1 files changed, 69 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/cpu-imx27.c b/arch/arm/mach-imx/cpu-imx27.c
new file mode 100644
index 000000000..1d2893908
--- /dev/null
+++ b/arch/arm/mach-imx/cpu-imx27.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ */
+
+/*
+ * i.MX27 specific CPU detection code
+ */
+
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/module.h>
+
+#include "hardware.h"
+
+static int mx27_cpu_rev = -1;
+static int mx27_cpu_partnumber;
+
+#define SYS_CHIP_ID             0x00    /* The offset of CHIP ID register */
+#define SYSCTRL_OFFSET		0x800	/* Offset from CCM base address */
+
+static int mx27_read_cpu_rev(void)
+{
+	void __iomem *ccm_base;
+	struct device_node *np;
+	u32 val;
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,imx27-ccm");
+	ccm_base = of_iomap(np, 0);
+	of_node_put(np);
+	BUG_ON(!ccm_base);
+	/*
+	 * now we have access to the IO registers. As we need
+	 * the silicon revision very early we read it here to
+	 * avoid any further hooks
+	*/
+	val = imx_readl(ccm_base + SYSCTRL_OFFSET + SYS_CHIP_ID);
+
+	mx27_cpu_partnumber = (int)((val >> 12) & 0xFFFF);
+
+	switch (val >> 28) {
+	case 0:
+		return IMX_CHIP_REVISION_1_0;
+	case 1:
+		return IMX_CHIP_REVISION_2_0;
+	case 2:
+		return IMX_CHIP_REVISION_2_1;
+	default:
+		return IMX_CHIP_REVISION_UNKNOWN;
+	}
+}
+
+/*
+ * Returns:
+ *	the silicon revision of the cpu
+ *	-EINVAL - not a mx27
+ */
+int mx27_revision(void)
+{
+	if (mx27_cpu_rev == -1)
+		mx27_cpu_rev = mx27_read_cpu_rev();
+
+	if (mx27_cpu_partnumber != 0x8821)
+		return -EINVAL;
+
+	return mx27_cpu_rev;
+}
+EXPORT_SYMBOL(mx27_revision);