[RFC PATCH 4/4] fpga: zynqmp: Add user-key encrypted FPGA Image loading support

[Nava kishore Manne <nava.manne@xxxxxxxxxx>]

This patch adds support to load the user-key encrypted FPGA
Image loading to the Xilinx ZynqMP Soc.

Signed-off-by: Nava kishore Manne <nava.manne@xxxxxxxxxx>
---
 drivers/fpga/zynqmp-fpga.c           | 24 ++++++++++++++++++++++--
 include/linux/firmware/xlnx-zynqmp.h |  2 ++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/fpga/zynqmp-fpga.c b/drivers/fpga/zynqmp-fpga.c
index 125743c9797f..565ebe9e1610 100644
--- a/drivers/fpga/zynqmp-fpga.c
+++ b/drivers/fpga/zynqmp-fpga.c
@@ -22,6 +22,8 @@
  */
 struct zynqmp_fpga_priv {
 	struct device *dev;
+	const char *key_buf;
+	size_t key_size;
 	u32 flags;
 };
 
@@ -33,6 +35,8 @@ static int zynqmp_fpga_ops_write_init(struct fpga_manager *mgr,
 
 	priv = mgr->priv;
 	priv->flags = info->flags;
+	priv->key_buf = info->enc_key_buf;
+	priv->key_size = info->enc_key_buf_size;
 
 	return 0;
 }
@@ -41,9 +45,9 @@ static int zynqmp_fpga_ops_write(struct fpga_manager *mgr,
 				 const char *buf, size_t size)
 {
 	struct zynqmp_fpga_priv *priv;
-	dma_addr_t dma_addr;
+	dma_addr_t dma_addr, key_addr;
 	u32 eemi_flags = 0;
-	char *kbuf;
+	char *kbuf, *key_kbuf;
 	int ret;
 
 	priv = mgr->priv;
@@ -54,13 +58,29 @@ static int zynqmp_fpga_ops_write(struct fpga_manager *mgr,
 
 	memcpy(kbuf, buf, size);
 
+	if (priv->flags & FPGA_MGR_ENCRYPTED_USER_KEY_BITSTREAM) {
+		eemi_flags |= XILINX_ZYNQMP_PM_FPGA_ENC_USER_KEY;
+		key_kbuf = dma_alloc_coherent(priv->dev, size, &key_addr,
+					      GFP_KERNEL);
+		if (!key_kbuf)
+			return -ENOMEM;
+		memcpy(key_kbuf, priv->key_buf, priv->key_size);
+	}
+
 	wmb(); /* ensure all writes are done before initiate FW call */
 
 	if (priv->flags & FPGA_MGR_PARTIAL_RECONFIG)
 		eemi_flags |= XILINX_ZYNQMP_PM_FPGA_PARTIAL;
 
+	if (priv->flags & FPGA_MGR_ENCRYPTED_USER_KEY_BITSTREAM)
+		ret = zynqmp_pm_fpga_enc_key_load(key_addr, priv->key_size);
+
 	ret = zynqmp_pm_fpga_load(dma_addr, size, eemi_flags);
 
+	if (priv->flags & FPGA_MGR_ENCRYPTED_USER_KEY_BITSTREAM)
+		dma_free_coherent(priv->dev, priv->key_size,
+				  key_kbuf, key_addr);
+
 	dma_free_coherent(priv->dev, size, kbuf, dma_addr);
 
 	return ret;
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index 7aa9ad40ff53..a767386d930a 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/include/linux/firmware/xlnx-zynqmp.h
@@ -56,9 +56,11 @@
  * Firmware FPGA Manager flags
  * XILINX_ZYNQMP_PM_FPGA_FULL:	FPGA full reconfiguration
  * XILINX_ZYNQMP_PM_FPGA_PARTIAL: FPGA partial reconfiguration
+ * XILINX_ZYNQMP_PM_FPGA_ENC_USER_KEY: User-key Encrypted FPGA reconfiguration
  */
 #define XILINX_ZYNQMP_PM_FPGA_FULL	0x0U
 #define XILINX_ZYNQMP_PM_FPGA_PARTIAL	BIT(0)
+#define XILINX_ZYNQMP_PM_FPGA_ENC_USER_KEY	BIT(3)
 
 enum pm_api_id {
 	PM_GET_API_VERSION = 1,
-- 
2.17.1