Add support for preserving the boot configuration done by the
platform firmware per host bridge basis, based on the presence of
'linux,pci-probe-only' property in the respective PCI host bridge
device-tree node. It also unifies the ACPI and DT based boot flows
in this regard.
This patch series is a complete version of the incomplete series
( https://lore.kernel.org/linux-pci/[email protected]/ )
posted by Bjorn which in turn was an attempted split work of the single V6 patch
( https://lore.kernel.org/linux-pci/[email protected]/ )
posted by me.
Vidya Sagar (4):
PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to
pci_register_host_bridge()
PCI: of: Add of_pci_preserve_config() for per-host bridge support
PCI: Unify ACPI and DT 'preserve config' support
PCI: Use preserve_config in place of pci_flags
drivers/acpi/pci_root.c | 12 ------
drivers/pci/controller/pci-host-common.c | 4 --
drivers/pci/of.c | 54 +++++++++++++++++++-----
drivers/pci/pci-acpi.c | 22 ++++++++++
drivers/pci/pci.h | 12 ++++++
drivers/pci/probe.c | 34 ++++++++++-----
6 files changed, 101 insertions(+), 37 deletions(-)
--
2.25.1
Move the PRESERVE_BOOT_CONFIG _DSM evaluation from acpi_pci_root_create()
to pci_register_host_bridge().
This will help unify the ACPI _DSM path and the DT-based
"linux,pci-probe-only" paths.
This should be safe because it happens earlier than it used to:
acpi_pci_root_create
pci_create_root_bus
pci_register_host_bridge
+ bridge->preserve_config = pci_preserve_config(bridge)
pci_acpi_preserve_config
+ acpi_evaluate_dsm_typed(DSM_PCI_PRESERVE_BOOT_CONFIG)
- acpi_evaluate_dsm_typed(DSM_PCI_PRESERVE_BOOT_CONFIG)
No functional change intended.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/acpi/pci_root.c | 12 ------------
drivers/pci/pci-acpi.c | 22 ++++++++++++++++++++++
drivers/pci/pci.h | 5 +++++
drivers/pci/probe.c | 11 +++++++++++
4 files changed, 38 insertions(+), 12 deletions(-)
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 58b89b8d950e..ddc2b3e89111 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -1008,7 +1008,6 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
int node = acpi_get_node(device->handle);
struct pci_bus *bus;
struct pci_host_bridge *host_bridge;
- union acpi_object *obj;
info->root = root;
info->bridge = device;
@@ -1050,17 +1049,6 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
if (!(root->osc_ext_control_set & OSC_CXL_ERROR_REPORTING_CONTROL))
host_bridge->native_cxl_error = 0;
- /*
- * Evaluate the "PCI Boot Configuration" _DSM Function. If it
- * exists and returns 0, we must preserve any PCI resource
- * assignments made by firmware for this host bridge.
- */
- obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 1,
- DSM_PCI_PRESERVE_BOOT_CONFIG, NULL, ACPI_TYPE_INTEGER);
- if (obj && obj->integer.value == 0)
- host_bridge->preserve_config = 1;
- ACPI_FREE(obj);
-
acpi_dev_power_up_children_with_adr(device);
pci_scan_child_bus(bus);
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 004575091596..9cc447da9475 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -119,6 +119,28 @@ phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle)
return (phys_addr_t)mcfg_addr;
}
+bool pci_acpi_preserve_config(struct pci_host_bridge *host_bridge)
+{
+ if (ACPI_HANDLE(&host_bridge->dev)) {
+ union acpi_object *obj;
+
+ /*
+ * Evaluate the "PCI Boot Configuration" _DSM Function. If it
+ * exists and returns 0, we must preserve any PCI resource
+ * assignments made by firmware for this host bridge.
+ */
+ obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(&host_bridge->dev),
+ &pci_acpi_dsm_guid,
+ 1, DSM_PCI_PRESERVE_BOOT_CONFIG,
+ NULL, ACPI_TYPE_INTEGER);
+ if (obj && obj->integer.value == 0)
+ return true;
+ ACPI_FREE(obj);
+ }
+
+ return false;
+}
+
/* _HPX PCI Setting Record (Type 0); same as _HPP */
struct hpx_type0 {
u32 revision; /* Not present in _HPP */
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 17fed1846847..180d3907b543 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -734,6 +734,7 @@ static inline void pci_restore_aer_state(struct pci_dev *dev) { }
#endif
#ifdef CONFIG_ACPI
+bool pci_acpi_preserve_config(struct pci_host_bridge *bridge);
int pci_acpi_program_hp_params(struct pci_dev *dev);
extern const struct attribute_group pci_dev_acpi_attr_group;
void pci_set_acpi_fwnode(struct pci_dev *dev);
@@ -747,6 +748,10 @@ int acpi_pci_wakeup(struct pci_dev *dev, bool enable);
bool acpi_pci_need_resume(struct pci_dev *dev);
pci_power_t acpi_pci_choose_state(struct pci_dev *pdev);
#else
+static inline bool pci_acpi_preserve_config(struct pci_host_bridge *bridge)
+{
+ return false;
+}
static inline int pci_dev_acpi_reset(struct pci_dev *dev, bool probe)
{
return -ENOTTY;
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 1325fbae2f28..ee086d029450 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -889,6 +889,14 @@ static void pci_set_bus_msi_domain(struct pci_bus *bus)
dev_set_msi_domain(&bus->dev, d);
}
+static bool pci_preserve_config(struct pci_host_bridge *host_bridge)
+{
+ if (pci_acpi_preserve_config(host_bridge))
+ return true;
+
+ return false;
+}
+
static int pci_register_host_bridge(struct pci_host_bridge *bridge)
{
struct device *parent = bridge->dev.parent;
@@ -983,6 +991,9 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
if (nr_node_ids > 1 && pcibus_to_node(bus) == NUMA_NO_NODE)
dev_warn(&bus->dev, "Unknown NUMA node; performance will be reduced\n");
+ /* Check if the boot configuration by FW needs to be preserved */
+ bridge->preserve_config = pci_preserve_config(bridge);
+
/* Coalesce contiguous windows */
resource_list_for_each_entry_safe(window, n, &resources) {
if (list_is_last(&window->node, &resources))
--
2.25.1
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().
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/of.c | 54 ++++++++++++++++++++++++++++++++++++++---------
drivers/pci/pci.h | 7 ++++++
2 files changed, 51 insertions(+), 10 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
@@ -234,27 +234,61 @@ int of_get_pci_domain_nr(struct device_node *node)
EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);
/**
- * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only
- * is present and valid
+ * 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.
*/
-void of_pci_check_probe_only(void)
+bool of_pci_preserve_config(struct device_node *node)
{
- u32 val;
+ u32 val = 0;
int ret;
- ret = of_property_read_u32(of_chosen, "linux,pci-probe-only", &val);
+ 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("linux,pci-probe-only without valid value, ignoring\n");
- return;
+ 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)
+{
+ 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) { }
--
2.25.1
Use preserve_config in place of checking for PCI_PROBE_ONLY flag
to enable support for "linux,pci-probe-only" on a per host bridge
basis.
This patch also obviates the use of adding PCI_REASSIGN_ALL_BUS flag
if !PCI_PROBE_ONLY, as pci_assign_unassigned_root_bus_resources()
takes care of reassigning the resources that are not already claimed.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/pci-host-common.c | 4 ----
drivers/pci/probe.c | 20 +++++++++-----------
2 files changed, 9 insertions(+), 15 deletions(-)
diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
index 45b71806182d..c96b2de163b5 100644
--- a/drivers/pci/controller/pci-host-common.c
+++ b/drivers/pci/controller/pci-host-common.c
@@ -73,10 +73,6 @@ int pci_host_common_probe(struct platform_device *pdev)
if (IS_ERR(cfg))
return PTR_ERR(cfg);
- /* Do not reassign resources if probe only */
- if (!pci_has_flag(PCI_PROBE_ONLY))
- pci_add_flags(PCI_REASSIGN_ALL_BUS);
-
bridge->sysdata = cfg;
bridge->ops = (struct pci_ops *)&ops->pci_ops;
bridge->msi_domain = true;
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 2c232c22d6af..b4adc33f88cf 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -3088,20 +3088,18 @@ int pci_host_probe(struct pci_host_bridge *bridge)
bus = bridge->bus;
+ /* If we must preserve the resource configuration, claim now */
+ if (bridge->preserve_config)
+ pci_bus_claim_resources(bus);
+
/*
- * We insert PCI resources into the iomem_resource and
- * ioport_resource trees in either pci_bus_claim_resources()
- * or pci_bus_assign_resources().
+ * Assign whatever was left unassigned. If we didn't claim above,
+ * this will reassign everything.
*/
- if (pci_has_flag(PCI_PROBE_ONLY)) {
- pci_bus_claim_resources(bus);
- } else {
- pci_bus_size_bridges(bus);
- pci_bus_assign_resources(bus);
+ pci_assign_unassigned_root_bus_resources(bus);
- list_for_each_entry(child, &bus->children, node)
- pcie_bus_configure_settings(child);
- }
+ list_for_each_entry(child, &bus->children, node)
+ pcie_bus_configure_settings(child);
pci_bus_add_devices(bus);
return 0;
--
2.25.1
Unify the 'preserve config' support across ACPI and device-tree
boot flows.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/probe.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ee086d029450..2c232c22d6af 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -894,6 +894,9 @@ static bool pci_preserve_config(struct pci_host_bridge *host_bridge)
if (pci_acpi_preserve_config(host_bridge))
return true;
+ if (host_bridge->dev.parent && host_bridge->dev.parent->of_node)
+ return of_pci_preserve_config(host_bridge->dev.parent->of_node);
+
return false;
}
--
2.25.1
Hi Bjorn,
Thanks for reviewing and refactoring V6 patch.
Could you please review this V7 series as well?
Thanks,
Vidya Sagar
> -----Original Message-----
> From: Vidya Sagar <[email protected]>
> Sent: Wednesday, May 8, 2024 11:12 PM
> To: [email protected]; [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]; [email protected]
> Cc: [email protected]; [email protected]; linux-
> [email protected]; [email protected];
> [email protected]; Thierry Reding <[email protected]>; Jon Hunter
> <[email protected]>; Krishna Thota <[email protected]>; Manikanta
> Maddireddy <[email protected]>; Vidya Sagar <[email protected]>;
> [email protected]
> Subject: [PATCH V7 0/4] PCI: Add support for preserving boot configuration
>
> Add support for preserving the boot configuration done by the platform firmware
> per host bridge basis, based on the presence of 'linux,pci-probe-only' property in
> the respective PCI host bridge device-tree node. It also unifies the ACPI and DT
> based boot flows in this regard.
>
> This patch series is a complete version of the incomplete series (
> https://lore.kernel.org/linux-pci/20240421190914.374399-1-
> [email protected]/ ) posted by Bjorn which in turn was an attempted split work
> of the single V6 patch ( https://lore.kernel.org/linux-
> pci/[email protected]/ ) posted by me.
>
> Vidya Sagar (4):
> PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to
> pci_register_host_bridge()
> PCI: of: Add of_pci_preserve_config() for per-host bridge support
> PCI: Unify ACPI and DT 'preserve config' support
> PCI: Use preserve_config in place of pci_flags
>
> drivers/acpi/pci_root.c | 12 ------
> drivers/pci/controller/pci-host-common.c | 4 --
> drivers/pci/of.c | 54 +++++++++++++++++++-----
> drivers/pci/pci-acpi.c | 22 ++++++++++
> drivers/pci/pci.h | 12 ++++++
> drivers/pci/probe.c | 34 ++++++++++-----
> 6 files changed, 101 insertions(+), 37 deletions(-)
>
> --
> 2.25.1
Hi Bjorn,
Sorry to bug you.
Please let me know if you need more information for this series.
Thanks,
Vidya Sagar
> -----Original Message-----
> From: Vidya Sagar <[email protected]>
> Sent: Friday, May 17, 2024 11:05 AM
> To: [email protected]; [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]; [email protected]
> Cc: [email protected]; [email protected]; linux-
> [email protected]; [email protected];
> [email protected]; Thierry Reding <[email protected]>; Jon Hunter
> <[email protected]>; Krishna Thota <[email protected]>; Manikanta
> Maddireddy <[email protected]>; [email protected]
> Subject: RE: [PATCH V7 0/4] PCI: Add support for preserving boot configuration
>
> External email: Use caution opening links or attachments
>
>
> Hi Bjorn,
> Thanks for reviewing and refactoring V6 patch.
> Could you please review this V7 series as well?
>
> Thanks,
> Vidya Sagar
>
> > -----Original Message-----
> > From: Vidya Sagar <[email protected]>
> > Sent: Wednesday, May 8, 2024 11:12 PM
> > To: [email protected]; [email protected]; [email protected];
> > [email protected]; [email protected]; [email protected]; [email protected];
> > [email protected]
> > Cc: [email protected]; [email protected]; linux-
> > [email protected]; [email protected];
> > [email protected]; Thierry Reding <[email protected]>; Jon
> > Hunter <[email protected]>; Krishna Thota <[email protected]>;
> > Manikanta Maddireddy <[email protected]>; Vidya Sagar
> > <[email protected]>; [email protected]
> > Subject: [PATCH V7 0/4] PCI: Add support for preserving boot
> > configuration
> >
> > Add support for preserving the boot configuration done by the platform
> > firmware per host bridge basis, based on the presence of
> > 'linux,pci-probe-only' property in the respective PCI host bridge
> > device-tree node. It also unifies the ACPI and DT based boot flows in this regard.
> >
> > This patch series is a complete version of the incomplete series (
> > https://lore.kernel.org/linux-pci/20240421190914.374399-1-
> > [email protected]/ ) posted by Bjorn which in turn was an attempted
> > split work of the single V6 patch ( https://lore.kernel.org/linux-
> > pci/[email protected]/ ) posted by me.
> >
> > Vidya Sagar (4):
> > PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to
> > pci_register_host_bridge()
> > PCI: of: Add of_pci_preserve_config() for per-host bridge support
> > PCI: Unify ACPI and DT 'preserve config' support
> > PCI: Use preserve_config in place of pci_flags
> >
> > drivers/acpi/pci_root.c | 12 ------
> > drivers/pci/controller/pci-host-common.c | 4 --
> > drivers/pci/of.c | 54 +++++++++++++++++++-----
> > drivers/pci/pci-acpi.c | 22 ++++++++++
> > drivers/pci/pci.h | 12 ++++++
> > drivers/pci/probe.c | 34 ++++++++++-----
> > 6 files changed, 101 insertions(+), 37 deletions(-)
> >
> > --
> > 2.25.1
>
On Wed, May 08, 2024 at 11:11:34PM +0530, Vidya Sagar wrote:
> Add support for preserving the boot configuration done by the
> platform firmware per host bridge basis, based on the presence of
> 'linux,pci-probe-only' property in the respective PCI host bridge
> device-tree node. It also unifies the ACPI and DT based boot flows
> in this regard.
>
> This patch series is a complete version of the incomplete series
> ( https://lore.kernel.org/linux-pci/[email protected]/ )
> posted by Bjorn which in turn was an attempted split work of the single V6 patch
> ( https://lore.kernel.org/linux-pci/[email protected]/ )
> posted by me.
>
> Vidya Sagar (4):
> PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to
> pci_register_host_bridge()
> PCI: of: Add of_pci_preserve_config() for per-host bridge support
> PCI: Unify ACPI and DT 'preserve config' support
> PCI: Use preserve_config in place of pci_flags
>
> drivers/acpi/pci_root.c | 12 ------
> drivers/pci/controller/pci-host-common.c | 4 --
> drivers/pci/of.c | 54 +++++++++++++++++++-----
> drivers/pci/pci-acpi.c | 22 ++++++++++
> drivers/pci/pci.h | 12 ++++++
> drivers/pci/probe.c | 34 ++++++++++-----
> 6 files changed, 101 insertions(+), 37 deletions(-)
Applied to pci/enumeration for v6.11, thanks!