From 25330c6041e9cc68e23541894035afd117d71456 Mon Sep 17 00:00:00 2001
From: Tom Rini <trini@kernel.crashing.org>
Date: Sun, 21 Jul 2002 20:07:21 -0700
Subject: PPC32: Allow Motorola machines with PPCBUG to get their boot args
 from NVRAM.

---
 arch/ppc/kernel/Makefile     |   1 +
 arch/ppc/kernel/prep_nvram.c | 148 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 149 insertions(+)
 create mode 100644 arch/ppc/kernel/prep_nvram.c

(limited to 'arch/ppc/kernel')

diff --git a/arch/ppc/kernel/Makefile b/arch/ppc/kernel/Makefile
index 3a8e5d1930b7..0c92373f434f 100644
--- a/arch/ppc/kernel/Makefile
+++ b/arch/ppc/kernel/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_PCI)		+= pci.o
 ifneq ($(CONFIG_PPC_ISERIES),y)
 obj-$(CONFIG_PCI)		+= pci-dma.o
 endif
+obj-$(CONFIG_PPCBUG_NVRAM)	+= prep_nvram.o
 obj-$(CONFIG_KGDB)		+= ppc-stub.o
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_TAU)		+= temp.o
diff --git a/arch/ppc/kernel/prep_nvram.c b/arch/ppc/kernel/prep_nvram.c
new file mode 100644
index 000000000000..7d8c7e7e91e1
--- /dev/null
+++ b/arch/ppc/kernel/prep_nvram.c
@@ -0,0 +1,148 @@
+/*
+ * BK Id: %F% %I% %G% %U% %#%
+ */
+/*
+ * arch/ppc/kernel/prep_nvram.c
+ *
+ * Copyright (C) 1998  Corey Minyard
+ *
+ * This reads the NvRAM on PReP compliant machines (generally from IBM or
+ * Motorola).  Motorola kept the format of NvRAM in their ROM, PPCBUG, the
+ * same, long after they had stopped producing PReP compliant machines.  So
+ * this code is useful in those cases as well.
+ *
+ */
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+
+#include <asm/sections.h>
+#include <asm/segment.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/machdep.h>
+#include <asm/prep_nvram.h>
+
+static char nvramData[MAX_PREP_NVRAM];
+static NVRAM_MAP *nvram=(NVRAM_MAP *)&nvramData[0];
+
+unsigned char __prep prep_nvram_read_val(int addr)
+{
+	outb(addr, PREP_NVRAM_AS0);
+	outb(addr>>8, PREP_NVRAM_AS1);
+	return inb(PREP_NVRAM_DATA);
+}
+  
+void __prep prep_nvram_write_val(int           addr,
+			  unsigned char val)
+{
+	outb(addr, PREP_NVRAM_AS0);
+	outb(addr>>8, PREP_NVRAM_AS1);
+   	outb(val, PREP_NVRAM_DATA);
+}
+  
+void __init init_prep_nvram(void)
+{
+	unsigned char *nvp;
+	int  i;
+	int  nvramSize;
+
+	/*
+	 * The following could fail if the NvRAM were corrupt but
+	 * we expect the boot firmware to have checked its checksum
+	 * before boot
+	 */
+	nvp = (char *) &nvram->Header;
+	for (i=0; i<sizeof(HEADER); i++)
+	{
+		*nvp = ppc_md.nvram_read_val(i);
+		nvp++;
+	}
+	
+	/*
+	 * The PReP NvRAM may be any size so read in the header to
+	 * determine how much we must read in order to get the complete
+	 * GE area
+	 */
+	nvramSize=(int)nvram->Header.GEAddress+nvram->Header.GELength;
+	if(nvramSize>MAX_PREP_NVRAM)
+	{
+		/*
+		 * NvRAM is too large
+		 */
+		nvram->Header.GELength=0;
+		return;
+	}
+
+	/*
+	 * Read the remainder of the PReP NvRAM
+	 */
+	nvp = (char *) &nvram->GEArea[0];
+	for (i=sizeof(HEADER); i<nvramSize; i++)
+	{
+		*nvp = ppc_md.nvram_read_val(i);
+		nvp++;
+	}
+}
+
+__prep
+char __prep *prep_nvram_get_var(const char *name)
+{
+	char *cp;
+	int  namelen;
+
+	namelen = strlen(name);
+	cp = prep_nvram_first_var();
+	while (cp != NULL) {
+		if ((strncmp(name, cp, namelen) == 0)
+		    && (cp[namelen] == '='))
+		{
+			return cp+namelen+1;
+		}
+		cp = prep_nvram_next_var(cp);
+	}
+
+	return NULL;
+}
+
+__prep
+char __prep *prep_nvram_first_var(void)
+{
+        if (nvram->Header.GELength == 0) {
+		return NULL;
+	} else {
+		return (((char *)nvram)
+			+ ((unsigned int) nvram->Header.GEAddress));
+	}
+}
+
+__prep
+char __prep *prep_nvram_next_var(char *name)
+{
+	char *cp;
+
+
+	cp = name;
+	while (((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength)
+	       && (*cp != '\0'))
+	{
+		cp++;
+	}
+
+	/* Skip over any null characters. */
+	while (((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength)
+	       && (*cp == '\0'))
+	{
+		cp++;
+	}
+
+	if ((cp - ((char *) nvram->GEArea)) < nvram->Header.GELength) {
+		return cp;
+	} else {
+		return NULL;
+	}
+}
+
+
+
-- 
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