arch/powerpc/platforms/embedded6xx/ls_uart.c

Source file repositories/reference/linux-study-clean/arch/powerpc/platforms/embedded6xx/ls_uart.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/platforms/embedded6xx/ls_uart.c
Extension
.c
Size
3549 bytes
Lines
148
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

if (lsr & (UART_LSR_THRE | UART_LSR_TEMT)) {
			for (j = 0; j < 16 && i < len; j++, i++)
				out_8(avr_addr + UART_TX, string[i]);
			if (i == len) {
				/* Read "OK" back: 4ms for the last "KKKK"
				   plus a couple bytes back */
				msleep(7);
				printk("linkstation: disarming the AVR watchdog: ");
				while (in_8(avr_addr + UART_LSR) & UART_LSR_DR)
					printk("%c", in_8(avr_addr + UART_RX));
				break;
			}
		}
		msleep(17);
	}
	printk("\n");
}

#define AVR_QUOT(clock) ((clock) + 8 * 9600) / (16 * 9600)

void avr_uart_configure(void)
{
	unsigned char cval = UART_LCR_WLEN8;
	unsigned int quot = AVR_QUOT(avr_clock);

	if (!avr_addr || !avr_clock)
		return;

	out_8(avr_addr + UART_LCR, cval);			/* initialise UART */
	out_8(avr_addr + UART_MCR, 0);
	out_8(avr_addr + UART_IER, 0);

	cval |= UART_LCR_STOP | UART_LCR_PARITY | UART_LCR_EPAR;

	out_8(avr_addr + UART_LCR, cval);			/* Set character format */

	out_8(avr_addr + UART_LCR, cval | UART_LCR_DLAB);	/* set DLAB */
	out_8(avr_addr + UART_DLL, quot & 0xff);		/* LS of divisor */
	out_8(avr_addr + UART_DLM, quot >> 8);			/* MS of divisor */
	out_8(avr_addr + UART_LCR, cval);			/* reset DLAB */
	out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO);	/* enable FIFO */
}

void avr_uart_send(const char c)
{
	if (!avr_addr || !avr_clock)
		return;

	out_8(avr_addr + UART_TX, c);
	out_8(avr_addr + UART_TX, c);
	out_8(avr_addr + UART_TX, c);
	out_8(avr_addr + UART_TX, c);
}

static void __init ls_uart_init(void)
{
	local_irq_disable();

#ifndef CONFIG_SERIAL_8250
	out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO);	/* enable FIFO */
	out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO |
	      UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);	/* clear FIFOs */
	out_8(avr_addr + UART_FCR, 0);
	out_8(avr_addr + UART_IER, 0);

	/* Clear up interrupts */
	(void) in_8(avr_addr + UART_LSR);
	(void) in_8(avr_addr + UART_RX);
	(void) in_8(avr_addr + UART_IIR);
	(void) in_8(avr_addr + UART_MSR);
#endif
	avr_uart_configure();

	local_irq_enable();
}

static int __init ls_uarts_init(void)
{
	struct device_node *avr;
	struct resource res;
	int len, ret;

	avr = of_find_node_by_path("/soc10x/serial@80004500");
	if (!avr)
		return -EINVAL;

	avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len);
	if (!avr_clock)
		return -EINVAL;

Annotation

Implementation Notes