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Date: Tue, 3 Jan 2023 16:29:05 -0800
From: Lizhi Hou <lizhi.hou@....com>
To: Clément Léger <clement.leger@...tlin.com>
CC: <linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <robh@...nel.org>,
<frowand.list@...il.com>, <helgaas@...nel.org>, <max.zhen@....com>,
<sonal.santan@....com>, <larry.liu@....com>, <brian.xu@....com>,
<stefano.stabellini@...inx.com>, <trix@...hat.com>,
"Allan.Nielsen@...rochip.com" <Allan.Nielsen@...rochip.com>,
"Horatiu.Vultur@...rochip.com" <Horatiu.Vultur@...rochip.com>,
"Steen.Hegelund@...rochip.com" <Steen.Hegelund@...rochip.com>
Subject: Re: [PATCH V5 2/3] PCI: Create device tree node for selected devices
On 1/3/23 11:45, Lizhi Hou wrote:
>
> On 1/2/23 09:16, Clément Léger wrote:
>> Le Thu, 15 Dec 2022 09:30:45 -0800,
>> Lizhi Hou <lizhi.hou@....com> a écrit :
>>
>>> 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@....com>
>>> Signed-off-by: Sonal Santan <sonal.santan@....com>
>>> Signed-off-by: Max Zhen <max.zhen@....com>
>>> Reviewed-by: Brian Xu <brian.xu@....com>
>>> ---
>>> 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 | 222
>>> ++++++++++++++++++++++++++++++++++++
>>> drivers/pci/pci-driver.c | 3 +-
>>> drivers/pci/pci.h | 19 +++
>>> drivers/pci/remove.c | 1 +
>>> 9 files changed, 334 insertions(+), 3 deletions(-)
>>> create mode 100644 drivers/pci/of_property.c
>>>
>>> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
>>> index 55c028af4bd9..1b2347aa1e5b 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 "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 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..cb34a73ac8a3 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 +601,75 @@ 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 *np;
>>> +
>>> + np = pci_device_to_OF_node(pdev);
>>> + if (!np || !of_node_check_flag(np, OF_DYNAMIC))
>>> + return;
>>> + pdev->dev.of_node = NULL;
>>> +
>>> + of_destroy_node(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)
>>> + goto failed;
>>> +
>>> + np = of_create_node(ppnode, name, &cset);
>>> + if (!np)
>>> + goto failed;
>>> +
>>> + 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_destroy_node(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..05c8ca05a71b
>>> --- /dev/null
>>> +++ b/drivers/pci/of_property.c
>>> @@ -0,0 +1,222 @@
>>> +// 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 <asm/unaligned.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_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)
>>> +
>>> +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 void of_pci_set_address(u32 *prop, u64 addr, u32 flags)
>>> +{
>>> + prop[0] = flags;
>>> + put_unaligned(addr, &prop[1]);
>>> +}
>> Here, the put_unaligned() call will assume you want to store a 32bits
>> value since prop is pointing to a u32 array. This can't work.
>>
>> Moreover, when storing a 64bits address in device-tree properties, they
>> are stored starting with their 32 MSB in the first cell and the
>> 32 LSB in the next cells.
>>
>> This should probably be something like this:
>>
>> static void of_pci_set_address(u32 *prop, u64 addr, u32 flags)
>> {
>> prop[0] = flags;
>> prop[1] = addr >> 32;
>> prop[2] = addr;
>> }
>>
>> [snip]
>
> Thanks for pointing this out. And I should add (__be64 *) as below.
>
> put_unaligned(addr, (__be64 *)&prop[1]);
I looked into it a bit more. You are correct. put_unaligned() does not
work here. I re-write it as below:
prop[1] = FIELD_GET(OF_PCI_ADDR_HI, addr);
prop[2] = FIELD_GET(OF_PCI_ADDR_LO, addr);
Similar changes will be made for "size"
Thanks,
Lizhi
>
>>
>>> +
>>> +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 flags;
>>> +
>>> + res = &pdev->resource[PCI_BRIDGE_RESOURCES];
>>> + for (j = 0; j < PCI_BRIDGE_RESOURCE_NUM; j++) {
>>> + if (!resource_size(&res[j]))
>>> + continue;
>>> +
>>> + flags = OF_PCI_ADDR_FIELD_NONRELOC;
>>> + if (of_pci_get_addr_flags(&res[j], &flags))
>>> + continue;
>>> +
>>> + val64 = res[j].start;
>>> + of_pci_set_address(rp[i].parent_addr, val64, flags);
>>> + of_pci_set_address(rp[i].child_addr, val64, flags);
>>> +
>>> + val64 = resource_size(&res[j]);
>>> + put_unaligned(val64, rp[i].size);
>> Same problem here, the size is meant to be a 64 bits values but will
>> assume you want to store it using a 32bits pointer.
> Will change to: put_unaligned(val64, (__be64 *)rp[i].size);
>>
>>> +
>>> + 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));
>>> + of_pci_set_address(reg[0].phys_addr, 0, 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_get_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);
>>> + of_pci_set_address(reg[i].phys_addr, 0, reg_val);
>>> + put_unaligned((u64)sz, reg[i].size);
>> And same here. Something like this should probably be used (untested):
>
> will change to: put_unaligned((u64)sz, (__be64 *)reg[i].size);
>
>
> Thanks,
>
> Lizhi
>
>>
>> static void of_pci_set_size(u32 *prop, u64 size)
>> {
>> prop[0] = size >> 32;
>> prop[1] = size;
>> }
>
>>
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