[PATCH V8 XRT Alveo 12/14] fpga: xrt: ICAP driver

[Lizhi Hou]

ICAP stands for Hardware Internal Configuration Access Port. ICAP is
discovered by walking the firmware metadata. A xrt device node will be
created for it. FPGA bitstream is written to hardware through ICAP.

Signed-off-by: Sonal Santan <sonal.santan@xxxxxxxxxx>
Signed-off-by: Max Zhen <max.zhen@xxxxxxxxxx>
Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxxxxx>
Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
---
 drivers/fpga/xrt/include/xleaf/icap.h |  27 +++
 drivers/fpga/xrt/lib/xleaf/icap.c     | 328 ++++++++++++++++++++++++++
 2 files changed, 355 insertions(+)
 create mode 100644 drivers/fpga/xrt/include/xleaf/icap.h
 create mode 100644 drivers/fpga/xrt/lib/xleaf/icap.c

diff --git a/drivers/fpga/xrt/include/xleaf/icap.h b/drivers/fpga/xrt/include/xleaf/icap.h
new file mode 100644
index 000000000000..96d39a8934fa
--- /dev/null
+++ b/drivers/fpga/xrt/include/xleaf/icap.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *	Lizhi Hou <Lizhi.Hou@xxxxxxxxxx>
+ */
+
+#ifndef _XRT_ICAP_H_
+#define _XRT_ICAP_H_
+
+#include "xleaf.h"
+
+/*
+ * ICAP driver leaf calls.
+ */
+enum xrt_icap_leaf_cmd {
+	XRT_ICAP_WRITE = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
+	XRT_ICAP_GET_IDCODE,
+};
+
+struct xrt_icap_wr {
+	void	*xiiw_bit_data;
+	u32	xiiw_data_len;
+};
+
+#endif	/* _XRT_ICAP_H_ */
diff --git a/drivers/fpga/xrt/lib/xleaf/icap.c b/drivers/fpga/xrt/lib/xleaf/icap.c
new file mode 100644
index 000000000000..071923f61537
--- /dev/null
+++ b/drivers/fpga/xrt/lib/xleaf/icap.c
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Alveo FPGA ICAP Driver
+ *
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *      Lizhi Hou<Lizhi.Hou@xxxxxxxxxx>
+ *      Sonal Santan <sonals@xxxxxxxxxx>
+ *      Max Zhen <maxz@xxxxxxxxxx>
+ */
+
+#include <linux/mod_devicetable.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/regmap.h>
+#include <linux/io.h>
+#include "metadata.h"
+#include "xleaf.h"
+#include "xleaf/icap.h"
+#include "xclbin-helper.h"
+
+#define XRT_ICAP "xrt_icap"
+
+#define ICAP_ERR(icap, fmt, arg...)	\
+	xrt_err((icap)->xdev, fmt "\n", ##arg)
+#define ICAP_WARN(icap, fmt, arg...)	\
+	xrt_warn((icap)->xdev, fmt "\n", ##arg)
+#define ICAP_INFO(icap, fmt, arg...)	\
+	xrt_info((icap)->xdev, fmt "\n", ##arg)
+#define ICAP_DBG(icap, fmt, arg...)	\
+	xrt_dbg((icap)->xdev, fmt "\n", ##arg)
+
+/*
+ * AXI-HWICAP IP register layout. Please see
+ * https://www.xilinx.com/support/documentation/ip_documentation/axi_hwicap/v3_0/pg134-axi-hwicap.pdf
+ */
+#define ICAP_REG_GIER		0x1C
+#define ICAP_REG_ISR		0x20
+#define ICAP_REG_IER		0x28
+#define ICAP_REG_WF		0x100
+#define ICAP_REG_RF		0x104
+#define ICAP_REG_SZ		0x108
+#define ICAP_REG_CR		0x10C
+#define ICAP_REG_SR		0x110
+#define ICAP_REG_WFV		0x114
+#define ICAP_REG_RFO		0x118
+#define ICAP_REG_ASR		0x11C
+
+#define ICAP_STATUS_EOS		0x4
+#define ICAP_STATUS_DONE	0x1
+
+/*
+ * Canned command sequence to obtain IDCODE of the FPGA
+ */
+static const __be32 idcode_stream[] = {
+	/* dummy word */
+	cpu_to_be32(0xffffffff),
+	/* sync word */
+	cpu_to_be32(0xaa995566),
+	/* NOP word */
+	cpu_to_be32(0x20000000),
+	/* NOP word */
+	cpu_to_be32(0x20000000),
+	/* ID code */
+	cpu_to_be32(0x28018001),
+	/* NOP word */
+	cpu_to_be32(0x20000000),
+	/* NOP word */
+	cpu_to_be32(0x20000000),
+};
+
+XRT_DEFINE_REGMAP_CONFIG(icap_regmap_config);
+
+struct icap {
+	struct xrt_device	*xdev;
+	struct regmap		*regmap;
+	struct mutex		icap_lock; /* icap dev lock */
+	u32			idcode;
+};
+
+static int wait_for_done(const struct icap *icap)
+{
+	int i = 0;
+	int ret;
+	u32 w;
+
+	for (i = 0; i < 10; i++) {
+		/*
+		 * it requires few micro seconds for ICAP to process incoming data.
+		 * Polling every 5us for 10 times would be good enough.
+		 */
+		udelay(5);
+		ret = regmap_read(icap->regmap, ICAP_REG_SR, &w);
+		if (ret)
+			return ret;
+		ICAP_INFO(icap, "XHWICAP_SR: %x", w);
+		if (w & (ICAP_STATUS_EOS | ICAP_STATUS_DONE))
+			return 0;
+	}
+
+	ICAP_ERR(icap, "bitstream download timeout");
+	return -ETIMEDOUT;
+}
+
+static int icap_write(const struct icap *icap, const __be32 *word_buf, int size)
+{
+	u32 value = 0;
+	int ret;
+	int i;
+
+	for (i = 0; i < size; i++) {
+		value = be32_to_cpu(word_buf[i]);
+		ret = regmap_write(icap->regmap, ICAP_REG_WF, value);
+		if (ret)
+			return ret;
+	}
+
+	ret = regmap_write(icap->regmap, ICAP_REG_CR, 0x1);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < 20; i++) {
+		ret = regmap_read(icap->regmap, ICAP_REG_CR, &value);
+		if (ret)
+			return ret;
+
+		if ((value & 0x1) == 0)
+			return 0;
+		ndelay(50);
+	}
+
+	ICAP_ERR(icap, "writing %d dwords timeout", size);
+	return -EIO;
+}
+
+static int bitstream_helper(struct icap *icap, const __be32 *word_buffer,
+			    u32 word_count)
+{
+	int wr_fifo_vacancy = 0;
+	u32 word_written = 0;
+	u32 remain_word;
+	int err = 0;
+
+	WARN_ON(!mutex_is_locked(&icap->icap_lock));
+	for (remain_word = word_count; remain_word > 0;
+	     remain_word -= word_written, word_buffer += word_written) {
+		err = regmap_read(icap->regmap, ICAP_REG_WFV, &wr_fifo_vacancy);
+		if (err) {
+			ICAP_ERR(icap, "read wr_fifo_vacancy failed %d", err);
+			break;
+		}
+		if (wr_fifo_vacancy <= 0) {
+			ICAP_ERR(icap, "no vacancy: %d", wr_fifo_vacancy);
+			err = -EIO;
+			break;
+		}
+		word_written = (wr_fifo_vacancy < remain_word) ?
+			wr_fifo_vacancy : remain_word;
+		if (icap_write(icap, word_buffer, word_written) != 0) {
+			ICAP_ERR(icap, "write failed remain %d, written %d",
+				 remain_word, word_written);
+			err = -EIO;
+			break;
+		}
+	}
+
+	return err;
+}
+
+static int icap_download(struct icap *icap, const char *buffer,
+			 unsigned long length)
+{
+	u32	num_chars_read = XCLBIN_HWICAP_BITFILE_BUF_SZ;
+	u32	byte_read;
+	int	err = 0;
+
+	if (length % sizeof(u32)) {
+		ICAP_ERR(icap, "invalid bitstream length %ld", length);
+		return -EINVAL;
+	}
+
+	mutex_lock(&icap->icap_lock);
+	for (byte_read = 0; byte_read < length; byte_read += num_chars_read) {
+		num_chars_read = length - byte_read;
+		if (num_chars_read > XCLBIN_HWICAP_BITFILE_BUF_SZ)
+			num_chars_read = XCLBIN_HWICAP_BITFILE_BUF_SZ;
+
+		err = bitstream_helper(icap, (__be32 *)buffer, num_chars_read / sizeof(u32));
+		if (err)
+			goto failed;
+		buffer += num_chars_read;
+	}
+
+	/* there is not any cleanup needs to be done if writing ICAP timeout. */
+	err = wait_for_done(icap);
+
+failed:
+	mutex_unlock(&icap->icap_lock);
+
+	return err;
+}
+
+/*
+ * Discover the FPGA IDCODE using special sequence of canned commands
+ */
+static int icap_probe_chip(struct icap *icap)
+{
+	int err;
+	u32 val = 0;
+
+	regmap_read(icap->regmap, ICAP_REG_SR, &val);
+	if (val != ICAP_STATUS_DONE)
+		return -ENODEV;
+	/* Read ICAP FIFO vacancy */
+	regmap_read(icap->regmap, ICAP_REG_WFV, &val);
+	if (val < 8)
+		return -ENODEV;
+	err = icap_write(icap, idcode_stream, ARRAY_SIZE(idcode_stream));
+	if (err)
+		return err;
+	err = wait_for_done(icap);
+	if (err)
+		return err;
+
+	/* Tell config engine how many words to transfer to read FIFO */
+	regmap_write(icap->regmap, ICAP_REG_SZ, 0x1);
+	/* Switch the ICAP to read mode */
+	regmap_write(icap->regmap, ICAP_REG_CR, 0x2);
+	err = wait_for_done(icap);
+	if (err)
+		return err;
+
+	/* Read IDCODE from Read FIFO */
+	regmap_read(icap->regmap, ICAP_REG_RF, &icap->idcode);
+	return 0;
+}
+
+static int
+xrt_icap_leaf_call(struct xrt_device *xdev, u32 cmd, void *arg)
+{
+	struct xrt_icap_wr *wr_arg = arg;
+	struct icap *icap;
+	int ret = 0;
+
+	icap = xrt_get_drvdata(xdev);
+
+	switch (cmd) {
+	case XRT_XLEAF_EVENT:
+		/* Does not handle any event. */
+		break;
+	case XRT_ICAP_WRITE:
+		ret = icap_download(icap, wr_arg->xiiw_bit_data,
+				    wr_arg->xiiw_data_len);
+		break;
+	case XRT_ICAP_GET_IDCODE:
+		*(u32 *)arg = icap->idcode;
+		break;
+	default:
+		ICAP_ERR(icap, "unknown command %d", cmd);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int xrt_icap_probe(struct xrt_device *xdev)
+{
+	void __iomem *base = NULL;
+	struct resource *res;
+	struct icap *icap;
+	int result = 0;
+
+	icap = devm_kzalloc(&xdev->dev, sizeof(*icap), GFP_KERNEL);
+	if (!icap)
+		return -ENOMEM;
+
+	icap->xdev = xdev;
+	xrt_set_drvdata(xdev, icap);
+	mutex_init(&icap->icap_lock);
+
+	xrt_info(xdev, "probing");
+	res = xrt_get_resource(xdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+
+	base = devm_ioremap_resource(&xdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	icap->regmap = devm_regmap_init_mmio(&xdev->dev, base, &icap_regmap_config);
+	if (IS_ERR(icap->regmap)) {
+		ICAP_ERR(icap, "init mmio failed");
+		return PTR_ERR(icap->regmap);
+	}
+	/* Disable ICAP interrupts */
+	regmap_write(icap->regmap, ICAP_REG_GIER, 0);
+
+	result = icap_probe_chip(icap);
+	if (result)
+		xrt_err(xdev, "Failed to probe FPGA");
+	else
+		xrt_info(xdev, "Discovered FPGA IDCODE %x", icap->idcode);
+	return result;
+}
+
+static struct xrt_dev_endpoints xrt_icap_endpoints[] = {
+	{
+		.xse_names = (struct xrt_dev_ep_names[]) {
+			{ .ep_name = XRT_MD_NODE_FPGA_CONFIG },
+			{ NULL },
+		},
+		.xse_min_ep = 1,
+	},
+	{ 0 },
+};
+
+static struct xrt_driver xrt_icap_driver = {
+	.driver = {
+		.name = XRT_ICAP,
+	},
+	.subdev_id = XRT_SUBDEV_ICAP,
+	.endpoints = xrt_icap_endpoints,
+	.probe = xrt_icap_probe,
+	.leaf_call = xrt_icap_leaf_call,
+};
+
+XRT_LEAF_INIT_FINI_FUNC(icap);
-- 
2.27.0