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-rw-r--r--cpu/arm1176/cpu.c188
1 files changed, 188 insertions, 0 deletions
diff --git a/cpu/arm1176/cpu.c b/cpu/arm1176/cpu.c
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+/*
+ * (C) Copyright 2004 Texas Insturments
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ *
+ * (C) Copyright 2002
+ * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * CPU specific code
+ */
+
+#include <common.h>
+#include <command.h>
+#include <s3c6400.h>
+
+static void cache_flush (void);
+
+/* read co-processor 15, register #1 (control register) */
+static unsigned long read_p15_c1 (void)
+{
+ unsigned long value;
+
+ __asm__ __volatile__(
+ "mrc p15, 0, %0, c1, c0, 0 @ read control reg\n"
+ : "=r" (value)
+ :
+ : "memory");
+ return value;
+}
+
+/* write to co-processor 15, register #1 (control register) */
+static void write_p15_c1 (unsigned long value)
+{
+ __asm__ __volatile__(
+ "mcr p15, 0, %0, c1, c0, 0 @ write it back\n"
+ :
+ : "r" (value)
+ : "memory");
+
+ read_p15_c1();
+}
+
+static void cp_delay (void)
+{
+ volatile int i;
+
+ /* Many OMAP regs need at least 2 nops */
+ for (i = 0; i < 100; i++)
+ __asm__ __volatile__("nop\n");
+}
+
+/* See also ARM Ref. Man. */
+#define C1_MMU (1 << 0) /* mmu off/on */
+#define C1_ALIGN (1 << 1) /* alignment faults off/on */
+#define C1_DC (1 << 2) /* dcache off/on */
+#define C1_WB (1 << 3) /* merging write buffer on/off */
+#define C1_BIG_ENDIAN (1 << 7) /* big endian off/on */
+#define C1_SYS_PROT (1 << 8) /* system protection */
+#define C1_ROM_PROT (1 << 9) /* ROM protection */
+#define C1_IC (1 << 12) /* icache off/on */
+#define C1_HIGH_VECTORS (1 << 13) /* location of vectors: low/high */
+#define RESERVED_1 (0xf << 3) /* must be 111b for R/W */
+
+int cpu_init (void)
+{
+ return 0;
+}
+
+int cleanup_before_linux (void)
+{
+ /*
+ * this function is called just before we call linux
+ * it prepares the processor for linux
+ *
+ * we turn off caches etc ...
+ */
+
+ disable_interrupts ();
+
+ /* turn off I/D-cache */
+ icache_disable();
+ dcache_disable();
+ cache_flush();
+
+ return 0;
+}
+
+
+/* * reset the cpu by setting up the watchdog timer and let him time out */
+void reset_cpu (ulong ignored)
+{
+ printf("reset... \n\n\n");
+ SW_RST_REG = 0x6400;
+ /* loop forever and wait for reset to happen */
+ while (1) {
+ if (serial_tstc()) {
+ serial_getc();
+ break;
+ }
+ }
+ /*NOTREACHED*/
+}
+
+int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+ disable_interrupts ();
+ reset_cpu (0);
+ /*NOTREACHED*/
+ return 0;
+}
+
+void icache_enable (void)
+{
+ ulong reg;
+
+ reg = read_p15_c1 (); /* get control reg. */
+ cp_delay ();
+ write_p15_c1 (reg | C1_IC);
+}
+
+void icache_disable (void)
+{
+ ulong reg;
+
+ reg = read_p15_c1 ();
+ cp_delay ();
+ write_p15_c1 (reg & ~C1_IC);
+}
+
+int icache_status (void)
+{
+ return (read_p15_c1 () & C1_IC) != 0;
+}
+
+/* It makes no sense to use the dcache if the MMU is not enabled */
+void dcache_enable (void)
+{
+ ulong reg;
+
+ reg = read_p15_c1 ();
+ cp_delay ();
+ write_p15_c1 (reg | C1_DC);
+}
+
+void dcache_disable (void)
+{
+ ulong reg;
+
+ reg = read_p15_c1 ();
+ cp_delay ();
+ write_p15_c1 (reg & ~C1_DC);
+}
+
+int dcache_status (void)
+{
+ return (read_p15_c1 () & C1_DC) != 0;
+}
+
+/* flush I/D-cache */
+static void cache_flush (void)
+{
+ /* invalidate both caches and flush btb */
+ asm ("mcr p15, 0, %0, c7, c7, 0": :"r" (0));
+ /* mem barrier to sync things */
+ asm ("mcr p15, 0, %0, c7, c10, 4": :"r" (0));
+}