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SubjectRe: [PATCH] PCI: rockchip: Fix register number offset to program IO outbound ATU
On Thu, Dec 12, 2019 at 03:29:36PM -0600, Bjorn Helgaas wrote:
> [+cc Vicente]
>
> On Wed, Dec 11, 2019 at 10:34:50AM +0100, Enric Balletbo i Serra wrote:
> > Since commit '62240a88004b ("PCI: rockchip: Drop storing driver private
> > outbound resource data)' the offset calculation is wrong to access the
> > register number to program the IO outbound ATU. The offset should be
> > based on the IORESOURCE_MEM resource size instead of the IORESOURCE_IO
> > size.
> >
> > ...
>
> > Fixes: 62240a88004b ("PCI: rockchip: Drop storing driver private outbound resource data)
> > Reported-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>
> Thanks, I applied this with Vicente's reported-by and tested-by and
> Andrew's ack to for-linus for v5.5.
>
> I'm confused about "msg_bus_addr". It is computed as
> "entry->res->start - entry->offset + <other stuff>". A struct
> resource contains a CPU physical address, and adding entry->offset
> gets you a PCI bus address. But later rockchip_pcie_probe() calls
> devm_ioremap(rockchip->msg_bus_addr), which expects a CPU physical
> address. So it looks like we're passing a PCI bus address when we
> should be passing a CPU physical address. What am I missing?

With a quick glance it does look like that is incorrect.

It's likely to have never been a problem because the only DT user
has an identity map as its MEM range:

ranges = <0x83000000 0x0 0xfa000000 0x0 0xfa000000 0x0 0x1e00000...

It doesn't help that it is called msg_bus_addr and not msg_cpu_addr.

Thanks,

Andrew Murray

>
> For the future, I do think we should consider:
>
> - Renaming rockchip_pcie_prog_ob_atu() and
> rockchip_pcie_prog_ib_atu() so they match
> dw_pcie_prog_outbound_atu() and dw_pcie_prog_inbound_atu().
>
> - Changing the rockchip_pcie_prog_ob_atu() and
> rockchip_pcie_prog_ib_atu() interfaces so they take a 64-bit
> pci_addr/cpu_addr instead of 32-bit lower_addr and upper_addr,
> also to follow the dw examples.
>
> - Renaming the rockchip_pcie_cfg_atu() local "offset" to "index" or
> similar since it's a register number, not a memory or I/O space
> offset.
>
> - Reworking the rockchip_pcie_cfg_atu() loops. Currently there are
> three different ways to compute the register number. The
> msg_bus_addr computation is split between the top and bottom of
> the function and uses "reg_no" left over from the IO loop and
> "offset" left from the memory loop. Maybe something like this:
>
> rockchip_pcie_prog_inbound_atu(rockchip, 2, 32 - 1, 0);
>
> atu_idx = 1;
>
> mem = resource_list_first_type(&bridge->windows, IORESOURCE_MEM);
> mem_entries = resource_size(mem->res) >> 20;
> mem_pci_addr = mem->res->start - mem->offset;
> for (i = 0; i < mem_entries; i++, atu_idx++)
> rockchip_pcie_prog_outbound_atu(rockchip, atu_idx,
> AXI_WRAPPER_MEM_WRITE, 20 - 1,
> mem_pci_addr + (i << 20));
>
> io = resource_list_first_type(&bridge->windows, IORESOURCE_IO);
> io_entries = resource_size(entry->res) >> 20;
> io_pci_addr = io->res->start - io->offset;
> for (i = 0; i < io_entries; i++, atu_idx++)
> rockchip_pcie_prog_outbound_atu(rockchip, atu_idx,
> AXI_WRAPPER_IO_WRITE, 20 - 1,
> io_pci_addr + (i << 20));
>
> rockchip_pcie_prog_outbound_atu(rockchip, atu_idx,
> AXI_WRAPPER_NOR_MSG, 20 - 1, 0);
> rockchip->msg_bus_addr = mem_pci_addr +
> (mem_entries + io_entries) << 20);
>
> > ---
> >
> > drivers/pci/controller/pcie-rockchip-host.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
> > index d9b63bfa5dd7..94af6f5828a3 100644
> > --- a/drivers/pci/controller/pcie-rockchip-host.c
> > +++ b/drivers/pci/controller/pcie-rockchip-host.c
> > @@ -834,10 +834,12 @@ static int rockchip_pcie_cfg_atu(struct rockchip_pcie *rockchip)
> > if (!entry)
> > return -ENODEV;
> >
> > + /* store the register number offset to program RC io outbound ATU */
> > + offset = size >> 20;
> > +
> > size = resource_size(entry->res);
> > pci_addr = entry->res->start - entry->offset;
> >
> > - offset = size >> 20;
> > for (reg_no = 0; reg_no < (size >> 20); reg_no++) {
> > err = rockchip_pcie_prog_ob_atu(rockchip,
> > reg_no + 1 + offset,
> > --
> > 2.20.1
> >

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