Messages in this thread |  | | Subject | Re: [PATCH] ata: ahci-platform: add reset control support | From | Hans de Goede <> | Date | Thu, 5 Apr 2018 15:27:03 +0200 |
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Hi,
On 05-04-18 15:17, Patrice CHOTARD wrote: > Hi Thierry > > On 04/05/2018 11:54 AM, Thierry Reding wrote: >> On Fri, Mar 23, 2018 at 10:30:53AM +0900, Kunihiko Hayashi wrote: >>> Add support to get and control a list of resets for the device >>> as optional and shared. These resets must be kept de-asserted until >>> the device is enabled. >>> >>> This is specified as shared because some SoCs like UniPhier series >>> have common reset controls with all ahci controller instances. >>> >>> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> >>> --- >>> .../devicetree/bindings/ata/ahci-platform.txt | 1 + >>> drivers/ata/ahci.h | 1 + >>> drivers/ata/libahci_platform.c | 24 +++++++++++++++++++--- >>> 3 files changed, 23 insertions(+), 3 deletions(-) >> >> This causes a regression on Tegra because we explicitly request the >> resets after the call to ahci_platform_get_resources(). > > I confirm, we got exactly the same behavior on STi platform. > >> >> From a quick look, ahci_mtk and ahci_st are in the same boat, adding the >> corresponding maintainers to Cc. >> >> Patrice, Matthias: does SATA still work for you after this patch? This >> has been in linux-next since next-20180327. > > SATA is still working after this patch, but a kernel warning is > triggered due to the fact that resets are both requested by > libahci_platform and by ahci_st driver.
So in your case you might be able to remove the reset handling from the ahci_st driver and rely on the new libahci_platform handling instead? If that works that seems like a win to me.
As said elsewhere in this thread I think it makes sense to keep (or re-add after a revert) the libahci_platform reset code, but make it conditional on a flag passed to ahci_platform_get_resources(). This way we get the shared code for most cases and platforms which need special handling can opt-out.
Regards,
Hans
> > Patrice > >> >> Given how this is one of the more hardware-specific bits, perhaps a >> better way to do this is to move reset handling into a Uniphier driver >> much like Tegra, Mediatek and ST? >> >> That said, I don't see SATA support for any of the Socionext hardware >> either in the DT bindings or drivers/ata, so perhaps it'd be best to >> back this out again until we have something that's more well tested? >> >> Thierry
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