On Wed, Oct 16, 2024 at 11:38:49PM +0530, Manivannan Sadhasivam wrote:
> 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.
Supposed not, ep->phys_base and ep->bus_addr_base should be same when
use cpu_addr_fixup(). but I warry about some old dts have not reflect
hardware bus address translate correct.
How about use below method:
https://lore.kernel.org/imx/20241008-pci_fixup_addr-v4-2-25e5200657bc@xxxxxxx/
Involve a varible 'using_dtbus_info' to controller it.
Frank
>
> - 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
> >
>
> --
> மணிவண்ணன் சதாசிவம்
