Re: [PATCH V3 XRT Alveo 17/18] fpga: xrt: partition isolation platform driver

Moritz Fischer
2021-02-21T20:37:02Z

On Wed, Feb 17, 2021 at 10:40:18PM -0800, Lizhi Hou wrote:
> Add partition isolation platform driver. partition isolation is
> a hardware function discovered by walking firmware metadata.
> A platform device node will be created for it. Partition isolation
> function isolate the different fpga regions
>
> 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/axigate.h | 25 ++
> drivers/fpga/xrt/lib/xleaf/axigate.c | 298 +++++++++++++++++++++++
> 2 files changed, 323 insertions(+)
> create mode 100644 drivers/fpga/xrt/include/xleaf/axigate.h
> create mode 100644 drivers/fpga/xrt/lib/xleaf/axigate.c
>
> diff --git a/drivers/fpga/xrt/include/xleaf/axigate.h b/drivers/fpga/xrt/include/xleaf/axigate.h
> new file mode 100644
> index 000000000000..2cef71e13b30
> --- /dev/null
> +++ b/drivers/fpga/xrt/include/xleaf/axigate.h
> @@ -0,0 +1,25 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Header file for XRT Axigate Leaf Driver
> + *
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + * Lizhi Hou <Lizhi.Hou@xilinx.com>
> + */
> +
> +#ifndef _XRT_AXIGATE_H_
> +#define _XRT_AXIGATE_H_
> +
> +#include "xleaf.h"
> +#include "metadata.h"
> +
> +/*
> + * AXIGATE driver IOCTL calls.
> + */
> +enum xrt_axigate_ioctl_cmd {
> + XRT_AXIGATE_FREEZE = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
> + XRT_AXIGATE_FREE,
> +};
> +
> +#endif /* _XRT_AXIGATE_H_ */
> diff --git a/drivers/fpga/xrt/lib/xleaf/axigate.c b/drivers/fpga/xrt/lib/xleaf/axigate.c
> new file mode 100644
> index 000000000000..382969f9925f
> --- /dev/null
> +++ b/drivers/fpga/xrt/lib/xleaf/axigate.c
> @@ -0,0 +1,298 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx Alveo FPGA AXI Gate Driver
> + *
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + * Lizhi Hou<Lizhi.Hou@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/axigate.h"
> +
> +#define XRT_AXIGATE "xrt_axigate"
> +
> +struct axigate_regs {
> + u32 iag_wr;
> + u32 iag_rvsd;
> + u32 iag_rd;
> +} __packed;

Just make them #defines, even more so if there are only 3 of them.
> +
> +struct xrt_axigate {
> + struct platform_device *pdev;
> + void *base;
> + struct mutex gate_lock; /* gate dev lock */
> +
> + void *evt_hdl;
> + const char *ep_name;
> +
> + bool gate_freezed;
> +};
> +
> +/* the ep names are in the order of hardware layers */
> +static const char * const xrt_axigate_epnames[] = {
> + XRT_MD_NODE_GATE_PLP,
> + XRT_MD_NODE_GATE_ULP,
> + NULL
> +};
> +
> +#define reg_rd(g, r) \
> + ioread32((void *)(g)->base + offsetof(struct axigate_regs, r))
> +#define reg_wr(g, v, r) \
> + iowrite32(v, (void *)(g)->base + offsetof(struct axigate_regs, r))
> +
> +static inline void freeze_gate(struct xrt_axigate *gate)
> +{
> + reg_wr(gate, 0, iag_wr);
> + ndelay(500);
> + reg_rd(gate, iag_rd);
> +}
> +
> +static inline void free_gate(struct xrt_axigate *gate)
> +{
> + reg_wr(gate, 0x2, iag_wr);
> + ndelay(500);
Magic constants?
> + (void)reg_rd(gate, iag_rd);
At the very least add a comment on why? Is this for PCI synchronization
reasons?

> + reg_wr(gate, 0x3, iag_wr);
> + ndelay(500);
Magic constants?
> + reg_rd(gate, iag_rd);
Does it nead a (void) or not? Be consistent, again, why do we read here
at all?
> +}
> +
> +static int xrt_axigate_epname_idx(struct platform_device *pdev)
> +{
> + int i;
> + int ret;
> + struct resource *res;
Nope. Indents:

struct resource *res;
int, i, ret;

> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + xrt_err(pdev, "Empty Resource!");
> + return -EINVAL;
> + }
> +
> + for (i = 0; xrt_axigate_epnames[i]; i++) {
> + ret = strncmp(xrt_axigate_epnames[i], res->name,
> + strlen(xrt_axigate_epnames[i]) + 1);
> + if (!ret)
> + break;
> + }
> +
> + ret = (xrt_axigate_epnames[i]) ? i : -EINVAL;
Why not just:

if (xrt_axigate_epnames[i])
return i;

return -EINVAL;
> + return ret;
> +}
> +
> +static void xrt_axigate_freeze(struct platform_device *pdev)
> +{
> + struct xrt_axigate *gate;
> + u32 freeze = 0;
Indents. Fix everywhere.
> +
> + gate = platform_get_drvdata(pdev);
> +
> + mutex_lock(&gate->gate_lock);
> + freeze = reg_rd(gate, iag_rd);
> + if (freeze) { /* gate is opened */
> + xleaf_broadcast_event(pdev, XRT_EVENT_PRE_GATE_CLOSE, false);
> + freeze_gate(gate);
> + }
> +
> + gate->gate_freezed = true;
s/freezed/frozen
> + mutex_unlock(&gate->gate_lock);
> +
> + xrt_info(pdev, "freeze gate %s", gate->ep_name);
debug?
> +}
> +
> +static void xrt_axigate_free(struct platform_device *pdev)
> +{
> + struct xrt_axigate *gate;
> + u32 freeze;
> +
> + gate = platform_get_drvdata(pdev);
> +
> + mutex_lock(&gate->gate_lock);
> + freeze = reg_rd(gate, iag_rd);
> + if (!freeze) { /* gate is closed */
> + free_gate(gate);
> + xleaf_broadcast_event(pdev, XRT_EVENT_POST_GATE_OPEN, true);
> + /* xrt_axigate_free() could be called in event cb, thus
> + * we can not wait for the completes
> + */
> + }
> +
> + gate->gate_freezed = false;
> + mutex_unlock(&gate->gate_lock);
> +
> + xrt_info(pdev, "free gate %s", gate->ep_name);
> +}
> +
> +static void xrt_axigate_event_cb(struct platform_device *pdev, void *arg)
> +{
> + struct platform_device *leaf;
> + struct xrt_event *evt = (struct xrt_event *)arg;
> + enum xrt_events e = evt->xe_evt;
> + enum xrt_subdev_id id = evt->xe_subdev.xevt_subdev_id;
> + int instance = evt->xe_subdev.xevt_subdev_instance;
> + struct xrt_axigate *gate = platform_get_drvdata(pdev);
> + struct resource *res;
Reverse x-mas tree;
xxxxxxxxxx
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xxxxxx
> +
> + switch (e) {
> + case XRT_EVENT_POST_CREATION:
> + break;
> + default:
> + return;
> + }
> +
> + if (id != XRT_SUBDEV_AXIGATE)
> + return;
> +
> + leaf = xleaf_get_leaf_by_id(pdev, id, instance);
> + if (!leaf)
> + return;
> +
> + res = platform_get_resource(leaf, IORESOURCE_MEM, 0);
> + if (!res || !strncmp(res->name, gate->ep_name, strlen(res->name) + 1)) {
> + (void)xleaf_put_leaf(pdev, leaf);
> + return;
> + }
> +
> + /*
> + * higher level axigate instance created,
> + * make sure the gate is openned. This covers 1RP flow which
> + * has plp gate as well.
> + */
> + if (xrt_axigate_epname_idx(leaf) > xrt_axigate_epname_idx(pdev))
> + xrt_axigate_free(pdev);
> + else
> + xleaf_ioctl(leaf, XRT_AXIGATE_FREE, NULL);
> +
> + (void)xleaf_put_leaf(pdev, leaf);
> +}
> +
> +static int
> +xrt_axigate_leaf_ioctl(struct platform_device *pdev, u32 cmd, void *arg)
> +{
> + switch (cmd) {
> + case XRT_XLEAF_EVENT:
> + xrt_axigate_event_cb(pdev, arg);
> + break;
> + case XRT_AXIGATE_FREEZE:
> + xrt_axigate_freeze(pdev);
> + break;
> + case XRT_AXIGATE_FREE:
> + xrt_axigate_free(pdev);
> + break;
> + default:
> + xrt_err(pdev, "unsupported cmd %d", cmd);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int xrt_axigate_remove(struct platform_device *pdev)
> +{
> + struct xrt_axigate *gate;
> +
> + gate = platform_get_drvdata(pdev);
> +
> + if (gate->base)
> + iounmap(gate->base);
> +
> + platform_set_drvdata(pdev, NULL);
> + devm_kfree(&pdev->dev, gate);
No! The point of using devres is so cleanup happens on removal.
While you're at it, if you move the ioremap to a devres version, this
function can basically go away entirely.
> +
> + return 0;
> +}
> +
> +static int xrt_axigate_probe(struct platform_device *pdev)
> +{
> + struct xrt_axigate *gate;
> + struct resource *res;
> + int ret;
> +
> + gate = devm_kzalloc(&pdev->dev, sizeof(*gate), GFP_KERNEL);
> + if (!gate)
> + return -ENOMEM;
> +
> + gate->pdev = pdev;
> + platform_set_drvdata(pdev, gate);
> +
> + xrt_info(pdev, "probing...");
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + xrt_err(pdev, "Empty resource 0");
> + ret = -EINVAL;
> + goto failed;
> + }
> +
> + gate->base = ioremap(res->start, res->end - res->start + 1);
> + if (!gate->base) {
> + xrt_err(pdev, "map base iomem failed");
> + ret = -EFAULT;
> + goto failed;
> + }
> +
> + gate->ep_name = res->name;
> +
> + mutex_init(&gate->gate_lock);
> +
> + return 0;
> +
> +failed:
> + xrt_axigate_remove(pdev);
> + return ret;
> +}
> +
> +static struct xrt_subdev_endpoints xrt_axigate_endpoints[] = {
> + {
> + .xse_names = (struct xrt_subdev_ep_names[]) {
> + { .ep_name = "ep_pr_isolate_ulp_00" },
> + { NULL },
> + },
> + .xse_min_ep = 1,
> + },
> + {
> + .xse_names = (struct xrt_subdev_ep_names[]) {
> + { .ep_name = "ep_pr_isolate_plp_00" },
> + { NULL },
> + },
> + .xse_min_ep = 1,
> + },
> + { 0 },
> +};
> +
> +static struct xrt_subdev_drvdata xrt_axigate_data = {
> + .xsd_dev_ops = {
> + .xsd_ioctl = xrt_axigate_leaf_ioctl,
> + },
> +};
> +
> +static const struct platform_device_id xrt_axigate_table[] = {
> + { XRT_AXIGATE, (kernel_ulong_t)&xrt_axigate_data },
> + { },
> +};
> +
> +static struct platform_driver xrt_axigate_driver = {
> + .driver = {
> + .name = XRT_AXIGATE,
> + },
> + .probe = xrt_axigate_probe,
> + .remove = xrt_axigate_remove,
> + .id_table = xrt_axigate_table,
> +};
> +
> +void axigate_leaf_init_fini(bool init)
> +{
> + if (init) {
> + xleaf_register_driver(XRT_SUBDEV_AXIGATE,
> + &xrt_axigate_driver, xrt_axigate_endpoints);
> + } else {
> + xleaf_unregister_driver(XRT_SUBDEV_AXIGATE);
> + }
> +}

This thing is duplicated in every file, maybe a macro would be an idea.
> --
> 2.18.4
>

- Moritz