[POWERPC] Add non-OF serial console support

Add serial console support for non-OF systems.  There is a generic serial
console layer which calls a serial console driver.  Included is the serial
console driver for the ns16550 class of uarts.  Necessary support routines
are added as well.

Signed-off-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

5 files changed, 359 insertions, 2 deletions

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 8660cc50cb18..62435d951dbd 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -40,8 +40,8 @@ zliblinuxheader := zlib.h zconf.h zutil.h
 $(addprefix $(obj)/,$(zlib) main.o): $(addprefix $(obj)/,$(zliblinuxheader)) \
                 $(addprefix $(obj)/,$(zlibheader))
 
-src-wlib := string.S stdio.c main.c flatdevtree.c flatdevtree_misc.c div64.S \
-                $(zlib)
+src-wlib := string.S stdio.c main.c flatdevtree.c flatdevtree_misc.c \
+                ns16550.c serial.c div64.S util.S $(zlib)
 src-plat := of.c
 src-boot := crt0.S $(src-wlib) $(src-plat) empty.c
 
diff --git a/arch/powerpc/boot/io.h b/arch/powerpc/boot/io.h
new file mode 100644
index 000000000000..32974ed49e02
--- /dev/null
+++ b/arch/powerpc/boot/io.h
@@ -0,0 +1,53 @@
+#ifndef _IO_H
+#define __IO_H
+/*
+ * Low-level I/O routines.
+ *
+ * Copied from <file:include/asm-powerpc/io.h> (which has no copyright)
+ */
+static inline int in_8(const volatile unsigned char *addr)
+{
+        int ret;
+
+        __asm__ __volatile__("lbz%U1%X1 %0,%1; twi 0,%0,0; isync"
+                             : "=r" (ret) : "m" (*addr));
+        return ret;
+}
+
+static inline void out_8(volatile unsigned char *addr, int val)
+{
+        __asm__ __volatile__("stb%U0%X0 %1,%0; sync"
+                             : "=m" (*addr) : "r" (val));
+}
+
+static inline unsigned in_le32(const volatile unsigned *addr)
+{
+        unsigned ret;
+
+        __asm__ __volatile__("lwbrx %0,0,%1; twi 0,%0,0; isync"
+                             : "=r" (ret) : "r" (addr), "m" (*addr));
+        return ret;
+}
+
+static inline unsigned in_be32(const volatile unsigned *addr)
+{
+        unsigned ret;
+
+        __asm__ __volatile__("lwz%U1%X1 %0,%1; twi 0,%0,0; isync"
+                             : "=r" (ret) : "m" (*addr));
+        return ret;
+}
+
+static inline void out_le32(volatile unsigned *addr, int val)
+{
+        __asm__ __volatile__("stwbrx %1,0,%2; sync" : "=m" (*addr)
+                             : "r" (val), "r" (addr));
+}
+
+static inline void out_be32(volatile unsigned *addr, int val)
+{
+        __asm__ __volatile__("stw%U0%X0 %1,%0; sync"
+                             : "=m" (*addr) : "r" (val));
+}
+
+#endif /* _IO_H */
diff --git a/arch/powerpc/boot/ns16550.c b/arch/powerpc/boot/ns16550.c
new file mode 100644
index 000000000000..1ffe72e35cdc
--- /dev/null
+++ b/arch/powerpc/boot/ns16550.c
@@ -0,0 +1,74 @@
+/*
+ * 16550 serial console support.
+ *
+ * Original copied from <file:arch/ppc/boot/common/ns16550.c>
+ * (which had no copyright)
+ * Modifications: 2006 (c) MontaVista Software, Inc.
+ *
+ * Modified by: Mark A. Greer <mgreer@mvista.com>
+ */
+#include <stdarg.h>
+#include <stddef.h>
+#include "types.h"
+#include "string.h"
+#include "stdio.h"
+#include "io.h"
+#include "ops.h"
+
+#define UART_DLL        0       /* Out: Divisor Latch Low */
+#define UART_DLM        1       /* Out: Divisor Latch High */
+#define UART_FCR        2       /* Out: FIFO Control Register */
+#define UART_LCR        3       /* Out: Line Control Register */
+#define UART_MCR        4       /* Out: Modem Control Register */
+#define UART_LSR        5       /* In:  Line Status Register */
+#define UART_LSR_THRE   0x20    /* Transmit-hold-register empty */
+#define UART_LSR_DR     0x01    /* Receiver data ready */
+#define UART_MSR        6       /* In:  Modem Status Register */
+#define UART_SCR        7       /* I/O: Scratch Register */
+
+static unsigned char *reg_base;
+static u32 reg_shift;
+
+static int ns16550_open(void)
+{
+        out_8(reg_base + (UART_FCR << reg_shift), 0x06);
+        return 0;
+}
+
+static void ns16550_putc(unsigned char c)
+{
+        while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
+        out_8(reg_base, c);
+}
+
+static unsigned char ns16550_getc(void)
+{
+        while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
+        return in_8(reg_base);
+}
+
+static u8 ns16550_tstc(void)
+{
+        return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
+}
+
+int ns16550_console_init(void *devp, struct serial_console_data *scdp)
+{
+        int n;
+
+        n = getprop(devp, "virtual-reg", &reg_base, sizeof(reg_base));
+        if (n != sizeof(reg_base))
+                return -1;
+
+        n = getprop(devp, "reg-shift", &reg_shift, sizeof(reg_shift));
+        if (n != sizeof(reg_shift))
+                reg_shift = 0;
+
+        scdp->open = ns16550_open;
+        scdp->putc = ns16550_putc;
+        scdp->getc = ns16550_getc;
+        scdp->tstc = ns16550_tstc;
+        scdp->close = NULL;
+
+        return 0;
+}
diff --git a/arch/powerpc/boot/serial.c b/arch/powerpc/boot/serial.c
new file mode 100644
index 000000000000..e8de4cf59be7
--- /dev/null
+++ b/arch/powerpc/boot/serial.c
@@ -0,0 +1,142 @@
+/*
+ * Generic serial console support
+ *
+ * Author: Mark A. Greer <mgreer@mvista.com>
+ *
+ * Code in serial_edit_cmdline() copied from <file:arch/ppc/boot/simple/misc.c>
+ * and was written by Matt Porter <mporter@kernel.crashing.org>.
+ *
+ * 2001,2006 (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 <stdarg.h>
+#include <stddef.h>
+#include "types.h"
+#include "string.h"
+#include "stdio.h"
+#include "io.h"
+#include "ops.h"
+
+extern void udelay(long delay);
+
+static int serial_open(void)
+{
+        struct serial_console_data *scdp = console_ops.data;
+        return scdp->open();
+}
+
+static void serial_write(char *buf, int len)
+{
+        struct serial_console_data *scdp = console_ops.data;
+
+        while (*buf != '\0')
+                scdp->putc(*buf++);
+}
+
+static void serial_edit_cmdline(char *buf, int len)
+{
+        int timer = 0, count;
+        char ch, *cp;
+        struct serial_console_data *scdp = console_ops.data;
+
+        cp = buf;
+        count = strlen(buf);
+        cp = &buf[count];
+        count++;
+
+        while (timer++ < 5*1000) {
+                if (scdp->tstc()) {
+                        while (((ch = scdp->getc()) != '\n') && (ch != '\r')) {
+                                /* Test for backspace/delete */
+                                if ((ch == '\b') || (ch == '\177')) {
+                                        if (cp != buf) {
+                                                cp--;
+                                                count--;
+                                                printf("\b \b");
+                                        }
+                                /* Test for ^x/^u (and wipe the line) */
+                                } else if ((ch == '\030') || (ch == '\025')) {
+                                        while (cp != buf) {
+                                                cp--;
+                                                count--;
+                                                printf("\b \b");
+                                        }
+                                } else if (count < len) {
+                                                *cp++ = ch;
+                                                count++;
+                                                scdp->putc(ch);
+                                }
+                        }
+                        break;  /* Exit 'timer' loop */
+                }
+                udelay(1000);  /* 1 msec */
+        }
+        *cp = 0;
+}
+
+static void serial_close(void)
+{
+        struct serial_console_data *scdp = console_ops.data;
+
+        if (scdp->close)
+                scdp->close();
+}
+
+static void *serial_get_stdout_devp(void)
+{
+        void *devp;
+        char devtype[MAX_PROP_LEN];
+        char path[MAX_PATH_LEN];
+
+        devp = finddevice("/chosen");
+        if (devp == NULL)
+                goto err_out;
+
+        if (getprop(devp, "linux,stdout-path", path, MAX_PATH_LEN) > 0) {
+                devp = finddevice(path);
+                if (devp == NULL)
+                        goto err_out;
+
+                if ((getprop(devp, "device_type", devtype, sizeof(devtype)) > 0)
+                                && !strcmp(devtype, "serial"))
+                        return devp;
+        }
+err_out:
+        return NULL;
+}
+
+static struct serial_console_data serial_cd;
+
+/* Node's "compatible" property determines which serial driver to use */
+int serial_console_init(void)
+{
+        void *devp;
+        int rc = -1;
+        char compat[MAX_PROP_LEN];
+
+        devp = serial_get_stdout_devp();
+        if (devp == NULL)
+                goto err_out;
+
+        if (getprop(devp, "compatible", compat, sizeof(compat)) < 0)
+                goto err_out;
+
+        if (!strcmp(compat, "ns16550"))
+                rc = ns16550_console_init(devp, &serial_cd);
+
+        /* Add other serial console driver calls here */
+
+        if (!rc) {
+                console_ops.open = serial_open;
+                console_ops.write = serial_write;
+                console_ops.edit_cmdline = serial_edit_cmdline;
+                console_ops.close = serial_close;
+                console_ops.data = &serial_cd;
+
+                return 0;
+        }
+err_out:
+        return -1;
+}
diff --git a/arch/powerpc/boot/util.S b/arch/powerpc/boot/util.S
new file mode 100644
index 000000000000..427ddfc11991
--- /dev/null
+++ b/arch/powerpc/boot/util.S
@@ -0,0 +1,88 @@
+/*
+ * Copied from <file:arch/powerpc/kernel/misc_32.S>
+ *
+ * This file contains miscellaneous low-level functions.
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ * Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
+ * and Paul Mackerras.
+ *
+ * kexec bits:
+ * Copyright (C) 2002-2003 Eric Biederman  <ebiederm@xmission.com>
+ * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+#include "ppc_asm.h"
+
+#define SPRN_PVR        0x11F   /* Processor Version Register */
+
+        .text
+
+/* udelay (on non-601 processors) needs to know the period of the
+ * timebase in nanoseconds.  This used to be hardcoded to be 60ns
+ * (period of 66MHz/4).  Now a variable is used that is initialized to
+ * 60 for backward compatibility, but it can be overridden as necessary
+ * with code something like this:
+ *    extern unsigned long timebase_period_ns;
+ *    timebase_period_ns = 1000000000 / bd->bi_tbfreq;
+ */
+        .data
+        .globl timebase_period_ns
+timebase_period_ns:
+        .long   60
+
+        .text
+/*
+ * Delay for a number of microseconds
+ */
+        .globl  udelay
+udelay:
+        mfspr   r4,SPRN_PVR
+        srwi    r4,r4,16
+        cmpwi   0,r4,1          /* 601 ? */
+        bne     .udelay_not_601
+00:     li      r0,86   /* Instructions / microsecond? */
+        mtctr   r0
+10:     addi    r0,r0,0 /* NOP */
+        bdnz    10b
+        subic.  r3,r3,1
+        bne     00b
+        blr
+
+.udelay_not_601:
+        mulli   r4,r3,1000      /* nanoseconds */
+        /*  Change r4 to be the number of ticks using:
+         *      (nanoseconds + (timebase_period_ns - 1 )) / timebase_period_ns
+         *  timebase_period_ns defaults to 60 (16.6MHz) */
+        mflr    r5
+        bl      0f
+0:      mflr    r6
+        mtlr    r5
+        lis     r5,0b@ha
+        addi    r5,r5,0b@l
+        subf    r5,r5,r6        /* In case we're relocated */
+        addis   r5,r5,timebase_period_ns@ha
+        lwz     r5,timebase_period_ns@l(r5)
+        add     r4,r4,r5
+        addi    r4,r4,-1
+        divw    r4,r4,r5        /* BUS ticks */
+1:      mftbu   r5
+        mftb    r6
+        mftbu   r7
+        cmpw    0,r5,r7
+        bne     1b              /* Get [synced] base time */
+        addc    r9,r6,r4        /* Compute end time */
+        addze   r8,r5
+2:      mftbu   r5
+        cmpw    0,r5,r8
+        blt     2b
+        bgt     3f
+        mftb    r6
+        cmpw    0,r6,r9
+        blt     2b
+3:      blr