MIPS: Alchemy: prom_putchar is board dependent

This patch replaces the general alchemy prom_putchar() implementation
in favor of board-specific versions:  The UART where the output of
prom_putchar is directed to really depends on the board, the current
implementation hardcodes this on a per-SoC basis which is just wrong.

So a generic uart tx function is provided in the alchemy headers,
and the boards can provide their own prom_putchar with custom
destination uart, and all in-kernel alchemy boards support
early printk.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/mips/include/asm/mach-au1x00/au1000.h b/arch/mips/include/asm/mach-au1x00/au1000.h
index c2e233997b6c..e11756d9aaa2 100644
--- a/arch/mips/include/asm/mach-au1x00/au1000.h
+++ b/arch/mips/include/asm/mach-au1x00/au1000.h
@@ -161,6 +161,25 @@ static inline int alchemy_get_cputype(void)
 	return ALCHEMY_CPU_UNKNOWN;
 }
 
+static inline void alchemy_uart_putchar(u32 uart_phys, u8 c)
+{
+	void __iomem *base = (void __iomem *)KSEG1ADDR(uart_phys);
+	int timeout, i;
+
+	/* check LSR TX_EMPTY bit */
+	timeout = 0xffffff;
+	do {
+		if (__raw_readl(base + 0x1c) & 0x20)
+			break;
+		/* slow down */
+		for (i = 10000; i; i--)
+			asm volatile ("nop");
+	} while (--timeout);
+
+	__raw_writel(c, base + 0x04);	/* tx */
+	wmb();
+}
+
 /* arch/mips/au1000/common/clocks.c */
 extern void set_au1x00_speed(unsigned int new_freq);
 extern unsigned int get_au1x00_speed(void);