void altera_jtag_serial_putc(char c)
> -{
>  	while (1) {
> -		unsigned st = readl(&jtag->control);
> +		unsigned st = readl(&regs->control);
>  		if (NIOS_JTAG_WSPACE(st))
>  			break;
>  #ifdef CONFIG_ALTERA_JTAG_UART_BYPASS
>  		if (!(st & NIOS_JTAG_AC)) /* no connection */
> -			return;
> +			return 0;
>  #endif
> -		WATCHDOG_RESET();

Please keep those WATCHDOG_RESET() calls, they're needed in case you
do have a WDT on your board.

>  	}
> -	writel ((unsigned char)c, &jtag->data);
> +	writel((unsigned char)c, &regs->data);
> +
> +	return 0;
>  }

[...]

> -static int altera_jtag_serial_getc(void)
> +static int altera_jtaguart_getc(struct udevice *dev)
>  {
> -	int c;
> +	struct altera_jtaguart_platdata *plat = dev->platdata;
> +	struct altera_jtaguart_regs *const regs = plat->reg;
>  	unsigned val;
> 
> -	while (1) {
> -		WATCHDOG_RESET ();
> -		val = readl (&jtag->data);
> -		if (val & NIOS_JTAG_RVALID)
> -			break;
> -	}
> -	c = val & 0x0ff;
> -	return (c);
> +	while (!((val = readl(&regs->data)) & NIOS_JTAG_RVALID))

Ewww, this is ugly. Please expand it into something like the following,
for the sake of readability.

while (1) {
	val = readl()
	if (val & cond)
		break;
}

> +		;
> +
> +	return (val & 0xff);
>  }

Looks good otherwise, thanks ! :)

[...]