arch/powerpc/platforms/powermac/udbg_scc.c

Source file repositories/reference/linux-study-clean/arch/powerpc/platforms/powermac/udbg_scc.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/platforms/powermac/udbg_scc.c
Extension
.c
Size
4000 bytes
Lines
185
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 (ch == stdout) {
			of_node_put(ch_def);
			ch_def = of_node_get(ch);
		}
		if (of_node_name_eq(ch, "ch-a")) {
			of_node_put(ch_a);
			ch_a = of_node_get(ch);
		}
	}
	if (ch_def == NULL && !force_scc)
		goto bail;

	ch = ch_def ? ch_def : ch_a;

	/* Get address within mac-io ASIC */
	reg = of_get_property(escc, "reg", NULL);
	if (reg == NULL)
		goto bail;
	addr = reg[0];

	/* Get address of mac-io PCI itself */
	reg = of_get_property(macio, "assigned-addresses", NULL);
	if (reg == NULL)
		goto bail;
	addr += reg[2];

	/* Lock the serial port */
	pmac_call_feature(PMAC_FTR_SCC_ENABLE, ch,
			  PMAC_SCC_ASYNC | PMAC_SCC_FLAG_XMON, 1);

	if (ch == ch_a)
		addr += 0x20;
	sccc = ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
	sccc += addr & ~PAGE_MASK;
	sccd = sccc + 0x10;

	mb();

	for (i = 20000; i != 0; --i)
		in_8(sccc);
	out_8(sccc, 0x09);		/* reset A or B side */
	out_8(sccc, 0xc0);

	/* If SCC was the OF output port, read the BRG value, else
	 * Setup for 38400 or 57600 8N1 depending on the machine
	 */
	if (ch_def != NULL) {
		out_8(sccc, 13);
		scc_inittab[1] = in_8(sccc);
		out_8(sccc, 12);
		scc_inittab[3] = in_8(sccc);
	} else if (of_machine_is_compatible("RackMac1,1")
		   || of_machine_is_compatible("RackMac1,2")
		   || of_machine_is_compatible("MacRISC4")) {
		/* Xserves and G5s default to 57600 */
		scc_inittab[1] = 0;
		scc_inittab[3] = 0;
	} else {
		/* Others default to 38400 */
		scc_inittab[1] = 0;
		scc_inittab[3] = 1;
	}

	for (i = 0; i < sizeof(scc_inittab); ++i)
		out_8(sccc, scc_inittab[i]);


	udbg_putc = udbg_scc_putc;
	udbg_getc = udbg_scc_getc;
	udbg_getc_poll = udbg_scc_getc_poll;

	udbg_puts("Hello World !\n");

 bail:
	of_node_put(macio);
	of_node_put(escc);
	of_node_put(stdout);
	of_node_put(ch_def);
	of_node_put(ch_a);
}

#ifdef CONFIG_PPC64
static void udbg_real_scc_putc(char c)
{
	while ((real_readb(sccc) & SCC_TXRDY) == 0)
		;
	real_writeb(c, sccd);
	if (c == '\n')
		udbg_real_scc_putc('\r');
}

Annotation

Implementation Notes