aboutsummaryrefslogtreecommitdiff
path: root/arch/ppc/boot/simple/mpc52xx_tty.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/ppc/boot/simple/mpc52xx_tty.c')
-rw-r--r--arch/ppc/boot/simple/mpc52xx_tty.c140
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;
+}