linux-kernel - Re: [PATCH] drivers: soc: xilinx: fix firmware driver Kconfig dependency

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Date:   Wed, 15 Apr 2020 08:16:55 +0200
From:   Michal Simek <michal.simek@...inx.com>
To:     Michal Simek <michal.simek@...inx.com>,
        Arnd Bergmann <arnd@...db.de>
Cc:     arm-soc <arm@...nel.org>, Rajan Vaja <rajan.vaja@...inx.com>,
        Jolly Shah <jolly.shah@...inx.com>,
        Tejas Patel <tejas.patel@...inx.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drivers: soc: xilinx: fix firmware driver Kconfig
 dependency

On 09. 04. 20 12:43, Michal Simek wrote:
> On 09. 04. 20 11:09, Arnd Bergmann wrote:
>> On Thu, Apr 9, 2020 at 8:37 AM Michal Simek <michal.simek@...inx.com> wrote:
>>>
>>> On 08. 04. 20 17:52, Arnd Bergmann wrote:
>>>> The firmware driver is optional, but the power driver depends on it,
>>>> which needs to be reflected in Kconfig to avoid link errors:
>>>>
>>>> aarch64-linux-ld: drivers/soc/xilinx/zynqmp_power.o: in function `zynqmp_pm_isr':
>>>> zynqmp_power.c:(.text+0x284): undefined reference to `zynqmp_pm_invoke_fn'
>>>>
>>>> The firmware driver can probably be allowed for compile-testing as
>>>> well, so it's best to drop the dependency on the ZYNQ platform
>>>> here and allow building as long as the firmware code is built-in.
>>>>
>>>> Fixes: ab272643d723 ("drivers: soc: xilinx: Add ZynqMP PM driver")
>>>> Signed-off-by: Arnd Bergmann <arnd@...db.de>
>>>> ---
>>>>  drivers/soc/xilinx/Kconfig | 4 ++--
>>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/soc/xilinx/Kconfig b/drivers/soc/xilinx/Kconfig
>>>> index 223f1f9d0922..646512d7276f 100644
>>>> --- a/drivers/soc/xilinx/Kconfig
>>>> +++ b/drivers/soc/xilinx/Kconfig
>>>> @@ -19,7 +19,7 @@ config XILINX_VCU
>>>>
>>>>  config ZYNQMP_POWER
>>>>       bool "Enable Xilinx Zynq MPSoC Power Management driver"
>>>> -     depends on PM && ARCH_ZYNQMP
>>>> +     depends on PM && ZYNQMP_FIRMWARE
>>>>       default y
>>>>       select MAILBOX
>>>>       select ZYNQMP_IPI_MBOX
>>>> @@ -35,7 +35,7 @@ config ZYNQMP_POWER
>>>>  config ZYNQMP_PM_DOMAINS
>>>>       bool "Enable Zynq MPSoC generic PM domains"
>>>>       default y
>>>> -     depends on PM && ARCH_ZYNQMP && ZYNQMP_FIRMWARE
>>>> +     depends on PM && ZYNQMP_FIRMWARE
>>>>       select PM_GENERIC_DOMAINS
>>>>       help
>>>>         Say yes to enable device power management through PM domains
>>>>
>>>
>>> The same issue is likely with others drivers dependencies too which
>>> depends on ARCH_ZYNQMP.
>>>
>>> It means all drivers which includes "linux/firmware/xlnx-zynqmp.h" and
>>> call zynqmp_pm_get_eemi_ops() should depend on ZYNQMP_FIRMWARE instead
>>> of ARCH_ZYNQMP.
>>
>> The only one I see that has a hard dependency on ARCH_ZYNQMP
>> without allowing compile-testing at the moment is drivers/edac/synopsys_edac.c
>> but that doesn't use the firmware interface.
>>
>> What I see in the header are declarations for exported functions:
>>
>> int zynqmp_pm_invoke_fn(u32 pm_api_id, u32 arg0, u32 arg1,
>>                         u32 arg2, u32 arg3, u32 *ret_payload);
>> #if IS_REACHABLE(CONFIG_ZYNQMP_FIRMWARE)
>> const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void);
>> #else
>> static inline struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
>> {
>>         return ERR_PTR(-ENODEV);
>> }
>> #endif
>>
>> The second one already allows compile-testing by turning into an
>> inline stub, but zynqmp_pm_invoke_fn() does not, and this is the
>> one causing the problem here.
>>
>> I still think my patch is a good fix for that issue, but if you want to
>> handle both interfaces the same way, we can also do that, either
>> removing the stub and using a proper dependency, or using
>> the same stub trick for both.
> 
> I have really not a problem with your fix above because the patch which
> was applied has started to remove dependencies on ARCH_ZYNQMP. It
> shouldn't be there because the same interface is used for new Xilinx
> Versal device.
> 
> That header has been reworked by patches from here.
> (last one) http://lkml.kernel.org/r/20200318115452.GA2491827@kroah.com
> that's why changes has to go on the top of it.
> 
> Anyway feel free to take it directly or I will take it and send you pull
> request. But will also look at other dependencies to make sure that they
> are correct.
> 
> Acked-by: Michal Simek <michal.simek@...inx.com>

Applied to zynqmp/soc.

Thanks,
Michal