On Mon, Sep 23, 2024 at 02:59:19PM -0400, Frank Li wrote:
> Endpoint Root complex
> ┌───────┐ ┌─────────┐
> ┌─────┐ │ EP │ │ │ ┌─────┐
> │ │ │ Ctrl │ │ │ │ CPU │
> │ DDR │ │ │ │ ┌────┐ │ └──┬──┘
> │ │◄──────┼─ATU ◄─┼────────┼─┤BarN│◄─┼─────────┘
> │ │ │ │ │ └────┘ │ Outbound Transfer
> └─────┘ │ │ │ │
> │ │ │ │
> │ │ │ │
> │ │ │ │ Inbound Transfer
> │ │ │ │ ┌──▼──┐
> ┌───────┐ │ │ │ ┌───────┼─────►│DDR │
> │ │ outbound Transfer* │ │ │ └─────┘
> ┌─────┐ │ Bus ┼─────►│ ATU ─┬────────┼─┘ │
> │ │ │ Fabric│Bus │ │ PCI Addr │
> │ CPU ├───►│ │Addr │ │ 0xA000_0000 │
> │ │CPU │ │0x8000_0000 │ │ │
> └─────┘Addr└───────┘ │ │ │ │
> 0x7000_0000 └───────┘ └─────────┘
>
> Add `bus_addr_base` to configure the outbound window address for CPU write.
> The bus fabric generally passes the same address to the PCIe EP controller,
> but some bus fabrics convert the address before sending it to the PCIe EP
> controller.
>
> Above diagram, CPU write data to outbound windows address 0x7000_0000,
> Bus fabric convert it to 0x8000_0000. ATU should use bus address
> 0x8000_0000 as input address and convert to PCI address 0xA000_0000.
>
> Previously, `cpu_addr_fixup()` was used to handle address conversion. Now,
> the device tree provides this information, preferring a common method.
>
> bus@5f000000 {
> compatible = "simple-bus";
> ranges = <0x5f000000 0x0 0x5f000000 0x21000000>,
> <0x80000000 0x0 0x70000000 0x10000000>;
>
> pcie-ep@5f010000 {
> reg = <0x5f010000 0x00010000>,
> <0x80000000 0x10000000>;
> reg-names = "dbi", "addr_space";
> ...
> };
> ...
> };
>
> 'ranges' in bus@5f000000 descript how address convert from CPU address
> to bus address.
>
> Use `of_property_read_reg()` to obtain the bus address and set it to the
> ATU correctly, eliminating the need for vendor-specific cpu_addr_fixup().
>
> Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
> ---
> drivers/pci/controller/dwc/pcie-designware-ep.c | 12 +++++++++++-
> drivers/pci/controller/dwc/pcie-designware.h | 1 +
> 2 files changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 43ba5c6738df1..51eefdcb1b293 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -9,6 +9,7 @@
> #include <linux/align.h>
> #include <linux/bitfield.h>
> #include <linux/of.h>
> +#include <linux/of_address.h>
> #include <linux/platform_device.h>
>
> #include "pcie-designware.h"
> @@ -294,7 +295,7 @@ static int dw_pcie_ep_map_addr(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
>
> atu.func_no = func_no;
> atu.type = PCIE_ATU_TYPE_MEM;
> - atu.cpu_addr = addr;
> + atu.cpu_addr = addr - ep->phys_base + ep->bus_addr_base;
If you convert the address here, aren't he drivers with cpu_addr_fixup() will be
broken? You should only update the address if the callback is not available.
- Mani
> atu.pci_addr = pci_addr;
> atu.size = size;
> ret = dw_pcie_ep_outbound_atu(ep, &atu);
> @@ -861,6 +862,7 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> struct device *dev = pci->dev;
> struct platform_device *pdev = to_platform_device(dev);
> struct device_node *np = dev->of_node;
> + int index;
>
> INIT_LIST_HEAD(&ep->func_list);
>
> @@ -873,6 +875,14 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> return -EINVAL;
>
> ep->phys_base = res->start;
> + ep->bus_addr_base = ep->phys_base;
> +
> + index = of_property_match_string(np, "reg-names", "addr_space");
> + if (index < 0)
> + return -EINVAL;
> +
> + of_property_read_reg(np, index, &ep->bus_addr_base, NULL);
> +
> ep->addr_size = resource_size(res);
>
> if (ep->ops->pre_init)
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 347ab74ac35aa..c189781524fb8 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -410,6 +410,7 @@ struct dw_pcie_ep {
> struct list_head func_list;
> const struct dw_pcie_ep_ops *ops;
> phys_addr_t phys_base;
> + phys_addr_t bus_addr_base;
> size_t addr_size;
> size_t page_size;
> u8 bar_to_atu[PCI_STD_NUM_BARS];
>
> --
> 2.34.1
>
--
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