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Message-ID: <20210406180017.00000875@Huawei.com>
Date: Tue, 6 Apr 2021 18:00:17 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Dan Williams <dan.j.williams@...el.com>
CC: <linux-cxl@...r.kernel.org>, <linux-pci@...r.kernel.org>,
<linux-acpi@...r.kernel.org>, <ira.weiny@...el.com>,
<vishal.l.verma@...el.com>, <alison.schofield@...el.com>,
<ben.widawsky@...el.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 4/8] cxl/core: Refactor CXL register lookup for
bridge reuse
On Thu, 1 Apr 2021 07:31:03 -0700
Dan Williams <dan.j.williams@...el.com> wrote:
> While CXL Memory Device endpoints locate the CXL MMIO registers in a PCI
> BAR, CXL root bridges have their MMIO base address described by platform
> firmware. Refactor the existing register lookup into a generic facility
> for endpoints and bridges to share.
>
> Reviewed-by: Ben Widawsky <ben.widawsky@...el.com>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
Nice to make the docs kernel-doc, but otherwise this is simple and makes sense
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> ---
> drivers/cxl/core.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++-
> drivers/cxl/cxl.h | 3 +++
> drivers/cxl/mem.c | 50 +++++-----------------------------------------
> 3 files changed, 65 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/cxl/core.c b/drivers/cxl/core.c
> index 7f8d2034038a..2ab467ef9909 100644
> --- a/drivers/cxl/core.c
> +++ b/drivers/cxl/core.c
> @@ -1,7 +1,8 @@
> // SPDX-License-Identifier: GPL-2.0-only
> -/* Copyright(c) 2020 Intel Corporation. All rights reserved. */
> +/* Copyright(c) 2020-2021 Intel Corporation. All rights reserved. */
> #include <linux/device.h>
> #include <linux/module.h>
> +#include "cxl.h"
>
> /**
> * DOC: cxl core
> @@ -10,6 +11,60 @@
> * point for cross-device interleave coordination through cxl ports.
> */
>
> +/*
> + * cxl_setup_device_regs() - Detect CXL Device register blocks
> + * @dev: Host device of the @base mapping
> + * @base: mapping of CXL 2.0 8.2.8 CXL Device Register Interface
Not much to add to make this kernel-doc. Just the one missing parameter
and mark it /** Given it's exported, it would be nice to tidy that up.
> + */
> +void cxl_setup_device_regs(struct device *dev, void __iomem *base,
> + struct cxl_device_regs *regs)
> +{
> + int cap, cap_count;
> + u64 cap_array;
> +
> + *regs = (struct cxl_device_regs) { 0 };
> +
> + cap_array = readq(base + CXLDEV_CAP_ARRAY_OFFSET);
> + if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
> + CXLDEV_CAP_ARRAY_CAP_ID)
> + return;
> +
> + cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array);
> +
> + for (cap = 1; cap <= cap_count; cap++) {
> + void __iomem *register_block;
> + u32 offset;
> + u16 cap_id;
> +
> + cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK,
> + readl(base + cap * 0x10));
> + offset = readl(base + cap * 0x10 + 0x4);
> + register_block = base + offset;
> +
> + switch (cap_id) {
> + case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
> + dev_dbg(dev, "found Status capability (0x%x)\n", offset);
> + regs->status = register_block;
> + break;
> + case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
> + dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
> + regs->mbox = register_block;
> + break;
> + case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
> + dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
> + break;
> + case CXLDEV_CAP_CAP_ID_MEMDEV:
> + dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
> + regs->memdev = register_block;
> + break;
> + default:
> + dev_dbg(dev, "Unknown cap ID: %d (0x%x)\n", cap_id, offset);
> + break;
> + }
> + }
> +}
> +EXPORT_SYMBOL_GPL(cxl_setup_device_regs);
> +
> struct bus_type cxl_bus_type = {
> .name = "cxl",
> };
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 37325e504fb7..cbd29650c4e2 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -67,5 +67,8 @@ struct cxl_regs {
> };
> };
>
> +void cxl_setup_device_regs(struct device *dev, void __iomem *base,
> + struct cxl_device_regs *regs);
> +
> extern struct bus_type cxl_bus_type;
> #endif /* __CXL_H__ */
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index 6951243d128e..ee55abfa147e 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -865,53 +865,15 @@ static int cxl_mem_mbox_send_cmd(struct cxl_mem *cxlm, u16 opcode,
> static int cxl_mem_setup_regs(struct cxl_mem *cxlm)
> {
> struct device *dev = &cxlm->pdev->dev;
> - int cap, cap_count;
> - u64 cap_array;
> + struct cxl_regs *regs = &cxlm->regs;
>
> - cap_array = readq(cxlm->base + CXLDEV_CAP_ARRAY_OFFSET);
> - if (FIELD_GET(CXLDEV_CAP_ARRAY_ID_MASK, cap_array) !=
> - CXLDEV_CAP_ARRAY_CAP_ID)
> - return -ENODEV;
> -
> - cap_count = FIELD_GET(CXLDEV_CAP_ARRAY_COUNT_MASK, cap_array);
> -
> - for (cap = 1; cap <= cap_count; cap++) {
> - void __iomem *register_block;
> - u32 offset;
> - u16 cap_id;
> -
> - cap_id = FIELD_GET(CXLDEV_CAP_HDR_CAP_ID_MASK,
> - readl(cxlm->base + cap * 0x10));
> - offset = readl(cxlm->base + cap * 0x10 + 0x4);
> - register_block = cxlm->base + offset;
> -
> - switch (cap_id) {
> - case CXLDEV_CAP_CAP_ID_DEVICE_STATUS:
> - dev_dbg(dev, "found Status capability (0x%x)\n", offset);
> - cxlm->regs.status = register_block;
> - break;
> - case CXLDEV_CAP_CAP_ID_PRIMARY_MAILBOX:
> - dev_dbg(dev, "found Mailbox capability (0x%x)\n", offset);
> - cxlm->regs.mbox = register_block;
> - break;
> - case CXLDEV_CAP_CAP_ID_SECONDARY_MAILBOX:
> - dev_dbg(dev, "found Secondary Mailbox capability (0x%x)\n", offset);
> - break;
> - case CXLDEV_CAP_CAP_ID_MEMDEV:
> - dev_dbg(dev, "found Memory Device capability (0x%x)\n", offset);
> - cxlm->regs.memdev = register_block;
> - break;
> - default:
> - dev_dbg(dev, "Unknown cap ID: %d (0x%x)\n", cap_id, offset);
> - break;
> - }
> - }
> + cxl_setup_device_regs(dev, cxlm->base, ®s->device_regs);
>
> - if (!cxlm->regs.status || !cxlm->regs.mbox || !cxlm->regs.memdev) {
> + if (!regs->status || !regs->mbox || !regs->memdev) {
> dev_err(dev, "registers not found: %s%s%s\n",
> - !cxlm->regs.status ? "status " : "",
> - !cxlm->regs.mbox ? "mbox " : "",
> - !cxlm->regs.memdev ? "memdev" : "");
> + !regs->status ? "status " : "",
> + !regs->mbox ? "mbox " : "",
> + !regs->memdev ? "memdev" : "");
> return -ENXIO;
> }
>
>
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