soc: xilinx: zynqmp: Add soc_xilinx_zynqmp driver

soc_xilinx_zynqmp driver allows identification of family & revision
of zynqmp SoC. This driver is selected by CONFIG_SOC_XILINX_ZYNQMP.
Add this config to xilinx_zynqmp_virt_defconfig file.
Probe this driver using platdata U_BOOT_DEVICE structure which is
specified in mach-zynqmp/cpu.c.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Reviewed-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/drivers/soc/soc_xilinx_zynqmp.c b/drivers/soc/soc_xilinx_zynqmp.c
new file mode 100644
index 0000000..7d33ce2
--- /dev/null
+++ b/drivers/soc/soc_xilinx_zynqmp.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx ZynqMP SOC driver
+ *
+ * Copyright (C) 2021 Xilinx, Inc.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <asm/cache.h>
+#include <soc.h>
+#include <zynqmp_firmware.h>
+#include <asm/arch/sys_proto.h>
+#include <asm/arch/hardware.h>
+
+/*
+ * Zynqmp has 4 silicon revisions
+ * v0 -> 0(XCZU9EG-ES1)
+ * v1 -> 1(XCZU3EG-ES1, XCZU15EG-ES1)
+ * v2 -> 2(XCZU7EV-ES1, XCZU9EG-ES2, XCZU19EG-ES1)
+ * v3 -> 3(Production Level)
+ */
+static const char zynqmp_family[] = "ZynqMP";
+
+struct soc_xilinx_zynqmp_priv {
+	const char *family;
+	char revision;
+};
+
+static int soc_xilinx_zynqmp_get_family(struct udevice *dev, char *buf, int size)
+{
+	struct soc_xilinx_zynqmp_priv *priv = dev_get_priv(dev);
+
+	return snprintf(buf, size, "%s", priv->family);
+}
+
+static int soc_xilinx_zynqmp_get_revision(struct udevice *dev, char *buf, int size)
+{
+	struct soc_xilinx_zynqmp_priv *priv = dev_get_priv(dev);
+
+	return snprintf(buf, size, "v%d", priv->revision);
+}
+
+static const struct soc_ops soc_xilinx_zynqmp_ops = {
+	.get_family = soc_xilinx_zynqmp_get_family,
+	.get_revision = soc_xilinx_zynqmp_get_revision,
+};
+
+static int soc_xilinx_zynqmp_probe(struct udevice *dev)
+{
+	struct soc_xilinx_zynqmp_priv *priv = dev_get_priv(dev);
+	u32 ret_payload[4];
+	int ret;
+
+	priv->family = zynqmp_family;
+
+	if (IS_ENABLED(CONFIG_SPL_BUILD) || current_el() == 3 ||
+	    !IS_ENABLED(CONFIG_ZYNQMP_FIRMWARE))
+		ret = zynqmp_mmio_read(ZYNQMP_PS_VERSION, &ret_payload[2]);
+	else
+		ret = xilinx_pm_request(PM_GET_CHIPID, 0, 0, 0, 0,
+					ret_payload);
+	if (ret < 0)
+		return ret;
+
+	priv->revision = ret_payload[2] & ZYNQMP_PS_VER_MASK;
+
+	return 0;
+}
+
+U_BOOT_DRIVER(soc_xilinx_zynqmp) = {
+	.name		= "soc_xilinx_zynqmp",
+	.id		= UCLASS_SOC,
+	.ops		= &soc_xilinx_zynqmp_ops,
+	.probe		= soc_xilinx_zynqmp_probe,
+	.priv_auto	= sizeof(struct soc_xilinx_zynqmp_priv),
+	.flags		= DM_FLAG_PRE_RELOC,
+};