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/*
* arch/ppc/boot/simple/mpc52xx_tty.c
*
* Minimal serial functions needed to send messages out a MPC52xx
* Programmable Serial Controller (PSC).
*
* Author: Dale Farnsworth <dfarnsworth@mvista.com>
*
* 2003-2004 (c) MontaVista, Software, Inc. This file is licensed under the
* terms of the GNU General Public License version 2. This program is licensed
* "as is" without any warranty of any kind, whether express or implied.
*/
#include <linux/config.h>
#include <linux/types.h>
#include <asm/uaccess.h>
#include <asm/mpc52xx.h>
#include <asm/mpc52xx_psc.h>
#include <asm/serial.h>
#include <asm/io.h>
#include <asm/time.h>
#ifdef MPC52xx_PF_CONSOLE_PORT
#define MPC52xx_CONSOLE MPC52xx_PSCx_OFFSET(MPC52xx_PF_CONSOLE_PORT)
#define MPC52xx_PSC_CONFIG_SHIFT ((MPC52xx_PF_CONSOLE_PORT-1)<<2)
#else
#error "MPC52xx_PF_CONSOLE_PORT not defined"
#endif
static struct mpc52xx_psc __iomem *psc =
(struct mpc52xx_psc __iomem *) MPC52xx_PA(MPC52xx_CONSOLE);
/* The decrementer counts at the system bus clock frequency
* divided by four. The most accurate time base is connected to the
* rtc. We read the decrementer change during one rtc tick
* and multiply by 4 to get the system bus clock frequency. Since a
* rtc tick is one seconds, and that's pretty long, we change the rtc
* dividers temporarly to set them 64x faster ;)
*/
static int
mpc52xx_ipbfreq(void)
{
struct mpc52xx_rtc __iomem *rtc =
(struct mpc52xx_rtc __iomem *) MPC52xx_PA(MPC52xx_RTC_OFFSET);
struct mpc52xx_cdm __iomem *cdm =
(struct mpc52xx_cdm __iomem *) MPC52xx_PA(MPC52xx_CDM_OFFSET);
int current_time, previous_time;
int tbl_start, tbl_end;
int xlbfreq, ipbfreq;
out_be32(&rtc->dividers, 0x8f1f0000); /* Set RTC 64x faster */
previous_time = in_be32(&rtc->time);
while ((current_time = in_be32(&rtc->time)) == previous_time) ;
tbl_start = get_tbl();
previous_time = current_time;
while ((current_time = in_be32(&rtc->time)) == previous_time) ;
tbl_end = get_tbl();
out_be32(&rtc->dividers, 0xffff0000); /* Restore RTC */
xlbfreq = (tbl_end - tbl_start) << 8;
ipbfreq = (in_8(&cdm->ipb_clk_sel) & 1) ? xlbfreq / 2 : xlbfreq;
return ipbfreq;
}
unsigned long
serial_init(int ignored, void *ignored2)
{
struct mpc52xx_gpio __iomem *gpio =
(struct mpc52xx_gpio __iomem *) MPC52xx_PA(MPC52xx_GPIO_OFFSET);
int divisor;
int mode1;
int mode2;
u32 val32;
static int been_here = 0;
if (been_here)
return 0;
been_here = 1;
val32 = in_be32(&gpio->port_config);
val32 &= ~(0x7 << MPC52xx_PSC_CONFIG_SHIFT);
val32 |= MPC52xx_GPIO_PSC_CONFIG_UART_WITHOUT_CD
<< MPC52xx_PSC_CONFIG_SHIFT;
out_be32(&gpio->port_config, val32);
out_8(&psc->command, MPC52xx_PSC_RST_TX
| MPC52xx_PSC_RX_DISABLE | MPC52xx_PSC_TX_ENABLE);
out_8(&psc->command, MPC52xx_PSC_RST_RX);
out_be32(&psc->sicr, 0x0);
out_be16(&psc->mpc52xx_psc_clock_select, 0xdd00);
out_be16(&psc->tfalarm, 0xf8);
out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1
| MPC52xx_PSC_RX_ENABLE
| MPC52xx_PSC_TX_ENABLE);
divisor = ((mpc52xx_ipbfreq()
/ (CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD * 16)) + 1) >> 1;
mode1 = MPC52xx_PSC_MODE_8_BITS | MPC52xx_PSC_MODE_PARNONE
| MPC52xx_PSC_MODE_ERR;
mode2 = MPC52xx_PSC_MODE_ONE_STOP;
out_8(&psc->ctur, divisor>>8);
out_8(&psc->ctlr, divisor);
out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
out_8(&psc->mode, mode1);
out_8(&psc->mode, mode2);
return 0; /* ignored */
}
void
serial_putc(void *ignored, const char c)
{
serial_init(0, NULL);
while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXEMP)) ;
out_8(&psc->mpc52xx_psc_buffer_8, c);
while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXEMP)) ;
}
char
serial_getc(void *ignored)
{
while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_RXRDY)) ;
return in_8(&psc->mpc52xx_psc_buffer_8);
}
int
serial_tstc(void *ignored)
{
return (in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_RXRDY) != 0;
}
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