Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 73afa6c4 authored by John Crispin's avatar John Crispin Committed by Ralf Baechle
Browse files

MIPS: ralink: Add tty detection 



MT7688 has several uarts that can be used for console. There are several
boards in the wild, that use ttyS1 or ttyS2. This patch applies a simply
autodetection routine to figure out which ttyS the bootloader used as
console. The uarts come up in 6 bit mode by default. The bootloader will
have set 8 bit mode on the console. Find that 8bit tty and use it.

Signed-off-by: default avatarJohn Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11459/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent b361bd76

arch/mips/ralink/early_printk.c

+26 −0
Original line number Diff line number Diff line
@@ -25,11 +25,13 @@ 
#define MT7628_CHIP_NAME1	0x20203832



#define UART_REG_TX		0x04

#define UART_REG_LCR		0x0c

#define UART_REG_LSR		0x14

#define UART_REG_LSR_RT2880	0x1c



static __iomem void *uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE);

static __iomem void *chipid_membase = (__iomem void *) KSEG1ADDR(CHIPID_BASE);

static int init_complete;



static inline void uart_w32(u32 val, unsigned reg)

{
@@ -47,8 +49,32 @@ static inline int soc_is_mt7628(void) 
		(__raw_readl(chipid_membase) == MT7628_CHIP_NAME1);

}



static void find_uart_base(void)

{

	int i;



	if (!soc_is_mt7628())

		return;



	for (i = 0; i < 3; i++) {

		u32 reg = uart_r32(UART_REG_LCR + (0x100 * i));



		if (!reg)

			continue;



		uart_membase = (__iomem void *) KSEG1ADDR(EARLY_UART_BASE +

							  (0x100 * i));

		break;

	}

}



void prom_putchar(unsigned char ch)

{

	if (!init_complete) {

		find_uart_base();

		init_complete = 1;

	}



	if (IS_ENABLED(CONFIG_SOC_MT7621) || soc_is_mt7628()) {

		uart_w32(ch, UART_TX);

		while ((uart_r32(UART_REG_LSR) & UART_LSR_THRE) == 0)