Hi, Rahul!
On 19.08.21 15:02, Rahul Singh wrote:
> XEN during boot will read the PCI device tree node “reg” property
> and will map the PCI config space to the XEN memory.
[snip]
> +static struct pci_config_window *gen_pci_init(struct dt_device_node *dev,
> + int ecam_reg_idx)
> +{
> + int err;
> + struct pci_config_window *cfg;
> + paddr_t addr, size;
> +
> + cfg = xzalloc(struct pci_config_window);
> + if ( !cfg )
> + return NULL;
> +
> + err = dt_pci_parse_bus_range(dev, cfg);
> + if ( !err ) {
> + cfg->busn_start = 0;
> + cfg->busn_end = 0xff;
> + printk(XENLOG_ERR "%s:No bus range found for pci controller\n",
> + dt_node_full_name(dev));
> + } else {
> + if ( cfg->busn_end > cfg->busn_start + 0xff )
> + cfg->busn_end = cfg->busn_start + 0xff;
> + }
> +
> + /* Parse our PCI ecam register address*/
> + err = dt_device_get_address(dev, ecam_reg_idx, &addr, &size);
I am a bit worried here that we don't get the reg index from the device tree,
but for generic ECAM we use reg[0] and for Xilinx we use reg[2].
For example, for Xilinx we have
reg = <0x00 0xfd0e0000 0x00 0x1000 0x00 0xfd480000 0x00 0x1000 0x80 0x00 0x00
0x1000000>;
reg-names = "breg\0pcireg\0cfg";
so, we can parse the reg-names and understand that the configuration space is
the last in the reg property.
The same I think can be done for other device trees probably.
Rahul, do you know if reg-names "cfg" is vendor specific of used widely?
Thank you,
Oleksandr
