diff options
Diffstat (limited to 'arch/ppc/boot/simple/mpc52xx_tty.c')
| -rw-r--r-- | arch/ppc/boot/simple/mpc52xx_tty.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/arch/ppc/boot/simple/mpc52xx_tty.c b/arch/ppc/boot/simple/mpc52xx_tty.c new file mode 100644 index 00000000000..3acc6b7c072 --- /dev/null +++ b/arch/ppc/boot/simple/mpc52xx_tty.c @@ -0,0 +1,140 @@ +/* + * 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; +} |