This Broadcom STB PCIe RC driver has one port and connects directly to one
device, be it a switch or an endpoint. We want to be able to leverage
the recently added mechansim that allocates and turns on/off subdevice
regulators.
All that needs to be done is to put the regulator DT nodes in the bridge
below host and to set the pci_ops methods add_bus and remove_bus.
Note that the pci_subdev_regulators_add_bus() method is wrapped for two
reasons:
1. To acheive linkup after the voltage regulators are turned on.
2. If, in the case of an unsuccessful linkup, to redirect
any PCIe accesses to subdevices, e.g. the scan for
DEV/ID. This redirection is needed because the Broadcom
PCIe HW wil issue a CPU abort if such an access is made when
there is no linkup.
Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx>
---
drivers/pci/controller/pcie-brcmstb.c | 56 ++++++++++++++++++++++++++-
1 file changed, 55 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 1a841c240abb..692df3dda77a 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -191,6 +191,7 @@ static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie,
static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val);
static inline void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val);
static inline void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val);
+static int brcm_pcie_add_bus(struct pci_bus *bus);
enum {
RGR1_SW_INIT_1,
@@ -295,6 +296,7 @@ struct brcm_pcie {
u32 hw_rev;
void (*perst_set)(struct brcm_pcie *pcie, u32 val);
void (*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
+ bool refusal_mode;
};
/*
@@ -711,6 +713,18 @@ static void __iomem *brcm_pcie_map_conf(struct pci_bus *bus, unsigned int devfn,
/* Accesses to the RC go right to the RC registers if slot==0 */
if (pci_is_root_bus(bus))
return PCI_SLOT(devfn) ? NULL : base + where;
+ if (pcie->refusal_mode) {
+ /*
+ * At this point we do not have link. There will be a CPU
+ * abort -- a quirk with this controller --if Linux tries
+ * to read any config-space registers besides those
+ * targeting the host bridge. To prevent this we hijack
+ * the address to point to a safe access that will return
+ * 0xffffffff.
+ */
+ writel(0xffffffff, base + PCIE_MISC_RC_BAR2_CONFIG_HI);
+ return base + PCIE_MISC_RC_BAR2_CONFIG_HI + (where & 0x3);
+ }
/* For devices, write to the config space index register */
idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0);
@@ -722,6 +736,8 @@ static struct pci_ops brcm_pcie_ops = {
.map_bus = brcm_pcie_map_conf,
.read = pci_generic_config_read,
.write = pci_generic_config_write,
+ .add_bus = brcm_pcie_add_bus,
+ .remove_bus = pci_subdev_regulators_remove_bus,
};
static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val)
@@ -1242,6 +1258,34 @@ static const struct of_device_id brcm_pcie_match[] = {
{},
};
+static int brcm_pcie_add_bus(struct pci_bus *bus)
+{
+ struct pci_host_bridge *hb;
+ struct brcm_pcie *pcie;
+ int ret;
+
+ if (!pcie_is_port_dev(bus->self))
+ return 0;
+
+ hb = pci_find_host_bridge(bus);
+ pcie = (struct brcm_pcie *) hb->sysdata;
+
+ ret = pci_subdev_regulators_add_bus(bus);
+ if (ret)
+ return ret;
+
+ /*
+ * If we have failed linkup there is no point to return an error as
+ * currently it will cause a WARNING() from pci_alloc_child_bus().
+ * We return 0 and turn on the "refusal_mode" so that any further
+ * accesses to the pci_dev just get 0xffffffff
+ */
+ if (brcm_pcie_linkup(pcie) != 0)
+ pcie->refusal_mode = true;
+
+ return 0;
+}
+
static int brcm_pcie_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node, *msi_np;
@@ -1333,7 +1377,17 @@ static int brcm_pcie_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, pcie);
- return pci_host_probe(bridge);
+ ret = pci_host_probe(bridge);
+ if (!ret && !brcm_pcie_link_up(pcie))
+ ret = -ENODEV;
+
+ if (ret) {
+ brcm_pcie_remove(pdev);
+ return ret;
+ }
+
+ return 0;
+
fail:
__brcm_pcie_remove(pcie);
return ret;
--
2.17.1
