[V1,2/2] PCI: Add support for "preserve-boot-config" property
Commit Message
Add support for "preserve-boot-config" property that can be used to
selectively (i.e. per host bridge) instruct the kernel to preserve the
boot time configuration done by the platform firmware.
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
---
drivers/pci/controller/pci-host-common.c | 5 ++++-
drivers/pci/of.c | 15 +++++++++++++++
drivers/pci/probe.c | 2 +-
include/linux/of_pci.h | 6 ++++++
4 files changed, 26 insertions(+), 2 deletions(-)
Comments
Hi Vidya,
kernel test robot noticed the following build warnings:
[auto build test WARNING on pci/next]
[also build test WARNING on pci/for-linus linus/master v6.7 next-20240109]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Vidya-Sagar/dt-bindings-Add-PCIe-preserve-boot-config-property/20240109-130938
base: https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link: https://lore.kernel.org/r/20240109050648.1347255-3-vidyas%40nvidia.com
patch subject: [PATCH V1 2/2] PCI: Add support for "preserve-boot-config" property
config: alpha-allnoconfig (https://download.01.org/0day-ci/archive/20240110/202401100554.kaCFjM87-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240110/202401100554.kaCFjM87-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401100554.kaCFjM87-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from drivers/pci/probe.c:11:
>> include/linux/of_pci.h:31:13: warning: 'of_pci_check_preserve_boot_config' defined but not used [-Wunused-function]
31 | static bool of_pci_check_preserve_boot_config(struct device_node *node)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +/of_pci_check_preserve_boot_config +31 include/linux/of_pci.h
30
> 31 static bool of_pci_check_preserve_boot_config(struct device_node *node)
32 {
33 return false;
34 }
35 #endif
36
Hi Vidya,
kernel test robot noticed the following build warnings:
[auto build test WARNING on pci/next]
[also build test WARNING on pci/for-linus linus/master v6.7 next-20240109]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Vidya-Sagar/dt-bindings-Add-PCIe-preserve-boot-config-property/20240109-130938
base: https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link: https://lore.kernel.org/r/20240109050648.1347255-3-vidyas%40nvidia.com
patch subject: [PATCH V1 2/2] PCI: Add support for "preserve-boot-config" property
config: arc-allnoconfig (https://download.01.org/0day-ci/archive/20240110/202401101015.Dch3YIjG-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240110/202401101015.Dch3YIjG-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401101015.Dch3YIjG-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/pci/of.c:271: warning: Function parameter or struct member 'node' not described in 'of_pci_check_preserve_boot_config'
vim +271 drivers/pci/of.c
260
261 /**
262 * of_pci_check_preserve_boot_config - Return true if the boot configuration
263 * needs to be preserved
264 *
265 * This function looks for a property called "preserve-boot-config" for a given
266 * PCIe controller's node and returns true if found. Having this property
267 * for a PCIe controller ensures that the kernel doesn't re-enumerate and
268 * reconfigure the BAR resources that are already done by the platform firmware.
269 */
270 bool of_pci_check_preserve_boot_config(struct device_node *node)
> 271 {
272 return of_property_read_bool(node, "preserve-boot-config");
273 }
274 EXPORT_SYMBOL_GPL(of_pci_check_preserve_boot_config);
275
@@ -68,13 +68,16 @@ int pci_host_common_probe(struct platform_device *pdev)
of_pci_check_probe_only();
+ bridge->preserve_config =
+ of_pci_check_preserve_boot_config(dev->of_node);
+
/* Parse and map our Configuration Space windows */
cfg = gen_pci_init(dev, bridge, ops);
if (IS_ERR(cfg))
return PTR_ERR(cfg);
/* Do not reassign resources if probe only */
- if (!pci_has_flag(PCI_PROBE_ONLY))
+ if (!(pci_has_flag(PCI_PROBE_ONLY) || bridge->preserve_config))
pci_add_flags(PCI_REASSIGN_ALL_BUS);
bridge->sysdata = cfg;
@@ -258,6 +258,21 @@ void of_pci_check_probe_only(void)
}
EXPORT_SYMBOL_GPL(of_pci_check_probe_only);
+/**
+ * of_pci_check_preserve_boot_config - Return true if the boot configuration
+ * needs to be preserved
+ *
+ * This function looks for a property called "preserve-boot-config" for a given
+ * PCIe controller's node and returns true if found. Having this property
+ * for a PCIe controller ensures that the kernel doesn't re-enumerate and
+ * reconfigure the BAR resources that are already done by the platform firmware.
+ */
+bool of_pci_check_preserve_boot_config(struct device_node *node)
+{
+ return of_property_read_bool(node, "preserve-boot-config");
+}
+EXPORT_SYMBOL_GPL(of_pci_check_preserve_boot_config);
+
/**
* devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI
* host bridge resources from DT
@@ -3085,7 +3085,7 @@ int pci_host_probe(struct pci_host_bridge *bridge)
* ioport_resource trees in either pci_bus_claim_resources()
* or pci_bus_assign_resources().
*/
- if (pci_has_flag(PCI_PROBE_ONLY)) {
+ if (pci_has_flag(PCI_PROBE_ONLY) || bridge->preserve_config) {
pci_bus_claim_resources(bus);
} else {
pci_bus_size_bridges(bus);
@@ -13,6 +13,7 @@ struct device_node *of_pci_find_child_device(struct device_node *parent,
unsigned int devfn);
int of_pci_get_devfn(struct device_node *np);
void of_pci_check_probe_only(void);
+bool of_pci_check_preserve_boot_config(struct device_node *node);
#else
static inline struct device_node *of_pci_find_child_device(struct device_node *parent,
unsigned int devfn)
@@ -26,6 +27,11 @@ static inline int of_pci_get_devfn(struct device_node *np)
}
static inline void of_pci_check_probe_only(void) { }
+
+static bool of_pci_check_preserve_boot_config(struct device_node *node)
+{
+ return false;
+}
#endif
#if IS_ENABLED(CONFIG_OF_IRQ)