arch/powerpc/boot/mpc52xx-psc.c

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