From: "Jonathan Zhang (Infra)" <jonzhang@fb.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Robert Richter <rrichter@amd.com>,
Alison Schofield <alison.schofield@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
Ben Widawsky <bwidawsk@kernel.org>,
"linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>
Subject: Re: [PATCH 09/15] cxl/acpi: Determine PCI host bridge's ACPI UID
Date: Thu, 8 Sep 2022 21:35:21 +0000 [thread overview]
Message-ID: <485824AC-DCEA-4DE2-A331-CAC5DE901600@fb.com> (raw)
In-Reply-To: <631a5a27f22ac_166f29479@dwillia2-xfh.jf.intel.com.notmuch>
> On Sep 8, 2022, at 2:10 PM, Dan Williams <dan.j.williams@intel.com> wrote:
>
> !-------------------------------------------------------------------|
> This Message Is From an External Sender
>
> |-------------------------------------------------------------------!
>
> Jonathan Zhang (Infra) wrote:
>>
>>
>>> On Aug 31, 2022, at 1:15 AM, Robert Richter <rrichter@amd.com> wrote:
>>>
>>> The UID is needed to read the RCH's CEDT entry with the RCRB base
>>> address. Determine the host's UID from its ACPI fw node.
>>>
>>> Signed-off-by: Robert Richter <rrichter@amd.com>
>>> ---
>>> drivers/cxl/acpi.c | 12 ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
>>> index f9cdf23a91a8..b3146b7ae922 100644
>>> --- a/drivers/cxl/acpi.c
>>> +++ b/drivers/cxl/acpi.c
>>> @@ -368,8 +368,20 @@ struct pci_host_bridge *cxl_find_next_rch(struct pci_host_bridge *host)
>>> static int __init cxl_restricted_host_probe(struct platform_device *pdev)
>>> {
>>> struct pci_host_bridge *host = NULL;
>>> + struct acpi_device *adev;
>>> + unsigned long long uid = ~0;
>>>
>>> while ((host = cxl_find_next_rch(host)) != NULL) {
>>> + adev = ACPI_COMPANION(&host->dev);
>>> + if (!adev || !adev->pnp.unique_id ||
>>> + (kstrtoull(adev->pnp.unique_id, 10, &uid) < 0))
>> The UID field holds 4 bytes of ASCII characters. kstrtoull() would fail
>> if the UID field has value such as ‘CX03’.
>
> The UID field is not 4 ASCII characters.
>
> We went through this before in the original code in
> drivers/cxl/acpi.c::add_host_bridge_dport().
>
> The CEDT.CHBS defines _UID as an integer so use acpi_evaluate_integer()
> to retrieve the UID to perform the comparison. I thought there was an
> errata filed to clarify this, but it seems the current spec still just
> says "value". The CFMWS also places _UID values in the target list,
> those are also handled as integers.
ACPI 6.4 spec section 6.1.12 describes _UID, it says the return value is:
An Integer or String containing the Unique ID.
In the BIOS I see, the _UIDs of PCIe devices hold ASCII characters (not NULL
terminated).
next prev parent reply other threads:[~2022-09-08 21:35 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 8:15 [PATCH 00/15] cxl: Add support for Restricted CXL hosts (RCD mode) Robert Richter
2022-08-31 8:15 ` [PATCH 01/15] cxl/core: Remove duplicate declaration of devm_cxl_iomap_block() Robert Richter
2022-08-31 8:54 ` Jonathan Cameron
2022-09-01 5:21 ` Robert Richter
2022-09-07 16:11 ` [PATCH 1/15] " Davidlohr Bueso
2022-09-09 10:38 ` Robert Richter
2022-09-08 5:44 ` [PATCH 01/15] " Dan Williams
2022-09-08 14:51 ` Robert Richter
2022-09-08 19:47 ` Dan Williams
2022-08-31 8:15 ` [PATCH 02/15] cxl/core: Check physical address before mapping it in devm_cxl_iomap_block() Robert Richter
2022-08-31 8:56 ` Jonathan Cameron
2022-09-01 5:31 ` Robert Richter
2022-09-08 5:48 ` Dan Williams
2022-09-09 12:19 ` Robert Richter
2022-09-16 18:04 ` Dan Williams
2022-09-28 10:28 ` Robert Richter
2022-09-30 19:07 ` Dan Williams
2022-08-31 8:15 ` [PATCH 03/15] cxl: Unify debug messages when calling devm_cxl_add_port() Robert Richter
2022-08-31 9:59 ` Jonathan Cameron
2022-09-01 5:36 ` Robert Richter
2022-09-06 7:30 ` Robert Richter
2022-09-06 8:52 ` Jonathan Cameron
2022-09-07 16:21 ` [PATCH 3/15] " Davidlohr Bueso
2022-09-08 5:53 ` [PATCH 03/15] " Dan Williams
2022-09-28 10:32 ` Robert Richter
2022-08-31 8:15 ` [PATCH 04/15] cxl: Unify debug messages when calling devm_cxl_add_dport() Robert Richter
2022-09-07 16:29 ` [PATCH 4/15] " Davidlohr Bueso
2022-09-08 5:55 ` [PATCH 04/15] " Dan Williams
2022-08-31 8:15 ` [PATCH 05/15] cxl/acpi: Add probe function to detect restricted CXL hosts in RCD mode Robert Richter
2022-08-31 10:08 ` Jonathan Cameron
2022-09-01 6:01 ` Robert Richter
2022-09-01 10:10 ` Jonathan Cameron
2022-09-06 7:19 ` Robert Richter
2022-09-06 8:53 ` Jonathan Cameron
2022-09-07 18:22 ` Bjorn Helgaas
2022-09-08 6:00 ` Dan Williams
2022-09-08 6:11 ` Dan Williams
2022-08-31 8:15 ` [PATCH 06/15] PCI/ACPI: Link host bridge to its ACPI fw node Robert Richter
2022-08-31 10:11 ` Jonathan Cameron
2022-09-07 18:37 ` Bjorn Helgaas
2022-09-07 20:15 ` Rafael J. Wysocki
2022-09-08 6:05 ` Dan Williams
2022-09-08 13:06 ` Rafael J. Wysocki
2022-09-08 19:45 ` Dan Williams
2022-09-09 10:20 ` Robert Richter
2022-09-14 22:11 ` Bjorn Helgaas
2022-09-16 23:16 ` Dan Williams
2022-09-08 13:04 ` Rafael J. Wysocki
2022-08-31 8:15 ` [PATCH 07/15] cxl/acpi: Check RCH's PCIe Host Bridge ACPI ID Robert Richter
2022-08-31 10:20 ` Jonathan Cameron
2022-09-01 6:16 ` Robert Richter
2022-09-01 10:14 ` Jonathan Cameron
2022-09-08 6:11 ` Dan Williams
2022-08-31 8:15 ` [PATCH 08/15] cxl/acpi: Check RCH's CXL DVSEC capabilities Robert Richter
2022-08-31 10:52 ` Jonathan Cameron
2022-08-31 11:12 ` Jonathan Cameron
2022-09-01 6:38 ` Robert Richter
2022-09-01 10:37 ` Jonathan Cameron
2022-09-06 10:20 ` Robert Richter
2022-09-01 6:30 ` Robert Richter
2022-09-01 10:23 ` Jonathan Cameron
2022-09-08 6:18 ` Dan Williams
2022-08-31 8:15 ` [PATCH 09/15] cxl/acpi: Determine PCI host bridge's ACPI UID Robert Richter
2022-08-31 11:00 ` Jonathan Cameron
2022-09-01 6:53 ` Robert Richter
2022-09-01 10:41 ` Jonathan Cameron
2022-09-08 6:18 ` Dan Williams
2022-09-08 20:47 ` Jonathan Zhang (Infra)
2022-09-08 21:10 ` Dan Williams
2022-09-08 21:35 ` Jonathan Zhang (Infra) [this message]
2022-09-08 22:31 ` Dan Williams
2022-09-08 22:41 ` Jonathan Zhang (Infra)
2022-08-31 8:15 ` [PATCH 10/15] cxl/acpi: Extract the RCH's RCRB base address from CEDT Robert Richter
2022-08-31 11:09 ` Jonathan Cameron
2022-09-01 7:04 ` Robert Richter
2022-08-31 8:15 ` [PATCH 11/15] cxl/acpi: Extract the host's component register base address from RCRB Robert Richter
2022-08-31 11:56 ` Jonathan Cameron
2022-09-01 7:38 ` Robert Richter
2022-09-01 11:00 ` Jonathan Cameron
2022-09-06 11:32 ` Robert Richter
2022-09-08 20:59 ` Jonathan Zhang (Infra)
2022-08-31 8:16 ` [PATCH 12/15] cxl/acpi: Skip devm_cxl_port_enumerate_dports() when in RCD mode Robert Richter
2022-08-31 11:58 ` Jonathan Cameron
2022-09-01 7:40 ` Robert Richter
2022-08-31 8:16 ` [PATCH 13/15] cxl/acpi: Rework devm_cxl_enumerate_ports() to support " Robert Richter
2022-08-31 12:11 ` Jonathan Cameron
2022-09-01 7:50 ` Robert Richter
2022-08-31 8:16 ` [PATCH 14/15] cxl/acpi: Enumerate ports in RCD mode to enable RCHs and RCDs Robert Richter
2022-08-31 12:16 ` Jonathan Cameron
2022-09-01 7:54 ` Robert Richter
2022-08-31 8:16 ` [PATCH 15/15] cxl/acpi: Specify module load order dependency for the cxl_acpi module Robert Richter
2022-09-16 18:12 ` Dan Williams
2022-08-31 12:23 ` [PATCH 00/15] cxl: Add support for Restricted CXL hosts (RCD mode) Jonathan Cameron
2022-09-01 8:19 ` Robert Richter
2022-09-08 6:41 ` Dan Williams
2022-09-08 5:43 ` Dan Williams
2022-09-08 18:52 ` Jonathan Zhang (Infra)
2022-09-08 19:51 ` Dan Williams
2022-09-08 20:36 ` Jonathan Zhang (Infra)
2022-09-08 21:02 ` Dan Williams
2022-09-16 18:16 ` Dan Williams
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