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From:   Nava kishore Manne <nava.kishore.manne@amd.com>
To:     <mdf@kernel.org>, <hao.wu@intel.com>, <yilun.xu@intel.com>,
        <trix@redhat.com>, <michal.simek@xilinx.com>,
        <linux-fpga@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH] fpga: zynqmp: Make word align the configuration data
Date:   Tue, 14 Mar 2023 15:12:22 +0530
Message-ID: <20230314094222.66916-1-nava.kishore.manne@amd.com>
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To avoid unwanted copies at firmware(PMUFW) this patch provides a fix
to align programmable logic(PL) configuration data if the data is not
word-aligned. To align the configuration data this patch adds a few
padding bytes and these additional padding bytes will not create any
functional impact on the PL configuration.

Signed-off-by: Nava kishore Manne <nava.kishore.manne@amd.com>
---
 drivers/fpga/zynqmp-fpga.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/fpga/zynqmp-fpga.c b/drivers/fpga/zynqmp-fpga.c
index c60f20949c47..70a12dc6e15c 100644
--- a/drivers/fpga/zynqmp-fpga.c
+++ b/drivers/fpga/zynqmp-fpga.c
@@ -15,6 +15,9 @@
 /* Constant Definitions */
 #define IXR_FPGA_DONE_MASK	BIT(3)
 
+#define DUMMY_PAD_BYTE		0xFF
+#define FPGA_WORD_SIZE		4
+
 /**
  * struct zynqmp_fpga_priv - Private data structure
  * @dev:	Device data structure
@@ -41,18 +44,26 @@ static int zynqmp_fpga_ops_write(struct fpga_manager *mgr,
 				 const char *buf, size_t size)
 {
 	struct zynqmp_fpga_priv *priv;
+	int word_align, ret, index;
 	dma_addr_t dma_addr;
 	u32 eemi_flags = 0;
 	char *kbuf;
-	int ret;
 
 	priv = mgr->priv;
+	word_align = size % FPGA_WORD_SIZE;
+	if (word_align)
+		word_align = FPGA_WORD_SIZE - word_align;
+
+	size = size + word_align;
 
 	kbuf = dma_alloc_coherent(priv->dev, size, &dma_addr, GFP_KERNEL);
 	if (!kbuf)
 		return -ENOMEM;
 
-	memcpy(kbuf, buf, size);
+	for (index = 0; index < word_align; index++)
+		kbuf[index] = DUMMY_PAD_BYTE;
+
+	memcpy(&kbuf[index], buf, size - index);
 
 	wmb(); /* ensure all writes are done before initiate FW call */
 
-- 
2.25.1