[PATCH v2 15/30] fdt: translate address if #size-cells = <0>
Simon Glass
sjg at chromium.org
Mon Sep 7 03:44:12 CEST 2020
Hi Dario,
On Sun, 6 Sep 2020 at 06:13, Dario Binacchi <dariobin at libero.it> wrote:
>
> The __of_translate_address routine translates an address from the
> device tree into a CPU physical address. A note in the description of
> the routine explains that the crossing of any level with
> #size-cells = <0> is to be considered an error not by specification but
> since inherited from IBM. This does not happen for Texas Instruments, or
> at least for the beaglebone device tree. Without this patch, in fact,
> the translation into physical addresses of the registers contained in the
> am33xx-clocks.dtsi nodes would not be possible. They all have a parent
> with #size-cells = <0>.
>
> The CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS symbol makes translation
> possible even in the case of crossing levels with #size-cells = <0>.
>
> The patch acts conservatively on address translation, except for
> removing a check within the of_translate_one function in the
> drivers/core/of_addr.c file:
>
> +
> ranges = of_get_property(parent, rprop, &rlen);
> - if (ranges == NULL && !of_empty_ranges_quirk(parent)) {
> - debug("no ranges; cannot translate\n");
> - return 1;
> - }
> if (ranges == NULL || rlen == 0) {
> offset = of_read_number(addr, na);
> memset(addr, 0, pna * 4);
> debug("empty ranges; 1:1 translation\n");
>
> There are two reasons:
> 1 The function of_empty_ranges_quirk always returns false, invalidating
> the following if statement in case of null ranges. Therefore one of
> the two checks is useless.
>
> 2 The implementation of the of_translate_one function found in the
> common/fdt_support.c file has removed this check while keeping the one
> about the 1:1 translation.
>
> The patch adds a test and modifies a check for the correctness of an
> address in the case of enabling translation also for zero size cells.
> The added test checks translations of addresses generated by nodes of
> a device tree similar to those you can find in the files am33xx.dtsi
> and am33xx-clocks.dtsi for which the patch was created.
>
> The patch was also tested on a beaglebone black board. The addresses
> generated for the registers of the loaded drivers are those specified
> by the AM335x reference manual.
>
> Signed-off-by: Dario Binacchi <dariobin at libero.it>
> Tested-by: Dario Binacchi <dariobin at libero.it>
>
> ---
>
> Changes in v2:
> - Fix a missing line in the commit message.
> - Add dm_flags to global_data structure and GD_DM_FLG_SIZE_CELLS_0 macro
> to test without recompiling.
> - Update the OF_CHECK_COUNTS macro in order to have just one
> #define by bringing the GD_DM_FLG_SIZE_CELLS_0 into the expression.
> - Lower-case the 0xC019 hex number.
>
> arch/sandbox/dts/test.dts | 21 ++++++++++
> common/fdt_support.c | 6 ++-
> drivers/core/Kconfig | 12 ++++++
> drivers/core/fdtaddr.c | 2 +-
> drivers/core/of_addr.c | 14 ++-----
> drivers/core/ofnode.c | 7 +++-
> drivers/core/root.c | 3 ++
> include/asm-generic/global_data.h | 6 +++
> test/dm/test-fdt.c | 68 ++++++++++++++++++++++++++++++-
> 9 files changed, 123 insertions(+), 16 deletions(-)
Looks very nice.
Reviewed-by: Simon Glass <sjg at chromium.org>
+Stefan Roese as an example of using run-time control in tests to
handle both cases in sandbox.
Nit below
[..]
> diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
> index d4a4e2215d..d0014e812c 100644
> --- a/include/asm-generic/global_data.h
> +++ b/include/asm-generic/global_data.h
> @@ -64,6 +64,7 @@ typedef struct global_data {
> struct global_data *new_gd; /* relocated global data */
>
> #ifdef CONFIG_DM
> + unsigned long dm_flags;
comment
> struct udevice *dm_root; /* Root instance for Driver Model */
> struct udevice *dm_root_f; /* Pre-relocation root instance */
> struct list_head uclass_root; /* Head of core tree */
> @@ -169,4 +170,9 @@ typedef struct global_data {
> #define GD_FLG_SKIP_LL_INIT 0x20000 /* Don't perform low-level init */
> #define GD_FLG_SMP_READY 0x40000 /* SMP init is complete */
>
> +/*
> + * Global Data Driver Model Flags
> + */
> +#define GD_DM_FLG_SIZE_CELLS_0 0x00001 /* Enable #size-cells=<0> translation */
> +
> #endif /* __ASM_GENERIC_GBL_DATA_H */
Regards,
Simon
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