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SubjectRe: [PATCH V3 XRT Alveo 17/18] fpga: xrt: partition isolation platform driver
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Hi Moritz,


On 02/21/2021 12:36 PM, Moritz Fischer wrote:
>
> 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.
We will use #define and regmap.
>> +
>> +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?
Will use #define for 500
>> + (void)reg_rd(gate, iag_rd);
> At the very least add a comment on why? Is this for PCI synchronization
> reasons?
Will add comment. Some old board requires this extra read and it will
not hurt performance.
>
>> + 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;
Will change this.
>
>> +
>> + 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;
Will change this.
>> + return ret;
>> +}
>> +
>> +static void xrt_axigate_freeze(struct platform_device *pdev)
>> +{
>> + struct xrt_axigate *gate;
>> + u32 freeze = 0;
> Indents. Fix everywhere.
Will fix this.
>> +
>> + 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
Will change terms to open / close.
>> + mutex_unlock(&gate->gate_lock);
>> +
>> + xrt_info(pdev, "freeze gate %s", gate->ep_name);
> debug?
axigate is a very critical part for programming FPGA. We hope to have an
explicit printk to indicate the axigate open/close.
>> +}
>> +
>> +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
> xxxxxxxxx
> xxxxxxxx
> xxxxxx
Will fix this.
>> +
>> + 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.
Will fix this.
>> +
>> + 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.
Will define a macro.

Thanks,
Lizhi
>> --
>> 2.18.4
>>
> - Moritz

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