The PCIe endpoint device such as Xilinx Alveo PCIe card maps the register
spaces from multiple hardware peripherals to its PCIe BAR. Normally,
the PCI core discovers devices and BARs using the PCI enumeration process.
There is no infrastructure to discover the hardware peripherals that are
present in a PCI device, and which can be accessed through the PCI BARs.
For Alveo PCIe card, the card firmware provides a flattened device tree to
describe the hardware peripherals on its BARs. The Alveo card driver can
load this flattened device tree and leverage device tree framework to
generate platform devices for the hardware peripherals eventually.
Apparently, the device tree framework requires a device tree node for the
PCIe device. Thus, it can generate the device tree nodes for hardware
peripherals underneath. Because PCIe is self discoverable bus, there might
not be a device tree node created for PCIe devices. This patch is to add
support to generate device tree node for PCIe devices. It introduces a
kernel option. When the option is turned on, the kernel will generate
device tree nodes for PCI bridges unconditionally. It will also generate
a device tree node for Xilinx Alveo U50 by using PCI quirks.
Initially, the basic properties are added for the dynamically generated
device tree nodes.
Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxx>
Signed-off-by: Sonal Santan <sonal.santan@xxxxxxx>
Signed-off-by: Max Zhen <max.zhen@xxxxxxx>
Reviewed-by: Brian Xu <brian.xu@xxxxxxx>
---
drivers/pci/Kconfig | 12 ++
drivers/pci/Makefile | 1 +
drivers/pci/bus.c | 2 +
drivers/pci/msi/irqdomain.c | 6 +-
drivers/pci/of.c | 71 ++++++++++
drivers/pci/of_property.c | 256 ++++++++++++++++++++++++++++++++++++
drivers/pci/pci-driver.c | 3 +-
drivers/pci/pci.h | 19 +++
drivers/pci/quirks.c | 11 ++
drivers/pci/remove.c | 1 +
10 files changed, 379 insertions(+), 3 deletions(-)
create mode 100644 drivers/pci/of_property.c
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 55c028af4bd9..8243a92fd97d 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -198,6 +198,18 @@ config PCI_HYPERV
The PCI device frontend driver allows the kernel to import arbitrary
PCI devices from a PCI backend to support PCI driver domains.
+config PCI_DYNAMIC_OF_NODES
+ bool "Device tree node for PCI devices"
+ depends on OF
+ select OF_DYNAMIC
+ help
+ This option enables support for generating device tree nodes for some
+ PCI devices. Thus, the driver of this kind can load and overlay
+ flattened device tree for its downstream devices.
+
+ Once this option is selected, the device tree nodes will be generated
+ for all PCI/PCIE bridges.
+
choice
prompt "PCI Express hierarchy optimization setting"
default PCIE_BUS_DEFAULT
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 2680e4c92f0a..cc8b4e01e29d 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_PCI_P2PDMA) += p2pdma.o
obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o
obj-$(CONFIG_VGA_ARB) += vgaarb.o
obj-$(CONFIG_PCI_DOE) += doe.o
+obj-$(CONFIG_PCI_DYNAMIC_OF_NODES) += of_property.o
# Endpoint library must be initialized before its users
obj-$(CONFIG_PCI_ENDPOINT) += endpoint/
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 3cef835b375f..8507cc32b61d 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -316,6 +316,8 @@ void pci_bus_add_device(struct pci_dev *dev)
*/
pcibios_bus_add_device(dev);
pci_fixup_device(pci_fixup_final, dev);
+ if (pci_is_bridge(dev))
+ of_pci_make_dev_node(dev);
pci_create_sysfs_dev_files(dev);
pci_proc_attach_device(dev);
pci_bridge_d3_update(dev);
diff --git a/drivers/pci/msi/irqdomain.c b/drivers/pci/msi/irqdomain.c
index e9cf318e6670..eeaf44169bfd 100644
--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -230,8 +230,10 @@ u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev)
pci_for_each_dma_alias(pdev, get_msi_id_cb, &rid);
of_node = irq_domain_get_of_node(domain);
- rid = of_node ? of_msi_map_id(&pdev->dev, of_node, rid) :
- iort_msi_map_id(&pdev->dev, rid);
+ if (of_node && !of_node_check_flag(of_node, OF_DYNAMIC))
+ rid = of_msi_map_id(&pdev->dev, of_node, rid);
+ else
+ rid = iort_msi_map_id(&pdev->dev, rid);
return rid;
}
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 196834ed44fe..0d5bbb08c61d 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -469,6 +469,8 @@ static int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *
} else {
/* We found a P2P bridge, check if it has a node */
ppnode = pci_device_to_OF_node(ppdev);
+ if (of_node_check_flag(ppnode, OF_DYNAMIC))
+ ppnode = NULL;
}
/*
@@ -599,6 +601,75 @@ int devm_of_pci_bridge_init(struct device *dev, struct pci_host_bridge *bridge)
return pci_parse_request_of_pci_ranges(dev, bridge);
}
+#if IS_ENABLED(CONFIG_PCI_DYNAMIC_OF_NODES)
+
+void of_pci_remove_node(struct pci_dev *pdev)
+{
+ struct device_node *dt_node;
+
+ dt_node = pci_device_to_OF_node(pdev);
+ if (!dt_node || !of_node_check_flag(dt_node, OF_DYNAMIC))
+ return;
+ pdev->dev.of_node = NULL;
+
+ of_destroy_node(dt_node);
+}
+
+void of_pci_make_dev_node(struct pci_dev *pdev)
+{
+ struct device_node *parent, *dt_node = NULL;
+ const char *pci_type = "dev";
+ struct of_changeset *cset;
+ const char *full_name;
+ int ret;
+
+ /*
+ * if there is already a device tree node linked to this device,
+ * return immediately.
+ */
+ if (pci_device_to_OF_node(pdev))
+ return;
+
+ /* check if there is device tree node for parent device */
+ if (!pdev->bus->self)
+ parent = pdev->bus->dev.of_node;
+ else
+ parent = pdev->bus->self->dev.of_node;
+ if (!parent)
+ return;
+
+ if (pci_is_bridge(pdev))
+ pci_type = "pci";
+
+ full_name = kasprintf(GFP_KERNEL, "%pOF/%s@%x,%x", parent, pci_type,
+ PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+ if (!full_name)
+ goto failed;
+
+ dt_node = of_create_node(parent, full_name, &cset);
+ if (!dt_node)
+ goto failed;
+ kfree(full_name);
+
+ ret = of_pci_add_properties(pdev, cset, dt_node);
+ if (ret)
+ goto failed;
+
+ ret = of_changeset_apply(cset);
+ if (ret)
+ goto failed;
+
+ pdev->dev.of_node = dt_node;
+
+ return;
+
+failed:
+ if (dt_node)
+ of_destroy_node(dt_node);
+ kfree(full_name);
+}
+#endif
+
#endif /* CONFIG_PCI */
/**
diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c
new file mode 100644
index 000000000000..cc66fa7517e0
--- /dev/null
+++ b/drivers/pci/of_property.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2022, Advanced Micro Devices, Inc.
+ */
+
+#include <linux/pci.h>
+#include <linux/of.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include "pci.h"
+
+struct of_pci_addr_pair {
+ __be32 phys_hi;
+ __be32 phys_mid;
+ __be32 phys_lo;
+ __be32 size_hi;
+ __be32 size_lo;
+};
+
+struct of_pci_range {
+ __be32 child_addr_hi;
+ __be32 child_addr_mid;
+ __be32 child_addr_lo;
+ __be32 parent_addr_hi;
+ __be32 parent_addr_mid;
+ __be32 parent_addr_lo;
+ __be32 size_hi;
+ __be32 size_lo;
+};
+
+#define OF_PCI_ADDR_SPACE_CONFIG 0x0
+#define OF_PCI_ADDR_SPACE_IO 0x1
+#define OF_PCI_ADDR_SPACE_MEM32 0x2
+#define OF_PCI_ADDR_SPACE_MEM64 0x3
+
+#define OF_PCI_ADDR_FIELD_NONRELOC BIT(31)
+#define OF_PCI_ADDR_FIELD_SS GENMASK(25, 24)
+#define OF_PCI_ADDR_FIELD_PREFETCH BIT(30)
+#define OF_PCI_ADDR_FIELD_BUS GENMASK(23, 16)
+#define OF_PCI_ADDR_FIELD_DEV GENMASK(15, 11)
+#define OF_PCI_ADDR_FIELD_FUNC GENMASK(10, 8)
+#define OF_PCI_ADDR_FIELD_REG GENMASK(7, 0)
+
+#define OF_PCI_ADDR_HI GENMASK_ULL(63, 32)
+#define OF_PCI_ADDR_LO GENMASK_ULL(31, 0)
+#define OF_PCI_SIZE_HI GENMASK_ULL(63, 32)
+#define OF_PCI_SIZE_LO GENMASK_ULL(31, 0)
+
+#define OF_PCI_ADDRESS_CELLS 3
+#define OF_PCI_SIZE_CELLS 2
+
+enum of_pci_prop_compatible {
+ PROP_COMPAT_PCI_VVVV_DDDD,
+ PROP_COMPAT_PCICLASS_CCSSPP,
+ PROP_COMPAT_PCICLASS_CCSS,
+ PROP_COMPAT_NUM,
+};
+
+static int of_pci_prop_device_type(struct pci_dev *pdev,
+ struct of_changeset *ocs,
+ struct device_node *np)
+{
+ return of_changeset_add_prop_string(ocs, np, "device_type", "pci");
+}
+
+static int of_pci_prop_address_cells(struct pci_dev *pdev,
+ struct of_changeset *ocs,
+ struct device_node *np)
+{
+ return of_changeset_add_prop_u32(ocs, np, "#address_cells",
+ OF_PCI_ADDRESS_CELLS);
+}
+
+static int of_pci_prop_size_cells(struct pci_dev *pdev,
+ struct of_changeset *ocs,
+ struct device_node *np)
+{
+ return of_changeset_add_prop_u32(ocs, np, "#size_cells",
+ OF_PCI_SIZE_CELLS);
+}
+
+static int of_pci_set_addr_flags(struct resource *res, u32 *addr_hi)
+{
+ u32 ss;
+
+ if (res->flags & IORESOURCE_IO)
+ ss = OF_PCI_ADDR_SPACE_IO;
+ else if (res->flags & IORESOURCE_MEM_64)
+ ss = OF_PCI_ADDR_SPACE_MEM64;
+ else if (res->flags & IORESOURCE_MEM)
+ ss = OF_PCI_ADDR_SPACE_MEM32;
+ else
+ return -EINVAL;
+
+ *addr_hi &= ~(OF_PCI_ADDR_FIELD_SS | OF_PCI_ADDR_FIELD_PREFETCH);
+ if (res->flags & IORESOURCE_PREFETCH)
+ *addr_hi |= OF_PCI_ADDR_FIELD_PREFETCH;
+
+ *addr_hi |= ss;
+
+ return 0;
+}
+
+static int of_pci_prop_ranges(struct pci_dev *pdev, struct of_changeset *ocs,
+ struct device_node *np)
+{
+ struct of_pci_range rp[PCI_BRIDGE_RESOURCE_NUM];
+ struct resource *res;
+ int i = 0, j, ret;
+ u64 val64;
+ u32 val;
+
+ res = &pdev->resource[PCI_BRIDGE_RESOURCES];
+ for (j = 0; j < PCI_BRIDGE_RESOURCE_NUM; j++) {
+ if (!resource_size(&res[j]))
+ continue;
+
+ val = OF_PCI_ADDR_FIELD_NONRELOC;
+ if (of_pci_set_addr_flags(&res[j], &val))
+ continue;
+
+ rp[i].parent_addr_hi = cpu_to_be32(val);
+
+ val64 = res[j].start;
+ rp[i].parent_addr_mid =
+ cpu_to_be32(FIELD_GET(OF_PCI_ADDR_HI, val64));
+ rp[i].parent_addr_lo =
+ cpu_to_be32(FIELD_GET(OF_PCI_ADDR_LO, val64));
+
+ val64 = resource_size(&res[j]);
+ rp[i].size_hi = cpu_to_be32(FIELD_GET(OF_PCI_SIZE_HI, val64));
+ rp[i].size_lo = cpu_to_be32(FIELD_GET(OF_PCI_SIZE_LO, val64));
+
+ rp[i].child_addr_hi = rp[i].parent_addr_hi;
+ rp[i].child_addr_mid = rp[i].parent_addr_mid;
+ rp[i].child_addr_lo = rp[i].parent_addr_lo;
+ i++;
+ }
+
+ ret = of_changeset_add_prop_u32_array(ocs, np, "ranges", (u32 *)rp,
+ i * sizeof(*rp) / sizeof(u32));
+
+ return ret;
+}
+
+static int of_pci_prop_reg(struct pci_dev *pdev, struct of_changeset *ocs,
+ struct device_node *np)
+{
+ struct of_pci_addr_pair *reg;
+ int i = 1, resno, ret = 0;
+ u32 reg_val, base_addr;
+ resource_size_t sz;
+
+ reg = kzalloc(sizeof(*reg) * (PCI_STD_NUM_BARS + 1), GFP_KERNEL);
+ if (!reg)
+ return -ENOMEM;
+
+ reg_val = FIELD_PREP(OF_PCI_ADDR_FIELD_SS, OF_PCI_ADDR_SPACE_CONFIG) |
+ FIELD_PREP(OF_PCI_ADDR_FIELD_BUS, pdev->bus->number) |
+ FIELD_PREP(OF_PCI_ADDR_FIELD_DEV, PCI_SLOT(pdev->devfn)) |
+ FIELD_PREP(OF_PCI_ADDR_FIELD_FUNC, PCI_FUNC(pdev->devfn));
+ reg[0].phys_hi = cpu_to_be32(reg_val);
+
+ base_addr = PCI_BASE_ADDRESS_0;
+ for (resno = PCI_STD_RESOURCES; resno <= PCI_STD_RESOURCE_END;
+ resno++, base_addr += 4) {
+ sz = pci_resource_len(pdev, resno);
+ if (!sz)
+ continue;
+
+ ret = of_pci_set_addr_flags(&pdev->resource[resno], ®_val);
+ if (!ret)
+ continue;
+
+ reg_val &= ~OF_PCI_ADDR_FIELD_REG;
+ reg_val |= FIELD_PREP(OF_PCI_ADDR_FIELD_REG, base_addr);
+ reg[i].phys_hi = cpu_to_be32(reg_val);
+ reg[i].size_hi = cpu_to_be32(FIELD_GET(OF_PCI_SIZE_HI, sz));
+ reg[i].size_lo = cpu_to_be32(FIELD_GET(OF_PCI_SIZE_LO, sz));
+ i++;
+ }
+
+ ret = of_changeset_add_prop_u32_array(ocs, np, "reg", (u32 *)reg,
+ i * sizeof(*reg) / sizeof(u32));
+ kfree(reg);
+
+ return ret;
+}
+
+static int of_pci_prop_compatible(struct pci_dev *pdev,
+ struct of_changeset *ocs,
+ struct device_node *np)
+{
+ const char *compat_strs[PROP_COMPAT_NUM] = { 0 };
+ int i, ret;
+
+ compat_strs[PROP_COMPAT_PCI_VVVV_DDDD] =
+ kasprintf(GFP_KERNEL, "pci%x,%x", pdev->vendor, pdev->device);
+ compat_strs[PROP_COMPAT_PCICLASS_CCSSPP] =
+ kasprintf(GFP_KERNEL, "pciclass,%06x", pdev->class);
+ compat_strs[PROP_COMPAT_PCICLASS_CCSS] =
+ kasprintf(GFP_KERNEL, "pciclass,%04x", pdev->class >> 8);
+
+ ret = of_changeset_add_prop_string_array(ocs, np, "compatible",
+ compat_strs, PROP_COMPAT_NUM);
+ for (i = 0; i < PROP_COMPAT_NUM; i++)
+ kfree(compat_strs[i]);
+
+ return ret;
+}
+
+static int (*of_pci_endpoint_props[])(struct pci_dev *pdev,
+ struct of_changeset *ocs,
+ struct device_node *np) = {
+ of_pci_prop_reg,
+ of_pci_prop_compatible,
+ NULL
+};
+
+static int (*of_pci_bridge_props[])(struct pci_dev *pdev,
+ struct of_changeset *ocs,
+ struct device_node *np) = {
+ of_pci_prop_device_type,
+ of_pci_prop_address_cells,
+ of_pci_prop_size_cells,
+ of_pci_prop_ranges,
+ of_pci_prop_reg,
+ of_pci_prop_compatible,
+ NULL
+};
+
+int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs,
+ struct device_node *np)
+{
+ int (**prop_func)(struct pci_dev *pdev, struct of_changeset *ocs,
+ struct device_node *np);
+ int i, ret;
+
+ if (pci_is_bridge(pdev))
+ prop_func = of_pci_bridge_props;
+ else
+ prop_func = of_pci_endpoint_props;
+
+ for (i = 0; prop_func[i]; i++) {
+ ret = prop_func[i](pdev, ocs, np);
+ if (ret) {
+ /*
+ * The added properties will be released when the
+ * changeset is destroyed.
+ */
+ return ret;
+ }
+ }
+
+ return 0;
+}
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 49238ddd39ee..1540c4c9a770 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1628,7 +1628,8 @@ static int pci_dma_configure(struct device *dev)
bridge = pci_get_host_bridge_device(to_pci_dev(dev));
if (IS_ENABLED(CONFIG_OF) && bridge->parent &&
- bridge->parent->of_node) {
+ bridge->parent->of_node &&
+ !of_node_check_flag(bridge->parent->of_node, OF_DYNAMIC)) {
ret = of_dma_configure(dev, bridge->parent->of_node, true);
} else if (has_acpi_companion(bridge)) {
struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 785f31086313..bd81dc4ca04f 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -678,6 +678,25 @@ static inline int devm_of_pci_bridge_init(struct device *dev, struct pci_host_br
#endif /* CONFIG_OF */
+struct of_changeset;
+
+#ifdef CONFIG_PCI_DYNAMIC_OF_NODES
+void of_pci_make_dev_node(struct pci_dev *pdev);
+void of_pci_remove_node(struct pci_dev *pdev);
+int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs,
+ struct device_node *np);
+#else
+static inline void
+of_pci_make_dev_node(struct pci_dev *pdev)
+{
+}
+
+static inline void
+of_pci_remove_node(struct pci_dev *pdev)
+{
+}
+#endif /* CONFIG_PCI_DYNAMIC_OF_NODES */
+
#ifdef CONFIG_PCIEAER
void pci_no_aer(void);
void pci_aer_init(struct pci_dev *dev);
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 4944798e75b5..5d76932f59ec 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5956,3 +5956,14 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56b1, aspm_l1_acceptable_latency
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56c0, aspm_l1_acceptable_latency);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x56c1, aspm_l1_acceptable_latency);
#endif
+
+/*
+ * For PCI device which have multiple downstream devices, its driver may use
+ * a flattened device tree to describe the downstream devices.
+ * To overlay the flattened device tree, the PCI device and all its ancestor
+ * devices need to have device tree nodes on system base device tree. Thus,
+ * before driver probing, it might need to add a device tree node as the final
+ * fixup.
+ */
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_XILINX, 0x5020, of_pci_make_dev_node);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_XILINX, 0x5021, of_pci_make_dev_node);
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 4c54c75050dc..0eaa9d9a3609 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -23,6 +23,7 @@ static void pci_stop_dev(struct pci_dev *dev)
device_release_driver(&dev->dev);
pci_proc_detach_device(dev);
pci_remove_sysfs_dev_files(dev);
+ of_pci_remove_node(dev);
pci_dev_assign_added(dev, false);
}
--
2.17.1
