On 1/24/2025 11:48 AM, Manivannan Sadhasivam wrote:
On Tue, Jan 21, 2025 at 02:32:21PM +0530, Krishna Chaitanya Chundru wrote:
Allow DWC glue drivers to allocate the host bridge, avoiding redundant
device tree reads primarily in dw_pcie_ecam_supported().
I don't understand what you mean by 'redundant device tree reads'. Please
explain.
In dw_pcie_ecam_supported () we are trying to read bus-range to find
maximum bus range value. devm_pci_alloc_host_bridge() is already reading
bus range it. If we move devm_pci_alloc_host_bridge() to start of the
controller probe we can avoid reading the dt and use values stored in
the host bridge.
This was recommended by bjorn in the v2.
I will update the commit text in the next series.
- Mani
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-designware-host.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 3888f9fe5af1..0acf9db44f2c 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -484,8 +484,8 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
struct device *dev = pci->dev;
struct device_node *np = dev->of_node;
struct platform_device *pdev = to_platform_device(dev);
+ struct pci_host_bridge *bridge = pp->bridge;
struct resource_entry *win;
- struct pci_host_bridge *bridge;
struct resource *res;
int ret;
@@ -497,11 +497,12 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
return -ENODEV;
}
- bridge = devm_pci_alloc_host_bridge(dev, 0);
- if (!bridge)
- return -ENOMEM;
-
- pp->bridge = bridge;
+ if (!pp->bridge) {
+ bridge = devm_pci_alloc_host_bridge(dev, 0);
+ if (!bridge)
+ return -ENOMEM;
+ pp->bridge = bridge;
+ }
pp->cfg0_size = resource_size(res);
pp->cfg0_base = res->start;
--
2.34.1
