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

Tom Rix
2021-03-03T18:42:13Z

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 ?
> 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@xilinx.com>
> Signed-off-by: Max Zhen <max.zhen@xilinx.com>
> Signed-off-by: Lizhi Hou <lizhih@xilinx.com>
> ---
> 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@xilinx.com>
> + */
> +
> +#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
> + 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@xilinx.com>
> + * Sonal Santan <sonals@xilinx.com>
> + * Max Zhen <maxz@xilinx.com>
> + */
> +
> +#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
> +};
> +
> +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
> +}
> +
> +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.
> + 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
> + 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.

> + 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.

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);
> +}