[U-Boot] [EXT] Re: Issues with driver binding and probing

[Aaron Williams <awilliams@marvell.com>]

Hi Simon,

On Friday, October 11, 2019 4:42:55 PM PDT Simon Glass wrote:
> Hi Aaron,
> 
> On Wed, 25 Sep 2019 at 22:08, Aaron Williams <awilliams@marvell.com> wrote:
> > Hi Simon,
> > 
> > On Wednesday, September 25, 2019 8:40:48 PM PDT Bin Meng wrote:
> > > External Email
> > > 
> > > ----------------------------------------------------------------------
> > > +Simon
> > > 
> > > Hi Aaron,
> > > 
> > > On Thu, Sep 26, 2019 at 11:10 AM Aaron Williams <awilliams@marvell.com>
> > 
> > wrote:
> > > > Hi all,
> > > > 
> > > > I have an issue where I have a nexus driver and a sub serial driver on
> > > > top
> > > > of it. The base nexus driver is getting bound and probed properly,
> > > > however the serial drivers (pci-console) below it are not.
> > > > 
> > > > My device tree looks something like this:
> > > >         pci-console-nexus at 0x03000000 {
> > > >         
> > > >                 /* Remote PCI console buffer location */
> > > >                 compatible = "marvell,pci-console-nexus";
> > > 
> > > Is this a PCI controller node?
> > 
> > No, actually it points to a location in memory which is shared by a PCI
> > host with the software. It is a software only structure with no actual
> > hardware behind it. We use this as a serial console across the PCI bus,
> > but it's just shared memory. There is a nexus device then multiple
> > consoles underneath it. U-Boot will initialize the data structures (if
> > needed) and claim one of the consoles while it is use. The data
> > structures may or may not already be initialized by earlier bootloaders
> > or the ATF. The ATF may also claim one of the consoles.
> 
> What uclass is this node? Does that uclass have a post_bind method
> that calls dm_scan_fdt_dev()?
> 
> > > >                 status = "okay";
> > > >                 #address-cells = <2>;
> > > >                 #size-cells = <1>;
> > > >                 skip-init;
> > > >                 num-consoles = <8>;
> > > >                 reg = <0 0x03000000 0 0x40000>;
> > > >                 ranges = <0 0 0 0x3000100 0x4000>,
> > > >                 
> > > >                          <1 0 0 0x3004100 0x4000>,
> > > >                          <2 0 0 0x3008100 0x4000>,
> > > >                          <3 0 0 0x300c100 0x4000>,
> > > >                          <4 0 0 0x3010100 0x4000>,
> > > >                          <5 0 0 0x3014100 0x4000>,
> > > >                          <6 0 0 0x3018100 0x4000>,
> > > >                          <7 0 0 0x301c100 0x4000>;
> > > >                 
> > > >                 console at 0 {
> > > >                 
> > > >                         compatible = "marvell,pci-console";
> > > 
> > > If this is a PCI device, it can be handled by the PCI codes.
> > > 
> > > >                         status = "okay";
> > > >                         reg = <0 0 0x4000>;
> > > >                         tx-buffer-size = <0x2f80>;
> > > >                         rx-buffer-size = <0x1000>;
> > > >                 
> > > >                 };
> > > > 
> > > > ...
> > > > 
> > > >                 console at 7 {
> > > >                 
> > > >                         compatible = "marvell,pci-console";
> > > >                         status = "okay";
> > > >                         reg = <7 0 0x4000>;
> > > >                         tx-buffer-size = <0x2f80>;
> > > >                         rx-buffer-size = <0x1000>;
> > > >                 
> > > >                 };
> > > >         
> > > >         };
> > > > 
> > > > When U-Boot binds the drivers it sees and binds pci-console-nexus but
> > > > it
> > > > never even attempts to go any deeper in the device tree. Both drivers
> > > > are
> > > > used. The nexus datastructure is a shared resouce that can be used by
> > > > ATF.
> > > > 
> > > > I added a bind function in the nexus driver that basically does:
> > > >         dev_for_each_subnode(node, parent) {
> > > >         
> > > >                 ret = device_bind_driver_to_node(parent, DRIVER_NAME,
> > > >                 
> > > >                                 ofnode_get_name(node), node,
> > > >                                 &dev);
> > > >                 
> > > >                 get_uclass(UCLASS_SERIAL, &uc);
> > > >                 dev->uclass = uic;
> > > >         
> > > >         }
> > > > 
> > > > With this I see the consoles in the dm tree and uclass list, but the
> > > > sequences don't seem to be getting set.
> > > > 
> > > > What I notice when I type dm uclass is:
> > > > uclass 60: serial
> > > > - * serial at 87e028000000 @ 7fbeb3360, seq 0, (req 0)
> > > > -   serial at 87e029000000 @ 7fbeb3430, seq -1, (req 1)
> > > > -   console at 0 @ 7fbeb3660
> > > > -   console at 1 @ 7fbeb3780
> > > > -   console at 2 @ 7fbeb38a0
> > > > -   console at 3 @ 7fbeb39c0
> > > > -   console at 4 @ 7fbeb3ae0
> > > > -   console at 5 @ 7fbeb3c00
> > > > -   console at 6 @ 7fbeb3d20
> > > > -   console at 7 @ 7fbeb3e40
> > > > - * pci-bootcmd at 0x03fff000 @ 7fbeb3f60, seq 1, (req -1)
> > > > 
> > > > Does anyone have any ideas on how I should properly handle this? It
> > > > seems
> > > > that whatever I'm doing is overly complicated and I'm missing
> > > > something
> > > > for the DM layer to not go deeper into the tree past the nexus layer.
> > > > 
> > > > static const struct udevice_id octeontx_pcie_console_nexus_serial_id[]
> > > > = {
> > > > 
> > > >         { .compatible = "marvell,pci-console-nexus", },
> > > >         { },
> > > > 
> > > > };
> > > > 
> > > > U_BOOT_DRIVER(octeontx_pcie_console_nexus) = {
> > > > 
> > > >         .name = DRIVER_NAME "-nexus",
> > > >         .id = UCLASS_MISC,
> > > >         .flags = DM_FLAG_PRE_RELOC,
> > > >         .of_match =
> > > >         of_match_ptr(octeontx_pcie_console_nexus_serial_id),
> > > >         .ofdata_to_platdata =
> > > >         
> > > >                  octeontx_pcie_console_nexus_ofdata_to_platdata,
> > > >         
> > > >         .platdata_auto_alloc_size =
> > > >         
> > > >                 sizeof(struct octeontx_pcie_console_plat_data),
> > > >         
> > > >         .bind = octeontx_pcie_console_nexus_bind,
> > > >         .probe = octeontx_pcie_console_nexus_probe,
> > > >         .priv_auto_alloc_size =
> > > >         
> > > >                  sizeof(struct octeontx_pcie_console_nexus_priv),
> > > > 
> > > > };
> > > > 
> > > > static const struct dm_serial_ops octeontx_pcie_console_ops = {
> > > > 
> > > >         .setbrg = octeontx_pcie_console_setbrg,
> > > >         .getc = octeontx_pcie_console_getc,
> > > >         .putc = octeontx_pcie_console_putc,
> > > >         .pending = octeontx_pcie_console_pending,
> > > >         .clear = octeontx_pcie_console_clear,
> > > > 
> > > > };
> > > > 
> > > > static const struct udevice_id octeontx_pcie_console_serial_id[] = {
> > > > 
> > > >         { .compatible = "marvell,pci-console", },
> > > >         { },
> > > > 
> > > > };
> > > > 
> > > > U_BOOT_DRIVER(octeontx_pcie_console) = {
> > > > 
> > > >         .name = DRIVER_NAME,
> > > >         .id = UCLASS_SERIAL,
> > > >         .ops = &octeontx_pcie_console_ops,
> > > >         .of_match = of_match_ptr(octeontx_pcie_console_serial_id),
> > > >         .probe = octeontx_pcie_console_probe,
> > > >         .ofdata_to_platdata =
> > > >         octeontx_pcie_console_ofdata_to_platdata,
> > > >         .remove = octeontx_pcie_console_remove,
> > > >         .priv_auto_alloc_size = sizeof(struct
> > > >         octeontx_pcie_console_priv),
> > > >         .platdata_auto_alloc_size =
> > > >         
> > > >                 sizeof(struct octeontx_pcie_console_plat_data),
> > > >         
> > > >         .flags = DM_FLAG_OS_PREPARE | DM_FLAG_PRE_RELOC,
> > > > 
> > > > };
> > > 
> > > Regards,
> > > Bin
> > 
> > Regards,
> > 
> > Aaron

I found the issue and got it working. Now my issue is that I need it to carve 
out the block of memory so that Linux does not use it. I put in a reserved-
memory section in the device tree, however, Linux crashes when it uses this 
memory block and U-Boot does not seem to be honoring this. It may be because 
we're at 2018.03 and I need to backport more fixes and changes or it may be 
due to the memory address range being used:

        reserved-memory {
                #address-cells = <2>;
                #size-cells = <2>;
                ranges;

                /* The PCI console memory must be reserved */
                console_reserved: pci-console-nexus at 0x03000000 {
                        compatible = "marvell,pci-console-nexus-memory";
                        reg = <0 0x03000000 0 0x40000>;
                        no-map;
                };
        };

-Aaron