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Commit 67f4aaa2 authored by Michal Simek's avatar Michal Simek
Browse files

microblaze: Support early console on uart16550 



Early console support reuse setting from U-BOOT that's why
it is not necessary to setup baudrates, etc.

Signed-off-by: default avatarMichal Simek <monstr@monstr.eu>
parent 51f5fa50

arch/microblaze/Kconfig.debug

+1 −1
Original line number Original line Diff line number Diff line
@@ -10,7 +10,7 @@ source "lib/Kconfig.debug" 




config EARLY_PRINTK

config EARLY_PRINTK

	bool "Early printk function for kernel"

	bool "Early printk function for kernel"

	depends on SERIAL_UARTLITE_CONSOLE

	depends on SERIAL_UARTLITE_CONSOLE || SERIAL_8250_CONSOLE

	default n

	default n

	help

	help

	  This option turns on/off early printk messages to console.

	  This option turns on/off early printk messages to console.

arch/microblaze/include/asm/prom.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -27,6 +27,7 @@ 




/* Other Prototypes */

/* Other Prototypes */

extern int early_uartlite_console(void);

extern int early_uartlite_console(void);

extern int early_uart16550_console(void);





#ifdef CONFIG_PCI

#ifdef CONFIG_PCI

/*

/*

arch/microblaze/kernel/early_printk.c

+63 −0
Original line number Original line Diff line number Diff line
@@ -65,6 +65,50 @@ static struct console early_serial_uartlite_console = { 
};

};

#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */

#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */





#ifdef CONFIG_SERIAL_8250_CONSOLE

static void early_printk_uart16550_putc(char c)

{

	/*

	 * Limit how many times we'll spin waiting for TX FIFO status.

	 * This will prevent lockups if the base address is incorrectly

	 * set, or any other issue on the UARTLITE.

	 * This limit is pretty arbitrary, unless we are at about 10 baud

	 * we'll never timeout on a working UART.

	 */



	#define UART_LSR_TEMT	0x40 /* Transmitter empty */

	#define UART_LSR_THRE	0x20 /* Transmit-hold-register empty */

	#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)



	unsigned retries = 10000;



	while (--retries &&

		!((in_be32(base_addr + 0x14) & BOTH_EMPTY) == BOTH_EMPTY))

		;



	if (retries)

		out_be32(base_addr, c & 0xff);

}



static void early_printk_uart16550_write(struct console *unused,

					const char *s, unsigned n)

{

	while (*s && n-- > 0) {

		early_printk_uart16550_putc(*s);

		if (*s == '\n')

			early_printk_uart16550_putc('\r');

		s++;

	}

}



static struct console early_serial_uart16550_console = {

	.name = "earlyser",

	.write = early_printk_uart16550_write,

	.flags = CON_PRINTBUFFER,

	.index = -1,

};

#endif /* CONFIG_SERIAL_8250_CONSOLE */



static struct console *early_console;

static struct console *early_console;





void early_printk(const char *fmt, ...)

void early_printk(const char *fmt, ...)
@@ -103,6 +147,25 @@ int __init setup_early_printk(char *opt) 
	}

	}

#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */

#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */





#ifdef CONFIG_SERIAL_8250_CONSOLE

	base_addr = early_uart16550_console();

	base_addr &= ~3; /* clear register offset */

	if (base_addr) {

		early_console_initialized = 1;

#ifdef CONFIG_MMU

		early_console_reg_tlb_alloc(base_addr);

#endif

		early_console = &early_serial_uart16550_console;



		early_printk("early_printk_console is enabled at 0x%08x\n",

							base_addr);



		/* register_console(early_console); */



		return 0;

	}

#endif /* CONFIG_SERIAL_8250_CONSOLE */



	return 1;

	return 1;

}

}

arch/microblaze/kernel/prom.c

+34 −0
Original line number Original line Diff line number Diff line
@@ -89,6 +89,40 @@ int __init early_uartlite_console(void) 
{

{

	return of_scan_flat_dt(early_init_dt_scan_serial, NULL);

	return of_scan_flat_dt(early_init_dt_scan_serial, NULL);

}

}



/* MS this is Microblaze specifig function */

static int __init early_init_dt_scan_serial_full(unsigned long node,

				const char *uname, int depth, void *data)

{

	unsigned long l;

	char *p;

	unsigned int addr;



	pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);



/* find all serial nodes */

	if (strncmp(uname, "serial", 6) != 0)

		return 0;



	early_init_dt_check_for_initrd(node);



/* find compatible node with uartlite */

	p = of_get_flat_dt_prop(node, "compatible", &l);



	if ((strncmp(p, "xlnx,xps-uart16550", 18) != 0) &&

		(strncmp(p, "xlnx,axi-uart16550", 18) != 0))

		return 0;



	addr = *(u32 *)of_get_flat_dt_prop(node, "reg", &l);

	addr += *(u32 *)of_get_flat_dt_prop(node, "reg-offset", &l);

	return addr; /* return address */

}



/* this function is looking for early uartlite console - Microblaze specific */

int __init early_uart16550_console(void)

{

	return of_scan_flat_dt(early_init_dt_scan_serial_full, NULL);

}

#endif

#endif





void __init early_init_devtree(void *params)

void __init early_init_devtree(void *params)