[U-Boot] [PATCH v2 1/5] fdt: Support for ISA busses

Simon Glass sjg at chromium.org
Tue May 17 14:11:16 CEST 2016


Hi Paul,

On 16 May 2016 at 11:44, 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>
> ---
>
> Changes in v2:
> - Document the match function pointer in struct of_bus.
> - Make CONFIG_OF_ISA_BUS not user-selectable, and explain it in help text.
> - assert() that of_match_bus didn't fail instead of BUG(), and comment why.
> - s/&of_busses[0]/of_busses/
>
>  common/fdt_support.c | 101 +++++++++++++++++++++++++++++++++++++++++++++++++--
>  drivers/core/Kconfig |  23 ++++++++++++
>  2 files changed, 121 insertions(+), 3 deletions(-)

Reviewed-by: Simon Glass <sjg at chromium.org>

Tiny nit below.

>
> diff --git a/common/fdt_support.c b/common/fdt_support.c
> index 42e5d8a..96b5d0a 100644
> --- a/common/fdt_support.c
> +++ b/common/fdt_support.c
> @@ -964,10 +964,21 @@ static void of_dump_addr(const char *s, const fdt32_t *addr, int na)
>  static void of_dump_addr(const char *s, const fdt32_t *addr, int na) { }
>  #endif
>
> -/* Callbacks for bus specific translators */
> +/**
> + * struct of_bus - Callbacks for bus specific translators
> + * @match:     Return non-zero if the node whose parent is at
> + *             parentoffset in the FDT blob corresponds to a bus
> + *             of this type, otherwise return zero. If NULL a match
> + *             is assumed.
> + *
> + * Each bus type will include a struct of_bus in the of_busses array,
> + * providing implementations of some or all of the functions used to
> + * match the bus & handle address translation for its children.
> + */
>  struct of_bus {
>         const char      *name;
>         const char      *addresses;
> +       int             (*match)(void *blob, int parentoffset);
>         void            (*count_cells)(void *blob, int parentoffset,
>                                 int *addrc, int *sizec);
>         u64             (*map)(fdt32_t *addr, const fdt32_t *range,
> @@ -1022,8 +1033,70 @@ 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",
> @@ -1034,6 +1107,28 @@ 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;
> +
> +       for (bus = of_busses; bus; bus++) {
> +               if (!bus->match || bus->match(blob, parentoffset))
> +                       return bus;
> +       }
> +
> +       /*
> +        * We should always have matched the default bus at least, since
> +        * it has a NULL match field. If we didn't then it somehow isn't
> +        * in the of_busses array or something equally catastrophic has
> +        * gone wrong.
> +        */
> +       assert(0);
> +       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)
> @@ -1113,7 +1208,7 @@ 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);
> @@ -1142,7 +1237,7 @@ 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, pns)) {
>                         printf("%s: Bad cell count for %s\n", __FUNCTION__,
> diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
> index c5c9d2a..8749561 100644
> --- a/drivers/core/Kconfig
> +++ b/drivers/core/Kconfig
> @@ -178,4 +178,27 @@ 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
> +       depends on OF_TRANSLATE
> +       help
> +         Is this option is enabled then support for the ISA bus will
> +         be included for addresses read from DT. This is something that
> +         should be known to be required or not based upon the board
> +         being targetted, and whether or not it makes use of an ISA bus.
> +
> +         The bus is matched based upon its node name equalling "isa". The
> +         busses #address-cells should equal 2, with the first cell being

bus'

> +         used to hold flags & flag 0x1 indicating that the address range
> +         should be accessed using I/O port in/out accessors. The second
> +         cell holds the offset into ISA bus address space. The #size-cells
> +         property should equal 1, and of course holds the size of the
> +         address range used by a device.
> +
> +         If this option is not enabled then support for the ISA bus is
> +         not included and any such busses used in DT will be treated as
> +         typical simple-bus compatible busses. This will lead to
> +         mistranslation of device addresses, so ensure that this is
> +         enabled if your board does include an ISA bus.
> +
>  endmenu
> --
> 2.8.2
>

Regards,
Simon


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