From: Bjorn Helgaas <helgaas@kernel.org>
To: Vidya Sagar <vidyas@nvidia.com>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
"Len Brown" <lenb@kernel.org>, "Will Deacon" <will@kernel.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Rob Herring" <robh@kernel.org>,
"Frank Rowand" <frowand.list@gmail.com>,
"Thierry Reding" <treding@nvidia.com>,
"Jonathan Hunter" <jonathanh@nvidia.com>,
"Krishna Thota" <kthota@nvidia.com>,
"Manikanta Maddireddy" <mmaddireddy@nvidia.com>,
"Vidya Sagar" <sagar.tv@gmail.com>,
linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
"Bjorn Helgaas" <bhelgaas@google.com>
Subject: [PATCH v7-incomplete 2/3] PCI: of: Add of_pci_preserve_config() for per-host bridge support
Date: Sun, 21 Apr 2024 14:09:13 -0500 [thread overview]
Message-ID: <20240421190914.374399-3-helgaas@kernel.org> (raw)
In-Reply-To: <20240421190914.374399-1-helgaas@kernel.org>
From: Bjorn Helgaas <bhelgaas@google.com>
Add of_pci_preserve_config() to look for the "linux,pci-probe-only"
property under a specified node. If it's not found there, look under
"of_chosen" in addition.
If the caller didn't specify a node, look under "of_chosen".
With a future patch, this will support "linux,pci-probe-only" on a per host
bridge basis based on the presence of the property in the respective PCI
host bridge DT node.
Implement of_pci_check_probe_only() using of_pci_preserve_config().
---
drivers/pci/of.c | 60 +++++++++++++++++++++++++++++++++++++----------
drivers/pci/pci.h | 7 ++++++
2 files changed, 54 insertions(+), 13 deletions(-)
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 51e3dd0ea5ab..d21c0bed36f3 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -233,28 +233,62 @@ int of_get_pci_domain_nr(struct device_node *node)
}
EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);
+/**
+ * of_pci_preserve_config - Return true if the boot configuration needs to
+ * be preserved
+ * @node: Device tree node.
+ *
+ * This function looks for "linux,pci-probe-only" property for a given
+ * PCI controller's node and returns true if found. It will also look in the
+ * chosen node if the property is not found in the given controller's node.
+ * Having this property ensures that the kernel doesn't reconfigure the
+ * BARs and bridge windows that are already done by the platform firmware.
+ *
+ * Return: true if the property exists false otherwise.
+ */
+bool of_pci_preserve_config(struct device_node *node)
+{
+ u32 val = 0;
+ int ret;
+
+ if (!node) {
+ pr_warn("device node is NULL, trying with of_chosen\n");
+ node = of_chosen;
+ }
+
+retry:
+ ret = of_property_read_u32(node, "linux,pci-probe-only", &val);
+ if (ret) {
+ if (ret == -ENODATA || ret == -EOVERFLOW) {
+ pr_warn("Incorrect value for linux,pci-probe-only in %pOF, ignoring\n",
+ node);
+ return false;
+ }
+ if (ret == -EINVAL) {
+ if (node == of_chosen)
+ return false;
+
+ node = of_chosen;
+ goto retry;
+ }
+ }
+
+ if (val)
+ return true;
+ else
+ return false;
+}
+
/**
* of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
* is present and valid
*/
void of_pci_check_probe_only(void)
{
- u32 val;
- int ret;
-
- ret = of_property_read_u32(of_chosen, "linux,pci-probe-only", &val);
- if (ret) {
- if (ret == -ENODATA || ret == -EOVERFLOW)
- pr_warn("linux,pci-probe-only without valid value, ignoring\n");
- return;
- }
-
- if (val)
+ if (of_pci_preserve_config(of_chosen))
pci_add_flags(PCI_PROBE_ONLY);
else
pci_clear_flags(PCI_PROBE_ONLY);
-
- pr_info("PROBE_ONLY %s\n", val ? "enabled" : "disabled");
}
EXPORT_SYMBOL_GPL(of_pci_check_probe_only);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 180d3907b543..feedbedd65df 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -650,6 +650,7 @@ int of_pci_get_max_link_speed(struct device_node *node);
u32 of_pci_get_slot_power_limit(struct device_node *node,
u8 *slot_power_limit_value,
u8 *slot_power_limit_scale);
+bool of_pci_preserve_config(struct device_node *node);
int pci_set_of_node(struct pci_dev *dev);
void pci_release_of_node(struct pci_dev *dev);
void pci_set_bus_of_node(struct pci_bus *bus);
@@ -688,6 +689,12 @@ of_pci_get_slot_power_limit(struct device_node *node,
return 0;
}
+static inline bool
+of_pci_preserve_config(struct device_node *node)
+{
+ return false;
+}
+
static inline int pci_set_of_node(struct pci_dev *dev) { return 0; }
static inline void pci_release_of_node(struct pci_dev *dev) { }
static inline void pci_set_bus_of_node(struct pci_bus *bus) { }
--
2.34.1
next prev parent reply other threads:[~2024-04-21 19:09 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-10 3:07 [PATCH V2 0/2] Add support to preserve boot config in the DT flow Vidya Sagar
2024-01-10 3:07 ` [PATCH V2 1/2] dt-bindings: Add PCIe "preserve-boot-config" property Vidya Sagar
2024-01-12 14:33 ` Rob Herring
2024-01-10 3:07 ` [PATCH V2 2/2] PCI: Add support for " Vidya Sagar
2024-01-12 16:58 ` Bjorn Helgaas
2024-01-15 14:32 ` Vidya Sagar
2024-01-16 16:55 ` Rob Herring
2024-01-19 17:31 ` Bjorn Helgaas
2024-01-12 16:59 ` Bjorn Helgaas
2024-02-22 12:41 ` [PATCH V3] PCI: Add support for preserving boot configuration Vidya Sagar
2024-02-22 17:06 ` Bjorn Helgaas
2024-02-22 21:18 ` Vidya Sagar
2024-02-22 22:08 ` Bjorn Helgaas
2024-02-23 8:00 ` [PATCH V4] " Vidya Sagar
2024-03-05 14:10 ` Rob Herring
2024-03-05 14:24 ` Rob Herring
2024-04-01 7:50 ` [PATCH V5] " Vidya Sagar
2024-04-02 16:01 ` Rob Herring
2024-04-10 7:44 ` Vidya Sagar
2024-04-10 20:50 ` Bjorn Helgaas
2024-04-18 17:31 ` Vidya Sagar
2024-04-18 17:40 ` [PATCH V6] " Vidya Sagar
2024-04-21 19:03 ` Bjorn Helgaas
2024-04-21 19:09 ` [PATCH v7-incomplete 0/3] " Bjorn Helgaas
2024-04-21 19:09 ` [PATCH v7-incomplete 1/3] PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge() Bjorn Helgaas
2024-04-22 7:45 ` Andy Shevchenko
2024-04-21 19:09 ` Bjorn Helgaas [this message]
2024-04-21 19:09 ` [PATCH v7-incomplete 3/3] PCI: Unify ACPI and DT 'preserve config' support Bjorn Helgaas
2024-04-22 7:43 ` Andy Shevchenko
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=20240421190914.374399-3-helgaas@kernel.org \
--to=helgaas@kernel.org \
--cc=bhelgaas@google.com \
--cc=devicetree@vger.kernel.org \
--cc=frowand.list@gmail.com \
--cc=jonathanh@nvidia.com \
--cc=kthota@nvidia.com \
--cc=kw@linux.com \
--cc=lenb@kernel.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=lpieralisi@kernel.org \
--cc=mmaddireddy@nvidia.com \
--cc=rafael@kernel.org \
--cc=robh@kernel.org \
--cc=sagar.tv@gmail.com \
--cc=treding@nvidia.com \
--cc=vidyas@nvidia.com \
--cc=will@kernel.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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 read-only IMAP folder(s) and NNTP newsgroup(s).