Re: [PATCH RFC V2 3/3] PCI: Add basic properties for dynamically generated PCI OF node
From: Lizhi Hou
Date: Mon Oct 31 2022 - 19:21:12 EST
On 10/26/22 12:39, Rob Herring wrote:
On Wed, Oct 12, 2022 at 11:14:00AM -0700, Lizhi Hou wrote:
This patch addes 'reg', 'compatible' and 'device_typ' properties for
typo
Please read submitting-patches.rst and what it says about 'This patch'.
Sure. And I will merge patch 2 and 3.
dynamically generated PCI device tree node
Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxx>
Signed-off-by: Sonal Santan <sonal.santan@xxxxxxx>
Signed-off-by: Max Zhen <max.zhen@xxxxxxx>
Signed-off-by: Brian Xu <brian.xu@xxxxxxx>
---
drivers/pci/Makefile | 1 +
drivers/pci/of.c | 10 ++-
drivers/pci/of_property.c | 177 ++++++++++++++++++++++++++++++++++++++
I don't think we need a separate file here and patches 2 and 3 should be
combined. Patch 2 alone doesn't really make sense.
drivers/pci/pci.h | 3 +-
4 files changed, 189 insertions(+), 2 deletions(-)
create mode 100644 drivers/pci/of_property.c
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/of.c b/drivers/pci/of.c
index 83e042f495a6..00d716589660 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -619,6 +619,7 @@ void of_pci_make_dev_node(struct pci_dev *pdev)
{
struct device_node *parent, *dt_node;
const char *pci_type = "dev";
+ struct property *props;
char *full_name;
/*
@@ -645,10 +646,15 @@ void of_pci_make_dev_node(struct pci_dev *pdev)
if (!full_name)
goto failed;
- dt_node = of_create_node(parent, full_name, NULL);
+ props = of_pci_props_create(pdev);
+ if (!props)
+ goto failed;
+
+ dt_node = of_create_node(parent, full_name, props);
if (!dt_node)
goto failed;
+ of_pci_props_destroy(props);
kfree(full_name);
pdev->dev.of_node = dt_node;
@@ -656,6 +662,8 @@ void of_pci_make_dev_node(struct pci_dev *pdev)
return;
failed:
+ if (props)
+ of_pci_props_destroy(props);
kfree(full_name);
}
#endif
diff --git a/drivers/pci/of_property.c b/drivers/pci/of_property.c
new file mode 100644
index 000000000000..693a08323aa4
--- /dev/null
+++ b/drivers/pci/of_property.c
@@ -0,0 +1,177 @@
+// 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>
+
+struct of_pci_prop {
+ char *name;
+ int (*prop_val)(struct pci_dev *pdev, void **val, u32 *len);
+};
+
+struct of_pci_addr_pair {
+ __be32 phys_hi;
+ __be32 phys_mid;
+ __be32 phys_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_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_SIZE_HI GENMASK_ULL(63, 32)
+#define OF_PCI_SIZE_LO GENMASK_ULL(31, 0)
+
+#define OF_PCI_PROP_COMPAT_LEN_MAX 256
+static int of_pci_prop_device_type(struct pci_dev *pdev, void **val, u32 *len)
+{
+ if (!pci_is_bridge(pdev))
+ return 0;
+
+ *val = kasprintf(GFP_KERNEL, "pci");
+ if (!*val)
+ return -ENOMEM;
+
+ *len = strlen(*val) + 1;
+
+ return 0;
+}
+
+static int of_pci_prop_reg(struct pci_dev *pdev, void **val, u32 *len)
+{
+ struct of_pci_addr_pair *reg;
+ u32 reg_val, base_addr, ss;
+ resource_size_t sz;
+ int i = 1, resno;
+
+ 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;
+
+ if (pci_resource_flags(pdev, resno) & IORESOURCE_IO)
+ ss = OF_PCI_ADDR_SPACE_IO;
+ else if (pci_resource_flags(pdev, resno) & IORESOURCE_MEM_64)
+ ss = OF_PCI_ADDR_SPACE_MEM64;
+ else
+ ss = OF_PCI_ADDR_SPACE_MEM32;
+
+ reg_val &= ~(OF_PCI_ADDR_FIELD_SS | OF_PCI_ADDR_FIELD_PREFETCH |
+ OF_PCI_ADDR_FIELD_REG);
+ reg_val |= FIELD_PREP(OF_PCI_ADDR_FIELD_SS, ss) |
+ FIELD_PREP(OF_PCI_ADDR_FIELD_REG, base_addr);
+ if (pci_resource_flags(pdev, resno) & IORESOURCE_PREFETCH)
+ reg_val |= OF_PCI_ADDR_FIELD_PREFETCH;
+ 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++;
+ }
+
+ *val = reg;
+ *len = i * sizeof(*reg);
+
+ return 0;
+}
+
+static int of_pci_prop_compatible(struct pci_dev *pdev, void **val, u32 *len)
+{
+ char *compat;
+
+ compat = kzalloc(OF_PCI_PROP_COMPAT_LEN_MAX, GFP_KERNEL);
The size here looks pretty arbitrary yet we should be able to calculate
the worst case.
I will remove this.
+ if (!compat)
+ return -ENOMEM;
+
+ *val = compat;
+ if (pdev->subsystem_vendor) {
+ compat += sprintf(compat, "pci%x,%x.%x.%x.%x",
+ pdev->vendor, pdev->device,
+ pdev->subsystem_vendor,
+ pdev->subsystem_device,
+ pdev->revision) + 1;
+ compat += sprintf(compat, "pci%x,%x.%x.%x",
+ pdev->vendor, pdev->device,
+ pdev->subsystem_vendor,
+ pdev->subsystem_device) + 1;
+ compat += sprintf(compat, "pci%x,%x",
+ pdev->subsystem_vendor,
+ pdev->subsystem_device) + 1;
+ }
+ compat += sprintf(compat, "pci%x,%x.%x",
+ pdev->vendor, pdev->device, pdev->revision) + 1;
+ compat += sprintf(compat, "pci%x,%x", pdev->vendor, pdev->device) + 1;
+ compat += sprintf(compat, "pciclass,%06x", pdev->class) + 1;
+ compat += sprintf(compat, "pciclass,%04x", pdev->class >> 8) + 1;
No checking/preventing overrunning the compat buffer?
I don't think we need all these compatible strings. One with VID/PID and
one with the class should be sufficient. But I'm not sure offhand what
subsystem_vendor/device device is...
Ok. I will keep pci%x,%x, pciclass,%06x, pciclass,%04x.
+
+ *len = (u32)(compat - (char *)*val);
+
+ return 0;
+}
+
+struct of_pci_prop of_pci_props[] = {
+ { .name = "device_type", .prop_val = of_pci_prop_device_type },
This only only applies to bridge nodes.
In of_pci_prop_device_type, it returns immediately for pci endpoint.
To make it obvious, I will separate bridge and endpoint property arrays.
+ { .name = "reg", .prop_val = of_pci_prop_reg },
+ { .name = "compatible", .prop_val = of_pci_prop_compatible },
+ {},
+};
+
+struct property *of_pci_props_create(struct pci_dev *pdev)
+{
+ struct property *props, *pp;
+ void *val;
+ u32 len;
+ int i;
+
+ props = kcalloc(ARRAY_SIZE(of_pci_props), sizeof(*props), GFP_KERNEL);
+ if (!props)
+ return NULL;
+
+ pp = props;
+ for (i = 0; of_pci_props[i].name; i++) {
+ len = 0;
+ of_pci_props[i].prop_val(pdev, &val, &len);
+ if (!len)
+ continue;
+ props->name = of_pci_props[i].name;
+ props->value = val;
+ props->length = len;
+ props++;
This creates an array of properties and then copies each one, and it
also exposes the internals of 'struct property' which we want to make
opaque. Neither of these is great.
I'd rather see the of_changeset API expanded to handle specific types of
properties. Something like this:
of_changeset_add_prop_string(cset, node, "device_type", "pci");
of_changeset_add_prop_string_array(cset, node, "compatible", compats, cnt);
of_changeset_add_prop_u32_array(cset, node, "reg", reg, cnt);
And perhaps these functions just wrap similar non-changeset functions
that produce a struct property.
IOW, it should be similar to the of_property_read_* APIs, but to
set/add rather than get.
Okay. I will add above 3 APIs and use them to create properties.
You are also missing 'ranges', '#address-cells, and '#size-cells' in
bridge nodes.
I will add them. Do you have more in mind that I need to add with this
patch?
Thanks,
Lizhi
Rob