On Tue, Jan 28, 2025 at 05:07:37PM -0500, Frank Li wrote:
> parent_bus_offset in resource_entry can indicate address information just
> ahead of PCIe controller. Most system's bus fabric use 1:1 map between
> input and output address. but some hardware like i.MX8QXP doesn't use 1:1
> map. See below diagram:
> ...
> @@ -448,6 +451,26 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
> if (IS_ERR(pp->va_cfg0_base))
> return PTR_ERR(pp->va_cfg0_base);
>
> + if (pci->use_parent_dt_ranges) {
> + if (pci->ops->cpu_addr_fixup) {
> + dev_err(dev, "Use parent bus DT ranges, cpu_addr_fixup() must be removed\n");
> + return -EINVAL;
> + }
> +
> + index = of_property_match_string(np, "reg-names", "config");
> + if (index < 0)
> + return -EINVAL;
> +
> + /*
> + * Retrieve the parent bus address of PCI config space.
> + * If the parent bus ranges in the device tree provide
> + * the correct address conversion information, set
> + * 'use_parent_dt_ranges' to true, The
> + * 'cpu_addr_fixup()' can be eliminated.
> + */
> + of_property_read_reg(np, index, &pp->cfg0_base, NULL);
> + }
I think all this code dealing with the "config" resource could go in a
helper function. It's kind of a lot of clutter in
dw_pcie_host_init().
It would be nice to assign pp->cfg0_base once, not assign res->start
to it and then possibly overwrite it later.
> @@ -841,6 +841,15 @@ void dw_pcie_iatu_detect(struct dw_pcie *pci)
> pci->region_align = 1 << fls(min);
> pci->region_limit = (max << 32) | (SZ_4G - 1);
>
> + if (pci->ops && pci->ops->cpu_addr_fixup) {
> + /*
> + * If the parent 'ranges' property in DT correctly describes
> + * the address translation, cpu_addr_fixup() callback is not
> + * needed.
> + */
> + dev_warn_once(pci->dev, "cpu_addr_fixup() usage detected. Please fix DT!\n");
> + }
Can you split the warnings out to a separate patch? I think we should
warn once in every initialization path where .cpu_addr_fixup() could
be used, i.e.,
dw_pcie_host_init()
dw_pcie_ep_init()
cdns_pcie_host_setup()
cdns_pcie_ep_setup()
IMO these should warn if .cpu_addr_fixup() is implemented, regardless
of use_parent_dt_ranges.
I'm still puzzling over some of the rest of this, so no need to post a
revised series yet.
Bjorn
