xref: /OK3568_Linux_fs/kernel/arch/powerpc/boot/mpc52xx-psc.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun  * MPC5200 PSC serial console support.
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  * Author: Grant Likely <grant.likely@secretlab.ca>
6*4882a593Smuzhiyun  *
7*4882a593Smuzhiyun  * Copyright (c) 2007 Secret Lab Technologies Ltd.
8*4882a593Smuzhiyun  * Copyright (c) 2007 Freescale Semiconductor, Inc.
9*4882a593Smuzhiyun  *
10*4882a593Smuzhiyun  * It is assumed that the firmware (or the platform file) has already set
11*4882a593Smuzhiyun  * up the port.
12*4882a593Smuzhiyun  */
13*4882a593Smuzhiyun 
14*4882a593Smuzhiyun #include "types.h"
15*4882a593Smuzhiyun #include "io.h"
16*4882a593Smuzhiyun #include "ops.h"
17*4882a593Smuzhiyun 
18*4882a593Smuzhiyun /* Programmable Serial Controller (PSC) status register bits */
19*4882a593Smuzhiyun #define MPC52xx_PSC_SR		0x04
20*4882a593Smuzhiyun #define MPC52xx_PSC_SR_RXRDY		0x0100
21*4882a593Smuzhiyun #define MPC52xx_PSC_SR_RXFULL		0x0200
22*4882a593Smuzhiyun #define MPC52xx_PSC_SR_TXRDY		0x0400
23*4882a593Smuzhiyun #define MPC52xx_PSC_SR_TXEMP		0x0800
24*4882a593Smuzhiyun 
25*4882a593Smuzhiyun #define MPC52xx_PSC_BUFFER	0x0C
26*4882a593Smuzhiyun 
27*4882a593Smuzhiyun static void *psc;
28*4882a593Smuzhiyun 
psc_open(void)29*4882a593Smuzhiyun static int psc_open(void)
30*4882a593Smuzhiyun {
31*4882a593Smuzhiyun 	/* Assume the firmware has already configured the PSC into
32*4882a593Smuzhiyun 	 * uart mode */
33*4882a593Smuzhiyun 	return 0;
34*4882a593Smuzhiyun }
35*4882a593Smuzhiyun 
psc_putc(unsigned char c)36*4882a593Smuzhiyun static void psc_putc(unsigned char c)
37*4882a593Smuzhiyun {
38*4882a593Smuzhiyun 	while (!(in_be16(psc + MPC52xx_PSC_SR) & MPC52xx_PSC_SR_TXRDY)) ;
39*4882a593Smuzhiyun 	out_8(psc + MPC52xx_PSC_BUFFER, c);
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun 
psc_tstc(void)42*4882a593Smuzhiyun static unsigned char psc_tstc(void)
43*4882a593Smuzhiyun {
44*4882a593Smuzhiyun 	return (in_be16(psc + MPC52xx_PSC_SR) & MPC52xx_PSC_SR_RXRDY) != 0;
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun 
psc_getc(void)47*4882a593Smuzhiyun static unsigned char psc_getc(void)
48*4882a593Smuzhiyun {
49*4882a593Smuzhiyun 	while (!(in_be16(psc + MPC52xx_PSC_SR) & MPC52xx_PSC_SR_RXRDY)) ;
50*4882a593Smuzhiyun 	return in_8(psc + MPC52xx_PSC_BUFFER);
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun 
mpc5200_psc_console_init(void * devp,struct serial_console_data * scdp)53*4882a593Smuzhiyun int mpc5200_psc_console_init(void *devp, struct serial_console_data *scdp)
54*4882a593Smuzhiyun {
55*4882a593Smuzhiyun 	/* Get the base address of the psc registers */
56*4882a593Smuzhiyun 	if (dt_get_virtual_reg(devp, &psc, 1) < 1)
57*4882a593Smuzhiyun 		return -1;
58*4882a593Smuzhiyun 
59*4882a593Smuzhiyun 	scdp->open = psc_open;
60*4882a593Smuzhiyun 	scdp->putc = psc_putc;
61*4882a593Smuzhiyun 	scdp->getc = psc_getc;
62*4882a593Smuzhiyun 	scdp->tstc = psc_tstc;
63*4882a593Smuzhiyun 
64*4882a593Smuzhiyun 	return 0;
65*4882a593Smuzhiyun }
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