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SubjectRe: [PATCH] PCI: rockchip: Fix register number offset to program IO outbound ATU
[+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?

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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