linux-cxl.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Dan Williams <dan.j.williams@intel.com>
To: Ben Widawsky <ben.widawsky@intel.com>
Cc: linux-cxl@vger.kernel.org,
	Chet Douglas <chet.r.douglas@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Vishal Verma <vishal.l.verma@intel.com>
Subject: Re: [RFC PATCH v2 09/28] cxl/acpi: Map single port host bridge component registers
Date: Sun, 31 Oct 2021 11:03:37 -0700	[thread overview]
Message-ID: <CAPcyv4j+mv3+FyJd0OVBe_dUqzzYpS2gkEagiRp-Tqh9t7NMmg@mail.gmail.com> (raw)
In-Reply-To: <20211022183709.1199701-10-ben.widawsky@intel.com>

On Fri, Oct 22, 2021 at 11:37 AM Ben Widawsky <ben.widawsky@intel.com> wrote:
>
> Now that the port driver exists and is able to do proper decoder
> enumeration of the component registers, it becomes trivial to use that

This is the second occurrence of "becomes trivial" in this series,
it's distracting because it immediately sets off alarm bells that the
changelog is not in:

Background
Problem
Solution

...format.

> for host bridge uports. For reasons out of scope, a functional change
> would be visible if the HDM decoder was programmed by BIOS to values
> other than the full address range. Similarly if a type2 device was
> connected to this root port and programmed by BIOS, that can now be
> acted upon accordingly.

I would reserve discussion of "no functional change" for patches that
are pure cleanup. In this case this patch will cause the kernel to
behave differently when other conditions are met.

>
> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> ---
>  drivers/cxl/acpi.c | 25 ++++++++++++++++++++++++-
>  1 file changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index d61397055e9f..8cca0814dfb8 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -280,12 +280,14 @@ static int add_host_bridge_uport(struct device *match, void *arg)
>         struct cxl_port *root_port = arg;
>         struct device *host = root_port->dev.parent;
>         struct acpi_device *bridge = to_cxl_host_bridge(host, match);
> +       struct cxl_component_reg_map map;
>         struct acpi_pci_root *pci_root;
>         struct cxl_walk_context ctx;
>         int single_port_map[1], rc;
>         struct cxl_decoder *cxld;
>         struct cxl_dport *dport;
>         struct cxl_port *port;
> +       void __iomem *crb;
>
>         if (!bridge)
>                 return 0;
> @@ -318,10 +320,31 @@ static int add_host_bridge_uport(struct device *match, void *arg)
>                 return -ENODEV;
>         if (ctx.error)
>                 return ctx.error;
> +       /*
> +        * If the host bridge has more than 1 root port, it must have registers
> +        * controlling the HDM decoders. Those will be enumerated by the port
> +        * driver.
> +        */
>         if (ctx.count > 1)
>                 return 0;
>
> -       /* TODO: Scan CHBCR for HDM Decoder resources */
> +       /*
> +        * If the single ported host bridge has a component register block,
> +        * simply let the port driver handle the decoder enumeration.
> +        *
> +        * Host bridge component registers live in the system's physical address
> +        * space.
> +        */
> +       crb = ioremap(dport->component_reg_phys, CXL_COMPONENT_REG_BLOCK_SIZE);

This looks broken, the driver for the port should be mapping dport
component registers to offer services to upper layers.

There's also a missing iounmap.

> +       if (crb) {
> +               cxl_probe_component_regs(&root_port->dev, crb, &map);
> +               iounmap(crb);
> +               if (map.hdm_decoder.valid) {
> +                       dev_dbg(host,
> +                               "Found single port host bridge with component registers\n");
> +                       return 0;
> +               }
> +       }
>
>         /*
>          * Per the CXL specification (8.2.5.12 CXL HDM Decoder Capability
> --
> 2.33.1
>

  reply	other threads:[~2021-10-31 18:03 UTC|newest]

Thread overview: 112+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-22 18:36 [RFC PATCH v2 00/28] CXL Region Creation / HDM decoder programming Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 01/28] cxl: Rename CXL_MEM to CXL_PCI Ben Widawsky
2021-10-29 20:15   ` Dan Williams
2021-10-29 21:20     ` Ben Widawsky
2021-10-29 21:39       ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 02/28] cxl: Move register block enumeration to core Ben Widawsky
2021-10-29 20:23   ` Dan Williams
2021-10-29 21:23     ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 03/28] cxl/acpi: Map component registers for Root Ports Ben Widawsky
2021-10-29 20:28   ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 04/28] cxl: Add helper for new drivers Ben Widawsky
2021-10-29 20:30   ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 05/28] cxl/core: Convert decoder range to resource Ben Widawsky
2021-10-29 20:50   ` Dan Williams
2021-10-29 21:26     ` Ben Widawsky
2021-10-29 22:22       ` Dan Williams
2021-10-29 22:37         ` Ben Widawsky
2021-11-01 14:33           ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 06/28] cxl: Introduce endpoint decoders Ben Widawsky
2021-10-29 21:00   ` Dan Williams
2021-10-29 22:02     ` Ben Widawsky
2021-10-29 22:25       ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 07/28] cxl/core: Move target population locking to caller Ben Widawsky
2021-10-29 23:03   ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 08/28] cxl/port: Introduce a port driver Ben Widawsky
2021-10-30  1:37   ` Dan Williams
2021-10-31 17:53     ` Dan Williams
2021-10-31 18:10       ` Dan Williams
2021-11-01 17:36         ` Ben Widawsky
2021-11-01 17:53     ` Ben Widawsky
2021-11-01 17:54       ` Ben Widawsky
2021-11-02  3:31       ` Dan Williams
2021-11-02 16:27         ` Ben Widawsky
2021-11-02 17:21           ` Dan Williams
2021-11-02 16:58         ` Ben Widawsky
2021-11-04 19:10           ` Dan Williams
2021-11-04 19:49             ` Ben Widawsky
2021-11-04 20:04               ` Dan Williams
2021-11-04 21:25                 ` Ben Widawsky
2021-11-04 16:37     ` Ben Widawsky
2021-11-04 19:17       ` Dan Williams
2021-11-04 19:46         ` Ben Widawsky
2021-11-04 20:00           ` Dan Williams
2021-11-04 21:26             ` Ben Widawsky
2021-11-03 15:18   ` Jonathan Cameron
2021-10-22 18:36 ` [RFC PATCH v2 09/28] cxl/acpi: Map single port host bridge component registers Ben Widawsky
2021-10-31 18:03   ` Dan Williams [this message]
2021-11-01 17:07     ` Ben Widawsky
2021-11-02  2:15       ` Dan Williams
2021-11-02 16:31         ` Ben Widawsky
2021-11-02 17:46           ` Dan Williams
2021-11-02 17:57             ` Ben Widawsky
2021-11-02 18:10               ` Dan Williams
2021-11-02 18:27                 ` Ben Widawsky
2021-11-02 18:49                   ` Dan Williams
2021-11-02 21:15                     ` Ben Widawsky
2021-11-02 21:34                       ` Dan Williams
2021-11-02 21:47                         ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 10/28] cxl/core: Store global list of root ports Ben Widawsky
2021-10-31 18:32   ` Dan Williams
2021-11-01 18:43     ` Ben Widawsky
2021-11-02  2:04       ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 11/28] cxl/acpi: Rescan bus at probe completion Ben Widawsky
2021-10-31 19:25   ` Dan Williams
2021-11-01 18:56     ` Ben Widawsky
2021-11-01 21:45       ` Ben Widawsky
2021-11-02  1:56         ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 12/28] cxl/core: Store component register base for memdevs Ben Widawsky
2021-10-31 20:13   ` Dan Williams
2021-11-01 21:50     ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 13/28] cxl: Flesh out register names Ben Widawsky
2021-10-31 20:18   ` Dan Williams
2021-11-01 22:00     ` Ben Widawsky
2021-11-02  1:53       ` Dan Williams
2021-11-03 15:53   ` Jonathan Cameron
2021-11-03 16:03     ` Ben Widawsky
2021-11-03 16:42       ` Jonathan Cameron
2021-11-03 17:05         ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 14/28] cxl: Hide devm host for ports Ben Widawsky
2021-10-31 21:14   ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 15/28] cxl/core: Introduce API to scan switch ports Ben Widawsky
2021-11-01  5:39   ` Dan Williams
2021-11-01 22:56     ` Ben Widawsky
2021-11-02  1:45       ` Dan Williams
2021-11-02 16:39         ` Ben Widawsky
2021-11-02 20:00           ` Dan Williams
2021-11-16 16:50         ` Ben Widawsky
2021-11-16 17:51           ` Dan Williams
2021-11-16 18:02             ` Ben Widawsky
2021-11-03 16:08   ` Jonathan Cameron
2021-11-10 17:49     ` Ben Widawsky
2021-11-10 18:10       ` Jonathan Cameron
2021-11-10 21:03         ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 16/28] cxl: Introduce cxl_mem driver Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 17/28] cxl: Disable switch hierarchies for now Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 18/28] cxl/region: Add region creation ABI Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 19/28] cxl/region: Introduce concept of region configuration Ben Widawsky
2021-12-15 17:47   ` Jonathan Cameron
2021-10-22 18:37 ` [RFC PATCH v2 20/28] cxl/region: Introduce a cxl_region driver Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 21/28] cxl/acpi: Handle address space allocation Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 22/28] cxl/region: Address " Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 23/28] cxl/region: Implement XHB verification Ben Widawsky
2022-01-06 16:55   ` Jonathan Cameron
2022-01-06 16:58     ` Ben Widawsky
2022-01-06 17:33       ` Jonathan Cameron
2022-01-06 18:10         ` Jonathan Cameron
2022-01-06 18:34           ` Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 24/28] cxl/region: HB port config verification Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 25/28] cxl/region: Record host bridge target list Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 26/28] cxl/mem: Store the endpoint's uport Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 27/28] cxl/region: Gather HDM decoder resources Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 28/28] cxl: Program decoders for regions Ben Widawsky

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAPcyv4j+mv3+FyJd0OVBe_dUqzzYpS2gkEagiRp-Tqh9t7NMmg@mail.gmail.com \
    --to=dan.j.williams@intel.com \
    --cc=Jonathan.Cameron@huawei.com \
    --cc=alison.schofield@intel.com \
    --cc=ben.widawsky@intel.com \
    --cc=chet.r.douglas@intel.com \
    --cc=ira.weiny@intel.com \
    --cc=linux-cxl@vger.kernel.org \
    --cc=vishal.l.verma@intel.com \
    --subject='Re: [RFC PATCH v2 09/28] cxl/acpi: Map single port host bridge component registers' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).