ARM: Add cpuinfo command

This command is useful to show some information about
cp15 registers

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 145 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 44c4ad8d98..d2a7ef3fc3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -179,6 +179,13 @@ source arch/arm/mach-omap/Kconfig
 
 menu "Arm specific settings         "
 
+config CMD_ARM_CPUINFO
+	bool "cpuinfo command"
+	default y
+	help
+	  Say yes here to get a cpuinfo command to show some
+	  information about the cp15 registers
+	
 config CMDLINE_TAG
 	bool "Send commandline to kernel"
 	default y
diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile
index 2cbed3db1c..02c26f41ef 100644
--- a/arch/arm/cpu/Makefile
+++ b/arch/arm/cpu/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_ARM920T) += start-arm.o
 obj-$(CONFIG_ARM926EJS) += start-arm.o
 obj-$(CONFIG_ARMCORTEXA8) += start-arm.o
 obj-$(CONFIG_ARCH_IMX31) += start-arm.o
+obj-$(CONFIG_CMD_ARM_CPUINFO) += cpuinfo.o
diff --git a/arch/arm/cpu/cpuinfo.c b/arch/arm/cpu/cpuinfo.c
new file mode 100644
index 0000000000..632cffa446
--- /dev/null
+++ b/arch/arm/cpu/cpuinfo.c
@@ -0,0 +1,137 @@
+/*
+ * cpuinfo.c - Show information about cp15 registers
+ *
+ * Copyright (c) 2009 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ *
+ * 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 version 2
+ * as published by the Free Software Foundation.
+ *
+ * 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
+ */
+
+#include <common.h>
+#include <command.h>
+
+static void decode_cache(unsigned long size)
+{
+	int linelen = 1 << ((size & 0x3) + 3);
+	int mult = 2 + ((size >> 2) & 1);
+	int cache_size = mult << (((size >> 6) & 0x7) + 8);
+
+	if (((size >> 2) & 0xf) == 1)
+		printf("no cache\n");
+	else
+		printf("%d bytes (linelen = %d)\n", cache_size, linelen);
+}
+
+static char *post_arm7_archs[] = {"v4", "v4T", "v5", "v5T", "v5TE", "v5TEJ", "v6"};
+
+static char *crbits[] = {"M", "A", "C", "W", "P", "D", "L", "B", "S", "R",
+	"F", "Z", "I", "V", "RR", "L4", "", "", "", "", "", "FI", "U", "XP",
+	"VE", "EE", "L2"};
+
+static int do_cpuinfo(cmd_tbl_t *cmdtp, int argc, char *argv[])
+{
+	unsigned long mainid, cache, cr;
+	char *architecture, *implementer;
+	int i;
+
+	__asm__ __volatile__(
+		"mrc    p15, 0, %0, c0, c0, 0   @ read control reg\n"
+		: "=r" (mainid)
+		:
+		: "memory");
+
+	__asm__ __volatile__(
+		"mrc    p15, 0, %0, c0, c0, 1   @ read control reg\n"
+		: "=r" (cache)
+		:
+		: "memory");
+
+	__asm__ __volatile__(
+		"mrc    p15, 0, %0, c1, c0, 0   @ read control reg\n"
+			: "=r" (cr)
+			:
+			: "memory");
+
+	switch (mainid >> 24) {
+	case 0x41:
+		implementer = "ARM";
+		break;
+	case 0x44:
+		implementer = "Digital Equipment Corp.";
+		break;
+	case 0x40:
+		implementer = "Motorola - Freescale Semiconductor Inc.";
+		break;
+	case 0x56:
+		implementer = "Marvell Semiconductor Inc.";
+		break;
+	case 0x69:
+		implementer = "Intel Corp.";
+		break;
+	default:
+		implementer = "Unknown";
+	}
+
+	if ((mainid & 0x0008f000) == 0x00000000) {
+                /* pre-ARM7 */
+                architecture = "Pre-ARM7";
+        } else {
+                if ((mainid & 0x0008f000) == 0x00007000) {
+                        /* ARM7 */
+			if (mainid & (1 << 23))
+				architecture = "3";
+			else
+				architecture = "4T";
+                } else {
+                        /* post-ARM7 */
+			int arch = (mainid >> 16) & 0xf;
+			if (arch > 0 && arch < 8)
+				architecture = post_arm7_archs[arch - 1];
+			else
+				architecture = "Unknown";
+                }
+        }
+
+	printf("implementer: %s\narchitecture: %s\n",
+			implementer, architecture);
+
+	if (cache & (1 << 24)) {
+		/* seperate I/D cache */
+		printf("I-cache: ");
+		decode_cache(cache & 0xfff);
+		printf("D-cache: ");
+		decode_cache((cache >> 12) & 0xfff);
+	} else {
+		/* unified I/D cache */
+		printf("cache: ");
+		decode_cache(cache & 0xfff);
+	}
+
+	printf("Control register: ");
+	for (i = 0; i < 27; i++)
+		if (cr & (1 << i))
+			printf("%s ", crbits[i]);
+	printf("\n");
+
+	return 0;
+}
+
+U_BOOT_CMD_START(cpuinfo)
+	.maxargs        = CONFIG_MAXARGS,
+	.cmd            = do_cpuinfo,
+	.usage          = "Show info about CPU",
+U_BOOT_CMD_END
+