Re: [PATCH V3 XRT Alveo 12/18] fpga: xrt: ICAP platform driver

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Hi Tom,


On 03/03/2021 07:12 AM, Tom Rix wrote:
On 2/17/21 10:40 PM, Lizhi Hou wrote:
Add ICAP driver. ICAP is a hardware function discovered by walking
What does ICAP stand for ?
ICAP stands for Hardware Internal Configuration Access Port. I will add this.
firmware metadata. A platform 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 <lizhih@xxxxxxxxxx>
---
  drivers/fpga/xrt/include/xleaf/icap.h |  29 +++
  drivers/fpga/xrt/lib/xleaf/icap.c     | 317 ++++++++++++++++++++++++++
  2 files changed, 346 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..a14fc0ffa78f
--- /dev/null
+++ b/drivers/fpga/xrt/include/xleaf/icap.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Header file for XRT ICAP Leaf Driver
+ *
+ * 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 IOCTL calls.
+ */
+enum xrt_icap_ioctl_cmd {
+     XRT_ICAP_WRITE = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
maybe XRT_ICAP_GET_IDCODE
Sure.
+     XRT_ICAP_IDCODE,
+};
+
+struct xrt_icap_ioctl_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..0500a97bdef9
--- /dev/null
+++ b/drivers/fpga/xrt/lib/xleaf/icap.c
@@ -0,0 +1,317 @@
+// 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/platform_device.h>
+#include <linux/delay.h>
+#include <linux/device.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)->pdev, fmt "\n", ##arg)
+#define ICAP_WARN(icap, fmt, arg...) \
+     xrt_warn((icap)->pdev, fmt "\n", ##arg)
+#define ICAP_INFO(icap, fmt, arg...) \
+     xrt_info((icap)->pdev, fmt "\n", ##arg)
+#define ICAP_DBG(icap, fmt, arg...)  \
+     xrt_dbg((icap)->pdev, fmt "\n", ##arg)
+
+/*
+ * AXI-HWICAP IP register layout
+ */
+struct icap_reg {
+     u32     ir_rsvd1[7];
+     u32     ir_gier;
+     u32     ir_isr;
+     u32     ir_rsvd2;
+     u32     ir_ier;
+     u32     ir_rsvd3[53];
+     u32     ir_wf;
+     u32     ir_rf;
+     u32     ir_sz;
+     u32     ir_cr;
+     u32     ir_sr;
+     u32     ir_wfv;
+     u32     ir_rfo;
+     u32     ir_asr;
+} __packed;
+
+struct icap {
+     struct platform_device  *pdev;
+     struct icap_reg         *icap_regs;
+     struct mutex            icap_lock; /* icap dev lock */
+
+     unsigned int            idcode;
returned as a 64 bit value, but could be stored as 32 bit
Will change return to u32.
+};
+
+static inline u32 reg_rd(void __iomem *reg)
+{
+     if (!reg)
+             return -1;
+
+     return ioread32(reg);
Look at converting the io access to using regmap* api
Will change it.
+}
+
+static inline void reg_wr(void __iomem *reg, u32 val)
+{
+     if (!reg)
+             return;
+
+     iowrite32(val, reg);
+}
+
+static int wait_for_done(struct icap *icap)
+{
+     u32     w;
+     int     i = 0;
+
+     WARN_ON(!mutex_is_locked(&icap->icap_lock));
is this needed ? wait_for_done is only called in one place.
Will remove it.
+     for (i = 0; i < 10; i++) {
+             udelay(5);
comment on delay.
+             w = reg_rd(&icap->icap_regs->ir_sr);
+             ICAP_INFO(icap, "XHWICAP_SR: %x", w);
+             if (w & 0x5)
0x5 is a magic number, should be #defined
Sure.
+                     return 0;
+     }
+
+     ICAP_ERR(icap, "bitstream download timeout");
+     return -ETIMEDOUT;
+}
+
+static int icap_write(struct icap *icap, const u32 *word_buf, int size)
+{
+     int i;
+     u32 value = 0;
+
+     for (i = 0; i < size; i++) {
+             value = be32_to_cpu(word_buf[i]);
+             reg_wr(&icap->icap_regs->ir_wf, value);
+     }
+
+     reg_wr(&icap->icap_regs->ir_cr, 0x1);
+
+     for (i = 0; i < 20; i++) {
+             value = reg_rd(&icap->icap_regs->ir_cr);
+             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)
+{
+     u32 remain_word;
+     u32 word_written = 0;
+     int wr_fifo_vacancy = 0;
+     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) {
+             wr_fifo_vacancy = reg_rd(&icap->icap_regs->ir_wfv);
+             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 = DMA_HWICAP_BITFILE_BUFFER_SIZE;
+     u32     byte_read;
+     int     err = 0;
+
+     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 > DMA_HWICAP_BITFILE_BUFFER_SIZE)
+                     num_chars_read = DMA_HWICAP_BITFILE_BUFFER_SIZE;
+
+             err = bitstream_helper(icap, (u32 *)buffer, num_chars_read / sizeof(u32));
assumption that num_chars_read % 4 == 0

Add a check, or handle.
Sure.

+             if (err)
+                     goto failed;
+             buffer += num_chars_read;
+     }
+
+     err = wait_for_done(icap);
timeout is not handled
+
+failed:
+     mutex_unlock(&icap->icap_lock);
+
+     return err;
+}
+
+/*
+ * Run the following sequence of canned commands to obtain IDCODE of the FPGA
+ */
+static void icap_probe_chip(struct icap *icap)
+{
+     u32 w;
De magic this.

If this is a documented startup sequence, please add a link to the document.

Else add a comment about what you are doing here.

Where possible, convert the hex values to #defines.
Will add comment for this.

Thanks,
Lizhi

Tom

+
+     w = reg_rd(&icap->icap_regs->ir_sr);
+     w = reg_rd(&icap->icap_regs->ir_sr);
+     reg_wr(&icap->icap_regs->ir_gier, 0x0);
+     w = reg_rd(&icap->icap_regs->ir_wfv);
+     reg_wr(&icap->icap_regs->ir_wf, 0xffffffff);
+     reg_wr(&icap->icap_regs->ir_wf, 0xaa995566);
+     reg_wr(&icap->icap_regs->ir_wf, 0x20000000);
+     reg_wr(&icap->icap_regs->ir_wf, 0x20000000);
+     reg_wr(&icap->icap_regs->ir_wf, 0x28018001);
+     reg_wr(&icap->icap_regs->ir_wf, 0x20000000);
+     reg_wr(&icap->icap_regs->ir_wf, 0x20000000);
+     w = reg_rd(&icap->icap_regs->ir_cr);
+     reg_wr(&icap->icap_regs->ir_cr, 0x1);
+     w = reg_rd(&icap->icap_regs->ir_cr);
+     w = reg_rd(&icap->icap_regs->ir_cr);
+     w = reg_rd(&icap->icap_regs->ir_sr);
+     w = reg_rd(&icap->icap_regs->ir_cr);
+     w = reg_rd(&icap->icap_regs->ir_sr);
+     reg_wr(&icap->icap_regs->ir_sz, 0x1);
+     w = reg_rd(&icap->icap_regs->ir_cr);
+     reg_wr(&icap->icap_regs->ir_cr, 0x2);
+     w = reg_rd(&icap->icap_regs->ir_rfo);
+     icap->idcode = reg_rd(&icap->icap_regs->ir_rf);
+     w = reg_rd(&icap->icap_regs->ir_cr);
+     (void)w;
+}
+
+static int
+xrt_icap_leaf_ioctl(struct platform_device *pdev, u32 cmd, void *arg)
+{
+     struct xrt_icap_ioctl_wr        *wr_arg = arg;
+     struct icap                     *icap;
+     int                             ret = 0;
+
+     icap = platform_get_drvdata(pdev);
+
+     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_IDCODE:
+             *(u64 *)arg = icap->idcode;
+             break;
+     default:
+             ICAP_ERR(icap, "unknown command %d", cmd);
+             return -EINVAL;
+     }
+
+     return ret;
+}
+
+static int xrt_icap_remove(struct platform_device *pdev)
+{
+     struct icap     *icap;
+
+     icap = platform_get_drvdata(pdev);
+
+     platform_set_drvdata(pdev, NULL);
+     devm_kfree(&pdev->dev, icap);
+
+     return 0;
+}
+
+static int xrt_icap_probe(struct platform_device *pdev)
+{
+     struct icap     *icap;
+     int                     ret = 0;
+     struct resource         *res;
+
+     icap = devm_kzalloc(&pdev->dev, sizeof(*icap), GFP_KERNEL);
+     if (!icap)
+             return -ENOMEM;
+
+     icap->pdev = pdev;
+     platform_set_drvdata(pdev, icap);
+     mutex_init(&icap->icap_lock);
+
+     xrt_info(pdev, "probing");
+     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+     if (res) {
+             icap->icap_regs = ioremap(res->start, res->end - res->start + 1);
+             if (!icap->icap_regs) {
+                     xrt_err(pdev, "map base failed %pR", res);
+                     ret = -EIO;
+                     goto failed;
+             }
+     }
+
+     icap_probe_chip(icap);
+failed:
+     return ret;
+}
+
+static struct xrt_subdev_endpoints xrt_icap_endpoints[] = {
+     {
+             .xse_names = (struct xrt_subdev_ep_names[]) {
+                     { .ep_name = XRT_MD_NODE_FPGA_CONFIG },
+                     { NULL },
+             },
+             .xse_min_ep = 1,
+     },
+     { 0 },
+};
+
+static struct xrt_subdev_drvdata xrt_icap_data = {
+     .xsd_dev_ops = {
+             .xsd_ioctl = xrt_icap_leaf_ioctl,
+     },
+};
+
+static const struct platform_device_id xrt_icap_table[] = {
+     { XRT_ICAP, (kernel_ulong_t)&xrt_icap_data },
+     { },
+};
+
+static struct platform_driver xrt_icap_driver = {
+     .driver = {
+             .name = XRT_ICAP,
+     },
+     .probe = xrt_icap_probe,
+     .remove = xrt_icap_remove,
+     .id_table = xrt_icap_table,
+};
+
+void icap_leaf_init_fini(bool init)
+{
+     if (init)
+             xleaf_register_driver(XRT_SUBDEV_ICAP, &xrt_icap_driver, xrt_icap_endpoints);
+     else
+             xleaf_unregister_driver(XRT_SUBDEV_ICAP);
+}




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