[1/5] of_address: Add bus type match for pci ranges parser

So the parser can be used to parse range property of different bus
types, such as ISA bus.

As they're all using PCI-like method of range property, there is no need
start a new parser.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
 drivers/of/address.c       | 15 +++++++++++----
 include/linux/of_address.h |  3 +++
 2 files changed, 14 insertions(+), 4 deletions(-)

On Mon, Jul 20, 2020 at 1:49 AM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>
> So the parser can be used to parse range property of different bus
> types, such as ISA bus.

Regular MMIO buses are actually already supported, but not ISA.

>
> As they're all using PCI-like method of range property, there is no need
> start a new parser.
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
>  drivers/of/address.c       | 15 +++++++++++----
>  include/linux/of_address.h |  3 +++
>  2 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 8eea3f6e29a4..250c91767648 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -702,6 +702,10 @@ static int parser_init(struct of_pci_range_parser *parser,
>         parser->ns = of_bus_n_size_cells(node);
>         parser->dma = !strcmp(name, "dma-ranges");
>
> +       parser->bus = of_match_bus(node);
> +       if (!parser->bus)
> +               return -ENOENT;

You'll hit BUG() before you get here, so you can assume success.

> +
>         parser->range = of_get_property(node, name, &rlen);
>         if (parser->range == NULL)
>                 return -ENOENT;
> @@ -732,6 +736,7 @@ struct of_pci_range *of_pci_range_parser_one(struct of_pci_range_parser *parser,
>         int na = parser->na;
>         int ns = parser->ns;
>         int np = parser->pna + na + ns;
> +       int bus_na = 0;
>
>         if (!range)
>                 return NULL;
> @@ -739,8 +744,10 @@ struct of_pci_range *of_pci_range_parser_one(struct of_pci_range_parser *parser,
>         if (!parser->range || parser->range + np > parser->end)
>                 return NULL;
>
> -       if (parser->na == 3)
> -               range->flags = of_bus_pci_get_flags(parser->range);
> +       parser->bus->count_cells(parser->node, &bus_na, NULL);
> +
> +       if (parser->na == bus_na)
> +               range->flags = parser->bus->get_flags(parser->range);

I think you can just unconditionally call this and drop the else. For
plain MMIO bus, we'd just return IORESOURCE_MEM, but I think the flags
are ignored in that case.

>         else
>                 range->flags = 0;
>
> @@ -761,8 +768,8 @@ struct of_pci_range *of_pci_range_parser_one(struct of_pci_range_parser *parser,
>                 u32 flags = 0;
>                 u64 pci_addr, cpu_addr, size;
>
> -               if (parser->na == 3)
> -                       flags = of_bus_pci_get_flags(parser->range);
> +               if (parser->na == bus_na)

This too can be unconditional.

> +                       flags = parser->bus->get_flags(parser->range);
>                 pci_addr = of_read_number(parser->range, na);

Perhaps rename pci_addr to child_addr and cpu_addr to parent_addr.

>                 if (parser->dma)
>                         cpu_addr = of_translate_dma_address(parser->node,
> diff --git a/include/linux/of_address.h b/include/linux/of_address.h
> index 763022ed3456..3929b4637033 100644
> --- a/include/linux/of_address.h
> +++ b/include/linux/of_address.h
> @@ -6,8 +6,11 @@
>  #include <linux/of.h>
>  #include <linux/io.h>
>
> +struct of_bus;
> +
>  struct of_pci_range_parser {
>         struct device_node *node;
> +       struct of_bus *bus;
>         const __be32 *range;
>         const __be32 *end;
>         int na;
> --
> 2.28.0.rc1
>