nvme: Add NVM Express driver support

NVM Express (NVMe) is a register level interface that allows host
software to communicate with a non-volatile memory subsystem. This
interface is optimized for enterprise and client solid state drives,
typically attached to the PCI express interface.

This adds a U-Boot driver support of devices that follow the NVMe
standard [1] and supports basic read/write operations.

Tested with a 400GB Intel SSD 750 series NVMe card with controller
id 8086:0953.

[1] http://www.nvmexpress.org/resources/specifications/

Signed-off-by: Zhikang Zhang <zhikang.zhang@nxp.com>
Signed-off-by: Wenbin Song <wenbin.song@nxp.com>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/nvme/nvme-uclass.c b/drivers/nvme/nvme-uclass.c
new file mode 100644
index 0000000..0895bc9
--- /dev/null
+++ b/drivers/nvme/nvme-uclass.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2017 NXP Semiconductors
+ * Copyright (C) 2017 Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <dm.h>
+#include <dm/device.h>
+#include "nvme.h"
+
+static int nvme_info_init(struct uclass *uc)
+{
+	struct nvme_info *info = (struct nvme_info *)uc->priv;
+
+	info->ns_num = 0;
+	info->ndev_num = 0;
+	INIT_LIST_HEAD(&info->dev_list);
+	nvme_info = info;
+
+	return 0;
+}
+
+static int nvme_uclass_post_probe(struct udevice *udev)
+{
+	char name[20];
+	char *str;
+	struct udevice *ns_udev;
+	int i, ret;
+	struct nvme_dev *ndev = dev_get_priv(udev);
+
+	/* Create a blk device for each namespace */
+	for (i = 0; i < ndev->nn; i++) {
+		sprintf(name, "nvme-blk#%d", nvme_info->ns_num);
+		str = strdup(name);
+		if (!str)
+			return -ENOMEM;
+
+		/* The real blksz and size will be set by nvme_blk_probe() */
+		ret = blk_create_device(udev, "nvme-blk", str, IF_TYPE_NVME,
+					nvme_info->ns_num++, 512, 0, &ns_udev);
+		if (ret) {
+			free(str);
+			nvme_info->ns_num--;
+
+			return ret;
+		}
+		device_set_name_alloced(ns_udev);
+	}
+
+	return 0;
+}
+
+UCLASS_DRIVER(nvme) = {
+	.name	= "nvme",
+	.id	= UCLASS_NVME,
+	.init	= nvme_info_init,
+	.post_probe = nvme_uclass_post_probe,
+	.priv_auto_alloc_size = sizeof(struct nvme_info),
+};