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-rw-r--r--arch/m68k/atari/nvram.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/arch/m68k/atari/nvram.c b/arch/m68k/atari/nvram.c
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index 000000000000..7000d2443aa3
--- /dev/null
+++ b/arch/m68k/atari/nvram.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * CMOS/NV-RAM driver for Atari. Adapted from drivers/char/nvram.c.
+ * Copyright (C) 1997 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
+ * idea by and with help from Richard Jelinek <rj@suse.de>
+ * Portions copyright (c) 2001,2002 Sun Microsystems (thockin@sun.com)
+ * Further contributions from Cesar Barros, Erik Gilling, Tim Hockin and
+ * Wim Van Sebroeck.
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/mc146818rtc.h>
+#include <linux/module.h>
+#include <linux/nvram.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <asm/atarihw.h>
+#include <asm/atariints.h>
+
+#define NVRAM_BYTES 50
+
+/* It is worth noting that these functions all access bytes of general
+ * purpose memory in the NVRAM - that is to say, they all add the
+ * NVRAM_FIRST_BYTE offset. Pass them offsets into NVRAM as if you did not
+ * know about the RTC cruft.
+ */
+
+/* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with
+ * rtc_lock held. Due to the index-port/data-port design of the RTC, we
+ * don't want two different things trying to get to it at once. (e.g. the
+ * periodic 11 min sync from kernel/time/ntp.c vs. this driver.)
+ */
+
+static unsigned char __nvram_read_byte(int i)
+{
+ return CMOS_READ(NVRAM_FIRST_BYTE + i);
+}
+
+/* This races nicely with trying to read with checksum checking */
+static void __nvram_write_byte(unsigned char c, int i)
+{
+ CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
+}
+
+/* On Ataris, the checksum is over all bytes except the checksum bytes
+ * themselves; these are at the very end.
+ */
+#define ATARI_CKS_RANGE_START 0
+#define ATARI_CKS_RANGE_END 47
+#define ATARI_CKS_LOC 48
+
+static int __nvram_check_checksum(void)
+{
+ int i;
+ unsigned char sum = 0;
+
+ for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
+ sum += __nvram_read_byte(i);
+ return (__nvram_read_byte(ATARI_CKS_LOC) == (~sum & 0xff)) &&
+ (__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
+}
+
+static void __nvram_set_checksum(void)
+{
+ int i;
+ unsigned char sum = 0;
+
+ for (i = ATARI_CKS_RANGE_START; i <= ATARI_CKS_RANGE_END; ++i)
+ sum += __nvram_read_byte(i);
+ __nvram_write_byte(~sum, ATARI_CKS_LOC);
+ __nvram_write_byte(sum, ATARI_CKS_LOC + 1);
+}
+
+long atari_nvram_set_checksum(void)
+{
+ spin_lock_irq(&rtc_lock);
+ __nvram_set_checksum();
+ spin_unlock_irq(&rtc_lock);
+ return 0;
+}
+
+long atari_nvram_initialize(void)
+{
+ loff_t i;
+
+ spin_lock_irq(&rtc_lock);
+ for (i = 0; i < NVRAM_BYTES; ++i)
+ __nvram_write_byte(0, i);
+ __nvram_set_checksum();
+ spin_unlock_irq(&rtc_lock);
+ return 0;
+}
+
+ssize_t atari_nvram_read(char *buf, size_t count, loff_t *ppos)
+{
+ char *p = buf;
+ loff_t i;
+
+ spin_lock_irq(&rtc_lock);
+ if (!__nvram_check_checksum()) {
+ spin_unlock_irq(&rtc_lock);
+ return -EIO;
+ }
+ for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p)
+ *p = __nvram_read_byte(i);
+ spin_unlock_irq(&rtc_lock);
+
+ *ppos = i;
+ return p - buf;
+}
+
+ssize_t atari_nvram_write(char *buf, size_t count, loff_t *ppos)
+{
+ char *p = buf;
+ loff_t i;
+
+ spin_lock_irq(&rtc_lock);
+ if (!__nvram_check_checksum()) {
+ spin_unlock_irq(&rtc_lock);
+ return -EIO;
+ }
+ for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p)
+ __nvram_write_byte(*p, i);
+ __nvram_set_checksum();
+ spin_unlock_irq(&rtc_lock);
+
+ *ppos = i;
+ return p - buf;
+}
+
+ssize_t atari_nvram_get_size(void)
+{
+ return NVRAM_BYTES;
+}
+
+#ifdef CONFIG_PROC_FS
+static struct {
+ unsigned char val;
+ const char *name;
+} boot_prefs[] = {
+ { 0x80, "TOS" },
+ { 0x40, "ASV" },
+ { 0x20, "NetBSD (?)" },
+ { 0x10, "Linux" },
+ { 0x00, "unspecified" },
+};
+
+static const char * const languages[] = {
+ "English (US)",
+ "German",
+ "French",
+ "English (UK)",
+ "Spanish",
+ "Italian",
+ "6 (undefined)",
+ "Swiss (French)",
+ "Swiss (German)",
+};
+
+static const char * const dateformat[] = {
+ "MM%cDD%cYY",
+ "DD%cMM%cYY",
+ "YY%cMM%cDD",
+ "YY%cDD%cMM",
+ "4 (undefined)",
+ "5 (undefined)",
+ "6 (undefined)",
+ "7 (undefined)",
+};
+
+static const char * const colors[] = {
+ "2", "4", "16", "256", "65536", "??", "??", "??"
+};
+
+static void atari_nvram_proc_read(unsigned char *nvram, struct seq_file *seq,
+ void *offset)
+{
+ int checksum;
+ int i;
+ unsigned int vmode;
+
+ spin_lock_irq(&rtc_lock);
+ checksum = __nvram_check_checksum();
+ spin_unlock_irq(&rtc_lock);
+
+ seq_printf(seq, "Checksum status : %svalid\n", checksum ? "" : "not ");
+
+ seq_puts(seq, "Boot preference : ");
+ for (i = ARRAY_SIZE(boot_prefs) - 1; i >= 0; --i)
+ if (nvram[1] == boot_prefs[i].val) {
+ seq_printf(seq, "%s\n", boot_prefs[i].name);
+ break;
+ }
+ if (i < 0)
+ seq_printf(seq, "0x%02x (undefined)\n", nvram[1]);
+
+ seq_printf(seq, "SCSI arbitration : %s\n",
+ (nvram[16] & 0x80) ? "on" : "off");
+ seq_puts(seq, "SCSI host ID : ");
+ if (nvram[16] & 0x80)
+ seq_printf(seq, "%d\n", nvram[16] & 7);
+ else
+ seq_puts(seq, "n/a\n");
+
+ if (!MACH_IS_FALCON)
+ return;
+
+ seq_puts(seq, "OS language : ");
+ if (nvram[6] < ARRAY_SIZE(languages))
+ seq_printf(seq, "%s\n", languages[nvram[6]]);
+ else
+ seq_printf(seq, "%u (undefined)\n", nvram[6]);
+ seq_puts(seq, "Keyboard language: ");
+ if (nvram[7] < ARRAY_SIZE(languages))
+ seq_printf(seq, "%s\n", languages[nvram[7]]);
+ else
+ seq_printf(seq, "%u (undefined)\n", nvram[7]);
+ seq_puts(seq, "Date format : ");
+ seq_printf(seq, dateformat[nvram[8] & 7],
+ nvram[9] ? nvram[9] : '/', nvram[9] ? nvram[9] : '/');
+ seq_printf(seq, ", %dh clock\n", nvram[8] & 16 ? 24 : 12);
+ seq_puts(seq, "Boot delay : ");
+ if (nvram[10] == 0)
+ seq_puts(seq, "default\n");
+ else
+ seq_printf(seq, "%ds%s\n", nvram[10],
+ nvram[10] < 8 ? ", no memory test" : "");
+
+ vmode = (nvram[14] << 8) | nvram[15];
+ seq_printf(seq,
+ "Video mode : %s colors, %d columns, %s %s monitor\n",
+ colors[vmode & 7], vmode & 8 ? 80 : 40,
+ vmode & 16 ? "VGA" : "TV", vmode & 32 ? "PAL" : "NTSC");
+ seq_printf(seq,
+ " %soverscan, compat. mode %s%s\n",
+ vmode & 64 ? "" : "no ", vmode & 128 ? "on" : "off",
+ vmode & 256 ?
+ (vmode & 16 ? ", line doubling" : ", half screen") : "");
+}
+
+static int nvram_proc_read(struct seq_file *seq, void *offset)
+{
+ unsigned char contents[NVRAM_BYTES];
+ int i;
+
+ spin_lock_irq(&rtc_lock);
+ for (i = 0; i < NVRAM_BYTES; ++i)
+ contents[i] = __nvram_read_byte(i);
+ spin_unlock_irq(&rtc_lock);
+
+ atari_nvram_proc_read(contents, seq, offset);
+
+ return 0;
+}
+
+static int __init atari_nvram_init(void)
+{
+ if (!(MACH_IS_ATARI && ATARIHW_PRESENT(TT_CLK)))
+ return -ENODEV;
+
+ if (!proc_create_single("driver/nvram", 0, NULL, nvram_proc_read)) {
+ pr_err("nvram: can't create /proc/driver/nvram\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+device_initcall(atari_nvram_init);
+#endif /* CONFIG_PROC_FS */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.