The generic PCI host driver leaves the configuration and mgmt of the
clock/phy/etc on PCI root ports to the firmware and PCIe defined
mechanisms as is done on UEFI/ACPI systems. If the PCIe config
operations were abstracted as well then a number of the resulting
Linux PCie drivers would no longer be needed.
Given that Arm has standardized a generic SMC conduit for reading and
writing the PCIe config space. Using it on DT based systems seems a
natural way to reduce some of the driver diversity on DT based systems
as well.
This patch adds a compatible type "pci-host-smc-generic" which expects
that the 'reg' property of the root port is missing, and the PCI SMCCC
exists. When that happens it binds the SMC to the pci_ecam_ops.
Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
---
drivers/pci/controller/pci-host-common.c | 34 ++++++++++++++++-------
drivers/pci/controller/pci-host-generic.c | 6 ++++
2 files changed, 30 insertions(+), 10 deletions(-)
diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
index d3924a44db02..2673fd81d3e0 100644
--- a/drivers/pci/controller/pci-host-common.c
+++ b/drivers/pci/controller/pci-host-common.c
@@ -20,22 +20,41 @@ static void gen_pci_unmap_cfg(void *ptr)
pci_ecam_free((struct pci_config_window *)ptr);
}
+__weak int pcie_has_fw_conduit(void)
+{
+ return -EOPNOTSUPP;
+}
+
+__weak struct pci_config_window *pci_setup_fw_mapping(struct device *dev,
+ u16 seg, struct resource *bus_res)
+{
+ return NULL;
+}
+
static struct pci_config_window *gen_pci_init(struct device *dev,
- struct pci_host_bridge *bridge, const struct pci_ecam_ops *ops)
+ struct pci_host_bridge *bridge)
{
int err;
struct resource cfgres;
struct resource_entry *bus;
struct pci_config_window *cfg;
+ const struct pci_ecam_ops *ops;
+
+ bus = resource_list_first_type(&bridge->windows, IORESOURCE_BUS);
+ if (!bus)
+ return ERR_PTR(-ENODEV);
err = of_address_to_resource(dev->of_node, 0, &cfgres);
if (err) {
+ if (!pcie_has_fw_conduit())
+ return pci_setup_fw_mapping(dev, bridge->busnr, bus->res);
+
dev_err(dev, "missing \"reg\" property\n");
return ERR_PTR(err);
}
- bus = resource_list_first_type(&bridge->windows, IORESOURCE_BUS);
- if (!bus)
+ ops = of_device_get_match_data(dev);
+ if (!ops)
return ERR_PTR(-ENODEV);
cfg = pci_ecam_create(dev, &cfgres, bus->res, ops);
@@ -54,11 +73,6 @@ int pci_host_common_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct pci_host_bridge *bridge;
struct pci_config_window *cfg;
- const struct pci_ecam_ops *ops;
-
- ops = of_device_get_match_data(&pdev->dev);
- if (!ops)
- return -ENODEV;
bridge = devm_pci_alloc_host_bridge(dev, 0);
if (!bridge)
@@ -69,7 +83,7 @@ int pci_host_common_probe(struct platform_device *pdev)
of_pci_check_probe_only();
/* Parse and map our Configuration Space windows */
- cfg = gen_pci_init(dev, bridge, ops);
+ cfg = gen_pci_init(dev, bridge);
if (IS_ERR(cfg))
return PTR_ERR(cfg);
@@ -78,7 +92,7 @@ int pci_host_common_probe(struct platform_device *pdev)
pci_add_flags(PCI_REASSIGN_ALL_BUS);
bridge->sysdata = cfg;
- bridge->ops = (struct pci_ops *)&ops->pci_ops;
+ bridge->ops = (struct pci_ops *)&cfg->ops->pci_ops;
bridge->msi_domain = true;
return pci_host_probe(bridge);
diff --git a/drivers/pci/controller/pci-host-generic.c b/drivers/pci/controller/pci-host-generic.c
index 63865aeb636b..d20d33b3c689 100644
--- a/drivers/pci/controller/pci-host-generic.c
+++ b/drivers/pci/controller/pci-host-generic.c
@@ -56,6 +56,9 @@ static const struct pci_ecam_ops pci_dw_ecam_bus_ops = {
}
};
+static const struct pci_ecam_ops pci_generic_smc_ops = {
+};
+
static const struct of_device_id gen_pci_of_match[] = {
{ .compatible = "pci-host-cam-generic",
.data = &gen_pci_cfg_cam_bus_ops },
@@ -63,6 +66,9 @@ static const struct of_device_id gen_pci_of_match[] = {
{ .compatible = "pci-host-ecam-generic",
.data = &pci_generic_ecam_ops },
+ { .compatible = "pci-host-smc-generic",
+ .data = &pci_generic_smc_ops },
+
{ .compatible = "marvell,armada8k-pcie-ecam",
.data = &pci_dw_ecam_bus_ops },
--
2.37.1
