v4.19.13 snapshot.
diff --git a/arch/arm/mach-imx/cpu-imx27.c b/arch/arm/mach-imx/cpu-imx27.c
new file mode 100644
index 0000000..8d2ae40
--- /dev/null
+++ b/arch/arm/mach-imx/cpu-imx27.c
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+/*
+ * i.MX27 specific CPU detection code
+ */
+
+#include <linux/io.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 */
+
+static int mx27_read_cpu_rev(void)
+{
+ u32 val;
+ /*
+ * 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(MX27_IO_ADDRESS(MX27_SYSCTRL_BASE_ADDR + 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);