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-rw-r--r--arch/mips/sgi-ip22/ip22-nvram.c122
1 files changed, 122 insertions, 0 deletions
diff --git a/arch/mips/sgi-ip22/ip22-nvram.c b/arch/mips/sgi-ip22/ip22-nvram.c
new file mode 100644
index 000000000..e727ef519
--- /dev/null
+++ b/arch/mips/sgi-ip22/ip22-nvram.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ip22-nvram.c: NVRAM and serial EEPROM handling.
+ *
+ * Copyright (C) 2003 Ladislav Michl (ladis@linux-mips.org)
+ */
+#include <linux/export.h>
+
+#include <asm/sgi/hpc3.h>
+#include <asm/sgi/ip22.h>
+
+/* Control opcode for serial eeprom */
+#define EEPROM_READ 0xc000 /* serial memory read */
+#define EEPROM_WEN 0x9800 /* write enable before prog modes */
+#define EEPROM_WRITE 0xa000 /* serial memory write */
+#define EEPROM_WRALL 0x8800 /* write all registers */
+#define EEPROM_WDS 0x8000 /* disable all programming */
+#define EEPROM_PRREAD 0xc000 /* read protect register */
+#define EEPROM_PREN 0x9800 /* enable protect register mode */
+#define EEPROM_PRCLEAR 0xffff /* clear protect register */
+#define EEPROM_PRWRITE 0xa000 /* write protect register */
+#define EEPROM_PRDS 0x8000 /* disable protect register, forever */
+
+#define EEPROM_EPROT 0x01 /* Protect register enable */
+#define EEPROM_CSEL 0x02 /* Chip select */
+#define EEPROM_ECLK 0x04 /* EEPROM clock */
+#define EEPROM_DATO 0x08 /* Data out */
+#define EEPROM_DATI 0x10 /* Data in */
+
+/* We need to use these functions early... */
+#define delay() ({ \
+ int x; \
+ for (x=0; x<100000; x++) __asm__ __volatile__(""); })
+
+#define eeprom_cs_on(ptr) ({ \
+ __raw_writel(__raw_readl(ptr) & ~EEPROM_DATO, ptr); \
+ __raw_writel(__raw_readl(ptr) & ~EEPROM_ECLK, ptr); \
+ __raw_writel(__raw_readl(ptr) & ~EEPROM_EPROT, ptr); \
+ delay(); \
+ __raw_writel(__raw_readl(ptr) | EEPROM_CSEL, ptr); \
+ __raw_writel(__raw_readl(ptr) | EEPROM_ECLK, ptr); })
+
+
+#define eeprom_cs_off(ptr) ({ \
+ __raw_writel(__raw_readl(ptr) & ~EEPROM_ECLK, ptr); \
+ __raw_writel(__raw_readl(ptr) & ~EEPROM_CSEL, ptr); \
+ __raw_writel(__raw_readl(ptr) | EEPROM_EPROT, ptr); \
+ __raw_writel(__raw_readl(ptr) | EEPROM_ECLK, ptr); })
+
+#define BITS_IN_COMMAND 11
+/*
+ * clock in the nvram command and the register number. For the
+ * national semiconductor nv ram chip the op code is 3 bits and
+ * the address is 6/8 bits.
+ */
+static inline void eeprom_cmd(unsigned int *ctrl, unsigned cmd, unsigned reg)
+{
+ unsigned short ser_cmd;
+ int i;
+
+ ser_cmd = cmd | (reg << (16 - BITS_IN_COMMAND));
+ for (i = 0; i < BITS_IN_COMMAND; i++) {
+ if (ser_cmd & (1<<15)) /* if high order bit set */
+ __raw_writel(__raw_readl(ctrl) | EEPROM_DATO, ctrl);
+ else
+ __raw_writel(__raw_readl(ctrl) & ~EEPROM_DATO, ctrl);
+ __raw_writel(__raw_readl(ctrl) & ~EEPROM_ECLK, ctrl);
+ delay();
+ __raw_writel(__raw_readl(ctrl) | EEPROM_ECLK, ctrl);
+ delay();
+ ser_cmd <<= 1;
+ }
+ /* see data sheet timing diagram */
+ __raw_writel(__raw_readl(ctrl) & ~EEPROM_DATO, ctrl);
+}
+
+unsigned short ip22_eeprom_read(unsigned int *ctrl, int reg)
+{
+ unsigned short res = 0;
+ int i;
+
+ __raw_writel(__raw_readl(ctrl) & ~EEPROM_EPROT, ctrl);
+ eeprom_cs_on(ctrl);
+ eeprom_cmd(ctrl, EEPROM_READ, reg);
+
+ /* clock the data ouf of serial mem */
+ for (i = 0; i < 16; i++) {
+ __raw_writel(__raw_readl(ctrl) & ~EEPROM_ECLK, ctrl);
+ delay();
+ __raw_writel(__raw_readl(ctrl) | EEPROM_ECLK, ctrl);
+ delay();
+ res <<= 1;
+ if (__raw_readl(ctrl) & EEPROM_DATI)
+ res |= 1;
+ }
+
+ eeprom_cs_off(ctrl);
+
+ return res;
+}
+
+EXPORT_SYMBOL(ip22_eeprom_read);
+
+/*
+ * Read specified register from main NVRAM
+ */
+unsigned short ip22_nvram_read(int reg)
+{
+ if (ip22_is_fullhouse())
+ /* IP22 (Indigo2 aka FullHouse) stores env variables into
+ * 93CS56 Microwire Bus EEPROM 2048 Bit (128x16) */
+ return ip22_eeprom_read(&hpc3c0->eeprom, reg);
+ else {
+ unsigned short tmp;
+ /* IP24 (Indy aka Guiness) uses DS1386 8K version */
+ reg <<= 1;
+ tmp = hpc3c0->bbram[reg++] & 0xff;
+ return (tmp << 8) | (hpc3c0->bbram[reg] & 0xff);
+ }
+}
+
+EXPORT_SYMBOL(ip22_nvram_read);