Messages in this thread | | | Date | Tue, 11 Oct 2022 08:39:23 +0100 | From | Lee Jones <> | Subject | Re: [PATCH] Revert "mfd: syscon: Remove repetition of the regmap_get_val_endian()" |
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On Sat, 08 Oct 2022, Andy Shevchenko wrote:
> On Sat, Oct 08, 2022 at 09:45:16AM -0700, Linus Torvalds wrote: > > On Sat, Oct 8, 2022 at 8:47 AM Jason A. Donenfeld <Jason@zx2c4.com> wrote: > > > > > > This reverts commit 72a95859728a7866522e6633818bebc1c2519b17. It broke > > > reboots on big-endian MIPS and MIPS64 malta QEMU instances, which use > > > the syscon driver. Little-endian is not effected, which means likely > > > it's important to handle regmap_get_val_endian() in this function after > > > all. > > > > Hmm. The revert may indeed be the right thing to do, but we're still > > early in the release process, so let's go through the channels. > > > > I do note that commit 72a95859728a points to commit 0dbdb76c0ca8 > > ("regmap: mmio: Parse endianness definitions from DT") as the reason > > why it's not necessary any more, but that commit > > > > (a) doesn't seem to set config->val_format_endian (which somebody may > > care about). It does set the operation pointers etc, but doesn't set > > that field. > > It should. > > of_syscon_register() calls to regmap_init_mmio() with syscon_config data > structure as a parameter. > > Before 72a95859728a the of_syscon_register() fills the val_format_endian with > something it parses from DT. After that commit the default value (0) is > REGMAP_ENDIAN_DEFAULT. Now when __regmap_init_mmio_clk() is called it > creates a context base on DT since the field is 0. > > > (b) it uses regmap_get_val_endian(), which doesn't actually even look > > at the OF properties unless config->val_format_endian is > > REGMAP_ENDIAN_DEFAULT > > Which is 0! > > > so the code that commit 72a95859728a removed was actually quite a bit > > different from the code in commit 0dbdb76c0ca8. > > > > Maybe the problem is related to those semantic differences, and is > > easy to fix for somebody who knows what the heck that stuff is doing. > > But while looking into this, I think I know what is going on, > of_syscon_register() calls regmap API with dev == NULL, hence > fwnode == NULL, hence nothing to read from DT. > > But default (via regmap bus configuration) is LE and LE works fine. > > > And if not, please just send me the revert through the normal channels. Ok? > > Yeah, revert is a good move here.
Could you review and provide a tag for the revert patch please?
-- Lee Jones [李琼斯]
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