[U-Boot] [PATCH 2/9] fdt: Support for ISA busses

[Simon Glass]

Hi Paul,

On 29 January 2016 at 06:54, Paul Burton <paul.burton at imgtec.com> wrote:
> Support ISA busses in much the same way as Linux does. This allows for
> ISA bus addresses to be translated, and only if CONFIG_OF_ISA_BUS is
> selected in order to avoid including the code in builds which won't need
> it.
>
> Signed-off-by: Paul Burton <paul.burton at imgtec.com>
> ---
>
>  common/fdt_support.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++--
>  drivers/core/Kconfig |  4 +++
>  2 files changed, 85 insertions(+), 2 deletions(-)
>
> diff --git a/common/fdt_support.c b/common/fdt_support.c
> index 75d0858..0aba77d 100644
> --- a/common/fdt_support.c
> +++ b/common/fdt_support.c
> @@ -959,6 +959,7 @@ static void of_dump_addr(const char *s, const fdt32_t *addr, int na) { }
>  struct of_bus {
>         const char      *name;
>         const char      *addresses;
> +       int             (*match)(void *blob, int parentoffset);

Can you please add a comment to this method explaining what it does,
args, return value?

>         void            (*count_cells)(void *blob, int parentoffset,
>                                 int *addrc, int *sizec);
>         u64             (*map)(fdt32_t *addr, const fdt32_t *range,
> @@ -1013,8 +1014,70 @@ static int of_bus_default_translate(fdt32_t *addr, u64 offset, int na)
>         return 0;
>  }
>
> +#ifdef CONFIG_OF_ISA_BUS
> +
> +/* ISA bus translator */
> +static int of_bus_isa_match(void *blob, int parentoffset)
> +{
> +       const char *name;
> +
> +       name = fdt_get_name(blob, parentoffset, NULL);
> +       if (!name)
> +               return 0;
> +
> +       return !strcmp(name, "isa");
> +}
> +
> +static void of_bus_isa_count_cells(void *blob, int parentoffset,
> +                                  int *addrc, int *sizec)
> +{
> +       if (addrc)
> +               *addrc = 2;
> +       if (sizec)
> +               *sizec = 1;
> +}
> +
> +static u64 of_bus_isa_map(fdt32_t *addr, const fdt32_t *range,
> +                         int na, int ns, int pna)
> +{
> +       u64 cp, s, da;
> +
> +       /* Check address type match */
> +       if ((addr[0] ^ range[0]) & cpu_to_be32(1))
> +               return OF_BAD_ADDR;
> +
> +       cp = of_read_number(range + 1, na - 1);
> +       s  = of_read_number(range + na + pna, ns);
> +       da = of_read_number(addr + 1, na - 1);
> +
> +       debug("OF: ISA map, cp=%" PRIu64 ", s=%" PRIu64
> +             ", da=%" PRIu64 "\n", cp, s, da);
> +
> +       if (da < cp || da >= (cp + s))
> +               return OF_BAD_ADDR;
> +       return da - cp;
> +}
> +
> +static int of_bus_isa_translate(fdt32_t *addr, u64 offset, int na)
> +{
> +       return of_bus_default_translate(addr + 1, offset, na - 1);
> +}
> +
> +#endif /* CONFIG_OF_ISA_BUS */
> +
>  /* Array of bus specific translators */
>  static struct of_bus of_busses[] = {
> +#ifdef CONFIG_OF_ISA_BUS
> +       /* ISA */
> +       {
> +               .name = "isa",
> +               .addresses = "reg",
> +               .match = of_bus_isa_match,
> +               .count_cells = of_bus_isa_count_cells,
> +               .map = of_bus_isa_map,
> +               .translate = of_bus_isa_translate,
> +       },
> +#endif /* CONFIG_OF_ISA_BUS */
>         /* Default */
>         {
>                 .name = "default",
> @@ -1025,6 +1088,22 @@ static struct of_bus of_busses[] = {
>         },
>  };
>
> +static struct of_bus *of_match_bus(void *blob, int parentoffset)
> +{
> +       struct of_bus *bus;
> +
> +       if (ARRAY_SIZE(of_busses) == 1)
> +               return &of_busses[0];
> +
> +       for (bus = &of_busses[0]; bus; bus++) {
> +               if (!bus->match || bus->match(blob, parentoffset))
> +                       return bus;
> +       }
> +
> +       BUG();

What will this do? Can we propagate the error up instead?

> +       return NULL;
> +}
> +
>  static int of_translate_one(void * blob, int parent, struct of_bus *bus,
>                             struct of_bus *pbus, fdt32_t *addr,
>                             int na, int ns, int pna, const char *rprop)
> @@ -1104,7 +1183,7 @@ static u64 __of_translate_address(void *blob, int node_offset, const fdt32_t *in
>         parent = fdt_parent_offset(blob, node_offset);
>         if (parent < 0)
>                 goto bail;
> -       bus = &of_busses[0];
> +       bus = of_match_bus(blob, parent);
>
>         /* Cound address cells & copy address locally */
>         bus->count_cells(blob, parent, &na, &ns);
> @@ -1133,7 +1212,7 @@ static u64 __of_translate_address(void *blob, int node_offset, const fdt32_t *in
>                 }
>
>                 /* Get new parent bus and counts */
> -               pbus = &of_busses[0];
> +               pbus = of_match_bus(blob, parent);
>                 pbus->count_cells(blob, parent, &pna, &pns);
>                 if (!OF_CHECK_COUNTS(pna)) {
>                         printf("%s: Bad cell count for %s\n", __FUNCTION__,
> diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
> index c5c9d2a..339f52f 100644
> --- a/drivers/core/Kconfig
> +++ b/drivers/core/Kconfig
> @@ -178,4 +178,8 @@ config SPL_OF_TRANSLATE
>           used for the address translation. This function is faster and
>           smaller in size than fdt_translate_address().
>
> +config OF_ISA_BUS
> +       bool "Support the ISA bus in fdt_translate_address"
> +       depends on OF_TRANSLATE

Please add help here, perhaps with a small example.

> +
>  endmenu
> --
> 2.7.0
>

Regards,
Simon