[PATCH V8 0/3] Generate device tree node for pci devices

[PATCH V8 0/3] Generate device tree node for pci devices

[Lizhi Hou]

This patch series introduces OF overlay support for PCI devices which
primarily addresses two use cases. First, it provides a data driven method
to describe hardware peripherals that are present in a PCI endpoint and
hence can be accessed by the PCI host. Second, it allows reuse of a OF
compatible driver -- often used in SoC platforms -- in a PCI host based
system.

There are 2 series devices rely on this patch:

  1) Xilinx Alveo Accelerator cards (FPGA based device)
  2) Microchip LAN9662 Ethernet Controller

     Please see: https://lore.kernel.org/lkml/20220427094502.456111-1-clement.leger@bootlin.com/

Normally, the PCI core discovers PCI devices and their BARs using the
PCI enumeration process. However, the process does not provide a way to
discover the hardware peripherals that are present in a PCI device, and
which can be accessed through the PCI BARs. Also, the enumeration process
does not provide a way to associate MSI-X vectors of a PCI device with the
hardware peripherals that are present in the device. PCI device drivers
often use header files to describe the hardware peripherals and their
resources as there is no standard data driven way to do so. This patch
series proposes to use flattened device tree blob to describe the
peripherals in a data driven way. Based on previous discussion, using
device tree overlay is the best way to unflatten the blob and populate
platform devices. To use device tree overlay, there are three obvious
problems that need to be resolved.

First, we need to create a base tree for non-DT system such as x86_64. A
patch series has been submitted for this:
https://lore.kernel.org/lkml/20220624034327.2542112-1-frowand.list@gmail.com/
https://lore.kernel.org/lkml/20220216050056.311496-1-lizhi.hou@xilinx.com/

Second, a device tree node corresponding to the PCI endpoint is required
for overlaying the flattened device tree blob for that PCI endpoint.
Because PCI is a self-discoverable bus, a device tree node is usually not
created for PCI devices. This series adds support to generate a device
tree node for a PCI device which advertises itself using PCI quirks
infrastructure.

Third, we need to generate device tree nodes for PCI bridges since a child
PCI endpoint may choose to have a device tree node created.

This patch series is made up of three patches.

The first patch is adding OF interface to create or destroy OF node
dynamically.

The second patch introduces a kernel option, CONFIG_DYNAMIC_PCI_OF_NODEX.
When the option is turned on, the kernel will generate device tree nodes
for all PCI bridges unconditionally. The patch also shows how to use the
PCI quirks infrastructure, DECLARE_PCI_FIXUP_FINAL to generate a device
tree node for a device. Specifically, the patch generates a device tree
node for Xilinx Alveo U50 PCIe accelerator device. The generated device
tree nodes do not have any property.

The third patch adds basic properties ('reg', 'compatible' and
'device_type') to the dynamically generated device tree nodes. More
properties can be added in the future.

Here is the example of device tree nodes generated within the ARM64 QEMU.
# lspci -t    
-[0000:00]-+-00.0
           +-01.0-[01]--
           +-01.1-[02]----00.0
           +-01.2-[03]----00.0
           +-01.3-[04]----00.0
           +-01.4-[05]----00.0
           +-01.5-[06]--
           +-01.6-[07]--
           +-01.7-[08]--
           +-02.0-[09-0b]----00.0-[0a-0b]----00.0-[0b]--+-00.0
           |                                            \-00.1
           +-02.1-[0c]--
           \-03.0-[0d-0e]----00.0-[0e]----01.0

# tree /sys/firmware/devicetree/base/pcie\@10000000
/sys/firmware/devicetree/base/pcie@10000000
|-- #address-cells
|-- #interrupt-cells
|-- #size-cells
|-- bus-range
|-- compatible
|-- device_type
|-- dma-coherent
|-- interrupt-map
|-- interrupt-map-mask
|-- linux,pci-domain
|-- msi-parent
|-- name
|-- pci@1,0
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,1
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,2
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,3
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,4
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,5
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,6
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@1,7
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@2,0
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- pci@0,0
|   |   |-- #address-cells
|   |   |-- #size-cells
|   |   |-- compatible
|   |   |-- device_type
|   |   |-- pci@0,0
|   |   |   |-- #address-cells
|   |   |   |-- #size-cells
|   |   |   |-- compatible
|   |   |   |-- dev@0,0
|   |   |   |   |-- compatible
|   |   |   |   `-- reg
|   |   |   |-- dev@0,1
|   |   |   |   |-- compatible
|   |   |   |   `-- reg
|   |   |   |-- device_type
|   |   |   |-- ranges
|   |   |   `-- reg
|   |   |-- ranges
|   |   `-- reg
|   |-- ranges
|   `-- reg
|-- pci@2,1
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- ranges
|   `-- reg
|-- pci@3,0
|   |-- #address-cells
|   |-- #size-cells
|   |-- compatible
|   |-- device_type
|   |-- pci@0,0
|   |   |-- #address-cells
|   |   |-- #size-cells
|   |   |-- compatible
|   |   |-- device_type
|   |   |-- ranges
|   |   `-- reg
|   |-- ranges
|   `-- reg
|-- ranges
`-- reg

Changes since v7:
- Modified dynamic node creation interfaces
- Added unittest for new added interfaces

Changes since v6:
- Removed single line wrapper functions
- Added Signed-off-by Clément Léger <clement.leger@bootlin.com>

Changes since v5:
- Fixed code review comments
- Fixed incorrect 'ranges' and 'reg' properties

Changes since RFC v4:
- Fixed code review comments

Changes since RFC v3:
- Split the Xilinx Alveo U50 PCI quirk to a separate patch
- Minor changes in commit description and code comment

Changes since RFC v2:
- Merged patch 3 with patch 2
- Added OF interfaces of_changeset_add_prop_* and use them to create
  properties.
- Added '#address-cells', '#size-cells' and 'ranges' properties.

Changes since RFC v1:
- Added one patch to create basic properties.
- To move DT related code out of PCI subsystem, replaced of_node_alloc()
  with of_create_node()/of_destroy_node()

Lizhi Hou (3):
  of: dynamic: Add interfaces for creating device node dynamically
  PCI: Create device tree node for selected devices
  PCI: Add PCI quirks to generate device tree node for Xilinx Alveo U50

 drivers/of/dynamic.c        | 164 ++++++++++++++++++++++++++++
 drivers/of/unittest.c       |  19 +++-
 drivers/pci/Kconfig         |  12 ++
 drivers/pci/Makefile        |   1 +
 drivers/pci/bus.c           |   2 +
 drivers/pci/msi/irqdomain.c |   6 +-
 drivers/pci/of.c            |  79 ++++++++++++++
 drivers/pci/of_property.c   | 212 ++++++++++++++++++++++++++++++++++++
 drivers/pci/pci-driver.c    |   3 +-
 drivers/pci/pci.h           |  19 ++++
 drivers/pci/quirks.c        |  11 ++
 drivers/pci/remove.c        |   1 +
 include/linux/of.h          |  23 ++++
 13 files changed, 548 insertions(+), 4 deletions(-)
 create mode 100644 drivers/pci/of_property.c

-- 
2.34.1

[PATCH V8 1/3] of: dynamic: Add interfaces for creating device node dynamically

[Lizhi Hou]

of_create_node() creates device node dynamically. The parent device node
and full name are required for creating the node. It optionally creates
an OF changeset and attaches the newly created node to the changeset. The
device node pointer and the changeset pointer can be used to add
properties to the device node and apply the node to the base tree.

of_destroy_node() frees the device node created by of_create_node(). If
an OF changeset was also created for this node, it will destroy the
changeset before freeing the device node.

Expand of_changeset APIs to handle specific types of properties.
    of_changeset_add_prop_string()
    of_changeset_add_prop_string_array()
    of_changeset_add_prop_u32_array()

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
---
 drivers/of/dynamic.c  | 164 ++++++++++++++++++++++++++++++++++++++++++
 drivers/of/unittest.c |  19 ++++-
 include/linux/of.h    |  23 ++++++
 3 files changed, 205 insertions(+), 1 deletion(-)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 07d93753b12f..0fd9debcffee 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -486,6 +486,38 @@ struct device_node *__of_node_dup(const struct device_node *np,
 	return NULL;
 }
 
+/**
+ * of_changeset_create_node - Dynamically create a device node and attach to
+ * a given changeset.
+ *
+ * @parent: Pointer to parent device node
+ * @full_name: Node full name
+ * @cset: Pointer to changeset
+ *
+ * Return: Pointer to the created device node or NULL in case of an error.
+ */
+struct device_node *of_changeset_create_node(struct device_node *parent,
+					     const char *full_name,
+					     struct of_changeset *cset)
+{
+	struct device_node *np;
+	int ret;
+
+	np = __of_node_dup(NULL, full_name);
+	if (!np)
+		return NULL;
+	np->parent = parent;
+
+	ret = of_changeset_attach_node(cset, np);
+	if (ret) {
+		of_node_put(np);
+		return NULL;
+	}
+
+	return np;
+}
+EXPORT_SYMBOL(of_changeset_create_node);
+
 static void __of_changeset_entry_destroy(struct of_changeset_entry *ce)
 {
 	if (ce->action == OF_RECONFIG_ATTACH_NODE &&
@@ -959,3 +991,135 @@ int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 	return 0;
 }
 EXPORT_SYMBOL_GPL(of_changeset_action);
+
+static int of_changeset_add_prop_helper(struct of_changeset *ocs,
+					struct device_node *np,
+					const struct property *pp)
+{
+	struct property *new_pp;
+	int ret;
+
+	new_pp = __of_prop_dup(pp, GFP_KERNEL);
+	if (!new_pp)
+		return -ENOMEM;
+
+	ret = of_changeset_add_property(ocs, np, new_pp);
+	if (ret) {
+		kfree(new_pp->name);
+		kfree(new_pp->value);
+		kfree(new_pp);
+	}
+
+	return ret;
+}
+
+/**
+ * of_changeset_add_prop_string - Add a string property to a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @str:	pointer to null terminated string
+ *
+ * Create a string property and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_string(struct of_changeset *ocs,
+				 struct device_node *np,
+				 const char *prop_name, const char *str)
+{
+	struct property prop;
+
+	prop.name = (char *)prop_name;
+	prop.length = strlen(str) + 1;
+	prop.value = (void *)str;
+
+	return of_changeset_add_prop_helper(ocs, np, &prop);
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_string);
+
+/**
+ * of_changeset_add_prop_string_array - Add a string list property to
+ * a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @str_array:	pointer to an array of null terminated strings
+ * @sz:		number of string array elements
+ *
+ * Create a string list property and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_string_array(struct of_changeset *ocs,
+				       struct device_node *np,
+				       const char *prop_name,
+				       const char **str_array, size_t sz)
+{
+	struct property prop;
+	int i, ret;
+	char *vp;
+
+	prop.name = (char *)prop_name;
+
+	prop.length = 0;
+	for (i = 0; i < sz; i++)
+		prop.length += strlen(str_array[i]) + 1;
+
+	prop.value = kmalloc(prop.length, GFP_KERNEL);
+	if (!prop.value)
+		return -ENOMEM;
+
+	vp = prop.value;
+	for (i = 0; i < sz; i++) {
+		vp += snprintf(vp, (char *)prop.value + prop.length - vp, "%s",
+			       str_array[i]) + 1;
+	}
+	ret = of_changeset_add_prop_helper(ocs, np, &prop);
+	kfree(prop.value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_string_array);
+
+/**
+ * of_changeset_add_prop_u32_array - Add a property of 32 bit integers
+ * property to a changeset
+ *
+ * @ocs:	changeset pointer
+ * @np:		device node pointer
+ * @prop_name:	name of the property to be added
+ * @array:	pointer to an array of 32 bit integers
+ * @sz:		number of array elements
+ *
+ * Create a property of 32 bit integers and add it to a changeset.
+ *
+ * Return: 0 on success, a negative error value in case of an error.
+ */
+int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
+				    struct device_node *np,
+				    const char *prop_name,
+				    const u32 *array, size_t sz)
+{
+	struct property prop;
+	__be32 *val;
+	int i, ret;
+
+	val = kcalloc(sz, sizeof(__be32), GFP_KERNEL);
+	if (!val)
+		return -ENOMEM;
+
+	for (i = 0; i < sz; i++)
+		val[i] = cpu_to_be32(array[i]);
+	prop.name = (char *)prop_name;
+	prop.length = sizeof(u32) * sz;
+	prop.value = (void *)val;
+
+	ret = of_changeset_add_prop_helper(ocs, np, &prop);
+	kfree(val);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(of_changeset_add_prop_u32_array);
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index b5a7a31d8bd2..37d0f8a16eae 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -802,7 +802,9 @@ static void __init of_unittest_changeset(void)
 	struct property *ppname_n21, pname_n21 = { .name = "name", .length = 3, .value = "n21" };
 	struct property *ppupdate, pupdate = { .name = "prop-update", .length = 5, .value = "abcd" };
 	struct property *ppremove;
-	struct device_node *n1, *n2, *n21, *nchangeset, *nremove, *parent, *np;
+	struct device_node *n1, *n2, *n21, *n22, *nchangeset, *nremove, *parent, *np;
+	static const char * const str_array[] = { "str1", "str2", "str3" };
+	const u32 u32_array[] = { 1, 2, 3 };
 	struct of_changeset chgset;
 
 	n1 = __of_node_dup(NULL, "n1");
@@ -857,6 +859,17 @@ static void __init of_unittest_changeset(void)
 	unittest(!of_changeset_add_property(&chgset, parent, ppadd), "fail add prop prop-add\n");
 	unittest(!of_changeset_update_property(&chgset, parent, ppupdate), "fail update prop\n");
 	unittest(!of_changeset_remove_property(&chgset, parent, ppremove), "fail remove prop\n");
+	n22 = of_changeset_create_node(n2, "n22", &chgset);
+	unittest(n22, "fail create n22\n");
+	unittest(!of_changeset_add_prop_string(&chgset, n22, "prop-str", "abcd"),
+		 "fail add prop prop-str");
+	unittest(!of_changeset_add_prop_string_array(&chgset, n22, "prop-str-array",
+						     (const char **)str_array,
+						     ARRAY_SIZE(str_array)),
+		 "fail add prop prop-str-array");
+	unittest(!of_changeset_add_prop_u32_array(&chgset, n22, "prop-u32-array",
+						  u32_array, ARRAY_SIZE(u32_array)),
+		 "fail add prop prop-u32-array");
 
 	unittest(!of_changeset_apply(&chgset), "apply failed\n");
 
@@ -866,6 +879,9 @@ static void __init of_unittest_changeset(void)
 	unittest((np = of_find_node_by_path("/testcase-data/changeset/n2/n21")),
 		 "'%pOF' not added\n", n21);
 	of_node_put(np);
+	unittest((np = of_find_node_by_path("/testcase-data/changeset/n2/n22")),
+		 "'%pOF' not added\n", n22);
+	of_node_put(np);
 
 	unittest(!of_changeset_revert(&chgset), "revert failed\n");
 
@@ -874,6 +890,7 @@ static void __init of_unittest_changeset(void)
 	of_node_put(n1);
 	of_node_put(n2);
 	of_node_put(n21);
+	of_node_put(n22);
 #endif
 }
 
diff --git a/include/linux/of.h b/include/linux/of.h
index 0af611307db2..72c49ef153f7 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1556,6 +1556,29 @@ static inline int of_changeset_update_property(struct of_changeset *ocs,
 {
 	return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop);
 }
+
+struct device_node *of_changeset_create_node(struct device_node *parent,
+					     const char *full_name,
+					     struct of_changeset *cset);
+int of_changeset_add_prop_string(struct of_changeset *ocs,
+				 struct device_node *np,
+				 const char *prop_name, const char *str);
+int of_changeset_add_prop_string_array(struct of_changeset *ocs,
+				       struct device_node *np,
+				       const char *prop_name,
+				       const char **str_array, size_t sz);
+int of_changeset_add_prop_u32_array(struct of_changeset *ocs,
+				    struct device_node *np,
+				    const char *prop_name,
+				    const u32 *array, size_t sz);
+static inline int of_changeset_add_prop_u32(struct of_changeset *ocs,
+					    struct device_node *np,
+					    const char *prop_name,
+					    const u32 val)
+{
+	return of_changeset_add_prop_u32_array(ocs, np, prop_name, &val, 1);
+}
+
 #else /* CONFIG_OF_DYNAMIC */
 static inline int of_reconfig_notifier_register(struct notifier_block *nb)
 {
-- 
2.34.1

[PATCH V8 2/3] PCI: Create device tree node for selected devices

[Lizhi Hou]

The PCI endpoint device such as Xilinx Alveo PCI card maps the register
spaces from multiple hardware peripherals to its PCI 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 PCI 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
PCI device. Thus, it can generate the device tree nodes for hardware
peripherals underneath. Because PCI is self discoverable bus, there might
not be a device tree node created for PCI devices. This patch is to add
support to generate device tree node for PCI devices.

Added a kernel option. When the option is turned on, the kernel will
generate device tree nodes for PCI bridges unconditionally.

Initially, the basic properties are added for the dynamically generated
device tree nodes.

Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
---
 drivers/pci/Kconfig         |  12 ++
 drivers/pci/Makefile        |   1 +
 drivers/pci/bus.c           |   2 +
 drivers/pci/msi/irqdomain.c |   6 +-
 drivers/pci/of.c            |  79 ++++++++++++++
 drivers/pci/of_property.c   | 212 ++++++++++++++++++++++++++++++++++++
 drivers/pci/pci-driver.c    |   3 +-
 drivers/pci/pci.h           |  19 ++++
 drivers/pci/remove.c        |   1 +
 9 files changed, 332 insertions(+), 3 deletions(-)
 create mode 100644 drivers/pci/of_property.c

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 9309f2469b41..24c3107c68cc 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -193,6 +193,18 @@ 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 "Create Devicetree nodes 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 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 549c4bd5caec..89ef8c64bb22 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -341,6 +341,8 @@ 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 e33bcc872699..cd73d2250305 100644
--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -456,8 +456,10 @@ 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..42a5cfac2d34 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 (ppnode && of_node_check_flag(ppnode, OF_DYNAMIC))
+				ppnode = NULL;
 		}
 
 		/*
@@ -599,6 +601,83 @@ 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 *np;
+
+	np = pci_device_to_OF_node(pdev);
+	if (!np || !of_node_check_flag(np, OF_DYNAMIC))
+		return;
+	pdev->dev.of_node = NULL;
+
+	of_changeset_revert(np->data);
+	of_changeset_destroy(np->data);
+	of_node_put(np);
+}
+
+void of_pci_make_dev_node(struct pci_dev *pdev)
+{
+	struct device_node *ppnode, *np = NULL;
+	const char *pci_type = "dev";
+	struct of_changeset *cset;
+	const char *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)
+		ppnode = pdev->bus->dev.of_node;
+	else
+		ppnode = pdev->bus->self->dev.of_node;
+	if (!ppnode)
+		return;
+
+	if (pci_is_bridge(pdev))
+		pci_type = "pci";
+
+	name = kasprintf(GFP_KERNEL, "%s@%x,%x", pci_type,
+			 PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+	if (!name)
+		return;
+
+	cset = kmalloc(sizeof(*cset), GFP_KERNEL);
+	if (!cset)
+		goto failed;
+	of_changeset_init(cset);
+
+	np = of_changeset_create_node(ppnode, name, cset);
+	if (!np)
+		goto failed;
+	np->data = cset;
+
+	ret = of_pci_add_properties(pdev, cset, np);
+	if (ret)
+		goto failed;
+
+	ret = of_changeset_apply(cset);
+	if (ret)
+		goto failed;
+
+	pdev->dev.of_node = np;
+	kfree(name);
+
+	return;
+
+failed:
+	if (np)
+		of_node_put(np);
+	kfree(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..3d8267aa96e2
--- /dev/null
+++ b/drivers/pci/of_property.c
@@ -0,0 +1,212 @@
+// 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"
+
+#define OF_PCI_ADDRESS_CELLS		3
+#define OF_PCI_SIZE_CELLS		2
+
+struct of_pci_addr_pair {
+	u32		phys_addr[OF_PCI_ADDRESS_CELLS];
+	u32		size[OF_PCI_SIZE_CELLS];
+};
+
+struct of_pci_range {
+	u32		child_addr[OF_PCI_ADDRESS_CELLS];
+	u32		parent_addr[OF_PCI_ADDRESS_CELLS];
+	u32		size[OF_PCI_SIZE_CELLS];
+};
+
+#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)
+
+enum of_pci_prop_compatible {
+	PROP_COMPAT_PCI_VVVV_DDDD,
+	PROP_COMPAT_PCICLASS_CCSSPP,
+	PROP_COMPAT_PCICLASS_CCSS,
+	PROP_COMPAT_NUM,
+};
+
+static void of_pci_set_address(struct pci_dev *pdev, u32 *prop, u64 addr,
+			       u32 reg_num, u32 flags, bool reloc)
+{
+	prop[0] = 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));
+	prop[0] |= flags | reg_num;
+	if (!reloc) {
+		prop[0] |= OF_PCI_ADDR_FIELD_NONRELOC;
+		prop[1] = FIELD_GET(OF_PCI_ADDR_HI, addr);
+		prop[2] = FIELD_GET(OF_PCI_ADDR_LO, addr);
+	}
+}
+
+static int of_pci_get_addr_flags(struct resource *res, u32 *flags)
+{
+	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;
+
+	*flags = 0;
+	if (res->flags & IORESOURCE_PREFETCH)
+		*flags |= OF_PCI_ADDR_FIELD_PREFETCH;
+
+	*flags |= FIELD_PREP(OF_PCI_ADDR_FIELD_SS, 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;
+	struct resource *res;
+	int i = 0, j, ret;
+	u64 val64;
+	u32 flags;
+
+	rp = kcalloc(PCI_BRIDGE_RESOURCE_NUM, sizeof(*rp), GFP_KERNEL);
+	if (!rp)
+		return -ENOMEM;
+
+	res = &pdev->resource[PCI_BRIDGE_RESOURCES];
+	for (j = 0; j < PCI_BRIDGE_RESOURCE_NUM; j++) {
+		if (!resource_size(&res[j]))
+			continue;
+
+		if (of_pci_get_addr_flags(&res[j], &flags))
+			continue;
+
+		val64 = res[j].start;
+		of_pci_set_address(pdev, rp[i].parent_addr, val64, 0, flags,
+				   false);
+		memcpy(rp[i].child_addr, rp[i].parent_addr,
+		       sizeof(rp[i].child_addr));
+
+		val64 = resource_size(&res[j]);
+		rp[i].size[0] = FIELD_GET(OF_PCI_SIZE_HI, val64);
+		rp[i].size[1] = FIELD_GET(OF_PCI_SIZE_LO, val64);
+
+		i++;
+	}
+
+	ret = of_changeset_add_prop_u32_array(ocs, np, "ranges", (u32 *)rp,
+					      i * sizeof(*rp) / sizeof(u32));
+	kfree(rp);
+
+	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 flags, base_addr;
+	resource_size_t sz;
+
+	reg = kcalloc(PCI_STD_NUM_BARS + 1, sizeof(*reg), GFP_KERNEL);
+	if (!reg)
+		return -ENOMEM;
+
+	/* configuration space */
+	of_pci_set_address(pdev, reg[0].phys_addr, 0, 0, 0, true);
+
+	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_get_addr_flags(&pdev->resource[resno], &flags);
+		if (ret)
+			continue;
+
+		of_pci_set_address(pdev, reg[i].phys_addr, 0, base_addr, flags,
+				   true);
+		reg[i].size[0] = FIELD_GET(OF_PCI_SIZE_HI, (u64)sz);
+		reg[i].size[1] = FIELD_GET(OF_PCI_SIZE_LO, (u64)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;
+}
+
+int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs,
+			  struct device_node *np)
+{
+	int ret = 0;
+
+	if (pci_is_bridge(pdev)) {
+		ret |= of_changeset_add_prop_string(ocs, np, "device_type",
+						    "pci");
+		ret |= of_changeset_add_prop_u32(ocs, np, "#address-cells",
+						 OF_PCI_ADDRESS_CELLS);
+		ret |= of_changeset_add_prop_u32(ocs, np, "#size-cells",
+						 OF_PCI_SIZE_CELLS);
+		ret |= of_pci_prop_ranges(pdev, ocs, np);
+	}
+
+	ret |= of_pci_prop_reg(pdev, ocs, np);
+	ret |= of_pci_prop_compatible(pdev, ocs, np);
+
+	/*
+	 * The added properties will be released when the
+	 * changeset is destroyed.
+	 */
+	return ret;
+}
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 57ddcc59af30..9120ca63a82a 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1634,7 +1634,8 @@ 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 d2c08670a20e..58df456e6c92 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -674,6 +674,25 @@ 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/remove.c b/drivers/pci/remove.c
index 0145aef1b930..1462f2d9b194 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);
 	}
-- 
2.34.1

[PATCH V8 3/3] PCI: Add PCI quirks to generate device tree node for Xilinx Alveo U50

[Lizhi Hou]

The Xilinx Alveo U50 PCI card exposes multiple hardware peripherals on
its PCI BAR. The card firmware provides a flattened device tree to
describe the hardware peripherals on its BARs. This allows U50 driver to
load the flattened device tree and generate the device tree node for
hardware peripherals underneath.

To generate device tree node for U50 card, added PCI quirks to call
of_pci_make_dev_node() for U50.

Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
---
 drivers/pci/quirks.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 44cab813bf95..35745e7b457a 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -6023,3 +6023,14 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2d, dpc_log_size);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2f, dpc_log_size);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a31, dpc_log_size);
 #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);
-- 
2.34.1

Re: [PATCH V8 2/3] PCI: Create device tree node for selected devices

[Rob Herring]

On Tue, Apr 18, 2023 at 09:19:53PM -0700, Lizhi Hou wrote:
> The PCI endpoint device such as Xilinx Alveo PCI card maps the register
> spaces from multiple hardware peripherals to its PCI 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 PCI 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
> PCI device. Thus, it can generate the device tree nodes for hardware
> peripherals underneath. Because PCI is self discoverable bus, there might
> not be a device tree node created for PCI devices. This patch is to add
> support to generate device tree node for PCI devices.
> 
> Added a kernel option. When the option is turned on, the kernel will
> generate device tree nodes for PCI bridges unconditionally.
> 
> Initially, the basic properties are added for the dynamically generated
> device tree nodes.
> 
> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
> ---
>  drivers/pci/Kconfig         |  12 ++
>  drivers/pci/Makefile        |   1 +
>  drivers/pci/bus.c           |   2 +
>  drivers/pci/msi/irqdomain.c |   6 +-
>  drivers/pci/of.c            |  79 ++++++++++++++
>  drivers/pci/of_property.c   | 212 ++++++++++++++++++++++++++++++++++++
>  drivers/pci/pci-driver.c    |   3 +-
>  drivers/pci/pci.h           |  19 ++++
>  drivers/pci/remove.c        |   1 +
>  9 files changed, 332 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/pci/of_property.c
> 
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index 9309f2469b41..24c3107c68cc 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -193,6 +193,18 @@ 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 "Create Devicetree nodes 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 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 549c4bd5caec..89ef8c64bb22 100644
> --- a/drivers/pci/bus.c
> +++ b/drivers/pci/bus.c
> @@ -341,6 +341,8 @@ 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 e33bcc872699..cd73d2250305 100644
> --- a/drivers/pci/msi/irqdomain.c
> +++ b/drivers/pci/msi/irqdomain.c
> @@ -456,8 +456,10 @@ 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);

Whether or not this works depends if the host bridge has an 'msi-map' or 
not. For a pure DT system, I think you need to drop this change. The 
behavior shouldn't change based on dynamic vs. static nodes.

For this to work for all 3 cases, I think we need just:

rid = of_msi_map_id(&pdev->dev, of_node, rid); // NOP if of_node is NULL
rid = iort_msi_map_id(&pdev->dev, rid); // NOP if no IORT entry

But I'm not really sure if that really works for ACPI or not.

>  
>  	return rid;
>  }
> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> index 196834ed44fe..42a5cfac2d34 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 (ppnode && of_node_check_flag(ppnode, OF_DYNAMIC))
> +				ppnode = NULL;

Again, different behavior if dynamic. I'm not seeing why you need this 
change.

>  		}
>  
>  		/*
> @@ -599,6 +601,83 @@ 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 *np;
> +
> +	np = pci_device_to_OF_node(pdev);
> +	if (!np || !of_node_check_flag(np, OF_DYNAMIC))
> +		return;
> +	pdev->dev.of_node = NULL;
> +
> +	of_changeset_revert(np->data);
> +	of_changeset_destroy(np->data);
> +	of_node_put(np);
> +}
> +
> +void of_pci_make_dev_node(struct pci_dev *pdev)
> +{
> +	struct device_node *ppnode, *np = NULL;
> +	const char *pci_type = "dev";
> +	struct of_changeset *cset;
> +	const char *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)
> +		ppnode = pdev->bus->dev.of_node;
> +	else
> +		ppnode = pdev->bus->self->dev.of_node;
> +	if (!ppnode)
> +		return;
> +
> +	if (pci_is_bridge(pdev))
> +		pci_type = "pci";
> +
> +	name = kasprintf(GFP_KERNEL, "%s@%x,%x", pci_type,
> +			 PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
> +	if (!name)
> +		return;
> +
> +	cset = kmalloc(sizeof(*cset), GFP_KERNEL);
> +	if (!cset)
> +		goto failed;
> +	of_changeset_init(cset);
> +
> +	np = of_changeset_create_node(ppnode, name, cset);
> +	if (!np)
> +		goto failed;
> +	np->data = cset;
> +
> +	ret = of_pci_add_properties(pdev, cset, np);
> +	if (ret)
> +		goto failed;
> +
> +	ret = of_changeset_apply(cset);
> +	if (ret)
> +		goto failed;
> +
> +	pdev->dev.of_node = np;
> +	kfree(name);
> +
> +	return;
> +
> +failed:
> +	if (np)
> +		of_node_put(np);
> +	kfree(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..3d8267aa96e2
> --- /dev/null
> +++ b/drivers/pci/of_property.c
> @@ -0,0 +1,212 @@
> +// 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"
> +
> +#define OF_PCI_ADDRESS_CELLS		3
> +#define OF_PCI_SIZE_CELLS		2
> +
> +struct of_pci_addr_pair {
> +	u32		phys_addr[OF_PCI_ADDRESS_CELLS];
> +	u32		size[OF_PCI_SIZE_CELLS];
> +};
> +
> +struct of_pci_range {
> +	u32		child_addr[OF_PCI_ADDRESS_CELLS];
> +	u32		parent_addr[OF_PCI_ADDRESS_CELLS];
> +	u32		size[OF_PCI_SIZE_CELLS];
> +};
> +
> +#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)
> +
> +enum of_pci_prop_compatible {
> +	PROP_COMPAT_PCI_VVVV_DDDD,
> +	PROP_COMPAT_PCICLASS_CCSSPP,
> +	PROP_COMPAT_PCICLASS_CCSS,
> +	PROP_COMPAT_NUM,
> +};
> +
> +static void of_pci_set_address(struct pci_dev *pdev, u32 *prop, u64 addr,
> +			       u32 reg_num, u32 flags, bool reloc)
> +{
> +	prop[0] = 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));
> +	prop[0] |= flags | reg_num;
> +	if (!reloc) {
> +		prop[0] |= OF_PCI_ADDR_FIELD_NONRELOC;
> +		prop[1] = FIELD_GET(OF_PCI_ADDR_HI, addr);
> +		prop[2] = FIELD_GET(OF_PCI_ADDR_LO, addr);

No need for your own macros here. Use upper_32_bits() and 
lower_32_bits(). Same for size macros.

> +	}
> +}
> +
> +static int of_pci_get_addr_flags(struct resource *res, u32 *flags)
> +{
> +	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;
> +
> +	*flags = 0;
> +	if (res->flags & IORESOURCE_PREFETCH)
> +		*flags |= OF_PCI_ADDR_FIELD_PREFETCH;
> +
> +	*flags |= FIELD_PREP(OF_PCI_ADDR_FIELD_SS, 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;
> +	struct resource *res;
> +	int i = 0, j, ret;
> +	u64 val64;
> +	u32 flags;
> +
> +	rp = kcalloc(PCI_BRIDGE_RESOURCE_NUM, sizeof(*rp), GFP_KERNEL);
> +	if (!rp)
> +		return -ENOMEM;
> +
> +	res = &pdev->resource[PCI_BRIDGE_RESOURCES];
> +	for (j = 0; j < PCI_BRIDGE_RESOURCE_NUM; j++) {
> +		if (!resource_size(&res[j]))
> +			continue;
> +
> +		if (of_pci_get_addr_flags(&res[j], &flags))
> +			continue;
> +
> +		val64 = res[j].start;
> +		of_pci_set_address(pdev, rp[i].parent_addr, val64, 0, flags,
> +				   false);
> +		memcpy(rp[i].child_addr, rp[i].parent_addr,
> +		       sizeof(rp[i].child_addr));
> +
> +		val64 = resource_size(&res[j]);
> +		rp[i].size[0] = FIELD_GET(OF_PCI_SIZE_HI, val64);
> +		rp[i].size[1] = FIELD_GET(OF_PCI_SIZE_LO, val64);
> +
> +		i++;
> +	}
> +
> +	ret = of_changeset_add_prop_u32_array(ocs, np, "ranges", (u32 *)rp,
> +					      i * sizeof(*rp) / sizeof(u32));
> +	kfree(rp);
> +
> +	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 flags, base_addr;
> +	resource_size_t sz;
> +
> +	reg = kcalloc(PCI_STD_NUM_BARS + 1, sizeof(*reg), GFP_KERNEL);
> +	if (!reg)
> +		return -ENOMEM;
> +
> +	/* configuration space */
> +	of_pci_set_address(pdev, reg[0].phys_addr, 0, 0, 0, true);
> +
> +	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_get_addr_flags(&pdev->resource[resno], &flags);
> +		if (ret)
> +			continue;
> +
> +		of_pci_set_address(pdev, reg[i].phys_addr, 0, base_addr, flags,
> +				   true);
> +		reg[i].size[0] = FIELD_GET(OF_PCI_SIZE_HI, (u64)sz);
> +		reg[i].size[1] = FIELD_GET(OF_PCI_SIZE_LO, (u64)sz);
> +		i++;
> +	}
> +
> +	ret = of_changeset_add_prop_u32_array(ocs, np, "reg", (u32 *)reg,

I believe this should be 'assigned-addresses' rather than 'reg'. But the 
config space entry above does go in '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;
> +}
> +
> +int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs,
> +			  struct device_node *np)
> +{
> +	int ret = 0;
> +
> +	if (pci_is_bridge(pdev)) {
> +		ret |= of_changeset_add_prop_string(ocs, np, "device_type",
> +						    "pci");
> +		ret |= of_changeset_add_prop_u32(ocs, np, "#address-cells",
> +						 OF_PCI_ADDRESS_CELLS);
> +		ret |= of_changeset_add_prop_u32(ocs, np, "#size-cells",
> +						 OF_PCI_SIZE_CELLS);
> +		ret |= of_pci_prop_ranges(pdev, ocs, np);
> +	}
> +
> +	ret |= of_pci_prop_reg(pdev, ocs, np);
> +	ret |= of_pci_prop_compatible(pdev, ocs, np);
> +
> +	/*
> +	 * The added properties will be released when the
> +	 * changeset is destroyed.
> +	 */
> +	return ret;
> +}
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 57ddcc59af30..9120ca63a82a 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -1634,7 +1634,8 @@ 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)) {

Again, I don't think changing behavior for dynamic case is right. I 
haven't dug into what an ACPI+DT case would look like here. (Hint: 
someone that wants this merged can dig into that)

>  		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 d2c08670a20e..58df456e6c92 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -674,6 +674,25 @@ 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/remove.c b/drivers/pci/remove.c
> index 0145aef1b930..1462f2d9b194 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);
>  	}
> -- 
> 2.34.1
> 

Re: [PATCH V8 2/3] PCI: Create device tree node for selected devices

[Lizhi Hou]

On 4/19/23 16:11, Rob Herring wrote:
> On Tue, Apr 18, 2023 at 09:19:53PM -0700, Lizhi Hou wrote:
>> The PCI endpoint device such as Xilinx Alveo PCI card maps the register
>> spaces from multiple hardware peripherals to its PCI 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 PCI 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
>> PCI device. Thus, it can generate the device tree nodes for hardware
>> peripherals underneath. Because PCI is self discoverable bus, there might
>> not be a device tree node created for PCI devices. This patch is to add
>> support to generate device tree node for PCI devices.
>>
>> Added a kernel option. When the option is turned on, the kernel will
>> generate device tree nodes for PCI bridges unconditionally.
>>
>> Initially, the basic properties are added for the dynamically generated
>> device tree nodes.
>>
>> Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
>> ---
>>   drivers/pci/Kconfig         |  12 ++
>>   drivers/pci/Makefile        |   1 +
>>   drivers/pci/bus.c           |   2 +
>>   drivers/pci/msi/irqdomain.c |   6 +-
>>   drivers/pci/of.c            |  79 ++++++++++++++
>>   drivers/pci/of_property.c   | 212 ++++++++++++++++++++++++++++++++++++
>>   drivers/pci/pci-driver.c    |   3 +-
>>   drivers/pci/pci.h           |  19 ++++
>>   drivers/pci/remove.c        |   1 +
>>   9 files changed, 332 insertions(+), 3 deletions(-)
>>   create mode 100644 drivers/pci/of_property.c
>>
>> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
>> index 9309f2469b41..24c3107c68cc 100644
>> --- a/drivers/pci/Kconfig
>> +++ b/drivers/pci/Kconfig
>> @@ -193,6 +193,18 @@ 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 "Create Devicetree nodes 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 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 549c4bd5caec..89ef8c64bb22 100644
>> --- a/drivers/pci/bus.c
>> +++ b/drivers/pci/bus.c
>> @@ -341,6 +341,8 @@ 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 e33bcc872699..cd73d2250305 100644
>> --- a/drivers/pci/msi/irqdomain.c
>> +++ b/drivers/pci/msi/irqdomain.c
>> @@ -456,8 +456,10 @@ 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);
> Whether or not this works depends if the host bridge has an 'msi-map' or
> not. For a pure DT system, I think you need to drop this change. The
> behavior shouldn't change based on dynamic vs. static nodes.
Ok,  Both of_msi_map_id() and iort_msi_map_id() will return input rid 
for a pure DT system. I can drop this change.
>
> For this to work for all 3 cases, I think we need just:
>
> rid = of_msi_map_id(&pdev->dev, of_node, rid); // NOP if of_node is NULL
> rid = iort_msi_map_id(&pdev->dev, rid); // NOP if no IORT entry
>
> But I'm not really sure if that really works for ACPI or not.
>
>>   
>>   	return rid;
>>   }
>> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
>> index 196834ed44fe..42a5cfac2d34 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 (ppnode && of_node_check_flag(ppnode, OF_DYNAMIC))
>> +				ppnode = NULL;
> Again, different behavior if dynamic. I'm not seeing why you need this
> change.
This change is required. For dynamic generated node, we do not generate 
interrupt routing related properties. Thus we need to fallback to use 
pci_swizzle_interrupt_pin(). Generating interrupt routing related 
properties might be difficult. I think we can differ it to the future 
patches. Or just use pci_swizzle_interrupt_pin() which is much simpler.
>
>>   		}
>>   
>>   		/*
>> @@ -599,6 +601,83 @@ 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 *np;
>> +
>> +	np = pci_device_to_OF_node(pdev);
>> +	if (!np || !of_node_check_flag(np, OF_DYNAMIC))
>> +		return;
>> +	pdev->dev.of_node = NULL;
>> +
>> +	of_changeset_revert(np->data);
>> +	of_changeset_destroy(np->data);
>> +	of_node_put(np);
>> +}
>> +
>> +void of_pci_make_dev_node(struct pci_dev *pdev)
>> +{
>> +	struct device_node *ppnode, *np = NULL;
>> +	const char *pci_type = "dev";
>> +	struct of_changeset *cset;
>> +	const char *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)
>> +		ppnode = pdev->bus->dev.of_node;
>> +	else
>> +		ppnode = pdev->bus->self->dev.of_node;
>> +	if (!ppnode)
>> +		return;
>> +
>> +	if (pci_is_bridge(pdev))
>> +		pci_type = "pci";
>> +
>> +	name = kasprintf(GFP_KERNEL, "%s@%x,%x", pci_type,
>> +			 PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
>> +	if (!name)
>> +		return;
>> +
>> +	cset = kmalloc(sizeof(*cset), GFP_KERNEL);
>> +	if (!cset)
>> +		goto failed;
>> +	of_changeset_init(cset);
>> +
>> +	np = of_changeset_create_node(ppnode, name, cset);
>> +	if (!np)
>> +		goto failed;
>> +	np->data = cset;
>> +
>> +	ret = of_pci_add_properties(pdev, cset, np);
>> +	if (ret)
>> +		goto failed;
>> +
>> +	ret = of_changeset_apply(cset);
>> +	if (ret)
>> +		goto failed;
>> +
>> +	pdev->dev.of_node = np;
>> +	kfree(name);
>> +
>> +	return;
>> +
>> +failed:
>> +	if (np)
>> +		of_node_put(np);
>> +	kfree(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..3d8267aa96e2
>> --- /dev/null
>> +++ b/drivers/pci/of_property.c
>> @@ -0,0 +1,212 @@
>> +// 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"
>> +
>> +#define OF_PCI_ADDRESS_CELLS		3
>> +#define OF_PCI_SIZE_CELLS		2
>> +
>> +struct of_pci_addr_pair {
>> +	u32		phys_addr[OF_PCI_ADDRESS_CELLS];
>> +	u32		size[OF_PCI_SIZE_CELLS];
>> +};
>> +
>> +struct of_pci_range {
>> +	u32		child_addr[OF_PCI_ADDRESS_CELLS];
>> +	u32		parent_addr[OF_PCI_ADDRESS_CELLS];
>> +	u32		size[OF_PCI_SIZE_CELLS];
>> +};
>> +
>> +#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)
>> +
>> +enum of_pci_prop_compatible {
>> +	PROP_COMPAT_PCI_VVVV_DDDD,
>> +	PROP_COMPAT_PCICLASS_CCSSPP,
>> +	PROP_COMPAT_PCICLASS_CCSS,
>> +	PROP_COMPAT_NUM,
>> +};
>> +
>> +static void of_pci_set_address(struct pci_dev *pdev, u32 *prop, u64 addr,
>> +			       u32 reg_num, u32 flags, bool reloc)
>> +{
>> +	prop[0] = 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));
>> +	prop[0] |= flags | reg_num;
>> +	if (!reloc) {
>> +		prop[0] |= OF_PCI_ADDR_FIELD_NONRELOC;
>> +		prop[1] = FIELD_GET(OF_PCI_ADDR_HI, addr);
>> +		prop[2] = FIELD_GET(OF_PCI_ADDR_LO, addr);
> No need for your own macros here. Use upper_32_bits() and
> lower_32_bits(). Same for size macros.
Ok, sure.
>
>> +	}
>> +}
>> +
>> +static int of_pci_get_addr_flags(struct resource *res, u32 *flags)
>> +{
>> +	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;
>> +
>> +	*flags = 0;
>> +	if (res->flags & IORESOURCE_PREFETCH)
>> +		*flags |= OF_PCI_ADDR_FIELD_PREFETCH;
>> +
>> +	*flags |= FIELD_PREP(OF_PCI_ADDR_FIELD_SS, 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;
>> +	struct resource *res;
>> +	int i = 0, j, ret;
>> +	u64 val64;
>> +	u32 flags;
>> +
>> +	rp = kcalloc(PCI_BRIDGE_RESOURCE_NUM, sizeof(*rp), GFP_KERNEL);
>> +	if (!rp)
>> +		return -ENOMEM;
>> +
>> +	res = &pdev->resource[PCI_BRIDGE_RESOURCES];
>> +	for (j = 0; j < PCI_BRIDGE_RESOURCE_NUM; j++) {
>> +		if (!resource_size(&res[j]))
>> +			continue;
>> +
>> +		if (of_pci_get_addr_flags(&res[j], &flags))
>> +			continue;
>> +
>> +		val64 = res[j].start;
>> +		of_pci_set_address(pdev, rp[i].parent_addr, val64, 0, flags,
>> +				   false);
>> +		memcpy(rp[i].child_addr, rp[i].parent_addr,
>> +		       sizeof(rp[i].child_addr));
>> +
>> +		val64 = resource_size(&res[j]);
>> +		rp[i].size[0] = FIELD_GET(OF_PCI_SIZE_HI, val64);
>> +		rp[i].size[1] = FIELD_GET(OF_PCI_SIZE_LO, val64);
>> +
>> +		i++;
>> +	}
>> +
>> +	ret = of_changeset_add_prop_u32_array(ocs, np, "ranges", (u32 *)rp,
>> +					      i * sizeof(*rp) / sizeof(u32));
>> +	kfree(rp);
>> +
>> +	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 flags, base_addr;
>> +	resource_size_t sz;
>> +
>> +	reg = kcalloc(PCI_STD_NUM_BARS + 1, sizeof(*reg), GFP_KERNEL);
>> +	if (!reg)
>> +		return -ENOMEM;
>> +
>> +	/* configuration space */
>> +	of_pci_set_address(pdev, reg[0].phys_addr, 0, 0, 0, true);
>> +
>> +	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_get_addr_flags(&pdev->resource[resno], &flags);
>> +		if (ret)
>> +			continue;
>> +
>> +		of_pci_set_address(pdev, reg[i].phys_addr, 0, base_addr, flags,
>> +				   true);
>> +		reg[i].size[0] = FIELD_GET(OF_PCI_SIZE_HI, (u64)sz);
>> +		reg[i].size[1] = FIELD_GET(OF_PCI_SIZE_LO, (u64)sz);
>> +		i++;
>> +	}
>> +
>> +	ret = of_changeset_add_prop_u32_array(ocs, np, "reg", (u32 *)reg,
> I believe this should be 'assigned-addresses' rather than 'reg'. But the
> config space entry above does go in 'reg'.

Do you mean I need to add 'assigned-addresses' in this patch?

For 'reg', it needs to have pairs for memory space or I/O space. Here is 
what I saw in IEEE1275:

"In the first such pair, the phys-addr component shall be the 
Configuration Space address of the
beginning of the function's set of configuration registers (i.e. the 
rrrrrrrr field is zero) and the size component shall
be zero. Each additional (phys-addr, size) pair shall specify the 
address of an addressable region of Memory Space or I/
O Space associated with the function. In these pairs, if the "n" bit of 
phys.hi is 0, reflecting a relocatable address, then
phys.mid and phys.lo specify an address relative to the value of the 
associated base register. In general this value will be
zero, specifying an address range corresponding directly to the 
hardware's. If the "n" bit of phys.hi is 1, reflecting a nonrelocatable 
address, then phys.mid and phys.hi specify an absolute PCI address."

>
>> +					      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;
>> +}
>> +
>> +int of_pci_add_properties(struct pci_dev *pdev, struct of_changeset *ocs,
>> +			  struct device_node *np)
>> +{
>> +	int ret = 0;
>> +
>> +	if (pci_is_bridge(pdev)) {
>> +		ret |= of_changeset_add_prop_string(ocs, np, "device_type",
>> +						    "pci");
>> +		ret |= of_changeset_add_prop_u32(ocs, np, "#address-cells",
>> +						 OF_PCI_ADDRESS_CELLS);
>> +		ret |= of_changeset_add_prop_u32(ocs, np, "#size-cells",
>> +						 OF_PCI_SIZE_CELLS);
>> +		ret |= of_pci_prop_ranges(pdev, ocs, np);
>> +	}
>> +
>> +	ret |= of_pci_prop_reg(pdev, ocs, np);
>> +	ret |= of_pci_prop_compatible(pdev, ocs, np);
>> +
>> +	/*
>> +	 * The added properties will be released when the
>> +	 * changeset is destroyed.
>> +	 */
>> +	return ret;
>> +}
>> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
>> index 57ddcc59af30..9120ca63a82a 100644
>> --- a/drivers/pci/pci-driver.c
>> +++ b/drivers/pci/pci-driver.c
>> @@ -1634,7 +1634,8 @@ 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)) {
> Again, I don't think changing behavior for dynamic case is right. I
> haven't dug into what an ACPI+DT case would look like here. (Hint:
> someone that wants this merged can dig into that)

I think this is required. Without dynamic node, on pure DT system, 
has_acpi_companion() will return false. Then "ret" is 0 and the 
following iommu_device_use_default_domain() might be called.

With dynamic node, of_dma_configure() might return error because dma 
related properties are not generated. Thus, "ret" is none zero and the 
following iommu_device_use_default_domain() will be skipped.


Thanks,

Lizhi

>
>>   		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 d2c08670a20e..58df456e6c92 100644
>> --- a/drivers/pci/pci.h
>> +++ b/drivers/pci/pci.h
>> @@ -674,6 +674,25 @@ 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/remove.c b/drivers/pci/remove.c
>> index 0145aef1b930..1462f2d9b194 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);
>>   	}
>> -- 
>> 2.34.1
>>

Re: [PATCH V8 2/3] PCI: Create device tree node for selected devices

[Rob Herring]

On Thu, Apr 20, 2023 at 11:05 AM Lizhi Hou <lizhi.hou@amd.com> wrote:
> On 4/19/23 16:11, Rob Herring wrote:
> > On Tue, Apr 18, 2023 at 09:19:53PM -0700, Lizhi Hou wrote:
> >> The PCI endpoint device such as Xilinx Alveo PCI card maps the register
> >> spaces from multiple hardware peripherals to its PCI 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.

[...]

> >> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> >> index 196834ed44fe..42a5cfac2d34 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 (ppnode && of_node_check_flag(ppnode, OF_DYNAMIC))
> >> +                            ppnode = NULL;
> > Again, different behavior if dynamic. I'm not seeing why you need this
> > change.
> This change is required. For dynamic generated node, we do not generate
> interrupt routing related properties. Thus we need to fallback to use
> pci_swizzle_interrupt_pin(). Generating interrupt routing related
> properties might be difficult. I think we can differ it to the future
> patches. Or just use pci_swizzle_interrupt_pin() which is much simpler.

I don't think we need to generate anything else in the DT. I think we
need to break from the loop if (ppnode && of_property_present(ppnode,
"interrupt-map")) instead.


> >> +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 flags, base_addr;
> >> +    resource_size_t sz;
> >> +
> >> +    reg = kcalloc(PCI_STD_NUM_BARS + 1, sizeof(*reg), GFP_KERNEL);
> >> +    if (!reg)
> >> +            return -ENOMEM;
> >> +
> >> +    /* configuration space */
> >> +    of_pci_set_address(pdev, reg[0].phys_addr, 0, 0, 0, true);
> >> +
> >> +    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_get_addr_flags(&pdev->resource[resno], &flags);
> >> +            if (ret)
> >> +                    continue;
> >> +
> >> +            of_pci_set_address(pdev, reg[i].phys_addr, 0, base_addr, flags,
> >> +                               true);
> >> +            reg[i].size[0] = FIELD_GET(OF_PCI_SIZE_HI, (u64)sz);
> >> +            reg[i].size[1] = FIELD_GET(OF_PCI_SIZE_LO, (u64)sz);
> >> +            i++;
> >> +    }
> >> +
> >> +    ret = of_changeset_add_prop_u32_array(ocs, np, "reg", (u32 *)reg,
> > I believe this should be 'assigned-addresses' rather than 'reg'. But the
> > config space entry above does go in 'reg'.
>
> Do you mean I need to add 'assigned-addresses' in this patch?

Yes, but on further thought, I think they can just be omitted. They
are only needed
if we need of_pci_address_to_resource() to work.

>
> For 'reg', it needs to have pairs for memory space or I/O space. Here is
> what I saw in IEEE1275:
>
> "In the first such pair, the phys-addr component shall be the
> Configuration Space address of the
> beginning of the function's set of configuration registers (i.e. the
> rrrrrrrr field is zero) and the size component shall
> be zero. Each additional (phys-addr, size) pair shall specify the
> address of an addressable region of Memory Space or I/
> O Space associated with the function. In these pairs, if the "n" bit of
> phys.hi is 0, reflecting a relocatable address, then
> phys.mid and phys.lo specify an address relative to the value of the
> associated base register. In general this value will be
> zero, specifying an address range corresponding directly to the
> hardware's. If the "n" bit of phys.hi is 1, reflecting a nonrelocatable
> address, then phys.mid and phys.hi specify an absolute PCI address."

I think this is a case where true OpenFirmware and FDT differ
slightly. In OF, the DT reflects everything the firmware discovered
and configured. FDT is more just what's static and not discoverable.
(Though generating nodes here is more OF like.) For example, we don't
put the bus numbers in the DT as those are dynamic and assigned by the
OS. The purpose of the BAR registers in reg is to define the BAR size
(and address only if fixed). We don't need that unless what's
discoverable is wrong and we want to override it.


> >> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> >> index 57ddcc59af30..9120ca63a82a 100644
> >> --- a/drivers/pci/pci-driver.c
> >> +++ b/drivers/pci/pci-driver.c
> >> @@ -1634,7 +1634,8 @@ 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)) {
> > Again, I don't think changing behavior for dynamic case is right. I
> > haven't dug into what an ACPI+DT case would look like here. (Hint:
> > someone that wants this merged can dig into that)
>
> I think this is required. Without dynamic node, on pure DT system,
> has_acpi_companion() will return false. Then "ret" is 0 and the
> following iommu_device_use_default_domain() might be called.
>
> With dynamic node, of_dma_configure() might return error because dma
> related properties are not generated. Thus, "ret" is none zero and the
> following iommu_device_use_default_domain() will be skipped.

Again, dynamic is the wrong thing to key off of. If we need
properties, then they should be added. However, I think the host
bridge should have what's needed. If the code needs to handle this
case, then we need to figure out the right thing to do.

Rob

Re: [PATCH V8 2/3] PCI: Create device tree node for selected devices

[Lizhi Hou]

On 4/25/23 08:02, Rob Herring wrote:
> On Thu, Apr 20, 2023 at 11:05 AM Lizhi Hou <lizhi.hou@amd.com> wrote:
>> On 4/19/23 16:11, Rob Herring wrote:
>>> On Tue, Apr 18, 2023 at 09:19:53PM -0700, Lizhi Hou wrote:
>>>> The PCI endpoint device such as Xilinx Alveo PCI card maps the register
>>>> spaces from multiple hardware peripherals to its PCI 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.
> [...]
>
>>>> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
>>>> index 196834ed44fe..42a5cfac2d34 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 (ppnode && of_node_check_flag(ppnode, OF_DYNAMIC))
>>>> +                            ppnode = NULL;
>>> Again, different behavior if dynamic. I'm not seeing why you need this
>>> change.
>> This change is required. For dynamic generated node, we do not generate
>> interrupt routing related properties. Thus we need to fallback to use
>> pci_swizzle_interrupt_pin(). Generating interrupt routing related
>> properties might be difficult. I think we can differ it to the future
>> patches. Or just use pci_swizzle_interrupt_pin() which is much simpler.
> I don't think we need to generate anything else in the DT. I think we
> need to break from the loop if (ppnode && of_property_present(ppnode,
> "interrupt-map")) instead.
Sure. I will use 'interrupt-map' instead.
>
>
>>>> +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 flags, base_addr;
>>>> +    resource_size_t sz;
>>>> +
>>>> +    reg = kcalloc(PCI_STD_NUM_BARS + 1, sizeof(*reg), GFP_KERNEL);
>>>> +    if (!reg)
>>>> +            return -ENOMEM;
>>>> +
>>>> +    /* configuration space */
>>>> +    of_pci_set_address(pdev, reg[0].phys_addr, 0, 0, 0, true);
>>>> +
>>>> +    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_get_addr_flags(&pdev->resource[resno], &flags);
>>>> +            if (ret)
>>>> +                    continue;
>>>> +
>>>> +            of_pci_set_address(pdev, reg[i].phys_addr, 0, base_addr, flags,
>>>> +                               true);
>>>> +            reg[i].size[0] = FIELD_GET(OF_PCI_SIZE_HI, (u64)sz);
>>>> +            reg[i].size[1] = FIELD_GET(OF_PCI_SIZE_LO, (u64)sz);
>>>> +            i++;
>>>> +    }
>>>> +
>>>> +    ret = of_changeset_add_prop_u32_array(ocs, np, "reg", (u32 *)reg,
>>> I believe this should be 'assigned-addresses' rather than 'reg'. But the
>>> config space entry above does go in 'reg'.
>> Do you mean I need to add 'assigned-addresses' in this patch?
> Yes, but on further thought, I think they can just be omitted. They
> are only needed
> if we need of_pci_address_to_resource() to work.
Got it.
>
>> For 'reg', it needs to have pairs for memory space or I/O space. Here is
>> what I saw in IEEE1275:
>>
>> "In the first such pair, the phys-addr component shall be the
>> Configuration Space address of the
>> beginning of the function's set of configuration registers (i.e. the
>> rrrrrrrr field is zero) and the size component shall
>> be zero. Each additional (phys-addr, size) pair shall specify the
>> address of an addressable region of Memory Space or I/
>> O Space associated with the function. In these pairs, if the "n" bit of
>> phys.hi is 0, reflecting a relocatable address, then
>> phys.mid and phys.lo specify an address relative to the value of the
>> associated base register. In general this value will be
>> zero, specifying an address range corresponding directly to the
>> hardware's. If the "n" bit of phys.hi is 1, reflecting a nonrelocatable
>> address, then phys.mid and phys.hi specify an absolute PCI address."
> I think this is a case where true OpenFirmware and FDT differ
> slightly. In OF, the DT reflects everything the firmware discovered
> and configured. FDT is more just what's static and not discoverable.
> (Though generating nodes here is more OF like.) For example, we don't
> put the bus numbers in the DT as those are dynamic and assigned by the
> OS. The purpose of the BAR registers in reg is to define the BAR size
> (and address only if fixed). We don't need that unless what's
> discoverable is wrong and we want to override it.
Thanks for the comments. I will remove the memory and I/O pairs.
>
>
>>>> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
>>>> index 57ddcc59af30..9120ca63a82a 100644
>>>> --- a/drivers/pci/pci-driver.c
>>>> +++ b/drivers/pci/pci-driver.c
>>>> @@ -1634,7 +1634,8 @@ 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)) {
>>> Again, I don't think changing behavior for dynamic case is right. I
>>> haven't dug into what an ACPI+DT case would look like here. (Hint:
>>> someone that wants this merged can dig into that)
>> I think this is required. Without dynamic node, on pure DT system,
>> has_acpi_companion() will return false. Then "ret" is 0 and the
>> following iommu_device_use_default_domain() might be called.
>>
>> With dynamic node, of_dma_configure() might return error because dma
>> related properties are not generated. Thus, "ret" is none zero and the
>> following iommu_device_use_default_domain() will be skipped.
> Again, dynamic is the wrong thing to key off of. If we need
> properties, then they should be added. However, I think the host
> bridge should have what's needed. If the code needs to handle this
> case, then we need to figure out the right thing to do.

I see. I will remove this change. It is not needed for pure DT case.


Thanks,

Lizhi

>
> Rob