linux-stable/arch/powerpc/boot/ns16550.c
John Linn 2f0b45f846 [POWERPC] Xilinx: boot support for Xilinx uart 16550.
The Xilinx 16550 uart core is not a standard 16550 because it uses
word-based addressing rather than byte-based adressing. With
additional properties it is compatible with the open firmware
'ns16550' compatible binding.

This code updates the ns16550 driver to use the reg-offset property
so that the Xilinx UART 16550 can be used with it. The reg-shift
was already being handled.

Signed-off-by: John Linn <john.linn@xilinx.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
2008-04-24 13:32:46 -05:00

78 lines
1.9 KiB
C

/*
* 16550 serial console support.
*
* Original copied from <file:arch/ppc/boot/common/ns16550.c>
* (which had no copyright)
* Modifications: 2006 (c) MontaVista Software, Inc.
*
* Modified by: Mark A. Greer <mgreer@mvista.com>
*/
#include <stdarg.h>
#include <stddef.h>
#include "types.h"
#include "string.h"
#include "stdio.h"
#include "io.h"
#include "ops.h"
#define UART_DLL 0 /* Out: Divisor Latch Low */
#define UART_DLM 1 /* Out: Divisor Latch High */
#define UART_FCR 2 /* Out: FIFO Control Register */
#define UART_LCR 3 /* Out: Line Control Register */
#define UART_MCR 4 /* Out: Modem Control Register */
#define UART_LSR 5 /* In: Line Status Register */
#define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
#define UART_LSR_DR 0x01 /* Receiver data ready */
#define UART_MSR 6 /* In: Modem Status Register */
#define UART_SCR 7 /* I/O: Scratch Register */
static unsigned char *reg_base;
static u32 reg_shift;
static int ns16550_open(void)
{
out_8(reg_base + (UART_FCR << reg_shift), 0x06);
return 0;
}
static void ns16550_putc(unsigned char c)
{
while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
out_8(reg_base, c);
}
static unsigned char ns16550_getc(void)
{
while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
return in_8(reg_base);
}
static u8 ns16550_tstc(void)
{
return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
}
int ns16550_console_init(void *devp, struct serial_console_data *scdp)
{
int n;
u32 reg_offset;
if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1)
return -1;
n = getprop(devp, "reg-offset", &reg_offset, sizeof(reg_offset));
if (n == sizeof(reg_offset))
reg_base += reg_offset;
n = getprop(devp, "reg-shift", &reg_shift, sizeof(reg_shift));
if (n != sizeof(reg_shift))
reg_shift = 0;
scdp->open = ns16550_open;
scdp->putc = ns16550_putc;
scdp->getc = ns16550_getc;
scdp->tstc = ns16550_tstc;
scdp->close = NULL;
return 0;
}