[PATCH V5 XRT Alveo 14/20] fpga: xrt: ICAP driver

Lizhi Hou
2021-04-27T21:01:31Z

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@xilinx.com>
Signed-off-by: Max Zhen <max.zhen@xilinx.com>
Signed-off-by: Lizhi Hou <lizhi.hou@xilinx.com>
---
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@xilinx.com>
+ */
+
+#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..755ea2fc0e75
--- /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@xilinx.com>
+ * Sonal Santan <sonals@xilinx.com>
+ * Max Zhen <maxz@xilinx.com>
+ */
+
+#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 u32 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 u32 *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 u32 *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, (u32 *)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