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Commit 813c1410 authored by Kelvin Cheung's avatar Kelvin Cheung Committed by Ralf Baechle
Browse files

MIPS: Loongson1B: Improve early printk 



- Determine serial port for early printk according to kernel command line.
  - Move to 8250/16550 serial early printk driver.

Signed-off-by: default avatarKelvin Cheung <keguang.zhang@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8023/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent a13f0795

arch/mips/loongson1/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ config LOONGSON1_LS1B 
	select SYS_SUPPORTS_HIGHMEM

	select SYS_SUPPORTS_MIPS16

	select SYS_HAS_EARLY_PRINTK

	select USE_GENERIC_EARLY_PRINTK_8250

	select COMMON_CLK



endchoice

arch/mips/loongson1/common/prom.c

+13 −17
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ void __init prom_init_cmdline(void) 


void __init prom_init(void)

{

	void __iomem *uart_base;

	prom_argc = fw_arg0;

	prom_argv = (char **)fw_arg1;

	prom_envp = (char **)fw_arg2;
@@ -65,23 +66,18 @@ void __init prom_init(void) 


	memsize = env_or_default("memsize", DEFAULT_MEMSIZE);

	highmemsize = env_or_default("highmemsize", 0x0);

}



void __init prom_free_prom_memory(void)

{

	if (strstr(arcs_cmdline, "console=ttyS3"))

		uart_base = ioremap_nocache(LS1X_UART3_BASE, 0x0f);

	else if (strstr(arcs_cmdline, "console=ttyS2"))

		uart_base = ioremap_nocache(LS1X_UART2_BASE, 0x0f);

	else if (strstr(arcs_cmdline, "console=ttyS1"))

		uart_base = ioremap_nocache(LS1X_UART1_BASE, 0x0f);

	else

		uart_base = ioremap_nocache(LS1X_UART0_BASE, 0x0f);

	setup_8250_early_printk_port((unsigned long)uart_base, 0, 0);

}



#define PORT(offset)	(u8 *)(KSEG1ADDR(LS1X_UART0_BASE + offset))



void prom_putchar(char c)

void __init prom_free_prom_memory(void)

{

	int timeout;



	timeout = 1024;



	while (((readb(PORT(UART_LSR)) & UART_LSR_THRE) == 0)

			&& (timeout-- > 0))

		;



	writeb(c, PORT(UART_TX));

}